scholarly journals Comparative Studies of Dose Measurements in Cornea and Mantle Shielding Block for High Energy Gamma Radiation (60Co) in Radiotherapy Treatment

2018 ◽  
Vol 40 (1) ◽  
pp. 47-58
Author(s):  
M Shamsuzzaman ◽  
MS Rahman ◽  
Debasish Paul ◽  
M Jahangir Alam ◽  
Shyamal Ranjan Chakraborty
Keyword(s):  
Empirical Relation ◽  
High Energy ◽  
Mean Value ◽  
Field Size ◽  
Correction Factors ◽  
Calculated Dose ◽  
Energy Gamma ◽  
Dose Measurements ◽  
Radiotherapy Treatment ◽  
Study Dose

Cornea and Mantle shielding blocks were used to evaluate the dosimetry features of blocked beam radiotherapy. These blocks were used to produce the blocked beams for 5×5 cm2 and 30×30 cm2 field sizes. Doses were measured and calculated by the Clarkson's method and compared mutually. The variations of 0.05%, 0.92% and 0.99% were observed at three dose investigation points of 5×5 cm2 field size for cornea block. For mantle block the variation between measured and calculated values were found to be 1.97%, 2.46%, 2.39%, 2.13%, 2.00% and 1.93% at six dose investigation points of 30×30 cm2 field size. In this study dose calculated by the empirical relation using correction factors CijxK and CFi were found approximately equal to the experimental value. In the cases of both cornea and mantle shielding the calculated mean value of uncertainty in dose measurement between calculated dose values of Clarkson’s method and empirical relation was found satisfactorily to be within ±5.0%, fulfilling to the International Commission on Radiation Units and Measurements (ICRU) [1]. The Chittagong Univ. J. Sci. 40(1) : 47-58, 2018

scholarly journals Dosimetric Characterization of Small Radiotherapy Electron Beams Collimated by Circular Applicators with the New Microsilicon Detector

2022 ◽  
Vol 12 (2) ◽  
pp. 600
Author(s):  
Serenella Russo ◽  
Silvia Bettarini ◽  
Barbara Grilli Leonulli ◽  
Marco Esposito ◽  
Paolo Alpi ◽  
...  
Keyword(s):  
Radiation Therapy ◽  
Electron Beams ◽  
High Energy ◽  
Field Size ◽  
The Novel ◽  
Linear Accelerators ◽  
Depth Dose ◽  
Dosimetric Data ◽  
Output Factors ◽  
Dose Measurements

High-energy small electron beams, generated by linear accelerators, are used for radiotherapy of localized superficial tumours. The aim of the present study is to assess the dosimetric performance under small radiation therapy electron beams of the novel PTW microSilicon detector compared to other available dosimeters. Relative dose measurements of circular fields with 20, 30, 40, and 50 mm aperture diameters were performed for electron beams generated by an Elekta Synergy linac, with energy between 4 and 12 MeV. Percentage depth dose, transverse profiles, and output factors, normalized to the 10 × 10 cm2 reference field, were measured. All dosimetric data were collected in a PTW MP3 motorized water phantom, at SSD of 100 cm, by using the novel PTW microSilicon detector. The PTW diode E and the PTW microDiamond were also used in all beam apertures for benchmarking. Data for the biggest field size were also measured by the PTW Advanced Markus ionization chamber. Measurements performed by the microSilicon are in good agreement with the reference values for all the tubular applicators and beam energies within the stated uncertainties. This confirms the reliability of the microSilicon detector for relative dosimetry of small radiation therapy electron beams collimated by circular applicators.

scholarly journals Surface and Buildup Region Dose Measurements with Markus Parallel-Plate Ionization Chamber, GafChromic EBT3 Film, and MOSFET Detector for High-Energy Photon Beams

2016 ◽  
Vol 2016 ◽  
pp. 1-10 ◽  
Author(s):  
Ugur Akbas ◽  
Nazmiye Donmez Kesen ◽  
Canan Koksal ◽  
Hatice Bilge
Keyword(s):  
Ionization Chamber ◽  
Parallel Plate ◽  
Incident Radiation ◽  
High Energy ◽  
Field Size ◽  
Surface Dose ◽  
Photon Beams ◽  
Radiation Beam ◽  
Mosfet Detector ◽  
Dose Measurements

The aim of the study was to investigate surface and buildup region doses for 6 MV and 15 MV photon beams using a Markus parallel-plate ionization chamber, GafChromic EBT3 film, and MOSFET detector for different field sizes and beam angles. The measurements were made in a water equivalent solid phantom at the surface and in the buildup region of the 6 MV and 15 MV photon beams at 100 cm source-detector distance for 5 × 5, 10 × 10, and 20 × 20 cm2field sizes and 0°, 30°, 60°, and 80° beam angles. The surface doses using 6 MV photon beams for 10 × 10 cm2field size were found to be 20.3%, 18.8%, and 25.5% for Markus chamber, EBT3 film, and MOSFET detector, respectively. The surface doses using 15 MV photon beams for 10 × 10 cm2field size were found to be 14.9%, 13.4%, and 16.4% for Markus chamber, EBT3 film, and MOSFET detector, respectively. The surface dose increased with field size for all dosimeters. As the angle of the incident radiation beam became more oblique, the surface dose increased. The effective measurement depths of dosimeters vary; thus, the results of the measurements could be different. This issue can lead to mistakes at surface and buildup dosimetry and must be taken into account.

scholarly journals A clinical implementation of in vivo dosimetry with n-type Isorad semiconductor diodes

2014 ◽  
Vol 29 (4) ◽  
pp. 313-320
Author(s):  
Laza Rutonjski ◽  
Borislava Petrovic ◽  
Milutin Baucal ◽  
Milan Teodorovic ◽  
Ozren Cudic ◽  
...  
Keyword(s):  
Quality Assurance ◽  
Mean Value ◽  
In Vivo Dosimetry ◽  
Quality Assurance Program ◽  
Clinical Implementation ◽  
Entrance Dose ◽  
Dose Measurements ◽  
Action Levels ◽  
Radiotherapy Treatment

The study was aimed to check the radiotherapy treatment accuracy and definition of action levels during implementation of in vivo dosimetry as a part of quality assurance program. The calibration and correction factors for in vivo entrance dose measurements for six n-type Isorad semiconductor diodes were determined as recommended by the European Society for Radiotherapy and Oncology Booklet No. 5. The patients for in vivo measurements have been divided in groups, according to the treatment site/techique, in order to investigate and detect the groups where the uncertainty was larger or where a systematic error occurred. The tolerance/action levels for all groups were also defined and checked. In this study, the entrance dose measurements were performed for total of 451 treatment fields, and 338 patients over one year period. The mean value and the standard deviation for different groups were: breast +1.0% ? 2.89%(1 SD), brain, and head and neck - +0.74% ? 2.04%(1 SD), and isocentric pelvis and abdomen - +0.1% ? 2.86%(1 SD). All measurements - +0.72% ? 2.64%(1 SD). In our experience, systematic in vivo dosimetry proved to be a very useful tool for quality assurance of patient's plan and treatment, both in detecting systematic errors and for estimating the accuracy of radiotherapy treatment delivery.

scholarly journals Characteristics Analysis of High Energy External Radiotherapy Beams in Water

2018 ◽  
Vol 5 (1) ◽  
pp. 51-60
Author(s):  
M. A. Rahman ◽  
M. Jahangir Alam ◽  
M. Akhtaruzzaman
Keyword(s):  
Beam Quality ◽  
Absorbed Dose ◽  
High Energy ◽  
Field Size ◽  
External Radiotherapy ◽  
Transmitted Beam ◽  
Depth Dose ◽  
Characteristics Analysis ◽  
Beam Characteristics ◽  
Radiotherapy Treatment

High energy external radiotherapy beam is being used widely for cancer treatment. Biological effect of radiation is concerned with the evaluation of energy absorbed in the tissue. The study of photon and electron beam characteristics is necessary before calibration machine. The aim of this study was to analysis characteristics of depth dose of different energy beams in water to enhance the quality of the radiotherapy treatment planning. Beam is attenuated by the medium and the transmitted beam with less intensity causes lesser absorbed dose as the depth increases. Relative attenuation on certain points on the beam axis and certain percentage of doses on different depths for 4-15 MV photon beams and 4-18 MeV electron beams have been investigated. Depth dose characteristics of the beams do not show identical attributes as interaction of the beams with matters is mainly governed by beam quality. Attenuation and penetration parameters show variation with dosimetric parameters like field size due to scattering and source to surface distance due to inverse square law but the major parameter in interaction is energy. Detailed analysis of the beam characteristics helps to select appropriate beam for radiotherapy treatment when variety of beam energies available and hence to increase accuracy in radiotherapy treatment.  

Quasi-monochromatic and polarized high-energy gamma rays

1964 ◽  
Vol 83 (5) ◽  
pp. 3-34 ◽  
Author(s):  
F.R. Arutyunyan ◽  
V.A. Tumanyan
Keyword(s):  
Gamma Rays ◽  
High Energy ◽  
High Energy Gamma ◽  
Energy Gamma

FEATURES OF MAGNETIC STRUCTURE OF SUNSPOTS GROUPS AT DEVELOPMENT OF SUSTAINED FLUXES HIGH ENERGY GAMMA RAY

2020 ◽  
Vol 3 (331) ◽  
pp. 66-72
Author(s):  
Gennady Sergeevich, Minasyants ◽  
◽  
Tamara Mihailovna, Minasyants ◽  
Vladimir Mihailovich, Tomozov ◽  
◽  
...  
Keyword(s):  
Magnetic Structure ◽  
Gamma Ray ◽  
High Energy ◽  
High Energy Gamma ◽  
Energy Gamma

scholarly journals Introducing the HD+B model for pulsar wind nebulae: a hybrid hydrodynamics/radiative approach

2020 ◽  
Vol 494 (3) ◽  
pp. 4357-4370
Author(s):  
B Olmi ◽  
D F Torres
Keyword(s):  
Gamma Ray ◽  
High Energy ◽  
Theoretical Modelling ◽  
X Rays ◽  
Pulsar Wind Nebulae ◽  
New Approach ◽  
Energy Gamma ◽  
Radiative Model ◽  
Pulsar Wind

ABSTRACT Identification and characterization of a rapidly increasing number of pulsar wind nebulae is, and will continue to be, a challenge of high-energy gamma-ray astrophysics. Given that such systems constitute -by far- the most numerous expected population in the TeV regime, such characterization is important not only to learn about the sources per se from an individual and population perspective, but also to be able to connect them with observations at other frequencies, especially in radio and X-rays. Also, we need to remove the emission from nebulae in highly confused regions of the sky for revealing other underlying emitters. In this paper, we present a new approach for theoretical modelling of pulsar wind nebulae: a hybrid hydrodynamic-radiative model able to reproduce morphological features and spectra of the sources, with relatively limited numerical cost.

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