PET Based Radiotherapy Planning

PET CT has become an integral part of radiotherapy treatment planning procedures. PET-based radiotherapy planning helps to better/delimate the gross tumor volume, staging the disease, and also helpful in identifying residual disease during follow-up. PET CT-based planning has a clear role in lung cancer, head and neck cancer, esophageal cancer, and cervical cancer.

The main reasons to utilize PET CT in lung cancer are

1) It significantly changes the lymph node staging in the thorax; and

2) In cases of atelectasis, PET CT defines the border of the tumor, allowing a smaller volume of the lung to be treated.

Pre-treatment planning PET CT in cervix cancers helps to alter the radiation treatment strategy (either by extending the irradiated volume to common iliac or para-aortic areas or escalating the radiation dose to involved nodes).