The Dilemma of Lung Dosimetry

Abstract

A legitimate criticism of health physics arises from the derivation of quite complex relationships for the permissible deposition of radionuclides in the body, in the absence of valid experience in man. I t has to be accepted that inhalation of substantial amounts of radon and daughter products has a finite probability of causing cancer in the bronchial epithelium. Establishment of a quantitative dose-effect relationship has a formidable array of impediments. The radioactive nuclides in mine air comprise a short-lived chain existing in physical forms from free ions through small nuclei to large dust particles. Intake and primary retention of these media has to be calculated from modcls. Subsequent translocation up the bronchial tree is a significant factor in exposure. If the nucleus of a basal cell of bronchial epithelium is assumed to be the biological target, the penetration of alpha particles to it can be modeled in various degrees of sophistication. This leads to a numerical relationship between nature and concentration of the ambient radioactivity and the relevant tissue dose or dose-rate. The quoted number may be high or low by a factor of about three. This is essentially a permissible dose type of calculation.The feasibility of programs to progressively eliminate these uncertainties will be discussed in trrms of refined study of mine exposees, relevance of data from radium or other human cases, and animal It is not a demonstrated dose-effect relationship. experimentation. THREE-PHASE APPROACH TO DOSIMETRY

Estimation et gestion du risque de cancer broncho-pulmonaire engendré par les produits de filiation du radon

“…Pour l'instant, elles montrent que le problème de la détermination du risque provoqué par l'exposition au radon dans les bâtiments est toujours ouvert. Jacobi, 1964 ;Parker, 1969). Elles ont créé les bases pour la construction des modèles publiés dans les années 80, que nous présentons au point 3.2.2.…”

LIPOSOMAL ENCAPSULATED Zn-DTPA FOR REMOVING INTRACELLULAR 169Yb*

“…28-32, Altshuler, Nelson and Kuschner 1964, Jacobi 1964, ICRP 1959, Parker 1969, EPA 1973, Barton, Moore and Rohwer 1973. A value of 10, recommended by ICRP-2 (1959), is used in this paper.…”

“…28-32, FRC 1967, Altshuler, Nelson and Kuschner 1964, Jacobi 1964, UNSCEAR 1977, pp. 68-80, Harley 1973, Parker 1969, Nelson and Parker 1974, EPA 1973, Barton, Moore and Rohwer 1973, Black et al 1968, Auxier 1976, Harley and Pasternack 1972, Turner, Haloway and Loebl 1978, Jacobi 1973, depending on the assumptions for lung mass, free ion fraction, deposition fractions, and daughter equilibrium. Table 7 gives reported dose values for the WLM by some of these authors and a comparison with the method used in this paper.…”

Environmental Radiation and the Lung

“…Sanders in his review states that inhalation studies with animals show carcinoma, neoplasm, and tumor induction and notes that the Russian literature reports increased tumor incidence down to 4 nCi or a total radiation dose of 42 rad. He reports a 50% tumor incidence at 3000 rad.…”