Microdosimetry at the CATANA 62â¯MeV proton beam with a sealed miniaturized TEPC.
Phys Med
; 64: 114-122, 2019 Aug.
Article
em En
| MEDLINE
| ID: mdl-31515010
ABSTRACT
A new mini-TEPC with cylindrical sensitive volume of 0.9â¯mm in diameter and height, and with external diameter of 2.7â¯mm, has been developed to work without gas flow. With such a mini counter we have measured the physical quality of the 62â¯MeV therapeutic proton beam of CATANA (Catania, Italy). Measurements were performed at six precise positions along the Spread-Out Bragg Peak (SOBP) 1.4, 19.4, 24.6, 29.0, 29.7 and 30.8â¯mm, corresponding to positions of clinical relevance (entrance, proximal, central, and distal-edge of the SOBP) or of high lineal energy transfer (LET) increment (distal-dose drop off). Without refilling the microdosimeter with new gas, the measurements were repeated at the same positions 4â¯months later, in order to study the stability of the response in sealed-mode operation. From the microdosimetric spectra the frequency-mean lineal energy y-F and the dose-mean lineal energy y-D were derived and compared with average LET values calculated by means of Geant4 simulations. The comparison points out, in particular, a good agreement between microdosimetric y-D and the total dose-average LET¯d, which is the average LET of the mixed radiation field, including the contribution by nuclear reactions.
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Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Prótons
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Radiometria
/
Microtecnologia
Tipo de estudo:
Health_economic_evaluation
Idioma:
En
Revista:
Phys Med
Assunto da revista:
BIOFISICA
/
BIOLOGIA
/
MEDICINA
Ano de publicação:
2019
Tipo de documento:
Article