In vivo dosimetry with MOSFETs: Dosimetric characterization and first clinical results in intraoperative radiotherapy

Journal Article · Tue Nov 01 04:00:00 EST 2005 · International Journal of Radiation Oncology, Biology and Physics

DOI:https://doi.org/10.1016/j.ijrobp.2005.02.049· OSTI ID:20702215

Consorti, Rita ^[1]; Petrucci, Assunta ^[1]; Fortunato, Falbo ^[1]; Soriani, Antonella ^[2]; Marzi, Simona ^[2]; Iaccarino, Giuseppe ^[2]; Landoni, Valeria ^[2]; Benassi, Marcello ^[2]

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1. Unita Operativa di Fisica Sanitaria, H.S. Filippo Neri, Rome (Italy)
2. Laboratorio di Fisica Medica, Istituto Regina Elena, Rome (Italy)

Purpose: To investigate the use of metal oxide silicon field effect transistors (MOSFETs) as in vivo dosimetry detectors during electron beams at high dose-per-pulse intraoperative radiotherapy. Methods and Materials: The MOSFET system response in terms of reproducibility, energy, dose rate and temperature dependence, dose-linearity from 1 to 25 Gy, angular response, and dose perturbation was analyzed in the 6-9-MeV electron beam energy range produced by an intraoperative radiotherapy-dedicated mobile accelerator. We compared these with the 6- and 9-MeV electron beams produced by a conventional accelerator. MOSFETs were also used in clinical dosimetry. Results: In experimental conditions, the overall uncertainty of the MOSFET response was within 3.5% ({+-}SD). The investigated electron energies and the dose rate did not significantly influence the MOSFET calibration factors. The dose perturbation was negligible. In vivo dosimetry results were in accordance with the predicted values within {+-}5%. A discordance occurred either for an incorrect position of the dosimeter on the patient or when a great difference existed between the clinical and calibration setup, particularly when performing exit dose measurements. Conclusion: Metal oxide silicon field effect transistors are suitable for in vivo dosimetry during intraoperative radiotherapy because their overall uncertainty is comparable to the accuracy required in target dose delivery.

• OSTI ID: 20702215
• Journal Information: International Journal of Radiation Oncology, Biology and Physics, Journal Name: International Journal of Radiation Oncology, Biology and Physics Journal Issue: 3 Vol. 63; ISSN IOBPD3; ISSN 0360-3016
• Country of Publication: United States
• Language: English

Related Subjects

62 RADIOLOGY AND NUCLEAR MEDICINE
ACCURACY
DOSE RATES
DOSEMETERS
DOSIMETRY
ELECTRON BEAMS
IN VIVO
MOSFET
PATIENTS
RADIATION DOSES
RADIOTHERAPY