Usefulness of Thermoluminescent Slab Dosimeter for Postal Dosimetry Audit of External Radiotherapy Systems

Abstract

In this study, the feasibility of using a thermoluminescent slab dosimeter (TLSD) in postal dosimetry audit for radiotherapy systems is examined. First, changes in material structure are evaluated by measuring changes in TLSD weight and temperature after heating and cooling. Then, a fading correction factor is derived by measuring the relationship between the elapsed time after irradiation and thermoluminescence (TL) intensity. Finally, the uncertainty in the absorbed dosimetry using the TLSD with the TL absorbed dose correction factor is evaluated. It is shown that the TLSD weight and heat flow change after heating. These changes are reversible upon cooling. Therefore, the material structure of the TLSD does not change after heating. The fading effect for the TLSD can be minimized by setting the elapsed time to more than 100 h. Furthermore, measurement accuracy can be improved by correcting the fading. The overall measurement uncertainty or expanded relative standard uncertainty for this measurement method is 1.80%. The TLSD has high material stability and measurement accuracy under a certain condition equivalent to that of conventional postal dosimetry audit conducted using a glass dosimeter. The TLSD can be used as a 2D measurement device for postal dosimetry audit.

Dosimetric properties of a newly developed thermoluminescent sheet‐type dosimeter for clinical proton beams

“…The TL intensity was sharply faded 6 h after irradiation and gradual decay occurred after approximately 2 days after irradiation. Maruyama et al reported that TL intensity with their Cr‐doped Al 2 O 3 thermoluminescent slab dosimeter was sharply faded 24 h after irradiation and gradual decay occurred after 100 h 16 . Therefore, the TLDS we used in this study is considered to have slightly improved fading characteristics compared to their results.…”

“…Recently, with the advent of the charge‐coupled device (CCD) camera, the high‐resolution imaging of large areas has become much faster, so the amount of research on photon imaging using 2D thermoluminescent dosimeter (TLD) has been increased 9–17 . Annalakshmi et al reported that manganese doped lithium triborate has a single grow peak and linear dose response to beta‐ray irradiation up to 50 Gy 13 .…”

“…3 Recently, with the advent of the charge-coupled device (CCD) camera, the high-resolution imaging of large areas has become much faster, so the amount of research on photon imaging using 2D thermoluminescent dosimeter (TLD) has been increased. [9][10][11][12][13][14][15][16][17] Annalakshmi et al reported that manganese doped lithium triborate has a single grow peak and linear dose response to beta-ray irradiation up to 50 Gy. 13 Actually, the basic response characteristics of various thermoluminescent materials to the proton beam have also been studied, [10][11][12]15 but the reality is that none of them have reached the level of perfection that can be generalized.…”

Scintillation Properties of Dy-doped 50NaPO3–50Al(PO3)3 Glasses

“…To detect ionizing radiation efficiently, the use of bulk materials is essential since the probability of an interaction between ionizing radiation and a detector material simply depends on the volume of the material. To satisfy this requirement, bulk single crystals, (9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19) ceramics, (20)(21)(22)(23)(24)(25)(26)(27)(28)(29)(30)(31) and glasses (32)(33)(34)(35)(36)(37)(38) have been applied for scintillators and dosimeters. Among these material forms, glasses have some advantages such as high chemical durability and high light transmittance, which are preferable for scintillator and dosimeter uses.…”

Optical, TSL, and OSL Properties of Copper-doped Cesium Bromide Transparent Ceramics Prepared by SPS

“…(7) Since the TSL and OSL intensities are proportional to the incident radiation dose, storage phosphors are used for personal dose monitoring (8)(9)(10)(11)(12)(13) and imaging plates. (14)(15)(16)(17)(18)(19) So far, most research on scintillators and storage phosphors has been on various material forms including single crystals, (20)(21)(22)(23)(24) glasses, (25)(26)(27)(28)(29) and opaque ceramics. (30)(31)(32) In recent years, transparent ceramics have attracted much attention as a new material form.…”