Biomedical subjects
Publications and source records attributed to M Goitein.
We describe an optical scanner capable of projecting a radiation treatment field or other line drawing on a patient's skin under microprocessor control. The practical implementation of such a device is discussed.
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Proton-beam radiation therapy has been developed for the treatment of chordomas or sarcomas of bone or soft tissue that abut the central nervous system. The authors report the results of treatment of 10 patients, six with chordoma, three with chondrosarcoma, and one with a neurofibrosarcoma. Local control has been achieved for all patients (with, however, one marginal failure) with a follow-up period ranging from 2 months to 6 years. High doses of radiation, up to 76 Cobalt Gray Equivalents (CGE), have been delivered without significant morbidity. In particular, no neurological sequelae have been observed.
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Proton irradiation was used in the treatment of uveal melanomas in 36 eyes. The average follow-up period was 16 months. One patient developed metastatic disease and died. No eye has been enucleated and tumor regression has been observed in all 22 eyes with a follow-up of more than 12 months. This type of treatment offers definite advantages over previously used methods, can be used for the treatment of relatively large melanomas, and should be considered before enucleation.
Our experience with modulated energy proton beams in the definitive treatment of cancer patients indicates that, for the patients accepted, treatment volumes have been smaller and total doses higher than would have obtained for photon techniques alone used in our institution. The reactions of normal tissue have, with very few exceptions, been readily acceptable. The higher radiation doses employed should yield higher tumor control frequencies. Clearly, we cannot assess the efficacy of this modality because of the small number of patients followed for short periods. However, the results are judged by use to warrant intensive evaluation of this modality.
A 160-MeV proton beam has been modified to irradiate patients with localized tumors by using convention treatment schedules. This proton beam has the physical advantage of megavoltage x-rays of reducing the radiation dose to normal tissues adjacent to the tumor volume. A perineal proton technique used as boost therapy (2,000 to 2,500 rads) was evaluated in the definitive irradiation of 17 patients with localized prostatic carcinoma. This technique allows repeated daily treatment of the carefully defined target volume with a precision of +/- 2 mm. Total dose to the prostatic tumor, but not to the posterior rectum, has been increased by 500 to 700 rads. After 12 to 27 months of observation, no noteworthy rectal reaction has developed in a patient, easily managed urethral strictures have developed in two patients, and all but one are locally controlled.
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This is our first case of malignant melanoma of the ciliary body treated with proton beam irradiation, a technique that we developed for irradiating choroidal melanomas. After 21 months of follow-up no growth of the tumour has been observed, and shrinkage of the tumour was noted on the follow-up photographs and by ultrasonography. The 32P uptake test, which was positive before treatment, turned negative 14 months after irradiation. The described technique of proton beam irradiation might offer an alternative for the treatment of ciliary body melanomas when the present techniques of iridocyclectomy cannot be applied because of the size of the lesion.
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Choroidal malignant melanomas in nine patients were treated with proton beam irradiation at the Harvard Cyclotron Laboratory, Cambridge, Mass. Each patient received five proton beam treatments in eight to ten days, totalling 4,730 to 8,570 rads at the tumor. No complications occurred during the treatment or follow-up period, which, at the time of this writing, ranges from one to 24 months, with an average of 12 months. No further growth of the tumor has been observed in any patient. Different signs of tumor regression have been noted. Resolution of the serous retinal detachments that accompanied some tumors is the earliest finding. Pigment changes over the surface of the tumor and adjacent pigment epithelium is a usual initial tumor response. Fluorescein angiography initially showed decreased leakage of dye; later, destruction of the tumor's vasculature and elimination of fluorescein leakage became evident. Only large choroidal vessels remained patient. Ultrasonography revealed decreased height of the tumors postirradiation, and the radioactive phosphorus (32P) uptake test, repeated in one patient, turned negative on postirradiation measurements.
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Five patients with choroidal malignant melanomas were treated with proton irradiation with a cyclotron. We developed an accurate method of aiming the proton beam within the eye. Four to five tantalum rings, 2 mm in diameter, were sutured to the sclera at the edges of the tumor, which is localized by indirect ophthalmoscopy and transillumination. The rings were used as markers for stereotactic radiography to align precisely the tumors with the proton beam. The patients were given a total tumor dose of 4,730 to 6,670 rads, delivered in five equal fractions, over a period of eight to nine days. All patients tolerated the treatments well without any adverse effects. The tumor response to therapy could not be evaluated at the completion of treatment since there was no immediate observable reaction of the tumor or of the surrounding retina. Although there has been no definite regression in any patient, we observed a change in the "color" of the tumor in the first two patients and resolution of two serous retinal detachments.
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