An estimate of the margin required when defining blocks around the prostate.

The portal films of 54 consecutive patients treated for primary prostate cancer have been compared to the simulation films. The systematic and random uncertainty in the set-up, defined by the couch movement required to move the patient to the simulated position, was determined to be 1.6 mm UP (SD 3.

The incorporation of partial shielding of the spinal cord in a tissue deficit compensator in radiotherapy of the thorax.

A method to determine the shape of a patient by placing radiopaque wires and chains on the skin and taking two isocentric X-ray films is described. The wire locations are reconstructed by X-ray stereo photogrammetry, and a beam's eye view of the wire frame structure can be obtained with reference to the original setup of the "stereo-pair" films. An algorithm for paving between the wires with triangular plates is described which allows the calculation of the tissue deficit distance and compensator thickness.

A frameless method for stereotactic radiotherapy.

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.

Practical 3-D radiotherapy planning of brain tumors.

In postoperative radiotherapy of brain tumors it is usually the case that preoperative imaging studies, either CT or MRI, were performed outside of the purview of the radiation therapy department. Thus the target volume is defined in an imaging study that does not lend itself readily for entry to a 3-D treatment planning system. A method is described that adjusts the patient structure defined by scan data to an appropriate position for radiotherapy.

A method for the assessment of the output of irregularly shaped electron fields.

A simple approach to the calculation of dose in cone-collimated electron fields is presented. The method accounts for variations in lateral scatter with field size using a Clarkson Integration. The reduction in output by an irregularly shaped aperture is evaluated based on measurements of the output at various distances from the aperture in a field 2.

A port film marker.

A device is described consisting of brass strips embedded in a plastic plate. When inserted in a radiation beam, it produces an image of a cross centered in the field. Cuts in the brass at defined intervals project a scale on the film used to determine a magnification factor.

A non-contacting intraoperative electron cone apparatus.

Aluminum tubes, 20 cm long, of various diameter and face angle have been used to collimate electron beams for intraoperative radiotherapy. The tubes placed in a body cavity are clamped to the treatment couch. A thin rod is fixed coaxially to a disc which is placed on the entrance face of the tube.