A frameless method for stereotactic multiple arc radiotherapy (SMART) is described. Three short gold wires are implanted in the scalp approximately 100 mm apart. These are localized in a computed tomographic or angiographic study along with the target. Subsequently the gold markers are localized on beam films and the target position calculated using a computer program ISOLOC. This program provides the couch movements required to move the target to the isocentre and a micropositioner attached to the couch is used to make the adjustment. Beam films are repeated until the movements required are less than 1 mm in any direction. It is shown that the simple procedures of implanting the markers subcutaneously do not provide a stable reference system in about 25% of patients and the markers are now screwed into the cranium. The precision of the method is evaluated by phantom studies and measurements taken during several hundred treatments.

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During 1989 and the beginning of 1990, approximately 150.000 feet of cable was manufactured for use in the SSC Model Dipole Magnet Program. The wire for the cable was made to SSC specifications by three different manufacturers. The cable was made at New England Electric Wire on the SSC Production Cabling Machine, under supervision of either SSC Laboratory personnel or the wire manufacturer's representative. All the cable produced far SSC model dipoles was subjected to rigorous inspection in order to insure that ths magnet construction and performance would be predictable. The cable dimensions were measured at intervals of 10 feet or less with a cable measuring machine. Electrical properties were measured on samples from one end of each cable length. Critical current degradation due to cabling was checked by measuring the critical currents of the •wires used to make the cable and comparing these with the cable critical current. The results of die dimensional and electrical measurements will be discussed and compared with the SSC