title: Improved spatial resolution by MOSFET dosimetry of an x-ray microbeam.
abstract: Measurement of the lateral profile of the dose distribution across a narrow x-ray microbeam requires a dosimeter with a micron resolution. We investigated the use of a MOSFET dosimeter in an "edge-on" orientation with the gate insulating oxide layer parallel to the direction of the beam. We compared results using this technique to Gafchromic film measurements of a 200 micrometer wide planar x-ray microbeam. The microbeam was obtained by using a vernier micrometer-driven miniature collimator attached to a Therapax DXT300 x-ray machine operated at 100 kVp. The "edge-on" application allows utilization of the ultra thin sensitive volume of the MOSFET detector. Spatial resolution of both the MOSFET and Gafchromic film dosimeters appeared to be of about 1 micrometer. The MOSFET dosimeter appeared to provide more uniform dose profiles with the advantage of on-line measurements.
authors.affiliation: Radiation Physics Group, University of Wollongong, Australia. gkaplan@ucw.edu.au
authors.forename: G I
authors.initials: GI
authors.lastname: Kaplan
authors.forename: A B
authors.initials: AB
authors.lastname: Rosenfeld
authors.forename: B J
authors.initials: BJ
authors.lastname: Allen
authors.forename: J T
authors.initials: JT
authors.lastname: Booth
authors.forename: M G
authors.initials: MG
authors.lastname: Carolan
authors.forename: A
authors.initials: A
authors.lastname: Holmes-Siedle
mesh_terms: D055592:Biophysical Phenomena; D001703:Biophysics; D005069:Evaluation Studies as Topic; D006801:Humans; D019047:Phantoms, Imaging; D011834:Radiation Monitoring / Q000295:instrumentation* / Q000379:methods / Q000706:statistics & numerical data; D011880:Radiotherapy Planning, Computer-Assisted; D017356:Synchrotrons; D014965:X-Rays