Liquid ionization chamber calibrated gel dosimetry in conformal stereotactic radiotherapy of brain lesions.
Hypofractionated conformal stereotactic radiotherapy (HCSRT) is an established method of treating brain lesions such as arteriovenous malformations (AVMs) and brain metastases. The aim of this study was to investigate the reliability of treatment plans in the terms of dose distribution and absorbed dose for HCSRT.


METHODS
Treatment plans for three different clinical intracerebral targets, AVMs, were transferred to a CT study of a spherical water filled phantom simulating the human head and recalculated for the phantom geometry using a standard treatment planning system utilizing a pencil beam algorithm for dose calculation. The calculated absorbed dose, relative three dimensional (3D) dose distribution and dose conformity were investigated using gel dosimetry normalized to liquid ionization chamber (LIC) measurements.


RESULTS
The measured absorbed dose to the dose reference point was found to be within 2% of the calculated dose for all three targets. The measured dose distribution was found to be within 3% and 2 mm of the calculated dose for more than 93% of all points in the target volume for all three targets.


CONCLUSIONS
The results show that the investigated standard treatment planning system can correctly predict the absorbed dose and dose distribution in different types of intracerebral targets and that the treatment can be delivered according to the plan.
Björeland
Anders
A
Department of Clinical Physiology and Radiation Physics, Sundsvall Hospital, Sundsvall, Sweden.
Lindvall
Peter
P
Karlsson
Anna
A
Gustavsson
Helen
H
Bäck
Sven A J
SA
Karlsson
Mikael
M
Bergenheim
Tommy A
TA
D001932:Brain Neoplasms / Q000532:radiotherapy*; D002138:Calibration; D005782:Gels; D006801:Humans; D008279:Magnetic Resonance Imaging; D019047:Phantoms, Imaging; D011108:Polymers; D016634:Radiosurgery; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods*; D020266:Radiotherapy, Conformal / Q000295:instrumentation / Q000379:methods
D005782:Gels; D011108:Polymers