Bi-Crystal compensation method for the over-response of solid-state dosimetry
2014 (English)In: Materials and Applications for Sensors and Transducers III, 2014, Vol. 605, 540-543 p.Conference paper (Refereed)
Solid-state dosimetry employs highly sensitive semiconductors such as Gallium Nitride (GaN) and Silicon (Si), but they have a common drawback of over response compared to tissues for low-energy scattered photons, which induces inacceptable errors for radiotherapy application. To tackle this issue, we propose a compensation method consisting in using two different materials of dosimetric interest with different atomic numbers. Their responses are denoted as SC1 and SC2. The response ratio SC1/water as a function of the ratio SC1/SC2 exhibits a monotonic curve that can serve as reference to compensate the over-response of SC1. To validate this method, we have studied the dosimetric response of GaN (0.1 mm(3)) and Si crystals (2.5 mm(3)) by simulations, using a validated model based on the general cavity theory in a homogeneous water phantom. The dosimetric response of GaN and Si calculated using the model has errors within 2.5% compared to measured data. The local fluence spectra have been obtained by convolution of pencil beam kernel built by Monte Carlo simulations for different clinical irradiation conditions with field size (from 5x5 cm(2) up to 20x20 cm(2)) at depth in the phantom (from 2 cm to 25 cm). The obtained results confirm a monotone relationship between GaN/water dose ratio and GaN/Si dose ratio. The reference curve is independent of irradiation conditions (field size, dosimeter position...), and allows determination of compensation value by identification.
Place, publisher, year, edition, pages
2014. Vol. 605, 540-543 p.
, Key Engineering Materials, ISSN 1013-9826
Solid State Dosimetry, Radiotherapy, Over-response correction
Other Engineering and Technologies
IdentifiersURN: urn:nbn:se:uu:diva-247877DOI: 10.4028/www.scientific.net/KEM.605.540ISI: 000348035600133ISBN: 978-3-03835-051-4OAI: oai:DiVA.org:uu-247877DiVA: diva2:797631
3rd International Conference on Materials and Applications for Sensors and Transducers (IC-MAST), SEP 13-17, 2013, Prague, CZECH REPUBLIC