Measurement of fast neutron contamination caused by the presence of wedge and block using CR-39 detector

Khajetash, B. and Toossi, M. T. B. and Ghorbani, M. and Jahangiri, M. and Akbari, F. (2019) Measurement of fast neutron contamination caused by the presence of wedge and block using CR-39 detector. Journal of Cancer Research and Therapeutics, 15 (8). S103-S109.

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Objective: Undesired neutron contamination imposed to patients during treatment is among the main factors increasing the risk of secondary cancer in radiotherapy. This additional undesirable dose is due to neutron contamination production in high-energy accelerators. In this study, neutron contamination is investigated in the presence of wedge and block in 15 MV photon fields of Siemens Primus linear accelerator. Materials and Methods: Neutron production by 30°, 45°, and 60° wedges and cerrobend block was investigated. Measurements were conducted in a 10 cm × 10 cm field at the source to -surface distance of 100 cm at 0.5, 2, 3, and 4 cm depths of a 30 cm × 30 cm × 30 cm Perspex phantom using the CR-39 passive film detectors. Chemical etching was performed using sodium hydroxide solution with 6.25 M concentration as the etchant at 85°C for 3 h. Results: The neutron dosimetry results reveal that the presence of wedge and block increases the neutron contamination. However, the 45° wedge is most effective in producing neutron contamination. The results also show that the fast neutron contamination is lower in the steeper depths. Conclusion: The presence of a wedge in a therapeutic high-energy photon field is a source of neutron contamination and may be of concern regarding clinical aspects. The results of this study show that superficial tissues such as skin will incur higher fast neutron contamination than the deep tissues. © 2019 Journal of Cancer Research and Therapeutics | Published by Wolters Kluwer - Medknow.

Item Type: Article
Additional Information: Cited By :1 Export Date: 16 February 2020 Correspondence Address: Toossi, M.T.B.; Department of Medical Physics, Faculty of Medicine, Mashhad University of Medical Sciences, Pardise Daneshgah, Vakil Abad Blvd., Iran; email:
Uncontrolled Keywords: Cerrobend block CR-39 film medical linear accelerators neutron contamination neutron dosimetry wedge Article calibration fast neutron radiation film dosimetry ionizing radiation radiation measurement radioactive contamination chemistry devices dosimeter imaging phantom magnetic and electromagnetic equipment photon radiometry radiotherapy dosage CR 39 macrogol Fast Neutrons Particle Accelerators Phantoms, Imaging Photons Polyethylene Glycols Radiation Dosimeters
Subjects: QZ pathology-neoplasms-Genetics
Divisions: Mashhad University of Medical Sciences
Depositing User: mr lib1 lib1
Date Deposited: 21 Jun 2020 07:17
Last Modified: 21 Jun 2020 07:17

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