A new online detector for estimation of peripheral neutron equivalent dose in organ

Abstract

The results obtained indicate that direct evaluation of equivalent dose estimation in organs, both in phantom and patients, is perfectly feasible with this new detector. This will open the door to an easy implementation of specific peripheral neutron dose models for any type of treatment and facility.

Improving the neutron-to-photon discrimination capability of detectors used for neutron dosimetry in high energy photon beam radiotherapy

“…Thus, its influence is almost negligible if "balanced" incidence angles (uniformly covering 360°) are used. This is a usual approximation used in conventional radiotherapy treatments, that also took place in Irazola et al (2014). There is an important angular dependence of TNRD devices, different if beam incidence is comprised between (280°À 75°) or (250°À 105°).…”

“…Specifically, one of these detectors, named TNRD (Thermal Neutron Rate Detector), designed and developed by Bedogni et al, was characterized for peripheral neutron dose measurements in radiotherapy environments, according to the methodology described in Sánchez-Doblado et al (2012). The TNRD showed satisfactory performances in terms of user friendliness and high sensitivity (Irazola et al, 2014). Nevertheless, recent experiments with the detector located 'in-phantom' close to the field-edge, indicated the need for further investigations about the TNRD residual photon sensitivity.…”

Intensity-modulated radiation therapy and volumetric modulated arc therapy versus conventional conformal techniques at high energy: Dose assessment and impact on second primary cancer in the out-of-field region

“…8 This neutron dosimetric methodology has been successfully tested by means of and independent set of neutron detectors. 25,26 Due to difficulties raised on photon rejection when estimating neutron doses, this model was originally established for points at distances larger than 10 cm from the 50% isodose.…”

On the role of LET-dependent parameters in the determination of the absorbed dose by in-phantom recombination chambers

“…(9) is valid, the above equation can be written as: (12) If the composition of material t is (dosimetrically) not very different from material m, then the approximation: (13) can be used and Eq. (12) transformed into the form: (14) where (15) is the ratio of the mean restricted mass stopping powers of the charged particles in material t and in the gas. Again, the value of the restriction  is not crucial and can be related to the thickness of the material layer in which the absorbed dose is averaged.…”

“…Recently, the interest in such measurements has increased, mainly because of the attention paid to neutron doses (and equivalent doses) in terms of X-ray radiotherapy [11][12][13][14][15][16][17][18][19][20]. It is also associated with the broader use of proton therapy [21][22][23][24][25] and renewed interest in boron neutron capture therapy (BNCT) [26][27][28][29], thus, in the treatment modalities where the recombination chambers can be used for the characterization and monitoring of the beam for quality assurance purposes.…”