Item Details

title

HIGH FIELD MAGNETIC RESONANCE IMAGING-BASED GEL DOSIMETRY FOR SMALL RADIATION FIELDS

author

Ding, Xuanfeng

abstract

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.

subject

Gamma Knife

Gel dosimetry

MRI

Radiation therapy

Small field

T2 map

contributor

Bourland, Daniel J. (committee chair)

Hampton, Carnell J. (committee member)

Williams, Richard (committee member)

Guthold, Martin (committee member)

Carroll, David L. (committee member)

date

2012-06-12T08:36:03Z (accessioned)

2012-12-12T09:30:07Z (available)

2012 (issued)

degree

Physics (discipline)

embargo

2012-12-12 (terms)

identifier

http://hdl.handle.net/10339/37299 (uri)

language

en (iso)

publisher

Wake Forest University

type

Dissertation