Purpose: The aim of this paper is to investigate the limits of LET monitoring of therapeutic carbon ion beams with miniaturized microdosimetric detectors. Methods: Four different miniaturized microdosimeters have been used at the 62 MeV/u12C beam of INFN Southern National Laboratory (LNS) of Catania for this purpose, i.e. a mini-TEPC and a GEM-microdosimeter, both filled with propane gas, and a silicon and a diamond microdosimeter. The y-D(dose-mean lineal energy) values, measured at different depths in a PMMA phantom, have been compared withLET¯D(dose-mean LET) values in water, calculated at the same water-equivalent depth with a Monte Carlo simulation setup based on the GEANT4 toolkit. Results: In these first measurements, no detector was found to be significantly better than the others as a LET monitor. The y-Drelative standard deviation has been assessed to be 13% for all the detectors. On average, the ratio between y-Dand LET¯Dvalues is 0.9 ± 0.3, spanning from 0.73 ± 0.08 (in the proximal edge and Bragg peak region) to 1.1 ± 0.3 at the distal edge. Conclusions: All the four microdosimeters are able to monitor the dose-mean LET with the 11% precision up to the distal edge. In the distal edge region, the ratio of y-Dto LET¯Dchanges. Such variability is possibly due to a dependence of the detector response on depth, since the particle mean-path length inside the detectors can vary, especially in the distal edge region.

Miniaturized microdosimeters as LET monitors: First comparison of calculated and experimental data performed at the 62 MeV/u12C beam of INFN-LNS with four different detectors

Pola, A.;Bortot, D.;Fazzi, A.;Agosteo, S.;Treccani, M.;
2018

Abstract

Purpose: The aim of this paper is to investigate the limits of LET monitoring of therapeutic carbon ion beams with miniaturized microdosimetric detectors. Methods: Four different miniaturized microdosimeters have been used at the 62 MeV/u12C beam of INFN Southern National Laboratory (LNS) of Catania for this purpose, i.e. a mini-TEPC and a GEM-microdosimeter, both filled with propane gas, and a silicon and a diamond microdosimeter. The y-D(dose-mean lineal energy) values, measured at different depths in a PMMA phantom, have been compared withLET¯D(dose-mean LET) values in water, calculated at the same water-equivalent depth with a Monte Carlo simulation setup based on the GEANT4 toolkit. Results: In these first measurements, no detector was found to be significantly better than the others as a LET monitor. The y-Drelative standard deviation has been assessed to be 13% for all the detectors. On average, the ratio between y-Dand LET¯Dvalues is 0.9 ± 0.3, spanning from 0.73 ± 0.08 (in the proximal edge and Bragg peak region) to 1.1 ± 0.3 at the distal edge. Conclusions: All the four microdosimeters are able to monitor the dose-mean LET with the 11% precision up to the distal edge. In the distal edge region, the ratio of y-Dto LET¯Dchanges. Such variability is possibly due to a dependence of the detector response on depth, since the particle mean-path length inside the detectors can vary, especially in the distal edge region.
Biophysics; Radiology, Nuclear Medicine and Imaging; Physics and Astronomy (all)
File in questo prodotto:
File Dimensione Formato  
11311-1062784_Bortot.pdf

accesso aperto

: Post-Print (DRAFT o Author’s Accepted Manuscript-AAM)
Dimensione 1.53 MB
Formato Adobe PDF
1.53 MB Adobe PDF Visualizza/Apri

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11311/1062784
Citazioni
  • ???jsp.display-item.citation.pmc??? 1
  • Scopus 15
  • ???jsp.display-item.citation.isi??? 14
social impact