Dosimetric characterization of a small-scale (Zn, Cd)S:Ag inorganic scintillating detector to be used in radiotherapy. (April 2021)

• Record Type: Journal Article
• Authors: Debnath, Sree Bash Chandra; Tonneau, Didier; Fauquet, Carole; Tallet, Agnes; Goncalves, Anthony; Darreon, Julien
• Is Part Of: Physica medica. Volume 84(2021)
• Page Start: 15
• Page End: 23
• Publication Date: 2021-04
• Subjects: Inorganic scintillating detector -- Dosimetry -- Small field dosimetry -- Radiotherapy; Medical physics -- Periodicals; Biophysics -- Periodicals; Biophysics -- Periodicals; Imagerie médicale -- Périodiques; Radiothérapie -- Périodiques; Rayons X -- Sécurité -- Mesures -- Périodiques; Physique -- Périodiques; Médecine -- Périodiques; 610.153
• DOI: 10.1016/j.ejmp.2021.03.022
• Languages: English
• ISSNs: 1120-1797

Abstract

Highlights: A novel small-scale (Zn, Cd)S:Ag inorganic scintillating detector was developed. High spatial resolution (~100 µm) beam profiling at 0.5 × 0.5 cm 2 field. Significant decrease of convolution effect in profiling using a point-like detector. Strong linearity and reproducibility under regular and small field beam. Negligible contribution of 'stem effect' (<1%) observed below 3x3 cm 2 field. Abstract: Purpose: In modern radiotherapy techniques, to ensure an accurate beam modeling process, dosimeters with high accuracy and spatial resolution are required. Therefore, this work aims to propose a simple, robust, and a small-scale fiber-integrated X-ray inorganic detector and investigate the dosimetric characteristics used in radiotherapy. Methods: The detector is based on red-emitting silver-activated zinc-cadmium sulfide (Zn, Cd)S:Ag nanoclusters and the proposed system has been tested under 6 MV photons with standard dose rate used in the patient treatment protocol. The article presents the performances of the detector in terms of dose linearity, repeatability, reproducibility, percentage depth dose distribution, and field output factor. A comparative study is shown using a microdiamond dosimeter and considering data from recent literature. Results: We accurately measured a small field beam profile of 0.5 × 0.5 cm 2 at a spatial resolution of 100 µm using a LINAC system. The dose linearity at 400 MU/min has shown less than 0.53% and 1.10% deviations from perfect linearity for the regular and smallest field. Percentage depth dose measurement agrees with microdiamond measurements within 1.30% and 2.94%, respectively for regular to small field beams. Besides, the stem effect analysis shows a negligible contribution in the measurements for fields smaller than 3x3 cm 2 . This study highlights the drastic decrease of the convolution effect using a point-like detector, especially in small dimension beam characterization. Field output factor has shown a good agreement while comparing it with the microdiamond dosimeter. Conclusion: All the results presented here anticipated that the developed detector can accurately measure delivered dose to the region of interest, claim accurate depth dose distribution hence it can be a suitable candidate for beam characterization and quality assurance of LINAC system.