Characterization of a GEM-based scintillation detector with He-CF4 gas mixture in clinical proton beams

Accurate, high-spatial resolution dosimetry in proton therapy is a time consuming task, and may be challenging in the case of small fields, due to the lack of adequate instrumentation. The purpose of this work is to develop a novel dose imaging detector with high spatial resolution and tissue equiva...

Full description

Saved in:
Bibliographic Details
Published in:Physics in medicine & biology 2016-04, Vol.61 (8), p.2972-2990
Main Authors: Nichiporov, D, Coutinho, L, Klyachko, A V
Format: Article
Language:English
Subjects:
Bragg peak
Carbon Compounds, Inorganic - chemistry
Electrons
Gases - chemistry
GEM detector
He/CF
Helium - chemistry
Humans
Protons
Scintillation Counting - instrumentation
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Accurate, high-spatial resolution dosimetry in proton therapy is a time consuming task, and may be challenging in the case of small fields, due to the lack of adequate instrumentation. The purpose of this work is to develop a novel dose imaging detector with high spatial resolution and tissue equivalent response to dose in the Bragg peak, suitable for beam commissioning and quality assurance measurements. A scintillation gas electron multiplier (GEM) detector based on a double GEM amplification structure with optical readout was filled with a He/CF4 gas mixture and evaluated in pristine and modulated proton beams of several penetration ranges. The detector's performance was characterized in terms of linearity in dose rate, spatial resolution, short- and long-term stability and tissue-equivalence of response at different energies. Depth-dose profiles measured with the GEM detector in the 115-205 MeV energy range were compared with the profiles measured under similar conditions using the PinPoint 3D small-volume ion chamber. The GEM detector filled with a He-based mixture has a nearly tissue equivalent response in the proton beam and may become an attractive and efficient tool for high-resolution 2D and 3D dose imaging in proton dosimetry, and especially in small-field applications.
ISSN:0031-9155
1361-6560
DOI:10.1088/0031-9155/61/8/2972