scholarly journals Methodology for determining radiation dose distribution of strontium-90 applicators for veterinary intraoperatory betatherapy

2021 ◽  
Vol 15 ◽  
pp. 594
Author(s):  
Michel De Campos Vettorato ◽  
Jéssica Leite Fogaça ◽  
Sheila Canevese Rahal ◽  
Marco Antônio Rodrigues Fernandes
Keyword(s):  
Veterinary Medicine ◽  
Radiation Dose ◽  
Radiation Field ◽  
Dose Distribution ◽  
Treatment Plan ◽  
Dose Effect ◽  
Beta Radiation ◽  
Dose Distributions ◽  
Strontium 90 ◽  
Imagej Software

Betatherapy is a modality within brachytherapy that uses beta radiation applicators, which are used in the treatment of superficial injuries. With the advancement of therapeutic techniques, new clinical protocols in veterinary medicine will be established. In this sense, betatherapy appears as an important option for performing radiotherapy procedures and, consequently, further studies are necessary to define the clinical oncological protocols. Therefore, the aim of this study was to present a methodology for determining the dose distribution of beta radiation from strontium-90 (90Sr) applicators for use in intraoperative radiotherapy in veterinary medicine. Planar radiation dose distributions from three 90Sr applicators were analyzed using radiographic films, which were exposed to beams from sources at different exposure times. The optical density (O.D.) of the radiation field was verified with a digital densitometer. After scanning the films, using the ImageJ software, the brightness intensities (BI) for the radiation exposure fields were measured. The analysis of the radiation dose distribution of the betatherapy applicators, produced results similar to those already described in the literature. The use of the ImageJ software, as well as the O.D. obtained, helped in the analysis of dosimetric studies. The behavior of the dose-effect curves provided a better understanding of the homogeneity of the radiation field in the treatment plan and, therefore, the radiation dose distributions in the treatment fields indicate the use of these types of applicators in veterinary radiotherapy procedures.

scholarly journals Assessment of ocular beta radiation dose distribution due to 106Ru/106Rh brachytherapy applicators using MCNPX Monte Carlo code

2014 ◽  
Vol 2 (3) ◽  
pp. 02038 ◽  
Author(s):  
Nilseia Barbosa ◽  
Luiz da Rosa ◽  
Artur Menezes ◽  
Juraci Reis ◽  
Alessandro Facure ◽  
...  
Keyword(s):  
Monte Carlo ◽  
Radiation Dose ◽  
Dose Distribution ◽  
Beta Radiation ◽  
Monte Carlo Code

Evaluation of air cavities on dose distributions with air-filled apparatuses having different volumes using Gafchromic EBT3 films in brachytherapy

2018 ◽  
Vol 17 (4) ◽  
pp. 411-416
Author(s):  
Mehmet Bahadır Çelik ◽  
Nezahat Olacak ◽  
Songül Barlaz Us ◽  
Emin Tavlayan
Keyword(s):  
Dose Distribution ◽  
Dose Effect ◽  
Water Medium ◽  
Special Device ◽  
Dose Distributions ◽  
Clinical Dose ◽  
Depth Dose ◽  
Gafchromic Films ◽  
Depth Dose Curve ◽  
Air Cavities

AbstractAimThe data used in brachytherapy planning are obtained from homogeneous mediums. In practice, the heterogeneous tissues and materials affect the dose distribution of brachytherapy. It is aimed to investigate the effect of air cavities on brachytherapy dose distribution using a specially designed device.Material and methodsIn this study, the special device designed with different volumes of air and water to be irradiated and measured at different depths using EBT3 Gafchromic films. EBT3 Gafchromic films were preferred for this study because they can be cut to the shape of the experimental geometry, are water resistance and double directional usability.ResultsIn our study, sudden dose increases and decreases were observed at the water–air–water interfaces. Increases were 9, 11·8 and 15% in the 13, 18 and 22 mm apparatus, respectively. These effects were expected and the results were consistent with the literature and within the tolerance limits stated in the clinical dose guidelines. The most important result is that the percent depth–dose curve of the radiation passing through the air to the water and only passing through the water medium is different. The average differences were 1·97, 2·97 and 2·31% for the 13, 18 and 22 mm apparatus, respectively.ConclusionAlthough the effect of heterogeneity may be neglected according to clinical guidelines, it is suggested that the dose effect of heterogeneity is taken into account so that the dose can be estimated sensitively. Brachytherapy plans using dose data without considering air gaps may cause erroneous dose distributions due to heterogeneity of tissue.

Analysis of the Physical and Radiobiological Equivalence of the Calculated and Measured Dose Distributions for Prostate Stereotactic Radiotherapy

2021 ◽  
Vol 66 (3) ◽  
pp. 68-75
Author(s):  
E. Sukhikh ◽  
L. Sukhikh ◽  
A. Vertinsky ◽  
P. Izhevsky ◽  
I. Sheino ◽  
...  
Keyword(s):  
Radiation Therapy ◽  
Dose Distribution ◽  
Three Dimensional ◽  
Anterior Wall ◽  
Dose Distributions ◽  
Stereotactic Radiation ◽  
Dose Volume Histograms ◽  
Dose Volume ◽  
Gamma Index ◽  
Measured Dose

Purpose: Carrying out the analysis of the physical and radiobiological equivalence of dose distributions obtained during the planning of hypofractionated stereotactic radiation therapy of the prostate cancer and verification using a three-dimensional cylindrical dosimeter. Material and Methods: Based on the anatomical data of twelve patients diagnosed with prostate carcinoma, stage T2N0M0 with low risk, plans were developed for stereotactic radiation therapy with volumetric modulates arc therapy (VMAT). The dose per fraction was 7,25 Gy for 5 fractions (total dose 36,25 Gy) with a normal photon energy of 10 MV. The developed plans were verified using a three-dimensional cylindrical ArcCHECK phantom. During the verification process, the three-dimensional dose distribution in the phantom was measured, based on which the values of the three-dimensional gamma index and the dose–volume histogram within each contoured anatomical structures were calculated with 3DVH software. The gamma index value γ (3 %, 2 mm, GN) at a threshold equal to 20 % of the dose maximum of the plan and the percentage of coincidence of points at least 95 % was chosen as a criterion of physical convergence of the calculated and measured dose distribution according to the recommendations of AAPM TG-218. To analyze the radiobiological equivalence of the calculated and measured dose distribution, the local control probability (TCP) and normal tissue complication probability (NTCP) criteria were used based on the calculated and measured dose–volume histograms. Contours of the target (PTV) and the anterior wall of the rectum were used for the analysis. The approach based on the concept of equivalent uniform dose (EUD) by A. Niemierko was used to calculate the values of TCP/NTCP criteria. Results: The results of physical convergence of plans for all patients on the contour of the whole body were higher than 95 % for the criteria γ (3 %, 2 mm, GN). The convergence along the PTV contour is in the range (75.5–95.2)%. The TCP and NTCP values obtained from the measured dose-volume histograms were higher than the planned values for all patients. It was found that the accelerator delivered a slightly higher dose to the PTV and the anterior wall of the rectum than originally planned. Conclusion: The capabilities of modern dosimetric equipment allow us move to the verification of treatment plans based on the analysis of TCP / NTCP radiobiological equivalence, taking into account the individual characteristics of the patient and the capabilities of radiation therapy equipment.

Magnetic resonance imaging of radiation dose distributions using a polymer-gel dosimeter

1994 ◽  
Vol 39 (9) ◽  
pp. 1437-1455 ◽  
Author(s):  
M J Maryanski ◽  
R J Schulz ◽  
G S Ibbott ◽  
J C Gatenby ◽  
J Xie ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Radiation Dose ◽  
Polymer Gel ◽  
Resonance Imaging ◽  
Dose Distributions ◽  
Gel Dosimeter ◽  
Polymer Gel Dosimeter

MEASUREMENT OF INTERNAL RADIATION DOSE DISTRIBUTION IN CT EXAMINATIONS USING POLYETHYLENE TEREPHTHALATE RESIN

2018 ◽  
Vol 181 (4) ◽  
pp. 303-309 ◽  
Author(s):  
C Yamauchi-Kawaura ◽  
S Yamamoto ◽  
K Fujii ◽  
M Komori ◽  
M Yamauchi ◽  
...  
Keyword(s):  
Radiation Dose ◽  
Polyethylene Terephthalate ◽  
Dose Distribution ◽  
Internal Radiation

Khảo sát một số đặc tính bức xạ của buồng ion hóa CC13 và diode bán dẫn razor đối với các chùm photon kích thước nhỏ trên máy gia tốc tuyến tính xạ trị Clinac IX

2020 ◽  
Author(s):  
Tu Vu Ngoc
Keyword(s):  
Radiation Field ◽  
Dose Response ◽  
Dose Distribution ◽  
Ionization Chamber ◽  
Field Size ◽  
Photon Beams ◽  
Silicon Diode ◽  
Depth Dose ◽  
The Difference

Purpose: Compare percent depth dose (PDD) and off-center ratio (OCR) measured by the CC13 ionization chamber and the RAZOR silicon diode in small photon beams. Method and Materials: Some dosimetric characteristics, such as PDD, OCR, penumbra and radiation field size, were considered in this study for 2x2, 3x3, and 4x4 cm2 field sizes. We used the CC13 ionization chamber and the RAZOR silicon diode to measure dose distribution with depth along the axis and off-center of the beam. From the results obtained, the team investigated the differences in radiation parameters measured by the two types of probes above. Results: There are significant differences in the radiation parameters investigated for the CC13 ionization chamber and the RAZOR silicon diode, especially the width of penumbra. For PDD curves, the difference is less than 5% from dmax to 30 cm, however the difference becomes greater in the build-up region, which reaches to 33% at the water phatom surface. The width of penumbra measured by CC13 is always larger than that of RAZOR, the ratio of the penumbra width between two detectors is 1.8 and 1.3 for energies of 6 MV and 15 MV, respectively. Conclusion: The RAZOR silicon diode has better dose response than the CC13 ionization chamber for measuring the PDD and the OCR in small photon beams.

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