Reference dosimetry at the neutron capture therapy facility at Studsvik

• Published in: Medical physics (Lancaster) Vol. 30; no. 7; pp. 1569 - 1579
• Main Authors: Munck af Rosenschöld, P. M., Giusti, V., Ceberg, C. P., Capala, J., Sköld, K., Persson, B. R. R.
• Format: Journal Article
• Language: English
• Published: United States American Association of Physicists in Medicine 01-07-2003
• Subjects: Algorithms; Ancillary equipment; BNCT; calibration; Calibration - standards; dosimetry; Dosimetry/exposure assessment; Gas‐filled counters: ionization chambers, proportional, and avalanche counters; ionisation chambers; Ionization chambers; mixed beam; Monte Carlo methods; neutron capture therapy; Neutron Capture Therapy - instrumentation; Neutron Capture Therapy - standards; Neutrons; Particle beam detectors; phantoms; Phantoms, Imaging; Photons; Physicists; polymers; Radiation therapy; Radiometry - instrumentation; Radiometry - methods; Radiometry - standards; Radiotherapy Dosage; Reproducibility of Results; Sensitivity and Specificity; Sweden; Units and standards; Sweden; dosimetry; BNCT; mixed beam
• ISSN: 0094-2405; 2473-4209
• DOI: 10.1118/1.1580484

The purpose of this publication was to present and evaluate the methods for reference dosimetry in the epithermal neutron beam at the neutron capture therapy facility at Studsvik. Measurements were performed in a PMMA phantom and in air using ionization chambers and activation probes in order to calibrate the epithermal neutron beam. Appropriate beam-dependant calibration factors were determined using Monte Carlo methods for the detectors used in the present publication. Using the presented methodology, the photon, neutron and total absorbed dose to PMMA was determined with an estimated uncertainty of ±5.0%, ±25%, and ±5.5% (2 SD), respectively. The uncertainty of the determination of the photon absorbed dose was comparable to the case in conventional radiotherapy, while the uncertainty of the neutron absorbed dose is much higher using the present methods. The thermal neutron group fluence, i.e., the neutron fluence in the energy interval 0–0.414 eV, was determined with an estimated uncertainty of ±2.8% (2 SD), which is acceptable for dosimetry in epithermal neutron beams.