PET/CT-based radiation therapy for lung cancers: Pros and cons of proton vs. photon radiation therapy

1224Aim:Radeation therapy (RT) is an important component of cancer treatment for both early stage and locally advanced lung cancers. Photon and proton therapies are both utilized for RT but have different physical characteristics. Photon RT actively exposes healthy tissues along the beam path in front of and beyond the tumor to incidental irradiation. However, due to a central-axis depth-dose distribution pattern known as the spread-out Bragg peak (SOBP), proton RT generally has a more optimal dose delivery in comparison to 3D conformal photon therapy and intensity-modulated radiation therapy (IMRT). The SOBP may potentially allow for improvements in clinical outcomes in select cases by more safely and efficiently applying dose escalation/acceleration or RT with other treatment modalities like chemotherapy and surgery without increasing side effects such as radiation pneumonitis in lung cancer. Although proton RT is a promising technique on a clinical and scientific level, some challenges exist including target determination and motion effects. Proton doses are very sensitive to anatomical changes and motion effects, intrafractional tumor motion and normal tissue motion need to be taken into account for each patient, particularly in customized proton compensator design. Breathing causes lung and other thoracic normal tissues as well as cancer lesions to move during treatment. With the use of respiratory-gated 4D-positron emission tomography (PET) and 4D-computed tomography (C...
Source: Journal of Nuclear Medicine - Category: Nuclear Medicine Authors: Tags: Educational Exhibits Source Type: research