Improved spatial resolution by MOSFET dosimetry of an x-ray microbeam.
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.
Kaplan
G I
GI
Radiation Physics Group, University of Wollongong, Australia. gkaplan@ucw.edu.au
Rosenfeld
A B
AB
Allen
B J
BJ
Booth
J T
JT
Carolan
M G
MG
Holmes-Siedle
A
A
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