[The results of proton radiosurgery for pituitary endosellar adenomas].

465 patients with pituitary endosellar adenomas have passed irradiation on the synchrocyclotron PNPI (1000 MeV). Due to the high energy of the proton beam the rotating-convergent shoot-through technique was used. The single dose of 80-100 Gy was given. In patients with prolactin adenomas clinical remission was detected in 80%, and the stabilization of the disease was achieved in 15%. Pregnancies in 21 patients ended in the birth of healthy children, and 4 of them gave the birth twice. Complete clinical remission was observed in 92% of patients with Cushing's disease. Sustained recovery and full normalization of growth hormone level were observed during long-term follow-up in 86% of patients with acromegaly. There was significant reducing of the high hormone level on the fifth year of follow-up in any clinical form of pituitary adenomas while the development of the secondary hypopituitarism was not defected in the most of the patients. Clinical remission in patients with non-secreting adenomas was 95%. Irradiation by the proton beam was not accompanied by serious life-threatening complications. Thus this type of treatment for pituitary endosellar adenomas is highly effective and safe and, sometimes, the only method.

[Influence of ultrafractionation on the effect of whole body uniform irradiation with protons of 1000 MeV energy]. / Vliianie ul'trafraktsionirovaniia na éffekt obshchego ravnomernogo oblucheniia protonami s énergiei 1000 MéV.

In experiments with rats a study was made of the radiobiological influence of a pulse frequency (45.9 and 4.5 c-1) of a 1000 MeV proton beam. The estimates of metabolic parameters of the peripheral blood and spleen 24 h and the survival rate during 60 days following irradiation have demonstrated the increase in the biological effectiveness of the proton beam with decreasing pulse frequency. As to 60Co-gamma-radiation, RBE of protons was 1.10 +/- 0.04 at the pulse frequency of 9 c-1 and 0.98 +/- 0.03 at 45 c-1 as determined by the probit-logarithm dose method.

[Estimation of the contribution of the dose rate to the effect of whole body uniform irradiation with 1000 MeV protons]. / K otsenke vklada moshchnosti dozy v éffekt obshchego ravnomernogo oblucheniia protonami s énergiei 1000 MéV.

Some biochemical indices of peripheral blood and spleen and the survival rate of albino rats after whole-body uniform irradiation with 1000 MeV protons delivered in two ways have been studied. The data obtained indicate that the dose rate contributes to the biological effect of impulse proton radiation.

[Status and developmental prospects of the medical proton channel in the synchrocyclotron in Gatchina]. / Sostoianie i perspektivy razvitiia meditsinskogo protonnogo trakta na sinkhrotsiklotrone v Gatchine.

The medical proton beam on the synchrocyclotron in Gatchina modernized in 1980, is characterized by a simplicity of the beam adjustment that amounts to standard operations, the time of adjustment reduced considerably. The optical scheme ensures a good reproducibility of all the beam parameters from session to session. A large "zone of convergence" makes it possible to select a necessary irradiation field size with the diameter from 3 to 10 mm. A new medical complex with a 2-room premises for irradiation is envisaged on the basis of the "second beam" to expand the medical program. The piercing technique of moving field irradiation with protons at an energy of 1 Gy and the utilization of the convergent beam ensure the ratio of the focal dose to the surface dose 200:1.