A computed tomography-radiation therapy treatment planning system utilizing a whole body CT scanner

An external beam radiation therapy treatment planning system has been developed to run on the GE CT/T whole body scanner. The system interactively obtains treatment planning information directly from CT scans, including relative density conversion of user input inhomogeneity regions. The program generates beams isodose tables from input TAR-SAR data using the Cunningham model. Inhomogeneity corrections are applied using the power law TAR method at low energies and the TAR ratio method at high energies. Beam data are generated on the central axis and at off-axis locations coplanar with each CT scan, and isodose distributions are displayed on any transverse, coronal or sagittal plane. Examples of plans and initial verification results are discussed.