Guidance on radiation dose limits for the lens of the eye: overview of the recommendations in NCRP Commentary No. 26

Abstract

Radiation-induced damage to the lens of the eye can include the loss of clarity resulting in opacification or clouding several years after exposure. The impact is highly dependent on the type of radiation, how the exposure of the lens was delivered, the genetic susceptibilities of the individual exposed, and the location of the opacity relative to the visual axis of the individual. The preponderance of epidemiological evidence suggests that lens damage could occur at lower doses than previously considered and the NCRP has determined that it is prudent to reduce the recommended annual lens of the eye occupational dose limit from an equivalent dose of 150 mSv to an absorbed dose of 50 mGy. Significant additional research is still needed in the following areas: comprehensive evaluation of the overall effects of ionizing radiation on the eye, dosimetry methodology and dose-sparing optimization techniques, additional high quality epidemiology studies, and a basic understanding of the mechanisms of cataract development.

Influences of operator head posture and protective eyewear on eye lens doses in interventional radiology: A Monte Carlo Study

“…In response to growing evidence, ICRP recently recommended to lower the equivalent dose limit to the eye lens for occupational exposure from 150 to 20 mSv/yr over five consecutive years, with no single year exceeding 50 mSv/yr . The National Council on Radiation Protection and Measurements (NCRP) also released new guidelines recommending that the annual absorbed dose limit to eye lens for occupational exposure be reduced to 50 mGy …”

“…1 The National Council on Radiation Protection and Measurements (NCRP) also released new guidelines recommending that the annual absorbed dose limit to eye lens for occupational exposure be reduced to 50 mGy. 7 According to United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR), among all medical professionals who are exposed to x rays, interventional radiologists involved in x-ray fluoroscopic procedures receive the greatest occupational radiation exposure due to scattered photons from the patient. 8 Many studies have been conducted to measure radiation exposure to radiologists' eye lenses in various interventional procedures.…”

NCRP Program Area Committee 1

“…In discussion, PAC 1 considered the recommended dose-limit changes particularly noting that while cataracts seem to be benign because surgery can easily repair the problem, for those doing close work, the surgery is often not optimal and sometimes surgery is not successful. Papers summarizing this work have recently been published (Dauer et al 2016, 2017). …”

Introduction to the Bill Morgan Memorial Special Issue on Biology, Epidemiology, and Implications for Radiation Protection

“…Responding to this ICRP recommendation, NCRP established SC 1-23 under PAC 1 so as to provide guidance on lens dose limits in the U.S. Lawrence T. Dauer (SC 1-23 Co-Chair and NCRP Board of Director) provides an outline of SC 1-23's report published as NCRP Commentary No. 26 (NCRP 2016;Dauer et al 2017). Pertinently, Nobuyuki Hamada (SC 1-23 Consultant, PAC 1 member and TG102 corresponding member) discusses dose rate dependence of the lenticular radiation response (Hamada 2017).…”