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oai:null:10339/372992026-09-02T15:04:22Zcom_10339_14934col_10339_38132

Ding, Xuanfeng 2012-06-12T08:36:03Z 2012-12-12T09:30:07Z 2012 https://wakespace.lib.wfu.edu/handle/10339/37299 Small megavoltage photon radiation fields (< 3cm diameter) are used in advanced radiation therapy techniques, such as intensity modulated radiotherapy, and stereotactic radiosurgery, as well as for cellular and preclinical radiobiology studies (very small fields, <1 mm diameter). Radiation dose characteristics for these small fields are difficult to determine in multiple dimensions because of steep dose gradients (30-40% per mm) and conditions of electronic disequilibrium. Conventional radiation dosimetry techniques have limitations for small fields because detector size may be large compared to radiation field size and/or dose acquisition may be restricted to one or two dimensions. Polymer gel dosimetryer, is a three-dimensional (3D) dosimeter based on radiation-induced polymerization of tissue equivalent gelatin. Polymer gel dosimeters can be read using magnetic resonance imaging (MRI), which detects changes in relaxivity due to gel polymerization. Spatial resolution for dose readout is limited to 0.25-0.5mm pixel size because of available the magnetic field strengths (1.5T and 3T) and the stability of polymer gelatin at room temperature. en Wake Forest University Gamma Knife Gel dosimetry MRI Radiation therapy Small field T2 map HIGH FIELD MAGNETIC RESONANCE IMAGING-BASED GEL DOSIMETRY FOR SMALL RADIATION FIELDS Dissertation Bourland, Daniel J. Hampton, Carnell J. Williams, Richard Guthold, Martin Carroll, David L. Physics 2012-12-12 open.access