Microdosimetry of targeted radionuclides Book Section
| Authors: | Roeske, J. C.; Humm, J. L. |
| Editors: | Zaidi, H.; Sgouros, G. |
| Article/Chapter Title: | Microdosimetry of targeted radionuclides |
| Abstract: | Microdosimetry is the study of the stochastic process of energy deposition from radiation within small volumes. Small in the context of microdosimetry typically refers to tissue equivalent volumes commensurate with the size of the biological targets of relevance. This has commonly meant spherical volumes of between 0.3 and 20 mm-the realm in which energy deposition can be experimentally measured using a proportional counter. Such chambers are constructed of tissue equivalent plastic and operated with a tissue equivalent gas. Since these devices, used for the purpose of measuring microdosimetric spectra, were developed by Rossi [1] they are frequently referred to as ‘Rossi chambers’. One of the greatest applications of the Rossi chambers is to characterize unknown mixed radiation beams found at reactor facilities. Since Rossi counters measure radiation deposits within the chamber event by event, accumulation of the magnitude of events using a multi-channel analyser results in a spectrum of the energy deposition. Because the magnitude and spectrum of energy deposition differs for radiations of different LET (linear energy transfer), microdosimetry has developed methods of curve stripping to separate the contribution to the absorbed dose from photons, electrons, neutrons (recoil protons) and heavy ions. This has been an important contribution to radiation protection, where the radiobiological effectiveness (RBE) of different radiations depends upon the LET of the radiation. In fact, microdosimetry goes further than measuring the LET of the radiation field. By measuring the stochastics of individual radiation interactions within small, cell-equivalent volumes, it serves as a methodology of determining the entire spectrum of radiation deposits and LETs experienced by a cell or The energy deposition spectra measured by Rossi counters are presented in two formats: specific energy z and lineal energy y. Specific energy is defined as z 1/4 "=m, where " is the magnitude of the energy deposit within a massm: It is the stochastic analogue of absorbed dose D. Lineal energy is defined as y 1/4 "=l, where l is the mean chord length of the simulated cavity. Lineal energy is the stochastic analogue of LET. © 2002 by Taylor & Francis Group, LLC. |
| Book Title: | Therapeutic Applications of Monte Carlo Calculations in Nuclear Medicine |
| ISBN: | 9781420033250 |
| Publisher: | CRC Press |
| Publication Place: | Boca Raton, FL |
| Date Published: | 2002-01-01 |
| Start Page: | 202 |
| End Page: | 227 |
| Language: | English |
| PROVIDER: | scopus |
| DOI/URL: | |
| Notes: | Book Chapter: 9 -- Source: Scopus |
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