| Abstract [eng] |
Head and neck cancer (HNC) presents complex treatment challenges due to the proximity of tumours to critical organs, increasing the risk of radiation-induced complications. This study showed how demographic, anatomical, and clinical factors are influenced by radiation dose delivery and the associated risk of secondary cancers. The analysis indicated that HNC incidence was highest among men aged 60–69, with the oral cavity and oropharynx being the most affected sites. Statistical analysis showed that depending on the patient's age, the irradiation doses of organs such as the oesophagus and parotid glands differ, while gender had the least impact on the change in irradiation dose of critical organs. The assessment of Excess Absolute Risk (EAR) revealed a consistent trend that patients with more advanced disease stages particularly those classified as Stage IV (T4_N1_M0) faced significantly higher long-term risks. To assess the accuracy of treatment planning system (TPS) dose estimations, out-of-field doses were measured using a cylindrical ionization chamber (PTW 30013) positioned within the SHANE anthropomorphic phantom. These measured values were compared with TPS-calculated doses using two algorithms: the Anisotropic Analytical Algorithm (AAA) and Acuros XB. Both algorithms exhibited consistent underestimation of out-of-field doses, with the most significant discrepancy 57.1 % observed in Channel 4 (spinal cord region) at 0 cm using the Acuros XB algorithm. Moreover, at distances beyond 10 cm from the treatment field edge, underestimations remained notable, particularly in Channels 3 and 4. These findings highlight the limitations of TPS algorithms in accurately predicting peripheral dose, reinforcing the importance of incorporating phantom-based dose measurements into routine radiotherapy planning to ensure reliable dose assessment for organs at risk (OARs), ultimately contributing to improved long-term patient outcomes. |
