Recent reports on the effect of low doses of ionizing radiation and its dose–effect relationship

Abstract

Recently, the risk associated with low doses of ionizing radiation has gained new interest. Here, we analyze and discuss the major differences between two reports recently published on this issue; the report of the French Academy of Sciences and of the French Academy of Medicine published in March 2005, and the BEIR VII-Phase 2 Report of the American National Academy of Sciences published as a preliminary version in July 2005. The conclusion of the French Report is that the linear no-threshold relationship (LNT) may greatly overestimate the carcinogenic effect of low doses (<100 mSv) and even more that of very low doses (<10 mSv), such as those delivered during X-ray examinations. Conversely, the conclusion of the BEIR VII report is that LNT should be used for assessing the detrimental effects of these low and very low doses. The causes of these diverging conclusions should be carefully examined. They seem to be mostly associated with the interpretation of recent biological data. The point of view of the French Report is that these recent data are incompatible with the postulate on which LNT is implicitly based, namely the constancy of the carcinogenic effect per unit dose, irrespective of dose and dose rate.

Low dose radiation response curves, networks and pathways in human lymphoblastoid cells exposed from 1 to 10cGy of acute gamma radiation

“…The limitations of epidemiological extrapolations to low-dose exposures continue to fuel the scientific and public-policy debates on how to estimate health effects for low-dose exposures [5,7]. There is a major question as to whether low-dose tissue responses are linear as proposed by the LNT model, super-linear with higher relative risks at low doses, or sublinear/threshold with correspondingly lower risks at low doses.…”

“…This model predicts that even the smallest doses of ionizing radiation (IR) will increase the risk for tumors [6]. In contrast, the French Academy of Sciences [2,7] questioned the acceptance of the Linear no-threshold (LNT) model for low-doses in light of the mounting evidence for non-linearity in biochemical and cellular effects after low-dose exposures [2,3,[8][9][10]. Addressing this controversy is important because inappropriate estimates of low dose risks may lead to undesirable consequences, such as discouraging patients from undergoing useful medical examinations, limiting space flight, or requiring costly radioprotective measures.…”

Genes and environment: effects on the development of second malignancies in retinoblastoma survivors

“…It has long been established that exposure to even low doses (up to 3 Gy) of ionizing radiation (such as from x-rays or atomic bomb exposure) can have a carcinogenic effect, although the details of the dose-effect relationship are controversial [18,19].…”

Characterization of a novel scale maille contralateral breast shield: SMART Armor

“…Such dose outside the geometric boundaries of the treatment fields is known as peripheral dose. There are three main sources of peripheral dose: (a) leakage through the treatment collimation (x‐rays); (b) scattered radiation from the secondary collimators and beam modifiers such as the MLC, physical wedges (x‐rays and electrons); and (c) internal scatter originating in the patient (x‐rays) 7, 8. Butson et al.…”