[The CT-stereotaxic neutron brachytherapy of brain tumors with californium sources on the ANET-B apparatus]. / KT-stereotaksicheskaia neitronnaia brakhiterapiia opukholei golovnogo mozga kalifornievymi istochnikami na apparate "ANET-B".

A method for stereotaxic intratissue radiotherapy of brain tumors based on the findings of computed tomography is described. Radiosurgical implantation of sources with increased 252Cf content emitting mixed neutron + gamma-radiation was accomplished by means of an ANET-B apparatus by the afterloading method. Neutron irradiation is particularly effective in patients with malignant tumors possessing a large fraction of cells in a state of deep anoxia. Dosimetric planning was conducted by means of an original computer system. Devices and radiation-technical equipment for adaptation of the ANET-B apparatus for irradiation of neurosurgical patients are described. The indications for the use of this method and its place among the complex of measures for the treatment of patients with new growths of the brain are discussed. The first experience in using CT-stereotaxic neutron brachytherapy with californium sources on the ANET-B apparatus for the treatment of 6 patients with malignant glial tumors of the brain is dwelt on.

[Computerized system of dosimetric planning of interstitial multiposition stereotaxic irradiation in neutron therapy of brain tumors]. / Kompiuternaia sistema dozimetricheskogo planirovaniia vnutritkanevogo mnogopozitsionnogo stereotaksicheskogo oblucheniia pri neitronnoi terapii opukholei golovnogo mozga.

A computerized system PLUT-B intended for a dosimetric design of stereotaxic neutron brachytherapy of brain tumors, was developed. It is capable of simulating dose distribution in various parameters of irradiation, manipulating them, retaining the surgical aspects within the field of vision, and arriving at an acceptable dosimetric plan. The system permits visualization of a target with an applied dose field in the multiwindow mode, layer-by-layer vision in any direction, displaying a scheme of implantation, and drawing up of maps of isodose distributions. It is intended to be used by a physician, convenient in operation, the time at the design stage is 35-40 minutes.

[The ANET-B apparatus with 252Cf sources for intracavitary radiotherapy of cancer patients]. / Apparat ANET-B s istochnikami 252Cf dlia provedeniia vnutripolostnoi luchevoi terapii onkologicheskikh bol'nykh.

The authors give a brief description and the basic physico-technical characteristics of the AHET-B radiation therapeutic unit with 252Cf sources (the total radionuclide quantity is 2100 micrograms) for intracavitary radiation of malignant neoplasms of the uterine neck, uterine body and rectum. The results of the physical and technical testing and of the main dosimetric and maintenance study are given. Measures for the radiation safety of the unit users are described. The above experiments made it possible to begin clinical testing of the unit. 46 uterine neck cancer, 65 uterine body cancer and 10 rectum cancer patients were treated from February 1983 to February 1987. The preliminary results of the clinical testing are positive.

[Radiation safety during work on the ANET-V therapeutic apparatus with 252Cf sources]. / Radiatsionnaia bezopasnost' pri rabote na terapevticheskom apparate "Anet-V" s istochnikami 252Cf.

The Soviet ANET-W intracavitary neutron therapy apparatus is charged with 252Cf sources, the total mass of the radionuclide being 2100 micrograms. The radiation exposure of the staff has been studied and the results presented. Possible emergency situations have been analysed, methods of their prevention and liquidation worked out. Induced radioactivity in the patient's body has been estimated. Radiation dose levels for the medical staff are 10-15 times lower for the ANET-W apparatus than those for 252Cf sources administered by the manual series system but 10 times higher than those for the AGAT-W gamma-apparatus. The design, blocking system and emergency reset of the sources provide for safe work on the ANET-W apparatus. During liquidation of an emergency situation irradiation of the staff does not exceed 0.3 of the annual maximum tolerance dose. The level of induced activity in the patient's body is insignificant as in 10.5 min it does not exceed background values.

[Interstitial neutron therapy using flexible 252Cf sources]. / Vnutritkanevaia neitronnaia terapiia s ispol'zovaniem gibkikh istochnikov iz 252Cf.

The authors describe the technique of interstitial neutron therapy using 252Cf flexible sources developed at the clinic of the Research Institute of Medical Radiology, USSR AMS. Altogether 75 patients with head and neck tumors of different site and spread were treated. The characteristics of the 252Cf flexible sources and the neutron radiation dose field distribution are provided. This technique is based upon the utilization of the afterloading principle. Clinical observations are illustrated by different uses of flexible sources (loop-shaped, planar, radiosurgical). Dosimetry methods are described, general problems of radiation safety are considered. A conclusion has been made of a possibility to extend indications to interstitial therapy using 252Cf flexible sources.

[Dosage fields of the "ANET-B" apparatus with 252Cf]. / Doznye polia apparata "ANET-B" s 252Cf.

The paper is concerned with the results of the calculation of dose fields of neutron and gamma-radiation for an ANET-B unit. Experimental measurements were done in the tissue equivalent phantom by using photoluminescent and alumophosphate glasses, thermoluminescent and threshold detectors with neptunium foil. Divergences between calculated and all experimental data did not exceed 10-12%. It has been shown that the ratio of the contribution of neutron and gamma-components of 252Cf radiation for the ANET-B unit to the summary absorbed dose at an arbitrary point of a tissue equivalent phantom depends considerably on a distance between this point and the center of a source and changes from 2 (for a distance of 0.5 cm) to 1 (for a distance of 10 cm).