Evaluation of the electrical properties of a lead (II) iodide based-dosimeter based on mechanical flexibility for surface dose measurements in radiotherapy

Abstract

In radiotherapy, point doses via surface dose measurement are confirmed using a dosimeter attached to the patient's skin. This results in an error margin of about 11.8% or higher because the attachment site is visually confirmed. Thus, a digital flexible array dosimeter that can analyse body surface area is needed. Here, a lead (II) iodide (PbI 2 )-based unit cell flexible dosimeter was developed, and its electrical properties were evaluated based on its mechanical flexibility by assessing its reproducibility and linearity for bending. The relative standard deviation (RSD) for measurement by the sensor over 10,000 cycles was 1.74% and 2.21% at 6 MV and 15 MV, respectively, which is higher than RSD's evaluation criterion (<1.5%). Although the linearity of measurement by the sensor over 10,000 cycles met the evaluation criteria of a coefficient of determination R 2 > 0.9990, the sensitivity at 15 MV was lower than that at 6 MV. The results of this study confirm the applicability and usefulness of the PbI 2 -based flexible dosimeter in radiation measurements. K: Dosimetry concepts and apparatus; Materials for solid-state detectors; Radiation damage to detector materials (solid state); Radiotherapy concepts 1Corresponding author.

Development and evaluation of lead(II) iodide-based polycrystalline digital dosimeter for quality assurance in brachytherapy

“…These results indicate that the output signals of the PbI 2 -based digital dosimeter has excellent signal stability and high reproducibility. Since it presents a uniform signal depending on the irradiated dose, similar to other previous studies, it is considered to have precise reproducibility when calculating the dose based on the signal [7][8][9][10].…”

“…Moreover, n denotes the number of measurements. The evaluation criteria were set within 1.5% of the RSD value, corresponding to a 95% confidence level [7][8][9][10].…”

“…The device was fabricated using a photoconductor material, lead (II) iodide (PbI 2 ). The photoconductor used in the fabrication of the dosimeter has excellent sensitivity to radiation because of its high atomic number (Z pb : 82, Z I : 56) and density (6.2 g/cm 3 ) [7].…”