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1.  ORGAN-SPECIFIC EXTERNAL DOSE COEFFICIENTS AND PROTECTIVE APRON TRANSMISSION FACTORS FOR HISTORICAL DOSE RECONSTRUCTION FOR MEDICAL PERSONNEL 
Health physics  2011;101(1):13-27.
While radiation absorbed dose (Gy) to the skin or other organs is sometimes estimated for patients from diagnostic radiologic examinations or therapeutic procedures, rarely is occupationally-received radiation absorbed dose to individual organs/tissues estimated for medical personnel, e.g., radiologic technologists or radiologists. Generally, for medical personnel, equivalent or effective radiation doses are estimated for compliance purposes. In the very few cases when organ doses to medical personnel are reconstructed, the data is usually for the purpose of epidemiologic studies, e.g., a study of historical doses and risks to a cohort of about 110,000 radiologic technologists presently underway at the U.S. National Cancer Institute. While ICRP and ICRU have published organ-specific external dose conversion coefficients (DCCs), i.e., absorbed dose to organs and tissues per unit air kerma and dose equivalent per unit air kerma, those factors have been primarily published for mono-energetic photons at selected energies. This presents two related problems for historical dose reconstruction, both of which are addressed here. It is necessary to derive conversion factors values for (i) continuous distributions of energy typical of diagnostic medical x rays (bremsstrahlung radiation), and (ii) for energies of particular radioisotopes used in medical procedures, neither of which are presented in published tables. For derivation of DCCs for bremsstrahlung radiation, combinations of x-ray tube potentials and filtrations were derived for different time periods based on a review of relevant literature. Three peak tube potentials (70 kV, 80 kV, and 90 kV) with four different amounts of beam filtration were determined to be applicable for historic dose reconstruction. The probability of these machine settings were assigned to each of the four time periods (earlier than 1949, 1949-1954, 1955-1968, and after 1968). Continuous functions were fit to each set of discrete values of the ICRP/ICRU mono-energetic DCCs and the functions integrated over the air-kerma weighted photon fluence of the 12 defined x-ray spectra. The air kerma-weighted DCCs in this work were developed specifically for an irradiation geometry of anterior to posterior (AP) and for the following tissues: thyroid, breast, ovary, lens of eye, lung, colon, testes, heart, skin (anterior side only), red bone marrow (RBM), heart, and brain. In addition, a series of functional relationships to predict DT per Ka values for RBM dependent on body mass index [BMI (kg m−2) ≡ weight per height2] and average photon energy were derived from a published analysis. Factors to account for attenuation of radiation by protective lead aprons were also developed. Because lead protective aprons often worn by radiology personnel not only reduce the intensity of x-ray exposure but also appreciably harden the transmitted fluence of bremsstrahlung x rays, DCCs were separately calculated for organs possibly protected by lead aprons by considering three cases: no apron, 0.25 mm Pb apron, and 0.5 mm Pb apron. For estimation of organ doses from conducting procedures with radioisotopes, continuous functions of the reported mono-energetic values were developed and DCCs were derived by estimation of the function at relevant energies. By considering the temporal changes in primary exposure-related parameters, e.g., energy distribution, the derived DCCs and transmission factors presented here allow for more realistic historical dose reconstructions for medical personnel when monitoring badge readings are the primary data on which estimation of an individual's organ doses are based.
doi:10.1097/HP.0b013e318204a60a
PMCID: PMC3964780  PMID: 21617389
2.  Surgeons' Exposure to Radiation in Single- and Multi-Level Minimally Invasive Transforaminal Lumbar Interbody Fusion; A Prospective Study 
PLoS ONE  2014;9(4):e95233.
Although minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) has widely been developed in patients with lumbar diseases, surgeons risk exposure to fluoroscopic radiation. However, to date, there is no studies quantifying the effective dose during MIS-TLIF procedure, and the radiation dose distribution is still unclear. In this study, the surgeons' radiation doses at 5 places on the bodies were measured and the effective doses were assessed during 31 consecutive 1- to 3-level MIS-TLIF surgeries. The operating surgeon, assisting surgeon, and radiological technologist wore thermoluminescent dosimeter on the unshielded thyroid, chest, genitals, right middle finger, and on the chest beneath a lead apron. The doses at the lens and the effective doses were also calculated. Mean fluoroscopy times were 38.7, 53.1, and 58.5 seconds for 1, 2, or 3 fusion levels, respectively. The operating surgeon's mean exposures at the lens, thyroid, chest, genitals, finger, and the chest beneath the shield, respectively, were 0.07, 0.07, 0.09, 0.14, 0.32, and 0.05 mSv in 1-level MIS-TLIF; 0.07, 0.08, 0.09, 0.18, 0.34, and 0.05 mSv in 2-level; 0.08, 0.09, 0.14, 0.15, 0.36, and 0.06 mSv in 3-level; and 0.07, 0.08, 0.10, 0.15, 0.33, and 0.05 mSv in all cases. Mean dose at the operating surgeon's right finger was significantly higher than other measurements parts (P<0.001). The operating surgeon's effective doses (0.06, 0.06, and 0.07 mSv for 1, 2, and 3 fusion levels) were low, and didn't differ significantly from those of the assisting surgeon or radiological technologist. Revision MIS-TLIF was not associated with higher surgeons' radiation doses compared to primary MIS-TLIF. There were significantly higher surgeons' radiation doses in over-weight than in normal-weight patients. The surgeons' radiation exposure during MIS-TLIF was within the safe level by the International Commission on Radiological Protection's guidelines. The accumulated radiation exposure, especially to surgeon's hands, should be carefully monitored.
doi:10.1371/journal.pone.0095233
PMCID: PMC3988176  PMID: 24736321
3.  Comparing radiation exposure during percutaneous vertebroplasty using one- vs. two-fluoroscopic technique 
Background
Percutaneous vertebroplasty (PV) requires relatively lengthy fluoroscopic guidance, which might lead to substantial radiation exposure to patients or operators. The two-fluoroscopic technique (two-plane radiographs obtained using two fluoroscopes) during PV can provide simultaneous two-planar projections with reducing operative time. However, the two-fluoroscopic technique may expose the operator or patient to increased radiation dose. The aim of this study was to quantify the amount of radiation exposure to the patient or operator that occurs during PV using one- vs. two-fluoroscopic technique.
Methods
Two radiation dosimeters were placed on the right flank of each patient and on the upper sternum of each operator during 26 single-level PV procedures by one senior surgeon. The use of two-fluoroscopic technique (13 patients) and one-fluoroscopic technique (13 patients) were allocated in a consecutive and alternative manner. The operative time and mean radiation dose to each patient and operator were monitored and compared between groups.
Results
Mean radiation dose to the patient was 1.97 ± 1.20 mSv (95% CI, 0.71 to 3.23) for the one-fluoroscopic technique group vs. 0.95 ± 0.34 mSv (95% CI, 0.85 to 1.23) for the two-fluoroscopic technique group (P =0.031). Mean radiation dose to the operator was 0.27 ± 0.12 mSv (95% CI, 0.17–0.56) for the one-fluoroscopic technique group vs. 0.25 ± 0.14 mSv (95% CI, 0.06–0.44) for the two-fluoroscopic technique group (P = 0.653). The operative time was significantly different between groups: 47.15 ± 13.48 min (range, 20–75) for the one-fluoroscopic technique group vs. 36.62 ± 8.42 min (range, 21–50) for the two-fluoroscopic technique group (P =0.019).
Conclusion
Compared to the one-fluoroscopic technique, the two-fluoroscopic technique used during PV provides not only shorter operative times but also reduces the radiation exposure to the patient. There was no significant difference between the two techniques with regards to radiation exposure to the operator.
doi:10.1186/1471-2474-14-38
PMCID: PMC3557160  PMID: 23339360
Vertebral compression fracture; Osteoporosis; Vertebroplasty; Radiation dose
4.  Kyphoplasty: Traditional imaging compared with computer-guided intervention—time to rethink technique? 
Study design: Equivalence trial (IRB not required for cadaveric studies).
Objective: To compare computer-guided and fluoroscopic kyphoplasty. Factors of interest were radiation exposure, position of cannula within pedicles and procedure time.
Methods: Kyphoplasty was performed on two cadavers. Computer-navigated, cross-sectional images from a cone-beam CT were used for one and fluoroscopic imaging for the other. In each, T6–9 and T11–L2 vertebrae were selected. For both imaging methods, anteroposterior and lateral x-rays were taken. Radiation exposure for both procedures was measured by four dosimeters. Procedure time, radiation to surgeon and cadaver, and position of cannula placement within pedicles were recorded. The surgeon wore one under the lead gown, another on the lead gown at shoulder level, and a third as a ring on the dominant hand. A dosimeter was also placed on the cadaver.
Results: The radiation from the cone-beam, computer-guided imaging system was 0.0 mrem to the surgeon and 0.52 rads to the cadaver. Using fluoroscopic imaging, surgeon's and cadaver's exposure was 5 mrem and 0.047 rads, respectively. Procedure times were similar and neither device resulted in cannula malposition.
Conclusions: Cone-beam CT appears as accurate as the fluoroscopy; radiation exposure to the surgeon is eliminated, and radiation levels to the patient are acceptable.
doi:10.1055/s-0028-1100893
PMCID: PMC3609000  PMID: 23544024
5.  Radiation exposure from fluoroscopy during fixation of hip fracture and fracture of ankle: Effect of surgical experience 
Indian Journal of Orthopaedics  2008;42(4):471-473.
Background:
Over the years, there has been a tremendous increase in the use of fluoroscopy in orthopaedics. The risk of contracting cancer is significantly higher for an orthopedic surgeon. Hip and spine surgeries account for 99% of the total radiation dose. The amount of radiation to patients and operating surgeon depends on the position of the patient and the type of protection used during the surgery. A retrospective study to assess the influence of the radiation exposure of the operating surgeon during fluoroscopically assisted fixation of fractures of neck of femur (dynamic hip screw) and ankle (Weber B) was performed at a district general hospital in the United Kingdom.
Materials and Methods:
Sixty patients with undisplaced intertrochanteric fracture were included in the hip group, and 60 patients with isolated fracture of lateral malleolus without communition were included in the ankle group. The hip and ankle groups were further divided into subgroups of 20 patients each depending on the operative experience of the operating surgeon. All patients had fluoroscopically assisted fixation of fracture by the same approach and technique. The radiation dose and screening time of each group were recorded and analyzed.
Results:
The radiation dose and screening time during fluoroscopically assisted fixation of fracture neck of femur were significantly high with surgeons and trainees with less than 3 years of surgical experience in comparison with surgeons with more than 10 years of experience. The radiation dose and screening time during fluoroscopically assisted fixation of Weber B fracture of ankle were relatively independent of operating surgeon's surgical experience.
Conclusion:
The experience of operating surgeon is one of the important factors affecting screening time and radiation dose during fluoroscopically assisted fixation of fracture neck of femur. The use of snapshot pulsed fluoroscopy and involvement of senior surgeons could significantly reduce the radiation dose and screening time.
doi:10.4103/0019-5413.43398
PMCID: PMC2740341  PMID: 19753238
Experience; fixation; fracture; radiation; surgeon
6.  The surgeon’s real dose exposure during balloon kyphoplasty procedure and evaluation of the cement delivery system: a prospective study 
European Spine Journal  2013;22(8):1758-1764.
Purpose
Balloon kyphoplasty is currently widely used for the treatment of vertebral compression fractures (VCFs). Procedure safety is directly linked to precise radiological imaging generated by various X-ray systems (C-arm, O-arm®, angiography table, etc.). This minimally invasive spinal surgery is, by definition, associated with significant radiation exposure for both patient and surgeon. Real dose exposure received by the surgeon is usually difficult to precisely record. In our center, all Balloon Kyphoplasty Procedures (BKP) are now performed using an O-arm® image guidance system to control cement augmentation in VCF. Our preliminary experience described reduced dose exposure compared to C-arm guided procedures. We present here an additional way to considerably reduce the amount of radiation received by the surgeon during BKP using a new injection system.
Methods
We prospectively evaluated O-arm® guided BKP in 20 consecutive patients alternatively allocated to either classic O-arm® BKP with direct bone filler injection or BKP using a new Cement Delivery System (CDS). Eye, wrist, finger and leg measurements were taken bilaterally and compared between the two groups.
Results
The radiation dose received by the surgeon’s finger, wrist and leg was reduced by greater than 80 % when using the CDS. It allows the surgeon to work way below the most severe annual limit of dose exposure, which may not be the case when using a classical bone filler direct injection mechanism.
Conclusion
We believe that when using this new intraoperative injection system, the surgeon’s overall anatomic exposure is significantly reduced without compromising the critical procedure steps.
Electronic supplementary material
The online version of this article (doi:10.1007/s00586-013-2702-z) contains supplementary material, which is available to authorized users.
doi:10.1007/s00586-013-2702-z
PMCID: PMC3731504  PMID: 23397218
Balloon kyphoplasty; Vertebral compression fractures; Radiation exposure; Minimal invasive spinal surgery; Cement delivery system
7.  Radiation Safety and Education in the Applicants of the Final Test for the Expert of Pain Medicine 
The Korean Journal of Pain  2012;25(1):16-21.
Background
The C-arm fluoroscope is known as the most important equipment in pain interventions. This study was conducted to investigate the completion rate of education on radiation safety, the knowledge of radiation exposure, the use of radiation protection, and so on.
Methods
Unsigned questionnaires were collected from the 27 pain physicians who applied for the final test to become an expert in pain medicine in 2011. The survey was composed of 12 questions about the position of the hospital, the kind of hospital, the use of C-arm fluoroscopy, radiation safety education, knowledge of annual permissible radiation dose, use of radiation protection, and efforts to reduce radiation exposure.
Results
In this study, although most respondents (93%) had used C-arm fluoroscopy, only 33% of the physicians completed radiation safety education. Even though nine (33%) had received education on radiation safety, none of the physicians knew the annual permissible radiation dose. In comparing the radiation safety education group and the no-education group, the rate of wearing radiation-protective glasses or goggles and the use of radiation badges or dosimeters were significantly higher in the education group. However, in the use of other protective equipment, knowledge of radiation safety, and efforts to reduce radiation exposure, there were no statistical differences between the two groups.
Conclusions
The respondents knew very little about radiation safety and had low interest in their radiation exposure. To make the use of fluoroscopy safer, additional education, as well as attention to and knowledge of practices of radiation safety are required for pain physicians.
doi:10.3344/kjp.2012.25.1.16
PMCID: PMC3259132  PMID: 22259711
education; fluoroscopy; radiation; radiation monitoring; radiation protection
8.  SOME EFFECTS OF RADIUM RADIATIONS ON WHITE MICE 
It has been estimated that 92 per cent of the total radiation emitted by radium in equilibrium with its subsequent products is given off in the form of α-rays. This, however, cannot be utilized when the source is enclosed in an ordinary container, because the α-rays are absorbed completely by even a small thickness of glass. About 3.2 per cent of the total radiation is emitted in the form of β-rays, and 4.8 per cent as gamma radiation. The effects produced on the radiated mice of these experiments were due mainly to the β-rays, which are easily absorbed by tissue. The γ-rays, being only slightly absorbed by organic matter, probably contributed very little to the observed effects. It is interesting to correlate the different effects produced by the same dose of radiation. The mice which received a dose of 1.9 millicurie hours showed no local effects on the skin or hair. Neither females nor males were sterilized, and the time at which they opened their eyes or reached sexual maturity was not affected, as far as we could tell. The only difference noted between the radiated animals and the controls was in the body weight. This dose accelerated the growth of the young mice, that is, while initially of the same weight, soon after irradiation they became distinctly bigger than the controls, but finally the animals of each group had substantially the same average weight. That this variation in body weight should be accidental is unlikely, since it was observed also in the animals treated by a slightly larger dose (2.4 millicurie hours). The number of animals (seven) which showed this effect is too small to prove conclusively the accelerating effect of small doses of radiation on the body growth of mice. But considering that similar results have been. obtained by radiating plants and beetles, it is reasonable that the observed increase in weight might be attributed, at least in part, to the effects of radiation. Since this paper was first written Russ, Chambers, and Scott have shown that small doses of x-rays accelerate the body growth of rats. In view of this additional evidence there can be little doubt that the increase in weight observed in our experiments was due to the radiation. A dose of 2.4 millicurie hours applied over the backs of the animals produced no local skin effects, but it accelerated the growth of the mice as in the previous case. In addition it caused permanent sterilization of all the females. A similar result was obtained with 4.9 millicurie hours, except that the effect on the rate of growth was uncertain. A dose of 6.8 millicurie hours produced a definite but mild skin erythema and retarded the development of lanugo hair. But since in this instance the emanation was applied over the heads of the animals, the dose reaching the ovaries was not sufficient to cause sterilization, as already explained. No other definite effect was noted. In connection with the sterilization of the females it should be noted that a dose of radiation which produced no visible skin changes was sufficient to cause permanent sterility. On account of the greater distance of the ovaries from the source of radiation as compared with that of the skin directly below the tube, and the depth of tissue which the rays had to traverse to reach the ovaries, the amount of radiation acting on the latter was much smaller than the amount falling on the skin. The radiation emitted by the emanation tube is reduced to about 50 per cent of its initial value after traversing 1 mm. of tissue. Still, while the skin was not visibly affected, the mice were sterilized. This shows that the ovaries are influenced very easily by radiation of this type. We can estimate the amount of radiation reaching the ovaries which is sufficient to cause sterility to be less than 25 per cent of the amount necessary to produce visible skin changes in the mice. It should be noted also that whenever sterility of the female mice was induced, it was permanent. Furthermore, those mice which were not rendered sterile by radiation were, as far as the experiments enable us to say, as prolific as the controls. Remembering that a dose of 1.9 millicurie hours had no apparent effect on the ovaries, while a slightly larger dose, 2.4 millicurie hours, caused permanent sterility, it might be concluded that it is not possible to produce temporary sterility by radiation. We know, however, that temporary sterility can be produced, at least when the animals are radiated at a later stage in their development. The mice in our experiments were radiated for the first time soon after birth, and it is not improbable that under these conditions temporary sterility cannot be obtained. Large sublethal doses produced severe skin burns, retarded the body growth of the animals, but failed to sterilize the males. About one-third of the total skin area of the mice showed marked effects from the radiation. The animals were very sick for a time, and their growth was temporarily stunted. But nevertheless they recovered and finally became apparently normal except for the narrow hairless strip of skin which had been closest to the emanation tube. Only the females were rendered permanently sterile. The males did not show even temporary sterility when the doses of radiation were close to the lethal dose. While the testes of mammals are known to be very easily affected by radiation, still they are more resistant than the ovaries. In addition, in these experiments they were at a greater distance from the source of radiation than the ovaries, and they were better protected by the thicker layer of tissue in the path of the rays. The fact that no sublethal dose in these experiments sterilized the males shows that under the conditions of irradiation adopted the amount of radiation reaching the testes was not sufficient to affect them noticeably. If the source of radiation had been applied closer to the reproductive organs of the males, they would have been sterilized by millicurie hour doses much smaller than the lethal dose. Some of the radiated animals were killed with ether, and macroscopic and microscopic examinations of the reproductive organs were made. The ovaries of the sterile females were generally atrophied and colored yellow. The normal histological structure was altered. The characteristic findings were the destruction of the Graafian follicles, with absence of ovum cells. The testes and the epididymis of the radiated mice of the present experiment appeared macroscopically and histologically normal, with the presence of abundant spermatozoa. Owing to the method adopted for the irradiation of the mice, the testes were too far from the source of radiation, and too well protected by the intervening tissue to be definitely affected by the rays.
PMCID: PMC2140509  PMID: 19871946
9.  A Randomized Controlled Trial about the Levels of Radiation Exposure Depends on the Use of Collimation C-arm Fluoroscopic-guided Medial Branch Block 
The Korean Journal of Pain  2013;26(2):148-153.
Background
C-arm fluoroscope has been widely used to promote more effective pain management; however, unwanted radiation exposure for operators is inevitable. We prospectively investigated the differences in radiation exposure related to collimation in Medial Branch Block (MBB).
Methods
This study was a randomized controlled trial of 62 MBBs at L3, 4 and 5. After the patient was laid in the prone position on the operating table, MBB was conducted and only AP projections of the fluoroscope were used. Based on a concealed random number table, MBB was performed with (collimation group) and without (control group) collimation. The data on the patient's age, height, gender, laterality (right/left), radiation absorbed dose (RAD), exposure time, distance from the center of the field to the operator, and effective dose (ED) at the side of the table and at the operator's chest were collected. The brightness of the fluoroscopic image was evaluated with histogram in Photoshop.
Results
There were no significant differences in age, height, weight, male to female ratio, laterality, time, distance and brightness of fluoroscopic image. The area of the fluoroscopic image with collimation was 67% of the conventional image. The RAD (29.9 ± 13.0, P = 0.001) and the ED at the left chest of the operators (0.53 ± 0.71, P = 0.042) and beside the table (5.69 ± 4.6, P = 0.025) in collimation group were lower than that of the control group (44.6 ± 19.0, 0.97 ± 0.92, and 9.53 ± 8.16), resepectively.
Conclusions
Collimation reduced radiation exposure and maintained the image quality. Therefore, the proper use of collimation will be beneficial to both patients and operators.
doi:10.3344/kjp.2013.26.2.148
PMCID: PMC3629341  PMID: 23614076
collimation; image quality; radiation absorbed dose; radiation exposure
10.  Balloon Kyphoplasty 
Executive Summary
Objective
To review the evidence on the effectiveness and cost-effectiveness of balloon kyphoplasty for the treatment of vertebral compression fractures (VCFs).
Clinical Need
Vertebral compression fractures are one of the most common types of osteoporotic fractures. They can lead to chronic pain and spinal deformity. They are caused when the vertebral body (the thick block of bone at the front of each vertebra) is too weak to support the loads of activities of daily living. Spinal deformity due to a collapsed vertebral body can substantially affect the quality of life of elderly people, who are especially at risk for osteoporotic fractures due to decreasing bone mass with age. A population-based study across 12 European centres recently found that VCFs have a negative impact on health-related quality of life. Complications associated with VCFs are pulmonary dysfunction, eating disorders, loss of independence, and mental status change due to pain and the use of medications. Osteoporotic VCFs also are associated with a higher rate of death.
VCFs affect an estimated 25% of women over age 50 years and 40% of women over age 80 years. Only about 30% of these fractures are diagnosed in clinical practice. A Canadian multicentre osteoporosis study reported on the prevalence of vertebral deformity in Canada in people over 50 years of age. To define the limit of normality, they plotted a normal distribution, including mean and standard deviations (SDs) derived from a reference population without any deformity. They reported a prevalence rate of 23.5% in women and a rate of 21.5% in men, using 3 SDs from the mean as the limit of normality. When they used 4 SDs, the prevalence was 9.3% and 7.3%, respectively. They also found the prevalence of vertebral deformity increased with age. For people older than 80 years of age, the prevalence for women and men was 45% and 36%, respectively, using 3 SDs as the limit of normality.
About 85% of VCFs are due to primary osteoporosis. Secondary osteoporosis and neoplasms account for the remaining 15%. A VCF is operationally defined as a reduction in vertebral body height of at least 20% from the initial measurement. It is considered mild if the reduction in height is between 20% and 25%; moderate, if it is between 25% and 40%; and severs, if it is more than 40%. The most frequently fractured locations are the third-lower part of the thorax and the superior lumbar levels. The cervical vertebrae and the upper third of the thorax are rarely involved.
Traditionally, bed rest, medication, and bracing are used to treat painful VCFs. However, anti-inflammatory and narcotic medications are often poorly tolerated by the elderly and may harm the gastrointestinal tract. Bed rest and inactivity may accelerate bone loss, and bracing may restrict diaphragmatic movement. Furthermore, medical treatment does not treat the fracture in a way that ameliorates the pain and spinal deformity.
Over the past decade, the injection of bone cement through the skin into a fractured vertebral body has been used to treat VCFs. The goal of cement injection is to reduce pain by stabilizing the fracture. The secondary indication of these procedures is management of painful vertebral fractures caused by benign or malignant neoplasms (e.g., hemangioma, multiple myeloma, and metastatic cancer).
The Technology
Balloon kyphoplasty is a modified vertebroplasty technique. It is a minimally invasive procedure that aims to relieve pain, restore vertebral height, and correct kyphosis. During this procedure, an inflatable bone tamp is inserted into the collapsed vertebral body. Once inflated, the balloon elevates the end plates and thereby restores the height of the vertebral body. The balloon is deflated and removed, and the space is filled with bone cement. Creating a space in the vertebral body enables the application of more viscous cement and at a much lower pressure than is needed for vertebroplasty. This may result in less cement leakage and fewer complications. Balloons typically are inserted bilaterally, into each fractured vertebral body. Kyphoplasty usually is done under general anesthesia in about 1.5 hours. Patients typically are observed for only a few hours after the surgery, but some may require an overnight hospital stay.
Health Canada has licensed KyphX Xpander Inflatable Bone Tamp (Kyphon Inc., Sunnyvale, CA), for kyphoplasty in patients with VCFs. KyphX is the only commercially available device for percutaneous kyphoplasty. The KyphX kit uses a series of bone filler device tubes. Each bone filler device must be loaded manually with cement. The cement is injected into the cavity by pressing an inner stylet.
In the United States, the Food and Drug Administration cleared the KyphX Inflatable Bone Tamp for marketing in July 1998. CE (Conformité European) marketing was obtained in February 2000 for the reduction of fracture and/or creation of a void in cancellous bone.
Review Strategy
The aim of this literature review was to evaluate the safety and effectiveness of balloon kyphoplasty in the treatment of painful VCFs.
INAHTA, Cochrane CCTR (formerly Cochrane Controlled Trials Register), and DSR were searched for health technology assessment reports. In addition, MEDLINE, EMBASE, and MEDLINE In-Process & Other Non-Indexed Citations were searched from January 1, 2000 to September 21, 2004. The search was limited to English-language articles and human studies.
The positive end points selected for this assessment were as follows:
Reduction in pain scores
Reduction in vertebral height loss
Reduction in kyphotic (Cobb) angle
Improvement in quality of life scores
The search did not yield any health technology assessments on balloon kyphoplasty. The search yielded 152 citations, including those for review articles. No randomized controlled trials (RCTs) on balloon kyphoplasty were identified. All of the published studies were either prospective cohort studies or retrospective studies with no controls. Eleven studies (all case series) met the inclusion criteria. There was also a comparative study published in German that had been translated into English.
Summary of Findings
The results of the 1 comparative study (level 3a evidence) that was included in this review showed that, compared with conservative medical care, balloon kyphoplasty significantly improved patient outcomes.
Patients who had balloon kyphoplasty reported a significant reduction in pain that was maintained throughout follow-up (6 months), whereas pain scores did not change in the control group. Patients in the balloon kyphoplasty group did not need pain medication after 3 days. In the control group, about one-half of the patients needed more pain medication in the first 4 weeks after the procedure. After 6 weeks, 82% of the patients in the control group were still taking pain medication regularly.
Adjacent fractures were more frequent in the control group than in the balloon kyphoplasty group.
The case series reported on several important clinical outcomes.
Pain: Four studies on osteoporosis patients and 1 study on patients with multiple myeloma/primary cancers used the Visual Analogue Scale (VAS) to measure pain before and after balloon kyphoplasty. All of these studies reported that patients had significantly less pain after the procedure. This was maintained during follow-up. Two other studies on patients with osteoporosis also used the VAS to measure pain and found a significant improvement in pain scores; however, they did not provide follow-up data.
Vertebral body height: All 5 studies that assessed vertebral body height in patients with osteoporosis reported a significant improvement in vertebral body height after balloon kyphoplasty. One study had 1-year follow-up data for 26 patients. Vertebral body height was significantly better at 6 months and 1 year for both the anterior and midline measurements.
Two studies reported that vertebral body height was restored significantly after balloon kyphoplasty for patients with multiple myeloma or metastatic disease. In another study, the researchers reported complete height restoration in 9% of patients, a mean 56% height restoration in 60% of patients, and no appreciable height restoration in 31% of the patients who received balloon kyphoplasty.
Kyphosis correction: Four studies that assessed Cobb angle before and after balloon kyphoplasty in patients with osteoporosis found a significant reduction in degree of kyphosis after the procedure. In these studies, the differences between preoperative and postoperative Cobb angles were 3.4°, 7°, 8.8°, and 9.9°.
Only 1 study investigated kyphosis correction in patients with multiple myeloma or metastatic disease. The authors reported a significant improvement (5.2°) in local kyphosis.
Quality of life: Four studies used the Short Form 36 (SF-36) Health Survey Questionnaire to measure the quality of life in patients with osteoporosis after they had balloon kyphoplasty. A significant improvement in most of the domains of the SF-36 (bodily pain, social functioning, vitality, physical functioning, mental health, and role functioning) was observed in 2 studies. One study found that general health declined, although not significantly, and another found that role emotional declined.
Both studies that used the Oswestry Disability Index found that patients had a better quality of life after balloon kyphoplasty. In one study, this improvement was statistically significant. In another study, researchers found that quality of life after kyphoplasty improved significantly, as measured with the Roland-Morris Disability Questionnaire. Yet another study used a quality of life questionnaire and found that 62% of the patients that had balloon kyphoplasty had returned to normal activities, whereas 2 patients had reduced mobility.
To measure quality of life in patients with multiple myeloma or metastatic disease, one group of researchers used the SF-36 and found significantly better scores on bodily pain, physical functioning, vitality, and social functioning after kyphoplasty. However, the scores for general health, mental health, role physical, and role emotional had not improved. A study that used the Oswestry Disability Index reported that patients’ scores were better postoperatively and at 3 months follow-up.
These were the main findings on complications in patients with osteoporosis:
The bone cement leaked in 37 (6%) of 620 treated fractures.
There were no reports of neurological deficits.
There were no reports of pulmonary embolism due to cement leakage.
There were 6 cases of cardiovascular events in 362 patients:
3 (0.8%) patients had myocardial infarction.
3 (0.8%) patients had cardiac arrhythmias.
There was 1 (0.27%) case of pulmonary embolism due to deep venous thrombosis.
There were 20 (8.4%) cases of new fractures in 238 patients.
For patients with multiple myeloma or metastatic disease, these were the main findings:
The bone cement leaked in 12 (9.6%) of 125 procedures.
There were no reports of neurological deficits.
Economic Analysis
Balloon kyphoplasty requires anesthesia. Standard vertebroplasty requires sedation and an analgesic. Based on these considerations, the professional fees (Cdn) for each procedure is shown in Table 1.
Professional Fees for Standard Vertebroplasty and Balloon Kyphoplasty
Balloon kyphoplasty has a sizable device cost add-on of $3,578 (the device cost per case) that standard vertebroplasty does not have. Therefore, the up-front cost (i.e., physician’s fees and device costs) is $187 for standard vertebroplasty and $3,812 for balloon kyphoplasty. (All costs are in Canadian currency.)
There are also “downstream costs” of the procedures, based on the different adverse outcomes associated with each. This includes the risk of developing new fractures (21% for vertebroplasty vs. 8.4% for balloon kyphoplasty), neurological complications (3.9% for vertebroplasty vs. 0% for balloon kyphoplasty), pulmonary embolism (0.1% for vertebroplasty vs. 0% for balloon kyphoplasty), and cement leakage (26.5% for vertebroplasty vs. 6.0% for balloon kyphoplasty). Accounting for these risks, and the base costs to treat each of these complications, the expected downstream costs are estimated at less than $500 per case. Therefore, the expected total direct medical cost per patient is about $700 for standard vertebroplasty and $4,300 for balloon kyphoplasty.
Kyphon, the manufacturer of the inflatable bone tamps has stated that the predicted Canadian incidence of osteoporosis in 2005 is about 29,000. The predicted incidence of cancer-related vertebral fractures in 2005 is 6,731. Based on Ontario having about 38% of the Canadian population, the incidence in the province is likely to be about 11,000 for osteoporosis and 2,500 for cancer-related vertebral fractures. This means there could be as many as 13,500 procedures per year in Ontario; however, this is highly unlikely because most of the cancer-related fractures likely would be treated with medication. Given a $3,600 incremental direct medical cost associated with balloon kyphoplasty, the budget impact of adopting this technology could be as high as $48.6 million per year; however, based on data from the Provider Services Branch, about 120 standard vertebroplasties are done in Ontario annually. Given these current utilization patterns, the budget impact is likely to be in the range of $430,000 per year. This is because of the sizable device cost add-on of $3,578 (per case) for balloon kyphoplasty that standard vertebroplasty does not have.
Policy Considerations
Other treatments for osteoporotic VCFs are medical management and open surgery. In cases without neurological involvement, the medical treatment of osteoporotic VCFs comprises bed rest, orthotic management, and pain medication. However, these treatments are not free of side effects. Bed rest over time can result in more bone and muscle loss, and can speed the deterioration of the underlying condition. Medication can lead to altered mood or mental status. Surgery in these patients has been limited because of its inherent risks and invasiveness, and the poor quality of osteoporotic bones. However, it may be indicated in patients with neurological deficits.
Neither of these vertebral augmentation procedures eliminates the need for aggressive treatment of osteoporosis. Osteoporotic VCFs are often under-diagnosed and under-treated. A survey of physicians in Ontario (1) who treated elderly patients living in long-term care homes found that although these physicians were aware of the rates of osteoporosis in these patients, 45% did not routinely assess them for osteoporosis, and 26% did not routinely treat them for osteoporosis.
Management of the underlying condition that weakens the vertebral bodies should be part of the treatment plan. All patients with osteoporosis should be in a medical therapy program to treat the underlying condition, and the referring health care provider should monitor the clinical progress of the patient.
The main complication associated with vertebroplasty and balloon kyphoplasty is cement leakage (extravertebral or vascular). This may result in more patient morbidity, longer hospitalizations, the need for open surgery, and the use of pain medications, all of which have related costs. Extravertebral cement leakage can cause neurological complications, like spinal cord compression, nerve root compression, and radiculopathy. In some cases, surgery is required to remove the cement and release the nerve. The rate of cement leakage is much lower after balloon kyphoplasty than after vertebroplasty. Furthermore, the neurological complications seen with vertebroplasty have not seen in the studies of balloon kyphoplasty. Rarely, cement leakage into the venous system will cause a pulmonary embolism. Finally, compared with vertebroplasty, the rate of new fractures is lower after balloon kyphoplasty.
Diffusion – International, National, Provincial
In Canada, balloon kyphoplasty has not yet been funded in any of the provinces. The first balloon kyphoplasty performed in Canada was in July 2004 in Ontario.
In the United States, the technology is considered by some states as medically reasonable and necessary for the treatment of painful vertebral body compression fractures.
Conclusion
There is level 4 evidence that balloon kyphoplasty to treat pain associated with VCFs due to osteoporosis is as effective as vertebroplasty at relieving pain. Furthermore, the evidence suggests that it restores the height of the affected vertebra. It also results in lower fracture rates in other vertebrae compared with vertebroplasty, and in fewer neurological complications due to cement leakage compared with vertebroplasty. Balloon kyphoplasty is a reasonable alternative to vertebroplasty, although it must be reiterated that this conclusion is based on evidence from level 4 studies.
Balloon kyphoplasty should be restricted to facilities that have sufficient volumes to develop and maintain the expertise required to maximize good quality outcomes. Therefore, consideration should be given to limiting the number of facilities in the province that can do balloon kyphoplasty.
PMCID: PMC3387743  PMID: 23074451
11.  Automatic Localization of Vertebral Levels in X-Ray Fluoroscopy Using 3D-2D Registration: A Tool to Reduce Wrong-Site Surgery 
Physics in medicine and biology  2012;57(17):5485-5508.
Surgical targeting of the incorrect vertebral level (“wrong-level” surgery) is among the more common wrong-site surgical errors, attributed primarily to a lack of uniquely identifiable radiographic landmarks in the mid-thoracic spine. Conventional localization method involves manual counting of vertebral bodies under fluoroscopy, is prone to human error, and carries additional time and dose. We propose an image registration and visualization system (referred to as LevelCheck), for decision support in spine surgery by automatically labeling vertebral levels in fluoroscopy using a GPU-accelerated, intensity-based 3D-2D (viz., CT-to-fluoroscopy) registration. A gradient information (GI) similarity metric and CMA-ES optimizer were chosen due to their robustness and inherent suitability for parallelization. Simulation studies involved 10 patient CT datasets from which 50,000 simulated fluoroscopic images were generated from C-arm poses selected to approximate C-arm operator and positioning variability. Physical experiments used an anthropomorphic chest phantom imaged under real fluoroscopy. The registration accuracy was evaluated as the mean projection distance (mPD) between the estimated and true center of vertebral levels. Trials were defined as successful if the estimated position was within the projection of the vertebral body (viz., mPD < 5mm). Simulation studies showed a success rate of 99.998% (1 failure in 50,000 trials) and computation time of 4.7 sec on a midrange GPU. Analysis of failure modes identified cases of false local optima in the search space arising from longitudinal periodicity in vertebral structures. Physical experiments demonstrated robustness of the algorithm against quantum noise and x-ray scatter. The ability to automatically localize target anatomy in fluoroscopy in near-real-time could be valuable in reducing the occurrence of wrong-site surgery while helping to reduce radiation exposure. The method is applicable beyond the specific case of vertebral labeling, since any structure defined in pre-operative (or intra-operative) CT or cone-beam CT can be automatically registered to the fluoroscopic scene.
doi:10.1088/0031-9155/57/17/5485
PMCID: PMC3429949  PMID: 22864366
Wrong-site surgery; surgical planning; vertebral level localization; spine surgery; 3D-2D registration; GPU-acceleration; fluoroscopy; cone-beam CT
12.  Risk of whole body radiation exposure and protective measures in fluoroscopically guided interventional techniques: a prospective evaluation 
BMC Anesthesiology  2003;3:2.
Background
Fluoroscopic guidance is frequently utilized in interventional pain management. The major purpose of fluoroscopy is correct needle placement to ensure target specificity and accurate delivery of the injectate. Radiation exposure may be associated with risks to physician, patient and personnel. While there have been many studies evaluating the risk of radiation exposure and techniques to reduce this risk in the upper part of the body, the literature is scant in evaluating the risk of radiation exposure in the lower part of the body.
Methods
Radiation exposure risk to the physician was evaluated in 1156 patients undergoing interventional procedures under fluoroscopy by 3 physicians. Monitoring of scattered radiation exposure in the upper and lower body, inside and outside the lead apron was carried out.
Results
The average exposure per procedure was 12.0 ± 9.8 seconds, 9.0 ± 0.37 seconds, and 7.5 ± 1.27 seconds in Groups I, II, and III respectively. Scatter radiation exposure ranged from a low of 3.7 ± 0.29 seconds for caudal/interlaminar epidurals to 61.0 ± 9.0 seconds for discography. Inside the apron, over the thyroid collar on the neck, the scatter radiation exposure was 68 mREM in Group I consisting of 201 patients who had a total of 330 procedures with an average of 0.2060 mREM per procedure and 25 mREM in Group II consisting of 446 patients who had a total of 662 procedures with average of 0.0378 mREM per procedure. The scatter radiation exposure was 0 mREM in Group III consisting of 509 patients who had a total 827 procedures. Increased levels of exposures were observed in Groups I and II compared to Group III, and Group I compared to Group II.
Groin exposure showed 0 mREM exposure in Groups I and II and 15 mREM in Group III. Scatter radiation exposure for groin outside the apron in Group I was 1260 mREM and per procedure was 3.8182 mREM. In Group II the scatter radiation exposure was 400 mREM and with 0.6042 mREM per procedure. In Group III the scatter radiation exposure was 1152 mREM with 1.3930 mREM per procedure.
Conclusion
Results of this study showed that scatter radiation exposure to both the upper and lower parts of the physician's body is present. Protection was offered by traditional measures to the upper body only.
doi:10.1186/1471-2253-3-2
PMCID: PMC194671  PMID: 12904269
13.  Pediatric interventional radiography equipment: safety considerations 
Pediatric Radiology  2006;36(Suppl 2):126-135.
This paper discusses pediatric image quality and radiation dose considerations in state-of-the-art fluoroscopic imaging equipment. Although most fluoroscopes are capable of automatically providing good image quality on infants, toddlers, and small children, excessive radiation dose levels can result from design deficiencies of the imaging device or inappropriate configuration of the equipment’s capabilities when imaging small body parts. Important design features and setup choices at installation and during the clinical use of the imaging device can improve image quality and reduce radiation exposure levels in pediatric patients. Pediatric radiologists and cardiologists, with the help of medical physicists, need to understand the issues involved in creating good image quality at reasonable pediatric patient doses. The control of radiographic technique factors by the generator of the imaging device must provide a large dynamic range of mAs values per exposure pulse during both fluoroscopy and image recording as a function of patient girth, which is the thickness of the patient in the posterior–anterior projection at the umbilicus (less than 10 cm to greater than 30 cm). The range of pulse widths must be limited to less than 10 ms in children to properly freeze patient motion. Variable rate pulsed fluoroscopy can be leveraged to reduce radiation dose to the patient and improve image quality. Three focal spots with nominal sizes of 0.3 mm to 1 mm are necessary on the pediatric unit. A second, lateral imaging plane might be necessary because of the child’s limited tolerance of contrast medium. Spectral and spatial beam shaping can improve image quality while reducing the radiation dose. Finally, the level of entrance exposure to the image receptor of the fluoroscope as a function of operator choices, of added filter thickness, of selected pulse rate, of the selected field-of-view and of the patient girth all must be addressed at installation.
doi:10.1007/s00247-006-0220-4
PMCID: PMC2663646  PMID: 16862405
Radiation exposure; Fluoroscopic equipment; Equipment settings
14.  Radiation exposure to personnel performing endoscopic retrograde cholangiopancreatography 
Postgraduate Medical Journal  2005;81(960):660-662.
Background: Endoscopic retrograde cholangiopancreatography (ERCP) relies on the use of ionising radiation but risks to operator and patient associated with radiation exposure are unclear. The aim of this prospective study was to estimate the radiation dose received by personnel performing fluoroscopic endoscopic procedures, mainly ERCP.
Methods: Consecutive procedures over a two month period were included. The use of thermoluminescent dosimeters to measure radiation exposure to the abdomen, thyroid gland, and hands of the operator permitted an estimation of the annual whole body effective dose equivalent.
Results: During the study period 66 procedures (61 ERCP) were performed and the estimated annual whole body effective dose equivalent received by consultant operators ranged between 3.35 and 5.87 mSv. These values are similar to those received by patients undergoing barium studies and equate to an estimated additional lifetime fatal cancer risk between 1 in 7000 and 1 in 3500. While within legal safety limits for radiation exposure to personnel, these doses are higher than values deemed acceptable for the general public.
Conclusions: It is suggested that personnel as well as patients may be exposed to significant values of radiation during ERCP. The study emphasises the need to carefully assess the indication for, and to use measures that minimise radiation exposure during any fluoroscopic procedure.
doi:10.1136/pgmj.2004.031526
PMCID: PMC1743365  PMID: 16210465
15.  A Study to Compare the Radiation Absorbed Dose of the C-arm Fluoroscopic Modes 
The Korean Journal of Pain  2011;24(4):199-204.
Background
Although many clinicians know about the reducing effects of the pulsed and low-dose modes for fluoroscopic radiation when performing interventional procedures, few studies have quantified the reduction of radiation-absorbed doses (RADs). The aim of this study is to compare how much the RADs from a fluoroscopy are reduced according to the C-arm fluoroscopic modes used.
Methods
We measured the RADs in the C-arm fluoroscopic modes including 'conventional mode', 'pulsed mode', 'low-dose mode', and 'pulsed + low-dose mode'. Clinical imaging conditions were simulated using a lead apron instead of a patient. According to each mode, one experimenter radiographed the lead apron, which was on the table, consecutively 5 times on the AP views. We regarded this as one set and a total of 10 sets were done according to each mode. Cumulative exposure time, RADs, peak X-ray energy, and current, which were viewed on the monitor, were recorded.
Results
Pulsed, low-dose, and pulsed + low-dose modes showed significantly decreased RADs by 32%, 57%, and 83% compared to the conventional mode. The mean cumulative exposure time was significantly lower in the pulsed and pulsed + low-dose modes than in the conventional mode. All modes had pretty much the same peak X-ray energy. The mean current was significantly lower in the low-dose and pulsed + low-dose modes than in the conventional mode.
Conclusions
The use of the pulsed and low-dose modes together significantly reduced the RADs compared to the conventional mode. Therefore, the proper use of the fluoroscopy and its C-arm modes will reduce the radiation exposure of patients and clinicians.
doi:10.3344/kjp.2011.24.4.199
PMCID: PMC3248583  PMID: 22220241
fluoroscopy; radiation; radiation dosage; radiographic image enhancement
16.  Minimally invasive percutaneous transpedicular screw fixation: increased accuracy and reduced radiation exposure by means of a novel electromagnetic navigation system 
Acta Neurochirurgica  2010;153(3):589-596.
Background
Minimally invasive percutaneous pedicle screw instrumentation methods may increase the need for intraoperative fluoroscopy, resulting in excessive radiation exposure for the patient, surgeon, and support staff. Electromagnetic field (EMF)-based navigation may aid more accurate placement of percutaneous pedicle screws while reducing fluoroscopic exposure. We compared the accuracy, time of insertion, and radiation exposure of EMF with traditional fluoroscopic percutaneous pedicle screw placement.
Methods
Minimally invasive pedicle screw placement in T8 to S1 pedicles of eight fresh-frozen human cadaveric torsos was guided with EMF or standard fluoroscopy. Set-up, insertion, and fluoroscopic times and radiation exposure and accuracy (measured with post-procedural computed tomography) were analyzed in each group.
Results
Sixty-two pedicle screws were placed under fluoroscopic guidance and 60 under EMF guidance. Ideal trajectories were achieved more frequently with EMF over all segments (62.7% vs. 40%; p = 0.01). Greatest EMF accuracy was achieved in the lumbar spine, with significant improvements in both ideal trajectory and reduction of pedicle breaches over fluoroscopically guided placement (64.9% vs. 40%, p = 0.03, and 16.2% vs. 42.5%, p = 0.01, respectively). Fluoroscopy time was reduced 77% with the use of EMF (22 s vs. 5 s per level; p < 0.0001) over all spinal segments. Radiation exposure at the hand and body was reduced 60% (p = 0.058) and 32% (p = 0.073), respectively. Time for insertion did not vary between the two techniques.
Conclusions
Minimally invasive pedicle screw placement with the aid of EMF image guidance reduces fluoroscopy time and increases placement accuracy when compared with traditional fluoroscopic guidance while adding no additional time to the procedure.
doi:10.1007/s00701-010-0882-4
PMCID: PMC3040822  PMID: 21153669
Minimally invasive; Electromagnetic field navigation; Pedicle screw; Fluoroscopy; Accuracy
17.  Establishing the radiation risk from fluoroscopic-assisted arthroscopic surgery of the hip 
International Orthopaedics  2012;36(9):1803-1806.
Purpose
The purpose of the study was to quantify patient exposure to ionising radiation during fluoroscopic-assisted arthroscopic surgery of the hip, establish a risk profile of this exposure, and reassure patients of radiation safety during the procedure.
Methods
We retrospectively analysed the dose area products for 50 consecutive patients undergoing arthroscopic hip surgery by an experienced hip arthroscopic surgeon. The effective dose and organ dose were derived using a Monte Carlo program.
Results
The mean total fluoroscopy time was 1.10 minutes and the mean dose area product value was 297.2 cGycm2. We calculated the entrance skin dose to be 52 mGy to the area where the beam was targeted (81 cm2). The mean effective dose for intra-operative fluoroscopy was 0.33 mSv, with a SD of 0.90 Sv.
Conclusion
This study confirms that fluoroscopic-assisted arthroscopic surgery of the hip is safe with a low maximum radiation dose and supports its continued use in preference to alternative imaging modalities.
doi:10.1007/s00264-012-1557-y
PMCID: PMC3427451  PMID: 22588691
18.  Radiation Protection in Canada 
Canadian Medical Association Journal  1965;92(19):993-1001.
The main emphasis of a provincial radiation protection program is on ionizing radiation produced by machines, although assistance is given to the Federal Radiation Protection Division in its program relating to radioactive substances. The basis for the Saskatchewan program of radiation protection is the Radiological Health Act 1961. An important provision of the Act is annual registration of radiation equipment. The design of the registration form encourages a “do-it-yourself” radiation and electrical safety inspection.
Installations are inspected every two years by a radiation health officer. Two hundred and twenty-one deficiencies were found during inspection of 224 items of radiation equipment, the commonest being failure to use personal film badges. Insufficient filtration of the beam, inadequate limitation of the beam, and unnecessary exposure of operators were other common faults.
Physicians have a responsibility to weigh the potential advantages against the hazards when requesting radiographic or fluoroscopic procedures.
PMCID: PMC1928469  PMID: 14282164
19.  Dosimetry during intramedullary nailing of the tibia 
Acta Orthopaedica  2009;80(5):568-572.
Background Intramedullary nailing under fluoroscopic guidance is a common operation. We studied the intraoperative radiation dose received by both the patient and the personnel.
Patients and methods 25 intramedullary nailing procedures of the tibia were studied. All patients suffered from tibial fractures and were treated using the Grosse-Kempf intramedullary nail, with free-hand technique for fixation of the distal screws, under fluoroscopic guidance. The exposure, at selected positions, was recorded using an ion chamber, while the dose area product (DAP) was measured with a DAP meter, attached to the tube head. Thermoluminescent dosimeters (TLDs) were used to derive the occupational dose to the personnel, and also to monitor the surface dose on the gonads of some of the patients.
Results The mean operation time was 101 (48–240) min, with a mean fluoroscopic time of 72 seconds and a mean DAP value of 75 cGy·cm2. The surface dose to the gonads of the patients was less than 8.8 mGy during any procedure, and thus cannot be considered to be a contraindication for the use of this technique. Occupational dose differed substantially between members of the operating personnel, the maximum dose recorded being to the operator of the fluoroscopic equipment (0.11 mSv).
Interpretation Our findings underscore the care required by the primary operator not to exceed the dose constraint of 10 mSv per year. The rest of the operating personnel, although they do not receive very high doses, should focus on the dose optimization of the technique.
doi:10.3109/17453670903350057
PMCID: PMC2823322  PMID: 19916691
20.  Significantly reduced radiation dose to operators during percutaneous vertebroplasty using a new cement delivery device 
Background
Percutaneous vertebroplasy (PVP) might lead to significant radiation exposure to patients, operators, and operating room personnel. Therefore, radiaton exposure is a concern. The aim of this study was to present a remote control cement delivery device and study whether it can reduce dose exposue to operators.
Methods
After meticulous preoperative preparation, a series of 40 osteoporosis patients were treated with unilateral approach PVP using the new cement delivery divice. We compared levels of fluoroscopic exposure to operator standing on different places during operation. group A: operator stood about 4 meters away from X-ray tube behind the lead sheet. group B: operator stood adjacent to patient as using conventional manual cement delivery device.
Results
During whole operation process, radiation dose to the operator (group A) was 0.10 ± 0.03 (0.07-0.15) μSv, group B was 12.09 ± 4.67 (10–20) μSv. a difference that was found to be statistically significant (P < 0.001) between group A and group B.
Conclusion
New cement delivery device plus meticulous preoperative preparation can significantly decrease radiation dose to operators.
doi:10.1186/1471-2474-15-260
PMCID: PMC4236675  PMID: 25084860
Percutaneous vertebroplasty; Cement delivery device; Radiation dose
21.  X-ray Dose Reduction through Adaptive Exposure in Fluoroscopic Imaging 
X-ray fluoroscopy is widely used for image guidance during cardiac intervention. However, radiation dose in these procedures can be high, and this is a significant concern, particularly in pediatric applications. Pediatrics procedures are in general much more complex than those performed on adults and thus are on average four to eight times longer1. Furthermore, children can undergo up to 10 fluoroscopic procedures by the age of 10, and have been shown to have a three-fold higher risk of developing fatal cancer throughout their life than the general population2,3.
We have shown that radiation dose can be significantly reduced in adult cardiac procedures by using our scanning beam digital x-ray (SBDX) system4-- a fluoroscopic imaging system that employs an inverse imaging geometry5,6 (Figure 1, Movie 1 and Figure 2). Instead of a single focal spot and an extended detector as used in conventional systems, our approach utilizes an extended X-ray source with multiple focal spots focused on a small detector. Our X-ray source consists of a scanning electron beam sequentially illuminating up to 9,000 focal spot positions. Each focal spot projects a small portion of the imaging volume onto the detector. In contrast to a conventional system where the final image is directly projected onto the detector, the SBDX uses a dedicated algorithm to reconstruct the final image from the 9,000 detector images.
For pediatric applications, dose savings with the SBDX system are expected to be smaller than in adult procedures. However, the SBDX system allows for additional dose savings by implementing an electronic adaptive exposure technique. Key to this method is the multi-beam scanning technique of the SBDX system: rather than exposing every part of the image with the same radiation dose, we can dynamically vary the exposure depending on the opacity of the region exposed. Therefore, we can significantly reduce exposure in radiolucent areas and maintain exposure in more opaque regions. In our current implementation, the adaptive exposure requires user interaction (Figure 3). However, in the future, the adaptive exposure will be real time and fully automatic.
We have performed experiments with an anthropomorphic phantom and compared measured radiation dose with and without adaptive exposure using a dose area product (DAP) meter. In the experiment presented here, we find a dose reduction of 30%.
doi:10.3791/3236
PMCID: PMC3230176  PMID: 21931295
22.  Radiation Exposure of the Hand and Chest during C-arm Fluoroscopy-Guided Procedures 
The Korean Journal of Pain  2013;26(1):51-56.
Background
The C-arm fluoroscope is an essential tool for the intervention of pain. The aim of this study was to investigate the radiation exposure experienced by the hand and chest of pain physicians during C-arm fluoroscopy-guided procedures.
Methods
This is a prospective study about radiation exposure to physicians during transforaminal epidural steroid injection (TFESI) and medial branch block (MBB). Four pain physicians were involved in this study. Data about effective dose (ED) at each physician's right hand and left side of the chest, exposure time, radiation absorbed dose (RAD), and the distance from the center of the X-ray field to the physician during X-ray scanning were collected.
Results
Three hundred and fifteen cases were included for this study. Demographic data showed no significant differences among the physicians in the TFESIs and MBBs. In the TFESI group, there was a significant difference between the ED at the hand and chest in all the physicians. In physician A, B and C, the ED at the chest was more than the ED at the hand. The distance from the center of the X-ray field to physician A was more than that of the other physicians, and for the exposure time, the ED and RAD in physician A was less than that of the other physicians. In the MBB group, there was no difference in the ED at the hand and chest, except for physician D. The distance from the center of the X-ray field to physician A was more than that of the other physicians and the exposure time in physician A was less than that of the other physicians.
Conclusions
In conclusion, the distance from the radiation source, position of the hand, experience and technique can correlate with the radiation dose.
doi:10.3344/kjp.2013.26.1.51
PMCID: PMC3546211  PMID: 23342208
distance; exposure time; radiation dose; radiation protection
23.  Survey of terminology used for the intraoperative direction of C-arm fluoroscopy 
Canadian Journal of Surgery  2013;56(2):109-112.
Background
Orthopedic surgeons depend on the intraoperative use of fluoroscopy to facilitate procedures across all subspecialties. The versatility of the C-arm fluoroscope allows acquisition of nearly any radiographic view. This versatility, however, creates the opportunity for difficulty in communication between surgeon and radiation technologist. Poor communication leads to delays, frustration and increased exposure to ionizing radiation. There is currently no standard terminology employed by surgeons and technologists with regards to direction of the fluoroscope.
Methods
The investigation consisted of a web-based survey in 2 parts. Part 1 was administered to the membership of the Canadian Orthopedic Association, part 2 to the membership of the Canadian Association of Medical Radiation Technologists. The survey consisted of open-ended or multiple-choice questions examining experience with the C-arm fluoroscope and the terminology preferred by both orthopedic surgeons and radiation technologists.
Results
The survey revealed tremendous inconsistency in language used by orthopedic surgeons and radiation technologists. It also revealed that many radiation technologists were inexperienced in operating the fluoroscope.
Conclusion
Adoption of a common language has been demonstrated to increase efficiency in performing defined tasks with the fluoroscope. We offer a potential system to facilitate communication based on current terminology used among Canadian orthopedic surgeons and radiation technologists.
doi:10.1503/cjs.015311
PMCID: PMC3617115  PMID: 23351496
24.  Analysis of Gene Expression Using Gene Sets Discriminates Cancer Patients with and without Late Radiation Toxicity 
PLoS Medicine  2006;3(10):e422.
Background
Radiation is an effective anti-cancer therapy but leads to severe late radiation toxicity in 5%–10% of patients. Assuming that genetic susceptibility impacts this risk, we hypothesized that the cellular response of normal tissue to X-rays could discriminate patients with and without late radiation toxicity.
Methods and Findings
Prostate carcinoma patients without evidence of cancer 2 y after curative radiotherapy were recruited in the study. Blood samples of 21 patients with severe late complications from radiation and 17 patients without symptoms were collected. Stimulated peripheral lymphocytes were mock-irradiated or irradiated with 2-Gy X-rays. The 24-h radiation response was analyzed by gene expression profiling and used for classification. Classification was performed either on the expression of separate genes or, to augment the classification power, on gene sets consisting of genes grouped together based on function or cellular colocalization.
X-ray irradiation altered the expression of radio-responsive genes in both groups. This response was variable across individuals, and the expression of the most significant radio-responsive genes was unlinked to radiation toxicity. The classifier based on the radiation response of separate genes correctly classified 63% of the patients. The classifier based on affected gene sets improved correct classification to 86%, although on the individual level only 21/38 (55%) patients were classified with high certainty. The majority of the discriminative genes and gene sets belonged to the ubiquitin, apoptosis, and stress signaling networks. The apoptotic response appeared more pronounced in patients that did not develop toxicity. In an independent set of 12 patients, the toxicity status of eight was predicted correctly by the gene set classifier.
Conclusions
Gene expression profiling succeeded to some extent in discriminating groups of patients with and without severe late radiotherapy toxicity. Moreover, the discriminative power was enhanced by assessment of functionally or structurally related gene sets. While prediction of individual response requires improvement, this study is a step forward in predicting susceptibility to late radiation toxicity.
Expression profiling can discriminate between groups of patients with and without severe late radiotherapy toxicity but not (yet) predict individual responses.
Editors' Summary
Background.
More than half the people who develop cancer receive radiotherapy as part of their treatment. That is, tumor cells are destroyed by exposing them to a source of ionizing radiation such as X-rays. Ionizing radiation damages the genetic material of cancer cells so that they can no longer divide. Unfortunately, it also damages nearby normal cells, although they are less sensitive to radiation than the cancer cells. Radiotherapists minimize how much radiation hits normal tissues by carefully aiming the X-rays at the tumor. Even so, patients often develop side effects such as sore skin or digestive problems during or soon after radiotherapy; the exact nature of the side effects depends on the part of the body exposed to the X-rays. In addition, a few patients develop severe late radiation toxicity, months or years after their treatment. Like early toxicity, late toxicity occurs in the normal tissues near the tumor site. For example, in prostate cancer—a tumor that forms in a gland in the male reproductive system that lies between the bladder and the end of the gut (the rectum)—late radiation toxicity affects rectal, bladder, and sexual function in 5%–10% of patients.
Why Was This Study Done?
It is not known why some patients develop late radiation toxicity, and it is impossible to predict before treatment which patients will have long-term health problems after radiotherapy. It would be useful to know this, because radiation levels might be reduced in those patients, while larger doses of radiation could be given to patients at low risk of late complications to ensure a complete eradication of their cancer. One theory is that some patients are genetically predisposed to develop severe late radiation toxicity. In other words, their genetic make-up makes it more likely that their tissues develop long-term complications after radiation damage. In this study, the researchers looked for markers of a genetic predisposition for late radiation toxicity by comparing radiation-induced changes in the pattern of cellular proteins in patients who had late radiation toxicity after radiotherapy with the changes seen in patients who did not develop such complications.
What Did the Researchers Do and Find?
The researchers recruited 38 patients who had been treated successfully with radiotherapy for prostate cancer two years previously. Of these, 21 had developed severe late radiation toxicity. They isolated lymphocytes (a type of immune system cell) from the patients' blood, stimulated the lymphocytes to divide, exposed them to X-rays, and analyzed the pattern of genes active in these cells—their gene expression profile—before and after irradiation. The researchers found that irradiation induced the expression of numerous genes in the lymphocytes, including many well-known radiation-responsive genes. They then used an analytical process called “random cross-validation” to look for a gene expression profile (or molecular signature) that was associated with late radiation toxicity. They report that a signature based on the radiation response of 50 individual genes correctly classified 63% of the patient population in terms of whether the patient had developed late radiation toxicity. A signature based on the radiation response of gene sets containing genes linked by function or cellular localization correctly classified 86% of the patient population.
What Do These Findings Mean?
Gene expression profiling identified groups of patients who had had severe late radiation toxicity pretty well, particularly when sets of related genes were used to classify the patients. The approach was not so good, however, at identifying individual patients who had had problems, being correct and certain only half the time. Additional studies are needed, therefore, before this promising approach can be used clinically to predict patient responses to radiotherapy. Overall, the study supports the idea that some patients are genetically predisposed to develop late radiation toxicity, and it also provides clues about which cellular pathways help to determine late radiation toxicity. Most of the genes and gene sets that discriminated between the patients with and without late radiation toxicity are involved in protein metabolism, apoptosis (a special sort of cell death), and stress signaling networks (pathways that protect cells from damage). This information, if confirmed, might help researchers to develop therapeutic interventions to minimize late radiation toxicity in vulnerable individuals.
Additional Information.
Please access these Web sites via the online version of this summary at http://dx.doi.org/10.1371/journal.pmed.0030422.
US National Cancer Institute patient information on radiotherapy and on prostate cancer
American Cancer Society information on radiation therapy
Cancer Research UK patient information on radiotherapy
Wikipedia pages on radiotherapy (note that Wikipedia is a free online encyclopedia that anyone can edit)
doi:10.1371/journal.pmed.0030422
PMCID: PMC1626552  PMID: 17076557
25.  Value of MRI imaging prior to a kyphoplasty for osteoporotic insufficiency fractures 
European Spine Journal  2009;18(9):1287-1292.
Previous studies have shown the safety and effectiveness of balloon kyphoplasty in the treatment of osteoporotic vertebral compression fractures (OVCFs). MRI and particularly the short tau inversion recovery (STIR) sequence are very sensitive for detecting vertebral edema as a result of fresh fractures or micro-fractures. Therefore, it has a great therapeutic relevance in differentiating vertebral deformities seen by conventional X-ray and CT scans. Although an MRI scan is expensive, to my knowledge no study has evaluated the benefits of preoperative MRI in evaluating a therapeutic plan for kyphoplasty. This is a prospective study evaluating the benefit of a preoperative MRI scan regarding changes of kyphoplasty therapy. Twenty-eight patients were included in this study. Twenty-four patients were treated by balloon kyphoplasty, in a total of 40 vertebral bodies. The mean age was 73 years. All patients suffered from OVCFs. As a first step, all patients got a CT scan. The individual therapeutic plan was then defined by the patients’ history, complaints and the results of the CT scan. As far as all criteria for kyphoplasty were fulfilled, an MRI examination including the STIR sequences was performed preoperatively. The number of times a change was made in therapy as a result from the additional information from the MRI was then evaluated. By performing a preoperatively MRI examination, the therapy plan was changed in 16 out of 28 (57%) patients. Eight patients underwent additional levels of kyphoplasty at the same procedure. In five patients, lesions were found to be old fractures and therefore were not treated operatively. Two of these patients received no kyphoplasty at all. Another patient only a part of the originally intended levels was treated. The other two cases received a kyphoplasty at different vertebral levels, as these vertebral bodies showed signs of an acute fracture in the MRI scan. Additionally, an incidental diagnosis of carcinoma of the kidney was made in two patients. Kyphoplasty was deferred and they were referred for further evaluation. One patient was found to have an aortic aneurysm. Kyphoplasty was performed and after that the patient was referred in order to treat the aneurysm. This study confirms the diagnostic benefits of an MRI scan before performing a kyphoplasty. For 16 out of 28 patients, the therapeutic plan was changed because of the information obtained by preoperative MRI. Preoperative MRI helped to generate the correct surgical strategy, by demonstrating the correct location of injury and by detecting concomitant diseases.
doi:10.1007/s00586-009-1045-2
PMCID: PMC2899533  PMID: 19504131
Kyphoplasty; MRI; Osteoporosis; Vertebral insufficiency fracture

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