Measurement of Photoneutrons Trace Density Resulting from Photoneutron Contamination in Treating Two Breast Cancer using a VARIAN IX Linear Accelerator Operating at 6MV and 18 MV

Abstract

In this study, we measured the neutron dose equivalent density, D (Tr/cm²), resulting from neutron contamination caused by optical neutrons during the treatment of two breast cancer cases with high-energy photoneutrons beams. A Varian IX linear accelerator, available at the Oncology Center of the University Hospital in Latakia, was used. The response of the linear accelerator was verified, and the results showed a correlation coefficient R² = 1, indicating that the accuracy and efficiency of the linear accelerator in delivering the prescribed radiation dose to patients are optimal. The response of CR-39 detectors (SSNTDS) was verified through five measurements, with five detectors placed sequentially at the treatment point (0.0), and exposed to various doses with different irradiation times. The results demonstrated a high linear correlation R² = 0.9993, indicating that the detectors exhibit a high response proportional to the radiation dose variations. Two breast cancer cases were studied using 15 CR-39 type detectors per case, which included taking measurements of the cancer site targeted for treatment as well as other sites outside the treatment field along the upper half of the patient's body. The results, after calculating the neutron dose equivalent density, indicated the presence of neutron effects within the treatment field (the malignant tumor site), as well as outside the area, suggesting neutron contamination in the surrounding tissues and other healthy parts of the body, even if they were not targeted within the treatment field.