Static pion beam treatment planning of deep seated tumors using computerized tomographic scans

Static negative pion beam treatment of deep seated tumors is in progress at LAMPF. The influence of the physical principles of pions on treatment planning, e.g., an enhanced peak dose, multiple scattering, variations of beam quality, pin beam emittance, and a fixed vertical beam, are discussed. Computerized tomographic (CT) scan data have proven invaluable in providing quantitative information on inhomogeneities within the anatomy. The methods of designing collimation and compensating bolus for tailoring the pion beam to individual patient ports are described. An interim method, using dosimetry measurements in a water phantom and CT scan data to construct patient isodose distribution is outlined. Typical treatment plans for patients with abdominal and head and neck cancers are presented. The method of X-ray simulation in verifying localization of CT-defined tumor volumes is demonstrated for the head and neck.