Abstract
The GEMPix is a small gaseous detector with a highly pixelated readout, consisting of a drift region, three Gas Electron Multipliers (GEMs) for signal amplification, and four Timepix ASICs with 55 µm pixel pitch and a total of 262,144 pixels. A continuous flow of a gas mixture such as Ar:CO2:CF4, Ar:CO2 or propane-based tissue equivalent gas is supplied externally at a rate of 5 L/h. This article reviews the medical applications of the GEMPix. These include relative dose measurements in conventional photon radiation therapy and in carbon ion beams, by which on-line 2D dose images provided a similar or better performance compared to gafchromic films. Depth scans in a water phantom with 12C ions allowed measuring the 3D energy deposition and reconstructing the Bragg curve of a pencil beam. Microdosimetric measurements performed in neutron and photon fields allowed comparing dose spectra with those from Tissue Equivalent Proportional Counters and, additionally, to obtain particle track images. Some preliminary measurements performed to check the capabilities as the detector in proton tomography are also illustrated. The most important on-going developments are: (1) a new, larger area readout to cover the typical maximum field size in radiation therapy of 20 × 20 cm2; (2) a sealed and low-pressure version to facilitate measurements and to increase the equivalent spatial resolution for microdosimetry; (3) 3D particle track reconstruction when operating the GEMPix as a Time Projection Chamber.
Highlights
The GEMPix is an innovative detector developed at CERN a few years ago within a Marie Curie Initial Training Network (ITN) funded by the EU under FP7 between 2012 and
The envisaged applications were the characterization of radiation fields at particle accelerators used in research, industry and medicine, the characterization of radiation fields on-board aircrafts and in space, the assessment of secondary dose to radiation therapy patients and the measurement of the properties of clinical hadron beams used in particle therapy
The most recent application of the GEMPix to medical physics lies in the field of microdosimetry
Summary
The GEMPix is an innovative detector developed at CERN a few years ago within a Marie Curie Initial Training Network (ITN) funded by the EU under FP7 between 2012 and. Its use as a tracking detector operated as a highly granular and compact Time Projection Chamber (TPC) has been shown [16]: the device can be operated in a hybrid mode with some pixels measuring deposited charge and others measuring the drift time of the charge in order to obtain a complete 3D reconstruction of the track It has been introduced as a novel method to detect the very weak (5.9 keV) X-ray emission of 55 Fe in radioactive waste produced by the operation of particle accelerators and experimental facilities, to determine its specific activity (Bq/g) in metallic waste characterization [17]. Recently,ionize thin layers havezone, been allowing used for athe detection of thermal neutrons: the strongly the gasofinBthe good discrimination from the gamma
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
