SPECT/CT in Measuring Lung Function in Patients With Cancer Undergoing Radiation Therapy

PRIMARY OBJECTIVES: I. To utilize SPECT/CT imaging with technetium Tc-99m microaggregated albumin (99mTc-MAA) and 99mTc-diethylenetriamine pentaacetic acid (99mTc-DTPA) to identify functional lung on serial imaging in patients receiving radiation treatment to the thorax, as well as to characterize reproducibility of perfusion and ventilation in non-irradiated lung tissue. SECONDARY OBJECTIVES: I. To estimate the dose response relationship on multiple spatial scales (global lung, regional lung, lung image voxel) between radiation dose and changes in lung ventilation and perfusion, both acutely (mid-radiation treatment) and long term (3 months post-treatment), using SPECT/CT imaging with 99mTc-MAA and 99mTc-DTPA. II. To estimate the degree of radiation response in lung tissue with varying levels of function (i.e. compare radiation dose response of well ventilated and well perfused tissue against lung tissue with poor perfusion and ventilation). TERTIARY OBJECTIVES: I. To evaluate proton radiation therapy for functional lung sparing in lung cancers and other cancer in the thorax through treatment planning comparisons to conventional photon radiation therapy. II. To evaluate the feasibility of incorporating standard-of-care fludeoxyglucose F 18 (18F-FDG) positron emission tomography (PET) images into proton and photon radiotherapy planning for dose escalation to functionally viable regions of gross thoracic disease. OUTLINE: Patients undergo 99mTc-MAA and 99mTc-DTPA SPECT/CT at baseline, mid-radiation therapy (up to 1 week post-treatment), and at 3-6 months post-treatment. Patients also undergo a pre-treatment 18F FDG PET/CT scan per standard of care. After completion of study, patients are followed up periodically.