Assessing doses of radiotherapy with the risk of developing cancer in the head and neck

Abstract Radiation is known to be a major cause of cancer in normal tissue. After treatment with radiotherapy, for young patients or the patients can survive for a long time, the radiation-induced cancer risk is noteworthy. This research investigated the dose delivered by the treatment of intensity modulated radiation therapy (IMRT) for head and neck cancer, such as NPC and oral cancer, and assessed the risk of developing radiation-induced secondary cancer in non-targeted normal tissues. A Rando phantom was used to simulate a patient with NPC or oral cancer, and thermoluminescent dosimeter (TLD) chips were placed inside the phantom to estimate the doses delivered by IMRT. In summary, the risks to patients with NPC was somewhat higher than for those with oral cancer, because the region of the PTV was lower, requiring larger field sizes be used for cases of NPC. The smaller the field size used, the less the risk was of developing secondary cancer. In addition, the higher the value of MU used, the higher the dose delivered to normal tissues was. The risk of radiation-induced secondary cancer was proportional to the delivered dose.