Premium
Radiation therapy dosimetry using magnetic resonance imaging of polymer gels
Author(s) -
Maryanski M. J.,
Ibbott G. S.,
Eastman P.,
Schulz R. J.,
Gore J. C.
Publication year - 1996
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 - 10.1118/1.597717
Subject(s) - dosimetry , brachytherapy , materials science , magnetic resonance imaging , radiation treatment planning , radiosurgery , medical imaging , radiation therapy , biomedical engineering , relaxation (psychology) , polymer , nuclear medicine , nuclear magnetic resonance , medical physics , physics , radiology , medicine , composite material
Further progress in the development of polymer gel dosimetry using MRI is reported, together with examples of its application to verify treatment plans for stereotactic radiosurgery and high dose rate brachytherapy. The dose distribution image produced in the tissue‐equivalent gel by radiation‐induced polymerization, and encoded in the spatial distribution of the NMR transverse relaxation rates ( R 2 ) of the water protons in the gel, is permanent. Maps of R 2 are constructed from magnetic resonance imaging data and serve as a template for dose maps, which can be used to verify complex dose distributions from external sources or brachytherapy applicators. The integrating, three‐dimensional, tissue‐equivalent characteristics of polymer gels make it possible to obtain dose distributions not readily measured by conventional methods. An improved gel formulation (BANG‐2) has a linear dose response that is independent of energy and dose rate for the situations studied to date. There is excellent agreement between the dose distributions predicted using treatment planning calculations and those measured using the gel method, and the clinical practical utility of MRI‐based polymer gel dosimetry is thereby demonstrated.