Technical considerations for fractionated stereotactic radiotherapy of hepatocellular carcinoma

Technical aspects of fractionated stereotactic radiotherapy for solitary hepatocellular carcinoma have been investigated. Precise positioning of the patient and substantial reduction of the liver movement due to respiration were achieved by placing the patient ventrally on the treatment couch without a body cast. Repeated CT examinations were required for verification of tumor targeting. Though there were geometrical limitations on gantry rotation when the linac couch was rotated from its standard position, dose distributions obtained were found to be excellent. A patient with a small solitary lesion in the posterior segment of the liver received 52 Gy in 13 fractions over 29 days. He tolerated the treatment well without experiencing any morbidities or deterioration of liver functions. Three months later his alpha-fetoprotein value returned to normal and CT examinations revealed tumor shrinkage as well as a reduction in the viability of the tumor cells. The results suggest that it is possible to overcome technical difficulties associated with fractionated stereotactic radiotherapy of intraabdominal tumors.