A method to correct for temperature dependence and measure simultaneously dose and temperature using a plastic scintillation detector

Abstract

Plastic scintillation detectors (PSDs) work well for radiation dosimetry. However, they show some temperature dependence, and a priori knowledge of the temperature surrounding the PSD is required to correct for this dependence. We present a novel approach to correct PSD response values for temperature changes instantaneously and without the need for prior knowledge of the temperature value. In addition to rendering the detector temperature-independent, this approach allows for actual temperature measurement using solely the PSD apparatus. With a temperature-controlled water tank, the temperature was varied from room temperature to more than 40°C and the PSD was used to measure the dose delivered from a cobalt-60 photon beam unit to within an average of 0.72% from the expected value. The temperature was measured during each acquisition with the PSD and a thermocouple and values were within 1°C of each other. The depth-dose curve of a 6-MV photon beam was also measured under warm non-stable conditions and this curve agreed to within an average of −0.98% from the curve obtained at room temperature. The feasibility of rendering PSDs temperature-independent was demonstrated with our approach, which also enabled simultaneous measurement of both dose and temperature. This novel approach improves both the robustness and versatility of PSDs.

A high‐Z inorganic scintillator–based detector for time‐resolved in vivo dosimetry during brachytherapy

“…Furthermore, online self -correcting technology for temperature dependence of detector probes has been developed for a detector system using multipoint plastic scintillators. 39 Developing a similar self -correcting algorithm for ZnSe:O could be considered, as ZnSe:O displays a large temperature dependence. However, manual correction for the difference between calibration and patient temperatures is still feasible.…”

Dosimetric performance of a multipoint plastic scintillator dosimeter as a tool for real‐time source tracking in high dose rate Ir brachytherapy

“…One such detector, the plastic scintillation detector (PSD), has several advantages that have been recently highlighted in the literature, a key one being their real-time response. [7][8][9][10][11][12][13][14][15][16][17] Although PSDs are affected by the stem effect and temperature variations, 12,13 several investigations have developed methods to correct both of these dependencies in the detector response. 7,9,14,15,[18][19][20][21] Most of the studies characterizing PSD response were conducted using an optical fiber connected to a single point of measurement as a sensitive volume.…”

“…A review by Tanderup et al highlighted the main aspects of various detectors that could be used as in vivo dosimeters in brachytherapy. One such detector, the plastic scintillation detector (PSD), has several advantages that have been recently highlighted in the literature, a key one being their real‐time response . Although PSDs are affected by the stem effect and temperature variations, several investigations have developed methods to correct both of these dependencies in the detector response …”

Optimization of a multipoint plastic scintillator dosimeter for high dose rate brachytherapy

“…Plastic scintillator detectors (PSDs) show promise for obtaining accurate real‐time radiotherapy dose measurements. Previous studies have demonstrated that PSDs can accurately measure dose in external beam radiotherapy and that they have high spatial resolution, linearity with dose, energy independence in the megavolt energy range, and water equivalence . In addition, some authors have found PSDs to be feasible for use in brachytherapy applications .…”

“…Previous studies have demonstrated that PSDs can accurately measure dose in external beam radiotherapy and that they have high spatial resolution, linearity with dose, energy independence in the megavolt energy range, and water equivalence. [3][4][5][6][7][8][9][10][11][12] In addition, some authors have found PSDs to be feasible for use in brachytherapy applications. [13][14][15][16][17] Despite the aforementioned advantages, PSD response is affected by the stem effect and temperature dependence.…”