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Confirmation of target localization and dosimetry for three‐dimensional treatment planning by magnetic resonance scanning of a ferrous sulfate gel head phantom
Author(s) -
Chan Maria Fan
Publication year - 1997
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 - 10.1118/1.598083
Subject(s) - imaging phantom , nuclear medicine , dosimetry , calibration , materials science , radiation treatment planning , absorbed dose , radiation therapy , physics , medicine , radiology , quantum mechanics
A detailed model of a FeMRI gel head phantom has been developed to verify the 3D radiation dose mapping of conformal therapy treatment planning. The phantom consists of a human skull filled with a solution that is 1 mM in ferrous sulfate, 1 mM in sodium chloride, and 0.1 N in sulfuric acid, gelled with 7.5% by weight gelatin. The phantom was irradiated and the absorbed dose from multiple non‐coplanar fields was measured using the MRI dose‐dependent variation of ferric sulfate. These studies were carried out using a 1.5 T MR imager and detailed analysis was performed on a UNIX workstation. The phantom and the calibration vials were scanned simultaneously using a multiple‐scan inversion recovery sequence. The values of T 1were evaluated on a pixel‐by‐pixel basis for entire volume through the use of custom‐built software on the 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.