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Confirmation of target localization and dosimetry for 3D conformal radiotherapy treatment planning by MR imaging of a ferrous sulfate gel head phantom
Author(s) -
Chan Maria F.,
Ayyangar Komanduri M.
Publication year - 1995
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 - 10.1118/1.597612
Subject(s) - imaging phantom , radiation treatment planning , nuclear medicine , dosimetry , calibration , materials science , radiation therapy , optics , medicine , physics , radiology , quantum mechanics
A detailed methodology has been developed to verify the three‐dimensional (3D) radiation dose mapping of conformal therapy radiation treatment planning by FeMRI dosimetry. A phantom that consisted of a human skull filled with a 1‐mM solution of ferrous sulfate and 0.1‐N sulfuric acid gelled with 7.5% (by weight) gelatin was employed. With a spherical target volume in the head phantom, five noncoplanar conformal beams were designed through the use of a 3D treatment planning system developed in‐house. The phantom was irradiated with a 6‐MV linear accelerator to a total dose of 25 Gy delivered to the periphery of the target volume. The phantom and a set of calibration vials were scanned simultaneously in a GE 1.5T MR imager with six different multiscan inversion‐recovery pulse sequences. The values of T 1 were evaluated on a pixel‐by‐pixel basis through the use of custom‐built software on a UNIX workstation and were converted to dose using calibration data. Comparisons of dose distributions between those measured by FeMRI and those calculated by 3D treatment planning show good agreement.