Confirmation of target localization and dosimetry for 3D conformal radiotherapy treatment planning by MR imaging of a ferrous sulfate gel head phantom.
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 T1 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.
Chan
M F
MF
Department of Radiation Therapy, Medical College of Ohio, Toledo 43699, USA.
Ayyangar
K M
KM
D055592:Biophysical Phenomena; D001703:Biophysics; D005296:Ferrous Compounds; D005782:Gels; D006257:Head; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods* / Q000706:statistics & numerical data; D019047:Phantoms, Imaging; D011874:Radiometry / Q000379:methods* / Q000706:statistics & numerical data; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods* / Q000706:statistics & numerical data; D011882:Radiotherapy, High-Energy / Q000379:methods / Q000706:statistics & numerical data
D005296:Ferrous Compounds; D005782:Gels; C020748:ferrous sulfate