RBE of spleen CFU-S to low dose rate Cf-252 neutron or photon radiation

Abstract Aim Aim of the study was to determine the effects of the β--emitter 186Re and 662 keV photon radiation in order to compare the biological effects of low dose rate (186Re) to high dose rate irradiation. Methods Prae-B-lymphocytes were exposed to 662 keV photon radiation or incubated with a liquid solution of 186Re. Cell count and viability were compared over the observation period of seven days, survival curves constructed and analysed at time of lowest cell-viability. Results Biphasic cell survival curves resulted for both radiation types. Survival curves were obtained at 24 h for photon radiation and 72 h for 186Re. The biphasic survival curve after photon radiation exposure can be explained by radiation hypersensitivity at doses below 1 Gy resulting in a D0 of 3.3 Gy. Doses exceeding 1.0 Gy showed a D0 of 10 Gy. The biphasic survival curve in case of 186Re incubation represents repair of sub lethal damage in the first section of the curve (D0 11.1 Gy) – in this case, biological effects of the β--emitter are attenuated by repair. Beyond an accumulated dose of 1.6 Gy, 186Re showed a steeper slope with a D0 of 4 Gy, corresponding to 2.5 times higher biological effects compared to acute photon irradiation (10 Gy). Conclusion Low dose rate radiation resulted in low biological effects at low doses. There is a threshold of accumulated dose above which biological effects of 186Re-incubation exceed those of photon irradiation.

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Low Dose Rate X-Ray Radiation Fields Implementation for Study of Energy Response of the Dosimeters Based on Scintillation Detectors

Devices and Methods of Measurements ◽

10.21122/2220-9506-2019-10-2-128-137 ◽

2019 ◽

Vol 10 (2) ◽

pp. 128-137

Author(s):

A. V. Novichenko ◽

R. V. Lukashevich ◽

K. G. Senkovsky

Keyword(s):

Energy Range ◽

Dose Rate ◽

Low Dose ◽

Photon Radiation ◽

Scintillation Detectors ◽

Sensitive Volume ◽

Energy Response ◽

X Ray ◽

Low Dose Rate ◽

Calibration Facility

Near background low dose rate measurements are important part of the environmental radiation monitoring. It is possible to fulfill energy response verification for the high sensitive dosimeters based on inorganic scintillation detectors in low energy region when creating reference X-ray fields with dose rates up to 5 µSv/h. The aim of this work was to create and study reference X-ray fields with low dose rate and narrow spectrum in the energy range from 15 to 250 keV using high-purity metal filters as a part of X-ray irradiator of AT300 X-ray calibration facility.To determine the main characteristics of created X-ray fields highly sensitive comparators of photon radiation based on NaI(Tl) scintillation detectors was used. The comparators were developed in “ATOMTEX”. To verify comparators energy response the reference AT5350/1 dosimeter and ionization chamber TM32003 with sensitive volume 10000 cm3 were used.Characteristics of X-ray fields that were created on the AT300 X-ray calibration facility to verify the energy response of high sensitive dosimeters based on scintillation detectors were investigated. The possibility to calibrate high sensitive dosimetric measuring instruments based on scintillation detectors in the energy range up to 250 keV in X-ray beams was shown.

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Low-dose rate brachytherapy for patients with low or intermediate-risk prostate cancer. Analysis of relapse-free survival

Experimental and Сlinical Urology ◽

10.29188/2222-8543-2019-11-2-44-49 ◽

2019 ◽

Vol 11 (2) ◽

pp. 44-49

Author(s):

V.A. Solodky ◽

◽

A.Yu. Pavlov ◽

A.D. Tsybulskiy ◽

A.S. Pchelintsev ◽

...

Keyword(s):

Prostate Cancer ◽

Dose Rate ◽

Low Dose ◽

Intermediate Risk ◽

Relapse Free Survival ◽

Free Survival ◽

Low Dose Rate ◽

Risk Prostate Cancer ◽

Low Dose Rate Brachytherapy

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LOW-DOSE-RATE OR HIGH-DOSE-RATE BRACHYTHERAPY IN COMBINATION WITH EXTERNAL BEAM RADIOTHERAPY FOR INTERMEDIATE AND HIGH-RISK PROSTATE CANCER

Problems in oncology ◽

10.37469/0507-3758-2018-64-1-79-83 ◽

2018 ◽

Vol 64 (1) ◽

pp. 79-83

Author(s):

Vladimir Solodkiy ◽

Andrey Pavlov ◽

Aleksey Tsybulskiy ◽

Anton Ivashin

Keyword(s):

Prostate Cancer ◽

High Risk ◽

Dose Rate ◽

Low Dose ◽

External Beam Radiotherapy ◽

Combined Treatment ◽

High Dose ◽

External Beam ◽

Low Dose Rate ◽

Risk Of Progression

Introduction. One of the main problems of modem on-courology is treatment for prostate cancer of intermediate and high risk of progression. Modern radiotherapy in this category of patients has an advantage over surgical methods of treatment. One way to improve the effectiveness of radiotherapy is to escalate the dose in the prostate gland. For this purpose a combination of brachytherapy and remote radiotherapy is used. This combination allows increasing the dose of radiation, thereby providing better local control, reducing complications from neighboring organs. Purpose of the study. To conduct a comparative analysis of efficacy and safety of radical treatment of patients with prostate cancer at medium and high risk of progression using a combination of high and low dose rate brachytherapy with external beam radiotherapy. Materials and methods. 107 patients with prostate cancer of the group of medium and high risk of progression combined treatment (brachytherapy with external beam radiotherapy) was conducted. 53 patients underwent combined treatment (HDR-brachytherapy and external beam radiotherapy). 54 patients underwent combined treatment (LDR-brachytherapy and external beam radiotherapy). The observation period was 5 years. Conclusion. In a comparative analysis in groups of combined radiotherapy with the use of high-dose and low-dose-rate brachytherapy, the same effectiveness of immediate and long-term results of treatment was demonstrated. A significant reduction in early and late toxic reactions in patients with high-power brachytherapy has been demonstrated.

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