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Three dimensional radiation dosimetry in lung‐equivalent regions by use of a radiation sensitive gel foam: Proof of principle
Author(s) -
De Deene Yves,
Vergote Koen,
Claeys Carolien,
De Wagter Carlos
Publication year - 2006
Publication title -
medical physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.473
H-Index - 180
eISSN - 2473-4209
pISSN - 0094-2405
DOI - 10.1118/1.2208939
Subject(s) - dosimeter , materials science , dosimetry , magnetization , magnetization transfer , relaxation (psychology) , proton , nuclear magnetic resonance , analytical chemistry (journal) , chemistry , magnetic field , nuclear medicine , magnetic resonance imaging , chromatography , nuclear physics , physics , radiology , medicine , psychology , social psychology , quantum mechanics
A polymer hydrogel foam is proposed as a potential three dimensional experimental dosimeter for radiation treatment verification in low‐density tissue such as the lung. A gel foam is created by beating a radiation sensitive polymer gel mixture in an anoxic atmosphere. The mass density of the gel foam is in the order of 0.25 – 0.35 kg ∕ dm 3 . Both nuclear magnetic resonance (NMR) spin‐spin relaxation rate ( R 2 ) and magnetization transfer ratio (MTR) have been used to map the dose distribution from the gel dosimeter. It is found that MTR has significant advantages compared to R 2 for mapping the dose distribution in the polymer gel foam dosimeters. The magnetization transfer ratio is found to be less dependent on the density and microstructure of the gel foam dosimeter while spin‐spin relaxation dispersion has been observed making the spin‐spin relaxation rate dependent on the interecho time interval. Optical microscopy reveals a microstructure that shows great similarity with human lung tissue. It is also shown how NMR hydrogen proton density measurements can be used to map the density distributions in gel dosimeters.