The purpose of this study was to characterize the type, nature and frequency of injuries sustained by chiropractic students during their undergraduate training.
Chiropractic students in their second, third and fourth year of study at a chiropractic college were asked to complete a questionnaire that chronicled and described the occurrence of any side effects they may have sustained at the hands of their peers during technique class. Students were also asked to record their anthropomorphic characteristic.
Of 450 questionnaires distributed, 292 were completed and returned to the authors. Of the 292 respondents, 127 reported to have experienced an injury, although the total number of injuries was 161. The most common site of injury was the lumbopelvic region. Students reported that it was during their second year of study that they experienced the highest number of injuries. Symptoms occurred the same day as the event in 85% of cases. The most common characteristic of symptoms reported was pain, followed by local stiffness, headache, dizziness, fatigue, diffuse stiffness and cramps. Two thirds of students described the extent of their injuries from ‘light’ to ‘a fair bit’. Three quarters of injuries resolved within the first 72 hours of the event. No treatment was sought by 89 (55%) of the respondents. More than half of students reported that their activities of daily living were either ‘not’ or ‘somewhat’ affected. There were three reports of long-term complaints. No statistically significant differences were found between the group of students reporting to be injured compared to those students not injured with respect to their age, gender, weight or height.
Chiropractic students experience side effects during their undergraduate training that are very similar to those experienced by patients under clinical care.
injuries; chiropractic students
The purpose of this study was to survey 200 randomly selected post-1980 graduates of the Canadian Memorial Chiropractic College practicing in five Canadian provinces to determine which, if any, technique systems they sought out instruction in and/or are utilizing either primarily or secondarily for patient care. Using a systematic sampling approach, 83 eligible data sets were received. Respondents reported to have sought out instruction in a total of 187 technique systems other than Diversified technique. In addition, although 86% of respondents stated they primarily used Diversified technique in practice, they reportedly used 134 different technique systems secondarily for patient care. This calculates to an average of 2.27 different techniques used per respondent. Future studies should survey a larger percentage of practitioners to better assess the validity of these findings.
chiropractic; technique system
Since its establishment in 1945, the Canadian Memorial Chiropractic College (CMCC) has predominately adhered to a Diversified model of chiropractic technique in the core curriculum; however, many students and graduates have voiced a desire for greater exposure to chiropractic techniques other than Diversified at CMCC. A course structure is presented that both exposes students to a plethora of different “Name techniques” and provides students with a forum to appraise them critically. The results of a student survey suggested that both of these learning objectives have been successfully met. In addition, an assignment was designed that enabled students to recommend which, if any, “Name techniques” should be included in the curriculum of the College. The recommendations from these assignments were compiled since the 1996/97 academic year. The results indicated an overwhelming demand for the inclusion of Thompson Terminal Point, Gonstead, Activator Methods, Palmer HIO and Active Release Therapy techniques either as part of the core curriculum or in an elective program. These recommendations parallel the practice activities of Canadian chiropractors.
brand name techniques; diversified technique; curriculum
To discuss the care of a patient with congenital torticollis who was treated with chiropractic diversified technique and a chiropractic technique proposed by Frogley and Wallace in a previously published article.
A 6-year-old female suffered from congenital torticollis with a left head-tilt subsequent to a difficult birth that culminated in a Caesarian section. Computerized tomography of the brain revealed plagiocephaly. Left facial asymmetry was demonstrated on visual observation.
Intervention and Outcome
The patient was treated with a chiropractic adjusting protocol as suggested by Frogley and Wallace and by diversified chiropractic technique. She tolerated the care well and experienced substantial changes in clinical presentation including a distinct improvement in head-tilt. The improvement in head-tilt has been maintained for a period of 1 year.
The conservative chiropractic methodology postulated by Frogley and Wallace in the care of headache patients should be investigated further in its use for congenial torticollis. The positive results observed with this patient lead the authors to recommend that additional studies be undertaken to assess whether these clinical observations can be replicated in other cases of congenital torticollis.
To describe the importance of health promotion techniques and use of active disease prevention techniques as part of chiropractic practice through a selective review of literature using a mnemonic device.
There is evidence that doctors of chiropractic use some health promotion techniques in practice such as instruction on exercise, dietary advice, smoking cessation recommendations and the encouraging of preventive chiropractic visits. Healthy People goals for the nation suggest that providers encourage preventive services, work toward better access to care and stress disease prevention. However, information on how this can be routinely done in chiropractic practice is fragmented. This article suggests ways to implement health promotion into the everyday management of the chiropractic patient.
Health promotion and disease prevention can be easily performed in chiropractic practice. The nature of the chiropractic supportive or maintenance visit gives doctors a unique platform on which they can launch full-scale health promotion efforts on their patients.
Health Promotion; Disease Prevention; Chiropractic; Wellness
In a previous article, the author discussed current trends in utilization rates of chiropractic “Name Techniques” in Canada, and provided recommendations for their inclusion into the curriculum at the Canadian Memorial Chiropractic College. In this article, a review of the literature on “Name Techniques” was conducted, with interpretation and synthesis by the author. One hundred and eleven articles were found. These were: technique discussions (N = 39), case studies (N = 25), case series (N = 5), experimental studies (N = 25) and clinical trials (N = 17). The literature suggested that prone leg length testing and some x-ray mensurations may have acceptable inter and intra-rater reliability. In addition, there are several case studies that reported significant clinical benefits by patients receiving Activator, Alexander, and Upper Cervical treatments. Patients also reported improvements in quality of life while under either Upper Cervical or Network Spinal Analysis care. This information may help develop professional practice guidelines, and it may have implications for chiropractic research and education.
In a previous article, the author reported on the recommendations gathered from student projects between 1996 and 1999 investigating their preferences for including certain chiropractic Name technique systems into the curriculum at the Canadian Memorial Chiropractic College (CMCC). These results were found to be congruent with the professional treatment technique used by Canadian chiropractors. This article reports on the data obtained during the 2000 and 2001 academic years, comparing these results to those previously gathered. In addition, because of the implementation of a new curriculum during this time period, there was unique opportunity to observe whether or not student perceptions differed between those students in the `old' curricular program, and those students in the `new' curricular program. The results gathered indicate that students in both curricular programs show an interest in learning Thompson Terminal Point, Activator Methods, Gonstead, and Active Release Therapy techniques in the core curriculum, as an elective, or during continuing educational programs provided by the college. Students continue to show less interest in learning CranioSacral Therapy, SacroOccipital Technique, Logan Basic, Applied Kinesiology and Chiropractic BioPhysics. Over time, student interest has moved away from Palmer HIO and other upper cervical techniques, and students show a declining interest in being offered instruction in either Network Spinal Analysis or Torque Release Techniques. Since these findings reflect the practice activities of Canadian chiropractors they may have implications not only towards pedagogical decision-making processes at CMCC, but they may also influence professional standards of care.
chiropractic Name technique systems; standards of care; professional practice activities; education
Sports chiropractic within Australia has a chequered historical background of unorthodox individualistic displays of egocentric treatment approaches that emphasise specific technique preference and individual prowess rather than standardised evidence based management. This situation has changed in recent years with the acceptance of many within sports chiropractic to operate under an evidence informed banner and to embrace a research culture. Despite recent developments within the sports chiropractic movement, the profession is still plagued by a minority of practitioners continuing to espouse certain marginal and outlandish technique systems that beleaguer the mainstream core of sports chiropractic as a cohesive and homogeneous group. Modern chiropractic management is frequently multimodal in nature and incorporates components of passive and active care. Such management typically incorporates spinal and peripheral manipulation, mobilisation, soft tissue techniques, rehabilitation and therapeutic exercises. Externally, sports chiropractic has faced hurdles too, with a lack of recognition and acceptance by organized and orthodox sports medical groups. Whilst some arguments against the inclusion of chiropractic may be legitimate due to its historical baggage, much of the argument appears to be anti-competitive, insecure and driven by a closed-shop mentality.sequently, chiropractic as a profession still remains a pariah to the organised sports medicine world. Add to this an uncertain continuing education system, a lack of protection for the title 'sports chiropractor', a lack of a recognized specialist status and a lack of support from traditional chiropractic, the challenges for the growth and acceptance of the sports chiropractor are considerable. This article outlines the historical and current challenges, both internal and external, faced by sports chiropractic within Australia and proposes positive changes that will assist in recognition and inclusion of sports chiropractic in both chiropractic and multi-disciplinary sports medicine alike.
The purpose of this report is to describe chiropractic treatment of lower back and unilateral leg pain in a pregnant patient.
A 26-year-old woman in her second trimester of pregnancy had severe pain in her lower back that radiated to her hips bilaterally and to her right leg. She reported tingling down her right lower leg to the dorsum of her foot. Although no diagnostic imaging was performed, her differential diagnoses included lumbalgia with associated radiculopathy.
Intervention and Outcome
Treatment consisted of manual traction in the side-lying position using a specialized chiropractic table and treatment technique (Cox flexion-distraction decompression) modified for pregnancy. Relief was noted after the first treatment, and complete resolution of her subjective and objective findings occurred after 8 visits.
When modified, this chiropractic technique appears to be an effective method for treating lower back pain with radiation to the leg in a pregnant patient who cannot lie prone.
Pregnancy; Low back pain; Radiculopathy; Chiropractic; Manipulation; Spinal
Asthma is a multifactorial dysfunction of the respiratory system. Nutritional, environmental, genetic, and emotional factors all play animportant part in the etiology of this condition. One form of chiropractic, Sacro Occipital Technique (SOT), offers some conservative alternatives to the treatment of asthma. SOT expands the chiropractic armamentarium of techniques available, allowing methods putatively affecting the viscera, vertebra, post and preganglionic reflexes, as well as cranial and sacral influences on the primary respiratory mechanism. Though more research is needed to evaluate the efficacy of chiropractic care of asthma, the conservative nature of chiropractic care with its minimal side effects, warrants patient and a health practitioner's consideration prior to embarking on any course of treatment that might have serious side effects.
Asthma; Chiropractic; Respiration; Cranium
The purpose of this case report is to describe the chiropractic management using upper cervical techniques of a 25-year-old woman diagnosed with juvenile myoclonic epilepsy (JME).
A 25-year-old woman had a history of JME, which was diagnosed at the age of 14 years. Her seizure episodes began shortly after trauma to her cervical spine and the onset of menarche.
Intervention and Outcome
After case history and physical examination, the patient received high-velocity, low-amplitude chiropractic spinal manipulation to her upper cervical spine using the Blair upper cervical chiropractic technique protocol. There was improvement in her seizure episodes and menstrual cycles following 12 weeks of chiropractic care.
This case study demonstrated improvement in a young woman with a seizure disorder after she received upper cervical chiropractic manipulation. This case suggests the need for more rigorous research to examine how upper cervical chiropractic techniques may provide therapeutic benefit to patients with seizure disorders.
Manipulation, Chiropractic; Myoclonic epilepsy, Juvenile; Cervical, Atlas; Menstrual cycle
The purpose of this case report is to describe the chiropractic management of a patient who had postoperative reconstructive surgery for an anterior cruciate ligament (ACL) tear.
A 25-year-old man experienced a rupture of his left ACL, as well as a bucket-handle tear of the medial meniscus and full-thickness tear within the posterior horn of the lateral meniscus, following direct-contact trauma while playing basketball.
Intervention and Outcome
Postoperative care included a 12-week functional chiropractic rehabilitation program along with Active Release Technique, Graston Technique, and Kinesio Taping. Following treatment, the patient recorded a 0/10 on the Numeric Pain Scale, recorded improvement on the Patient Specific Functional and Pain Scales, returned to play with no complications, and had complete restoration of range of motion and lower extremity muscle strength. At 1-year follow-up, the patient reported no pain and was fully functional.
A multimodal approach to the treatment of a postsurgical ACL repair was successful in restoring functional ability, as well as complete subjective pain relief. Chiropractic care may be a beneficial addition to the care of postoperative patients.
Anterior cruciate ligament; Rehabilitation; Athletic injuries; Chiropractic postoperative care
The purpose of this report is to present the case of a 10-year-old football player with bilateral plantar fasciitis who improved with a multimodal conservative approach using chiropractic treatment.
The patient presented with bilateral plantar heel pain at the origin of the plantar fascia with a duration of 3 weeks.
Intervention and Outcome
Treatment was provided for 6 visits over a 6-week period. Chiropractic care consisted of manipulative therapy, soft tissue therapy, and home rehabilitation exercises. The soft tissue technique (Graston Technique) was performed to the origin of the plantar fascia and the triceps surae bilaterally. High-velocity, low-amplitude manipulation was applied to the restricted ankle mortise joint. After 6 treatments, the patient reported resolution of foot pain bilaterally and improvements in activities of daily livings. Three months later, the patient reported no further complications and the absence of pain.
This patient with bilateral plantar fasciitis improved after a course of a multimodal treatment approach using chiropractic manipulation and soft tissue therapy in addition to exercise and stretching therapies.
Manipulation; Athletic injuries; Plantar fasciitis; Chiropractic; Rehabilitation
Reports of musculoskeletal injuries that some chiropractic students experienced while in the role of adjustor became increasingly evident and developed into the basis of this study. The main objective of this study was to survey a select student population and identify, by gender, the specific types of musculoskeletal injuries they experienced when learning adjustive techniques in the classroom, and performing them in the clinical setting.
A survey was developed to record musculoskeletal injuries that students reported to have sustained while practicing chiropractic adjustment set-ups and while delivering adjustments. The survey was modeled from similar instruments used in the university's clinic as well as those used in professional practice. Stratified sampling was used to obtain participants for the study. Data reported the anatomical areas of injury, adjustive technique utilized, the type of injury received, and the recovery time from sustained injuries. The survey also inquired as to the type and area of any past physical injuries as well as the mechanism(s) of injury.
Data obtained from the study identified injuries of the shoulder, wrist, elbow, neck, low back, and mid-back. The low back was the most common injury site reported by females, and the neck was the most common site reported by males. The reported wrist injuries in both genders were 1% male complaints and 17% female complaints. A total of 13% of female respondents reported shoulder injuries, whereas less than 1% of male respondents indicated similar complaints.
The data collected from the project indicated that obtaining further information on the subject would be worthwhile, and could provide an integral step toward developing methods of behavior modification in an attempt to reduce and/or prevent the incidence of musculoskeletal injuries.
To describe a case regarding a woman with 2-level cervical disk herniation with radicular symptoms conservatively treated with chiropractic care including high-velocity, low-amplitude (HVLA) manipulation with complete resolution of her symptoms.
A 40-year-old woman developed right finger paresthesia and neck pain. Results of electrodiagnostics were normal, but clinical examination revealed subtle findings of cervical radiculopathy. A subsequent magnetic resonance imaging revealed a large right posterolateral disk protrusion and spur impinging on the right hemicord with moderate to severe central canal and right neuroforaminal stenosis at C5-6 and C6-7. She was treated with HVLA manipulation to the cervical spine, as well as soft tissue techniques, traction, nonsteroidal anti-inflammatory drugs, and exercise.
Intervention and Outcome
Her clinical findings and symptoms resolved within 90 days of initiating care and did not return in 1 year. There were no untoward effects, including transient ones.
This case describes the clinical presentation and course of a patient with multilevel large herniated disks and associated radiculopathy who was treated with HVLA manipulation and other conservative approaches and appeared to have good outcomes.
Radiculopathy; Manipulation, Chiropractic; Cervical spine; Intervertebral disk displacement; Neck pain
This controlled study was designed to explore the effectiveness of foot orthotics in solving problems of the feet and other parts of the lower extremities and to reduce low back pain.
Thirty-two subjects (24 males) were recruited and randomly assigned into 3 study groups. There were 10 subjects in the chiropractic care plus orthotics group, 14 subjects in the orthotics group, and 8 in the control group. All subjects filled out a patient information sheet and pre-screening foot pain questionnaire. Foot orthotics information was collected and the data was sent to Foot Level-ers, Inc. for orthotic fabrication. Chiropractic treatment was performed using Activator Technique. In-home exercise was prescribed to subjects receiving orthotics and chiropractic care.
The control group did not experience much change during the testing period. The orthotics group showed improvement in symptoms (P = 0.053), activities of daily living (P = 0.058), sport and recreation (P = 0.186) and quality of life (P = 0.085). While trends were apparent, the improvements did not reach statistically significant levels. In contrast, there was no trend with pain (P = 0.492). The orthotics plus chiropractic group showed improvement in the four conditions over the study period. Greater improvement was seen in quality of life (P < 0.05), symptoms (P < 0.05) and activities of daily living (P < 0.05), which were statistically significant. Improvement was also seen in sports and recreation but it did not reach statistical significant level (P = 0.097).
This study showed that a combination of chiropractic care and orthotics improved symptoms, activities of daily living, sport and recreation and quality of life in workers whose job requires them to stand at least 6 hours daily.
Chiropractic; Orthotic Devices
This report presents a spinal adjustment approach to treat elderly patients with urinary incontinence.
This retrospective case series reports the clinical observation of 13 patients with urinary incontinence. They were treated for 1–8 weeks with Pro-Adjuster technique without any other additional drug and physical therapy treatment. The primary outcome measure for this analysis was the frequency of nocturia reported by the patients during each office visit to the chiropractor. Bladder control was reported by the patients as frequency of nocturia or the urgency of urination or instances of leakage, and the number of pad changes per day or a return of the sense of urinary urge.
A total of 13 patients' data (6 female, mean ages 65.7 ± 12.9 years) were included in the study. After 1–8 weeks of chiropractic adjustments, the urinary frequency at night was significantly reduced from 3.8 to 1.2 time a night (P < 0.001). Three patients improved bladder control with only 2 adjustments.
The Pro-adjuster treatment program seemed to reduce nocturia in patients with urinary incontinence.
Chiropractic; Urinary Incontinence
To discusses management of cervicogenic headache by chiropractic manipulation and an active rehabilitation program.
A 28-year-old female had headaches of approximately a 10-year duration that were located on the right occipital-cervical region with radiation into the right paraspinal musculature of the cervical spine. Prior allopathic intervention included pharmaceutical approaches without resolution of symptoms. The area involved demonstrated marked point tenderness to static/motion palpation techniques. Manual resisted muscle testing of the sub-occpitals, upper trapezious, levator scapulae and the rhomboids decreased her pain, while testing of the anterior scalenes and sternocleidomastoids muscles created an increase in her pain. Seated cervical spine range of motion was diminished in all ranges and was limited by an increase in her pain of the right sub-occipital joint. The remainder of the examination was unremarkable.
Intervention and Outcome
Treatment plan and intervention included patient education in posture and an in-office treatment program progressing to home therapy was reviewed with the patient. She noticed an increase in signs and symptoms after her first 3 visits followed by a decrease in her primary signs and symptoms during visits 3–5. An in-office active rehabilitation program was included with a continued positive response. She was released to home therapy and supportive chiropractic manipulation with continued positive response.
Management of cervicogenic headaches with chiropractic manipulation and rehabilitation is discussed. A literature review is included. Past trauma with altered postural biomechanics appeared to be the cause in this particular case. Management strategies including education of proper biomechanics, rehabilitation and chiropractic manipulation were effective in this case.
Headache; Chiropractic Manipulation; Rehabilitation
This case report describes the effect of exercise-based chiropractic treatment on chronic and intractable low back pain complicated by lumbar disk extrusion.
A 47-year–old male firefighter experienced chronic, unresponsive low back pain. Pre- and posttreatment outcome analysis was performed on numeric (0-10) pain scale, functional rating index, and the low back pain Oswestry data. Secondary outcome assessments included a 1-rep maximum leg press, balancing times, push-ups and sit-ups the patient performed in 60 seconds, and radiographic analysis.
Intervention and Outcome
The patient was treated with Pettibon manipulative and rehabilitative techniques. At 4 weeks, spinal decompression therapy was incorporated. After 12 weeks of treatment, the patient's self-reported numeric pain scale had reduced from 6 to 1. There was also overall improvement in muscular strength, balance times, self-rated functional status, low back Oswestry scores, and lumbar lordosis using pre- and posttreatment radiographic information.
Comprehensive, exercise-based chiropractic management may contribute to an improvement of physical fitness and to restoration of function, and may be a protective factor for low back injury. This case suggests promising interventions with otherwise intractable low back pain using a multimodal chiropractic approach that includes isometric strengthening, neuromuscular reeducation, and lumbar spinal decompression therapy.
Occupational health; Intervertebral disk displacement; Chiropractic; Rehabilitation; Lordosis
There is a need to further our understanding of the neurophysiological effects of chiropractic spinal manipulation on brain activity as it pertains to both musculoskeletal and non-musculoskeletal complaints. This paper aims to provide a basic overview of the most commonly utilised techniques in the neurosciences for functional imaging the brain (positron emission tomography, single-photon emission computerised tomography, functional magnetic resonance imaging, electroencephalography, and magnetoencephalography), and discuss their applicability in future chiropractic research. Functional neuroimaging modalities are used in a wide range of different research and clinical settings, and are powerful tools in the investigation of neuronal activity in the human brain. There are many potential applications for functional neuroimaging in future chiropractic research, but there are some feasibility issues, mainly pertaining to access and funding. We strongly encourage the use of functional neuroimaging in future investigations of the effects of chiropractic spinal manipulation on brain function.
imaging; neuroimaging; brain; chiropractic
This study explores the extent to which consumers seek wellness care when choosing chiropractors whose practice methods are known to include periodic evaluative and interventional methods to maintain wellness and prevent illness.
Using an international convenience sample of Sacro-Occipital Technique (SOT) practitioners, 1316 consecutive patients attending 27 different chiropractic clinics in the USA, Europe and Australia completed a one-page survey on intake to assess reason for seeking care. A forced choice response was obtained characterizing the patient’s reason for seeking chiropractic care.
More than 40% of chiropractic patient visits were initiated for the purposes of health enhancement and/or disease prevention.
Although prudence dictates great caution when generalizing from this study, if confirmed by subsequent research among other similar cohorts, the present results may lend support to continued arguments of consumer demand for a more comprehensive paradigm of chiropractic care, beyond routine musculoskeletal complaints, that conceptualizes the systemic, nonspecific effects of the chiropractic encounter in much broader terms.
chiropractic; wellness; care
The purpose of this study was to compare the characteristics of injuries sustained by chiropractic students during their undergraduate training at different chiropractic colleges. Teaching instructors from English-speaking chiropractic colleges in the United States, Europe, Africa and Australia/New Zealand were electronically requested to administer a retrospective study that sought to characterize injuries students experienced during their technique labs. Four colleges responded to the investigators’ request, returning a total of 405 questionnaires. Colleges were only identified by a letter and country/continent of origin. The number of responses from these four colleges was: College A (Africa) n=67; College B (United States) n=81; College C (Europe) n=143) and; College D (Australia/New Zealand) n=110. The percentage of students reportedly injured at each college was: College A (7%); College B (53%); College C (18%) and; College D (22%). These numbers were compared to previously gathered data from CMCC that reported a rate of student injury of 56% (n=292). There were no statistically significant differences between injured and non-injured groups of students with respect to age, body weight, height or sex. Additional gathered data that further characterizes these injuries among students from these four chiropractic colleges is currently under review.
chiropractic; student; injuries; technique
Shoulder pain and dysfunction is a chief complaint commonly presenting to a chiropractor's office. The purpose of this article is to review the most common etiologies of shoulder pain, focusing on those conditions of a myofascial origin. In addition to a review of the literature, the author draws upon his own clinical experience to describe a method to diagnose and manage, patients with shoulder pain of myofascial origin using ischemic compression techniques. This hands-on therapeutic approach conveys several benefits including: positive therapeutic outcomes; a favorable safety profile and; it is minimally strenuous on the doctor and well tolerated by the patient.
shoulder pain; dysfunction; myofascial pain syndromes; ischemic compression; chiropractic
Plastination is a unique method for the preservation of biological material for teaching and research. The plastinated specimens are dry, odorless, non-toxic and durable. They can be manipulated by teachers and students without protective equipment like gloves.
Invented in 1978 by Doctor Gunther von Hagens from the University of Heidelberg, this technique, that involves the replacement of water by a curable polymer, has spread rapidly all around the world and is actually used in over 250 universities and colleges. To our knowledge, the Université du Québec à Trois-Rivières, is the first institution to use plastinated specimens for teaching anatomy, neuroanatomy, pathology and radiology to students in chiropractic.
This paper describes the various steps of the method (fixation, dehydration, impregnation and curing) and presents some examples of the utilization of plastinated specimens.
plastination; anatomy; pathology; teaching; research
Radiation safety and protection is a concern of all users of radiodiagnostic equipment. A retrospective dosimetry study of current technical factors used in full spine and sectional radiography at a chiropractic test facility were compared to established entrance skin exposure limits and averages. The chiropractic filtration and longer source-image receptor distances result in lower patient exposure when compared with sectional views of the same anatomic area. Both techniques studied represented a remarkable reduction in comparison to Ontario averages and Federal limits.
spinal radiography; full spine; entrance skin exposure; variable filtration; source-image distance