Monitoring and Protection against Radiation Dose to Eyes of Operators Performing Neuroendovascular Procedures: A Nationwide Study in Japan

Abstract

Objective: To meet the new standard of the annual dose limit for the eye lens recommended by the International Commission on Radiation Protection, radiation doses of neuroendovascular procedures in Japanese institutions were investigated.Methods: Radiation doses to operators involved in 304 neuroendovascular procedures at 30 Japanese institutions were prospectively surveyed. The institutions recruited at an annual meeting of the Japanese Society for Neuroendovascular Therapy participated voluntarily. A maximum of 10 wireless dosimeters were attached to the radiation protection (RP) goggles, the ceiling-mounted RP shielding screen, and the operators' forehead and neck over the protective clothing.Doses recorded inside the goggles were defined as eye lens doses for operators who wore RP goggles, while doses to the forehead were defined as eye lens doses for those who did not. The shielding effect rates of the protection devices were calculated, and statistical analysis was performed for the comparison of radiation doses.Results: From 296 analyzed cases, mean eye lens radiation doses per procedure were 0.088 mGy for the left eye and 0.041 mGy for the right eye. For the left eye, that dose without RP equipment was 0.176 mGy and that with RP goggles plus an RP shielding screen was 0.034 mGy. Four parameters, including left eye dose, air kerma at the patient entrance reference point, fluoroscopic time, and the total number of frames, were assessed for five types of neurovascular procedures. Of them, transarterial embolization for dural arteriovenous fistula was associated with the highest eye lens dose at 0.138 mGy. The shielding effect rates of protection goggles were 60% for the left and 55% for the right RP goggle. The mean doses to the inner and outer surfaces of the RP shielding screen were 0.831 mGy and 0.040 mGy, respectively, amounting to a shielding effect rate of 95%. Conclusion:To meet the new standard, both RP goggles and RP shielding screens are strongly recommended to be used effectively. Without proper use of radiological protection devices, the number of neuroendovascular procedures that one operator performs per year will be limited under the new guideline.

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

“…The mean operator lens dose per case ranged from 0.019 to 0.800 (median = 0.113) mSv in a literature review of the radiation doses during various procedures, including percutaneous nephrolithotomy, vertebroplasty, orthopedic extremity nailing for the treatment of fractures, biliary tract procedures, transjugular intrahepatic portosystemic shunt creation (TIPS), head/neck endovascular therapeutic procedures, and endoscopic retrograde cholangiopancreatography (ERCP) [9]. A dose survey in Japan for neurovascular interventions revealed that the mean dose of the left eye lens per procedure was 0.088 mGy, or 0.176 mGy if ceiling-mounted shields or lead glasses were not used [10]. In fact, more than 2,000 healthcare workers in Japan, mostly physicians, have had their equivalent dose of the lens exceed 20 mSv per year in 2020 [11,12].…”

Evaluation of Peak Skin Doses and Lens Doses during Interventional Neuroradiology Using a Direct Measurement System

“…Moreover, it is essential to evaluate the lens dose for each patient during INR, as it is one of the most radiosensitive tissues in the human body. [13][14][15][16][17] Direct measurement of the patient's skin dose with thermoluminescent dosimeters or radiophotoluminescent glass dosimeters (RPLDs) was performed during diagnostic angiography and INR. 9,15,[18][19][20][21][22][23] However, these studies did not estimate the peak skin dose (PSD) or the right and left lens doses in detail.…”

“…Moreover, it is essential to evaluate the lens dose for each patient during INR, as it is one of the most radiosensitive tissues in the human body. 13 – 17) …”