Novel modification to leaded eyewear results in significant operator eye radiation dose reduction

Operator Intracranial Dose Protection During Fluoroscopic-Guided Interventions

PURPOSE

We utilized an anthropomorphic model made with a human skull to determine how different personal protective equipment influence operator intracranial radiation absorbed dose.

MATERIALS AND METHODS

A custom anthropomorphic phantom made with a human skull coated with polyurethane rubber, mimicking superficial tissues, and was mounted onto a plastic thorax. To simulate scatter, an acrylic plastic scatter phantom was placed onto the fluoroscopic table with a 1.5 mm lead apron on top. Two Radcal radiation detectors were utilized; one inside of the skull and a second outside. Fluoroscopic exposures were performed with and without radiation protective equipment in AP, 45-degree RAO, and 45-degree LAO projections.

RESULTS

The skull and soft tissues reduce intracranial radiation by 76% when compared to radiation outside the skull. LAO (308.95 μSv/min) and RAO projections (96.47μSv/min) result in significantly higher radiation exposure to the primary operator when compared to an AP projection (54 μSv/min). All tested radiation protection equipment demonstrated various reduction in intracranial radiation when compared to no protection. The hood (68% reduction in AP, 91% LAO, and 43% in RAO), full cover (53% reduction in AP, 76% in LAO, and 54% in RAO), and open top with ear coverage (43% reduction in AP, 77% reduction in LAO, and 22% in RAO) demonstrated the most reduction in intracranial radiation when compared to the control.

CONCLUSION

All tested equipment provided various degrees of additional intracranial protection. The skull and soft tissues attenuate a portion of intracranial radiation.

Evaluation of factors associated with the effectiveness of radiation protection glasses

The effects of lead equivalent and lens area of radiation-protective eyewear on lens exposure control were examined. The simulated patient underwent 10-min X-ray fluoroscopy, and the lens dose of the simulated surgeon wearing radiation protection glasses was measured using lens dosemeters attached to the corner of the eye and eyeball. In total, 10 types of radiation protection glasses were selected for measurement. Correlation analysis of the equivalent dose in the lens of the eye with lead equivalence and lens area was performed. The equivalent dose in the lens of the eye of the corner of the eye was negatively correlated with the area of the lens. The equivalent dose in the lens of the eye and the eyeball showed a strong negative correlation with lead equivalence. Lens dosemeters worn at the corner of the eye may overestimate the equivalent dose in the lens of the eye. Moreover, the reduction in exposure of the lens was significantly influenced by the lead equivalent.

A Prospective Cohort Study of Radiation Exposure to a Spine Surgeon's Exposed Body Parts During Utilization of Intraoperative Radiation-based Imaging

STUDY DESIGN

Prospective cohort study.

SUMMARY OF BACKGROUND DATA

C-arm fluoroscopy and O-arm navigation are vital tools in modern spine surgeries, but their repeated usage can endanger spine surgeons. Although a surgeon's chest and abdomen are protected by lead aprons, the eyes and extremities generally receive less protection.

OBJECTIVE

In this study, we compare differences in intraoperative radiation exposure across the protected and unprotected regions of a surgeon's body.

METHODS

Sixty-five consecutive spine surgeries were performed by a single spine-focused neurosurgeon over 9 months. Radiation exposure to the primary surgeon was measured through dosimeters worn over the lead apron, under the lead apron, on surgical loupes, and as a ring on the dominant hand. Differences were assessed with rigorous statistical testing and radiation exposure per surgical case was extrapolated.

RESULTS

During the study, the measured radiation exposure over the apron, 176 mrem, was significantly greater than that under the apron, 8 mrem (P = 0.0020), demonstrating a shielding protective effect. The surgeon's dominant hand was exposed to 329 mrem whereas the eyes were exposed to 152.5 mrem of radiation. Compared with the surgeon's protected abdominal area, the hands (P = 0.0002) and eyes (P = 0.0002) received significantly greater exposure. Calculated exposure per case was 2.8 mrem for the eyes and 5.1 mrem for the hands. It was determined that a spine-focused neurosurgeon operating 400 cases annually will incur a radiation exposure of 60,750 mrem to the hands and 33,900 mrem to the eyes over a 30-year career.

CONCLUSIONS

Our study found that spine surgeons encounter significantly more radiation exposure to the eyes and the extremities compared with protected body regions. Lifetime exposure exceeds the annual limits set by the International Commission on Radiologic Protection for the extremities (50,000 mrem/y) and the eyes (15,000 mrem/y), calling for increased awareness about the dangerous levels of radiation exposure that a spine surgeon incurs over one's career.

An investigation into potential improvements in the design of lead glasses for protecting the eyes of interventional cardiologists

The lens of the eye can be damaged by ionising radiation, so individuals whose eyes are exposed to radiation during their work may need to protect their eyes from exposure. Lead glasses are widely available, but there are questions about their efficiency in providing eye protection. In this study, Monte Carlo simulations are used to assess the efficiency of lead glasses in protecting the sensitive volume of the eye lens. Two designs currently available for interventional cardiologists are a wraparound (WA) style and ones with flat frontal lenses with side shielding. These designs were considered together with four modifications that would impact upon their efficiency: changing the lead equivalent thickness, adding lead to the frames, elongating the frontal lenses, and adding a closing shield to the bottom rim. For the eye closest to the source, standard models of lead glasses only decrease the radiation reaching the most sensitive region of the eye lens by 22% or less. Varying the lead thickness between 0.4 mm and 0.75 mm had little influence on the protection provided in the simulation of clinical use, neither did adding lead to the frames. Improved shielding was obtained by elongating the frontal lens, which could reduce radiation reaching the eye lens by up to 76%. Glasses with lenses that had a rim at the base, extending towards the face of the user, also provided better shielding than current models, decreasing the dose by up to 80%. In conclusion, elongating the frontal lens of lead glasses, especially of the WA design, could provide a three-fold increase in shielding efficiency and this is still valid for lenses with 0.4 mm lead equivalence.

Radiation Protection of the Eye Lens in Fluoroscopy-guided Interventional Procedures

The medical staff involved in fluoroscopy-guided procedures are at potential risks of radiation-induced cataract. Therefore, proper monitoring of the lens doses is critical, and radiation protection should be provided to the maximum extent that is reasonably achievable. The collar dosimeter is necessary to avoid underestimation of the lens dose, and the third dosimeter behind the protective eyewear would be helpful for those who are likely to exceed the dose limit. The reduction of the patient doses will correspondingly reduce the staff doses. Proper placement of the ceiling-mounted shields and minimization of the face-to-glass gap are the keys to effective shielding. The optimization of procedures and devices that help maintain a distance from the irradiated area and to prevent the looking-up posture will substantially reduce the lens dose.

Radiation safety for pain physicians: principles and recommendations

C-arm fluoroscopy is a useful tool for interventional pain management. However, with the increasing use of C-arm fluoroscopy, the risk of accumulated radiation exposure is a significant concern for pain physicians. Therefore, efforts are needed to reduce radiation exposure. There are three types of radiation exposure sources: (1) the primary X-ray beam, (2) scattered radiation, and (3) leakage from the X-ray tube. The major radiation exposure risk for most medical staff members is scattered radiation, the amount of which is affected by many factors. Pain physicians can reduce their radiation exposure by use of several effective methods, which utilize the following main principles: reducing the exposure time, increasing the distance from the radiation source, and radiation shielding. Some methods reduce not only the pain physician's but also the patient's radiation exposure. Taking images with collimation and minimal use of magnification are ways to reduce the intensity of the primary X-ray beam and the amount of scattered radiation. It is also important to carefully select the C-arm fluoroscopy mode, such as pulsed mode or low-dose mode, for ensuring the physician's and patient's radiation safety. Pain physicians should practice these principles and also be aware of the annual permissible radiation dose as well as checking their radiation exposure. This article aimed to review the literature on radiation safety in relation to C-arm fluoroscopy and provide recommendations to pain physicians during C-arm fluoroscopy-guided interventional pain management.

Disposable, Lightweight Shield Decreases Operator Eye and Brain Radiation Dose When Attached to Safety Eyewear During Fluoroscopically-Guided-Interventions

OBJECTIVE

Long-term radiation exposure from fluoroscopically-guided-interventions (FGIs) can cause cataracts and brain tumors in the operator. We have previously demonstrated that leaded eyewear does not decrease operator eye dose unless lead shielding is added to the lateral and inferior portions. Therefore, we developed a disposable, lightweight, lead-equivalent shield that can be attached to the operator's eyewear, conforming around the face and adhering to the surgical mask. This study evaluates the efficacy of our new prototype in lowering operator brain and eye dose when added to both leaded and non-leaded eyewear.

METHODS

The attenuating efficacy of leaded eyewear alone, leaded eyewear + prototype and non-leaded eyewear + prototype were compared to no eyewear protection in both a simulated setting and clinical practice. In the simulation, optically stimulated, luminescent nanoDot detectors (Landauer, Glenwood, II) were placed inside the ocular, temporal lobe, and midbrain spaces of a head phantom (ATOM model-701: CIRS, Norfolk, VA). The phantom was positioned to represent a primary operator performing right femoral access. Fluorography was performed on a plastic scatter phantom at 80kVp for an exposure of 3 Gy RAK. In the clinical setting, nanoDots were placed below the operator's eye both inside and outside the prototype during FGIs. Median and interquartile ranges were calculated for the dose at each nanoDot location for both the phantom and clinical study, with average dose reduction also reported.

RESULTS

Wearing standard leaded eyewear alone did not decrease operator ocular or brain dose. In the phantom experiment, the leaded glasses + prototype reduced dose to the lens, temporal lobe and midbrain by 83% (p<0.001), 78% (p<0.001), and 75% (p<0.001), respectively. The non-leaded glasses + prototype also reduced dose to the lens, temporal lobe and midbrain by 85% (p<0.001), 81% (p<0.001), and 71% (p<0.001). In the clinical setting, 15 FGIs were included, with median RAK of 98.4 mGy. Our prototype led to an average operator eye dose reduction of 89% (p<0.001).

CONCLUSIONS

Attaching our prototype to both leaded and non-leaded glasses significantly decreased eye and brain radiation dose to the operator. This face shield attachment provides meaningful radiation protection and should be considered as either a replacement or adjunct to routine eyewear.