In:
Journal of Radiotherapy in Practice, Cambridge University Press (CUP), Vol. 16, No. 4 ( 2017-12), p. 461-475
Abstract:
Optically stimulated luminescence dosimeters (OSLDs) have a number of advantages in radiation dosimetry making them an excellent dosimeter for in vivo dosimetry. The study aimed to study the dosimetric characteristics of a commercial optically stimulated luminescence (OSL) system by Landauer Inc., before using it for routine clinical practice for in vivo dosimetry in radiotherapy. Further, this study also aimed to investigate the cause of variability found in the literature in a few dosimetric parameters of carbon-doped aluminium oxide (Al 2 O 3 :C). Materials and methods The commercial OSLD system uses Al 2 O 3 :C nanoDot TM as an active radiation detector and InLight TM microStar ® as a readout assembly. Inter-detector response, energy, dose rate, field size and depth dependency of the detector response were evaluated for all available clinical range of photon beam energies in radiotherapy. Results Inter-detector variation in OSLD response was found within 3·44%. After single light exposure for the OSL readout, detector reading decreased by 0·29% per reading. The dose linearity was investigated between dose range 50–400 cGy. The dose response curve was found to be linear until 250 cGy, after this dose, the dose response curve was found to be supra-linear in nature. OSLD response was found to be energy independent for Co 60 to 10 MV photon energies. Conclusions The cause of variability found in the literature for some dosimetric characteristics of Al 2 O 3 :C is due to the difference in general geometry, construction of dosimeter, geometric condition of irradiation, phantom material and geometry, beam energy. In addition, the irradiation history of detector used and difference in readout methodologies had varying degree of uncertainties in measurements. However, the large surface area of the detector placed in the phantom with sufficient build-up and backscatter irradiated perpendicularly to incident radiation in Co 60 beam is a good method of choice for the calibration of a dosimeter. Understanding the OSLD response with all dosimetric parameters may help us in estimation of accurate dose delivered to patient during radiotherapy treatment.
Type of Medium:
Online Resource
ISSN:
1460-3969
,
1467-1131
DOI:
10.1017/S1460396917000346
Language:
English
Publisher:
Cambridge University Press (CUP)
Publication Date:
2017
detail.hit.zdb_id:
2194408-8
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