Naslov
Neutron detection around high energy linear accelerators in Clinical Hospital Center of Osijek

Autori
Poje, Marina ; Vuković, Branko ; Radolić, Vanja ; Miklavčić, Igor ; Faj, Dario

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, znanstveni

Izvornik
Book of abstracts ; The First International Conference on Radiation and Dosimetry in Various Fields of Research / Ristić, Goran - Niš : Elektronski fakultet Univerziteta u Nišu, 2012, 146-146

ISBN
978-86-6125-062-0

Skup
The First International Conference on Radiation and Dosimetry in Various Fields of Research

Mjesto i datum
Niš, Srbija, 24.04.2012. - 27.04.2012

Vrsta sudjelovanja
Poster

Vrsta recenzije
Međunarodna recenzija

Ključne riječi
Track-etched Detectors ; Neutron Dose ; Therapy on Linear Accelerators

Sažetak
High energy electron linear accelerators (15 – 25 MeV) are in wide use in radiotherapy. When photon beams with photon energies more than 10 MeV are used, unwanted neutrons can be produced in giant dipole resonance (GDR) reaction between photon beam and accelerator head material (led, tungsten). In this reaction an isotropic flux Φ of neutrons is produced (neutrons / cm^2 s), dominated by neutrons with energies between 700 keV and 1 MeV. Characterisation of full radiation field is important to correctly evaluate patients and medical personnel exposure. Neutron detection was done around 15 MeV photon beam of Siemens Mevatron MD2 and 18 MeV photon beam of Siemens Oncor Impression linear accelerators in Clinical Hospital Center of Osijek. It was performed by nuclear track etched detectors CR-39 associated with converter (radiator) that consist of 10^B. In nuclear reaction 10^B (n, α) 7^Li , α particle and Li ion are emitted, producing a latent tracks in the detector body itself. As a result of chemical etching these track become larger and visible under the optical microscope. After detector processing and determination of track density, with detector response known from the calibration exposure, we can evaluate neutron ambient dose equivalent H*(10). Previously described nuclear reaction is identical to one in BNCT (boron neutron capture therapy) in which 10^B is injected in the cancer cells and the tissue is exposed to the thermal neutrons. As a consequence a short range (~ 5μm) α particle and Li ion are emitted, and because of their short range they deposit majority of their energy inside the cancer cells and spare surrounding healthy tissue [1]. Detectors were set at several important locations with the goal to evaluate neutron ambient dose equivalent and/or neutron dose rate to which are exposed both, medical personnel and patients. Given values out of the bunker are in range from 2 to 5 μSv/h in dependence of measuring location what is consistent with already published values [2] [3]. Measurements made in the photon beam were considerably higher with significantly increased values in 18 MeV photon beam over measurements in 15 MeV photon beam. References: [1] IAEA TECDOC-1223 Current status of neutron capture therapy, 2001. [2] Vuković, B., Faj, D., Poje, M., Varga, M., Radolić, V., Miklavčić, I., Ivković, A., Planinić, J. ; A neutron track etch detector for electronlinear accelerators in radiotherapy Radiology and Oncology 2010 ; 44(1) ; 62-66. [3] Martinez-Ovalle, S. A., Barquero, R., Gomez- Ros, J.M. and Lallena, A. M. ; Ambient neutron dose equivalent outside concrete vault room for 15 and 18 MeV radiotherapy accelerators ; Radiation Protection Dosimetry (2011), 1–8

Izvorni jezik
Engleski

Znanstvena područja
Fizika

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