HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Figures Only Full Text Full Text (PDF) A correction has been published Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Hamacher, K. A. Articles by Sgouros, G. Search for Related Content PubMed PubMed Citation Articles by Hamacher, K. A. Articles by Sgouros, G.

Cellular Dose Conversion Factors for -Particle–Emitting Radionuclides of Interest in Radionuclide Therapy

Department of Medical Physics, Memorial Sloan-Kettering Cancer Center, New York, New York

-Particle–emitting radionuclides are of increasing interest in radionuclide therapy. The decay scheme of -emitting radionuclides typically includes a chain of unstable progeny. It is generally assumed that -particle emission by the parent radionuclide will break the chemical bond with its carrier molecule and that the resulting daughter atom will no longer be associated with the carrier molecule. If the daughter is very short lived, it will not have enough time to be carried any significant distance from the site of parent decay and a cellular, absorbed dose estimate must consider the energy deposited by the daughter as well as the parent. Depending on the site of parent decay and the expected removal rate of daughter atoms from this site, the contribution of emissions from longer-lived daughters may also be warranted. In this study, dose conversion factors (DCFs) for cellular dimensions that incorporate the fate of daughter radionuclides were derived for ²²⁵Ac, ²¹³Bi, ²¹¹At, and ²²³Ra, the -particle–emitting radionuclides of interest in radionuclide therapy. Methods: The dose contribution of daughter radionuclides at the site of parent decay was made dependent on a cutoff time parameter, which was used to estimate the fraction of daughter decays expected at the site of parent decay. Previously tabulated S values (cell-surface to nucleus and cell-surface to cell) for each daughter in the decay scheme were scaled by this fraction and a sum over all daughters was performed to yield a cutoff time–dependent set of corresponding DCF values for each radionuclide. Results: DCF values for the absorbed dose to the nuclear or cellular volume from cell-surface decays are presented as a function of the cutoff time for 4 different cellular and nuclear dimensions. Conclusion: In contrast to the cellular S values that account only for parent decay, the DCF values provided in this study make it possible to easily include the contribution of daughter decays in cellular -particle emitter dose calculations.

Key Words: -particles • dosimetry • S values • dose conversion factors • ²²⁵Ac • ²¹¹At • ²¹³Bi • ²²³Ra

This article has been cited by other articles:

				G. Akabani, S. J. Kennel, and M. R. Zalutsky Microdosimetric Analysis of {alpha}-Particle-Emitting Targeted Radiotherapeutics Using Histological Images J. Nucl. Med., May 1, 2003; 44(5): 792 - 805. [Abstract] [Full Text] [PDF]

				W. E. Bolch {alpha}-Particle Emitters in Radioimmunotherapy: New and Welcome Challenges to Medical Internal Dosimetry J. Nucl. Med., August 1, 2001; 42(8): 1222 - 1224. [Full Text] [PDF]