Regardless of manufacturer, the image intensifiers of almost all C-arm fluoroscopy units are long and cylindrical in shape, and they are much larger and longer than the beam generator. Therefore, when surgeons conduct surgeries, they often feel that if the image intensifier is positioned over the patient and the bed, their work space would become narrow. Thus, they intentionally or unconsciously position the smaller beam generator above the bed and closer to themselves during operation. Based on the results of this study, if the beam generator is positioned close to the surgeon's head, the surgeon will receive approximately 3-10 times more radiation than when it is farther away. This shows that even if the workspace is narrow and thus inconvenient to the surgeon, the beam generator should be positioned below the bed during operation.
Ionizing radiation does occur naturally and is also generated by various kinds of machines, but the amount received by human bodies from these sources is relatively small. However, the radiation generated by the C-arm fluoroscopy is very strong and the potential dose is very high. Adverse effects of ionizing radiation on human bodies include skin diseases, thyroid cancer, brain tumors, cataracts, etc3)
. Such effects are largely divided into two types. The "early effects" such as acute radiation lethality, local tissue damage on skin or gonads, hematologic effects, and cytogenetic effects, and the "late effects" including radiation-induced malignancies such as leukemia and other forms of cancer, deleterious local tissue effects, chromosomal toxicity, and/or cataract formation10)
To avoid these harmful radiation effects, many surgeons should make every effort to maximally reduce radiation exposure from the C-arm fluoroscopy. The first effective method is to wear shielding devices or protectors. In addition, results suggest that wearing lead glasses and gloves is essential for blocking radiation.
Secondly, the tube in the C-arm fluoroscopy where X-ray beams are generated should be positioned on the opposite side of the operator and below the bed. However, it should be also kept in mind that this position of the beams will increase the irradiation received by an assistant positioned on the opposite side of the table 3 to 10 times. Therefore, it makes sense to have the assistant and the scrub nurse stay at the same side with the operator.
The third method is to operate the C-arm fluoroscopy in such a way as to minimize exposure. One can operate the C-arm fluoroscopy either in continuous or pulsed modes. Using the pulsed mode rather than the continuous whenever possible can reduce radiation doses6,8,11)
The forth, exposure to the radiation scattered from patients and surroundings can add to direct radiation exposure. Wearing lead gloves and using the shielding panels or screens to prevent these scattered beams when conducting cerebral or cardiac intervention therapy can be good methods for reducing exposure, but these have many technical difficulties2,4,12,13)
A fifth approach involves using spinal navigation systems. According to reports by several researchers, navigation-guided kyphoplasty can reduce the amount of irradiation during operations by almost 30%. However, several problems must be overcome, such as the high cost of the equipment and increased preparation for operations using the safer equipment5,7)
Sixth, it is important to wear personal devices to measure the amount of irradiation in order to monitor the dose to the operator. Therefore, the operator should wear a dosimetry badge at all times and periodically check the cumulative radiation exposure.
Seventh, two fluoroscopes may be used for surgery. Mroz reported quantified fluoroscopic radiation exposure to the surgeon and patient during KP. They used two fluoroscopes for their KPs. With use of two fluoroscopes, unnecessary time which were spent in repetitive viewing the AP and lateral images will be saved thereby reducing the exposure10)
Finally, education of all spine surgeons and related workers on radiation physics is the most important.
Although radiation exposure to the torso and head of the operator is more important than other areas, the area that receives the highest doses is the hands14)
. Skin injury such as skin erythema occurs when the local skin exposure dose exceeds 2000 mGy. Wagner and Archer reported that the entrance skin dose (ESD) rate for fluoroscopy was typically 30 mGy/min, and longer procedures with more exposure could increase the risk of skin erythema for the patient20)
. This fact also applies to the hands of the operator who is in closest contact with the patient9)
. Direct monitoring of patient or operator skin dose during procedures is highly desirable, but current methods still have serious limitations21)
The International Commission on Radiologic Protection (ICRP) and the National Council on Radiation Protection and Measurements (NCRP) require that individuals exposed to greater than 10% of the permissible annual occupational exposure limit be regularly monitored ()13,16-19)
The surgeons are usually protected by the lead apron and thyroid shield, so the report on each protected dosimeter was less than the minimum reportable dose, as expected. However, we have to consider the unprotected areas, such as the eyes and the hands. A report by the National Council on Radiation Protection and Measurements in 1993 suggested annual occupational exposure limits of 50 mSv/year for the whole body, 150 mSv/year for the lens of eye, and 500 mSv/year for the extremities. In our study, if a surgeon conducts KP operations using the method of group D, the amount of radiation received by the torso of the surgeon will reach the annual limit after approximately 155 cases1)