RESUMEN
The authors describe a new method of dosimetric design of partial radiation exposures (PRE) in radiobiological experiments on rodents, using a universal lead component screen. A choice of a shape of irradiation fields and location of screen elements on the body of an animal is done according to a CT program, developed in the IBM PC version. This method helps to standardize physicotechnical support of PRE in radiobiological experiments.
Asunto(s)
Protección Radiológica , Dosificación Radioterapéutica , Dosimetría Termoluminiscente , Animales , Planificación de la Radioterapia Asistida por Computador , RatasRESUMEN
Proceeding from analysis of the influence of parameters of the target-filter system on radiation-physical characteristics of braking radiation, some recommendations were issued for assessment of the efficacy of the forming systems of medical accelerators of electrons. A new criterion--a coefficient of the forming system efficacy--was introduced, characterizing a beam formation tract with relation to a whole set of radiotherapeutic problems.
Asunto(s)
Electrones , Aceleradores de Partículas , Absorción , Eficiencia , Diseño de Equipo , Matemática , Modelos Estructurales , Dosificación RadioterapéuticaRESUMEN
The article describes a device for detecting ionizing irradiation on the basis of a diamond detector and gives its characteristics. It has been shown that the diamond detector device by its parameters is superior to a similar device based on the silicon detector and in a number of cases to the ionizing chamber device. It can therefore be used successfully in the systems measuring the dose-radiation field.
Asunto(s)
Carbono , Radiometría/instrumentación , Diamante , Diseño de Equipo , Dosis de Radiación , U.R.S.S.RESUMEN
The authors presented and analyzed the results of measurement of dose fields of photon and electron radiation using 3 types of detectors (ionization camera, Si detector and diamond detector), alternately switched on to the CADSCAN dose field analyzer. The results of a study of dose fields of inhibitory radiation at 18 MeV were indicative of the similarity of data obtained with the help of diamond and Si detectors and an ionization camera. Comparison of the results for electron radiation at 4, 17 and 20 MeV showed that data obtained with the diamond detector, coincided with absorbed dose distributions calculated on the basis of ionization measurements whereas dose accumulation values obtained with the help of the Si detector were very high.
Asunto(s)
Radiometría/instrumentación , Dosis de RadiaciónRESUMEN
The paper is concerned with an analysis of the radiation characteristics (depth doses, beam contours, radiation output) of several medical linear accelerators in the formation of high energy narrow beams (up to 2 x 2 cm). Experiments and computer-assisted numerical simulation have shown that the use of an additional collimator makes it possible to obtain characteristics of photon beam dose fields in biaxial rotation comparable to those in irradiation of small intracranial targets with proton beams at the energy of 1000 MeV.
Asunto(s)
Aceleradores de Partículas , Dosificación Radioterapéutica , Radioterapia de Alta Energía , HumanosRESUMEN
The paper is concerned with the results of experimental dosimetric studies on an anthropomorphic phantom using thermoluminescent dosimetry at the site of the joining of large fields of complex shape simulating total irradiation of the lymphatic collectors. The studies demonstrated the appropriateness of the joining at a distance of 1 cm between the fields. In such a variant adequate irradiation of the lymphatic system was achieved whereas an increase in a distance between the fields resulted in a risk of recurrence in under-irradiated areas without a significant decrease in radiation dose exposure to healthy organs and tissues.
Asunto(s)
Sistema Linfático/efectos de la radiación , Dosificación Radioterapéutica , Irradiación Corporal Total , Humanos , Modelos EstructuralesRESUMEN
The symmetry and reproducibility of the radiation field in the gamma-therapeutic device should be considered in terms of the recommendations given in the IEC Publications for medical electron accelerators, since the requirements for the exposed dose are similar in both cases. The calculations of the relationship between the source volume luminosity and the dimensions of the collimator system have shown that the increase in the diameter of the shutter hole for the operating beam results in much lower requirements for the source-shutter alignment, and so asymmetry and instability of the radiation field are essentially excluded.
Asunto(s)
Radioterapia/instrumentación , Tecnología Radiológica/instrumentación , Superficie Corporal , Rayos gamma , Humanos , Neoplasias/radioterapia , Dosificación RadioterapéuticaRESUMEN
Using a specially designed program, the authors managed to obtain dose distributions in irradiation by a rotation method in two planes of small intracranial targets with narrow photon beams (up to 1cm) with the energy of 0.2; 1.25; 15MeV. It has been shown that though these distributions less correspond to clinical requirements than those for proton beams the use of narrow photon beams seems promising in this field of radiology.
Asunto(s)
Irradiación Hipofisaria/métodos , Radioisótopos de Cobalto/uso terapéutico , Partículas Elementales , Humanos , Aceleradores de Partículas , Protones , Teleterapia por Radioisótopo , Rayos XRESUMEN
The paper presents methods and results of a study of radiation-physical characteristics of inhibitory radiation beam with the Grenz energy of 15MeV generated by an electron linear accelerator LUE-15M. Special emphasis is laid on primary dosimetric information used for the planning of radiotherapy: depth doses, beam profiles, dose functions of a collimated beam. It has been shown that in general the accelerator meets the requirements of the International Electrotechnical Commission. General error in the focal absorbed dose at the expense of variable parameters of the accelerator was evaluated. It does not exceed +/- 3.5%.
Asunto(s)
Aceleradores de Partículas , Dosificación Radioterapéutica , Radioterapia de Alta Energía , Tecnología RadiológicaRESUMEN
The paper is concerned with some features of the dose distribution of fields of a complex shape in gamma-beam irradiation using gamma-therapeutic units and electron linear accelerators in the complex of combined radiotherapy of patients with endometrial carcinoma. The authors have performed a comparative analysis of calculated and experimental results characterizing dose fields in the utilization of individually selected forming matrices and standard splitting units. It has been shown that the utilization of the forming matrices makes it possible to optimize gamma-beam irradiation with a necessary screening of a primary tumor focus and a preset level of dose exposure in the pelvic lateral parts and zones of regional metastases. Spatial dose distribution with the help of matrices gives an opportunity to use intense intracavitary irradiation with high energy sources using an Agat-B unit.