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Response of an implantable MOSFET dosimeter to Ir 192 HDR radiation
Author(s) -
Fagerstrom Jessica M.,
Micka John A.,
DeWerd Larry A.
Publication year - 2008
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 - 10.1118/1.3013574
Subject(s) - dosimeter , dosimetry , medical physics , mosfet , radiation , medical imaging , radiation exposure , materials science , nuclear medicine , medicine , optics , physics , electrical engineering , engineering , radiology , voltage , transistor
New in vivo dosimetry methods would be useful for clinical HDR brachytherapy. An implantable MOSFET Dose Verification System ® designed by Sicel Technologies, Inc. was examined for use with Ir192 HDR applications. This investigation demonstrated that varying the dose rate from 22 to 84 cGy ∕ min did not change detector response. The detectors exhibited a higher sensitivity to Ir192 energies than Co60 energies. A nonlinear accumulated dose effect was characterized by three third‐order polynomials fit to data from detectors placed at three different distances from the source. The detectors were found to have minimal rotational angular dependence. A strong longitudinal angular dependence was found when the detector's copper coil and electronics assembly were aligned between the MOSFETs and incident radiation. This orientation showed a 16% decrease in response relative to other orientations tested.