ABSTRACT
Additional programs in Europe began to emerge at that time. Italian neurosurgeon Federico Colombo and his team of physicists, led by R. C. Avanzo, published their SRS technique in an Italian journal (Avanzo et al. 1984; Colombo et al. 1985, 1986). Their technique used a 4-MV beam from a Varian Clinac 4 without the use of secondary collimators. Their treatment deliveries included multiple arcs of 150°–160° obtained by rotations of the gantry and treatment couch. Colombo reported treatment doses of 40-50 Gy to treat tumors of 2-4 cm in size, delivered in two fractions separated by 8-10 days. In Germany, the group at Heidelberg, led by Gűnther H. Hartmann, published their work with a 15-MV beam on a Siemens Mevatron 77 accelerator and using a commercial Riechert-Mundinger stereotactic frame to deliver multiple arc radiosurgery treatments (Hartmann et al. 1985). In their work, the authors described a dosimetry calculation using a pencil beam approximation for circularly collimated beams.
