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Title: Relative biological effectiveness of alpha-particle emitters in vivo at low doses

Journal Article · · Radiation Research; (United States)
DOI:https://doi.org/10.2307/3578710· OSTI ID:6551410
; ; ;  [1]
  1. Univ. of Medicine and Dentistry of New Jersey, Newark, NJ (United States)

The therapeutic potential of radionuclides that emit [alpha] particles, as well as their associated health hazards, have attracted considerable attention. The [sup 224]Ra daughters [sup 212]Pb and [sup 212]Bi, by virtue of their radiation properties which involve emission of [alpha] and [beta] particles in their decay to stable [sup 208]Pb, have been proposed as candidates for radioimmunotherapy. Using mouse testes as the experimental model and testicular spermhead survival as the biological end point, the present work examines the radiotoxicity of [sup 212]Pb and its daughters. When [sup 212]Pb, in equilibrium with its daughters [sup 212]Bi, [sup 212]Po and [sup 208]Tl, was administered directly into the testis, the dose required to achieve 37% survival (D[sub 37]) was 0.143 [+-] 0.014 Gy and the corresponding RBE of the mixed radiation field was 4.7 when compared to the D[sub 37] for acute external 120 kVp X rays. This datum, in conjunction with our earlier results for [sup 210]Po, was used to obtain an RBE-LET relationship for [alpha] particles emitted by tissue-incorporated radionuclides: RBE[sub [alpha]] = 4.8 - 6.1 x 10[sup [minus]2] LET + 1.0 x 10[sup [minus]3] LET[sup 2]. Similarly, the dependence of RBE on [alpha]-particle energy E[sub [alpha]] was given by RBE[sub [alpha]] = 22 E[sub [alpha]][sup [minus]0.73]. These relationships, based on in vivo experimental data, may be valuable in predicting biological effects of [alpha]-particle emitters. 46 refs., 6 figs.

OSTI ID:
6551410
Journal Information:
Radiation Research; (United States), Vol. 137:3; ISSN 0033-7587
Country of Publication:
United States
Language:
English