Comparison of Dosimetry Protocols for Electron Beam Radiotherapy Calibrations and Measurement Uncertainties

This paper presents guidelines for the calibration of radiation beams that were issued by the International Atomic Energy Agency (IAEA TRS 398), the American Association of Physicists in Medicine (AAPM TG 51) and the German task group (DIN 6800-2). These protocols are based on the use of an ionization chamber calibrated in terms of absorbed dose to water in a standard laboratory’s reference quality beam, where the previous protocols were based on air kerma standards. This study aims to determine uncertainties in dosimetry for electron beam radiotherapy using internationally established high-energy radiotherapy beam calibration standards. Methods: Dw was determined in 6-, 12- and 18 MeV electron energies under reference conditions using three cylindrical and two plane-parallel ion chambers in concert with the IAEA TRS 398, AAPM TG 51 and DIN 6800-2 absorbed dose protocols. From mean measured Dw values, the ratio TRS 398/TG 51 was found to vary between 0.988 and 1.004, while for the counterpart TRS 398/DIN 6800-2 and TG 51/DIN 6800-2, the variation ranges were 0.991–1.003 and 0.997–1.005, respectively. For the cylindrical chambers, the relative combined uncertainty (k = 1) in absorbed dose measurements was 1.44%, while for the plane-parallel chambers, it ranged from 1.53 to 1.88%. Conclusions: A high degree of consistency was demonstrated among the three protocols. It is suggested that in the use of the presently determined dose conversion factors across the three protocols, dose intercomparisons can be facilitated between radiotherapy centres.

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Dosimetry of High-Energy Photon Beams Based on Standards of Absorbed Dose to Water: Abstract

Journal of the International Commission on Radiation Units and Measurements ◽

10.1093/jicru_1.1.8 ◽

2001 ◽

Vol 1 (1) ◽

pp. 8-8 ◽

Cited By ~ 3

Author(s):

K. Hohlfeld ◽

P. Andreo ◽

O. Mattsson ◽

J. P. Simoen

Keyword(s):

Reference Conditions ◽

International Comparisons ◽

Absorbed Dose ◽

High Energy ◽

National Standards ◽

Photon Radiation ◽

Photon Beams ◽

Radiation Induced ◽

Absorbed Dose To Water ◽

Primary Standards

This report examines the methods by which absorbed dose to water can be determined for photon radiations with maximum energies from approximately 1 MeV to 50 MeV, the beam qualities most commonly used for radiation therapy. The report is primarily concerned with methods of measurement for photon radiation, but many aspects are also relevant to the dosimetry of other therapeutic beams (high-energy electrons, protons, etc.). It deals with methods that are sufficiently precise and well established to be incorporated into the dosimetric measurement chain as primary standards (i.e., methods based on ionisation, radiation-induced chemical changes, and calorimetry using either graphite or water). The report discusses the primary dose standards used in several national standards laboratories and reviews the international comparisons that have been made. The report also describes the reference conditions that are suitable for establishing primary standards and provides a formalism for determining absorbed dose, including a discussion of correction factors needed under conditions other than those used to calibrate an instrument at the standards laboratory.

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Novel Organic Material Induced by Electron Beam Irradiation for Medical Application

Polymers ◽

10.3390/polym12020306 ◽

2020 ◽

Vol 12 (2) ◽

pp. 306 ◽

Cited By ~ 1

Author(s):

Adrian Barylski ◽

Krzysztof Aniołek ◽

Andrzej S. Swinarew ◽

Sławomir Kaptacz ◽

Jadwiga Gabor ◽

...

Keyword(s):

Electron Beam ◽

Electron Beam Irradiation ◽

Absorbed Dose ◽

Medical Application ◽

High Energy ◽

Polymer Chains ◽

Degree Of Crystallinity ◽

Beam Irradiation ◽

The Impact ◽

The Degree Of Crystallinity

This study analyzed the effects of irradiation of polytetrafluoroethylene (PTFE) containing 40% of bronze using an electron beam with energy of 10 MeV. Dosages from 26 to156 kGy (2.6–15.6 Mrad) were used. The impact of a high-energy electron beam on the thermal, spectrophotometric, mechanical, and tribological properties was determined, and the results were compared with those obtained for pure PTFE. Thermal properties studies showed that such irradiation caused changes in melting temperature Tm and crystallization temperature Tc, an increase in crystallization heat ∆Hc, and a large increase in crystallinity χc proportional to the absorbed dose for both polymers. The addition of bronze decreased the degree of crystallinity of PTFE by twofold. Infrared spectroscopy (FTIR) studies confirmed that the main phenomenon associated with electron beam irradiation was the photodegradation of the polymer chains for both PTFE containing bronze and pure PTFE. This had a direct effect on the increase in the degree of crystallinity observed in DSC studies. The use of a bronze additive could lead to energy dissipation over the additive particles. An increase in hardness H and Young’s modulus E was also observed. The addition of bronze and the irradiation with an electron beam improved of the operational properties of PTFE.

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Sci-Thur PM: Planning & Delivery - 02: Treatment planning workflow for very high-energy electron beam radiotherapy

Medical Physics ◽

10.1118/1.4894982 ◽

2014 ◽

Vol 41 (8Part2) ◽

pp. 5-5

Author(s):

Magdalena Bazalova ◽

Bradley Qu ◽

Bianey Palma ◽

Bjorn Hårdemark ◽

Elin Hynning ◽

...

Keyword(s):

Electron Beam ◽

Treatment Planning ◽

High Energy ◽

Energy Electron ◽

High Energy Electron ◽

Very High Energy ◽

Electron Beam Radiotherapy ◽

Very High

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Modeling of Laboratory Animals Exposure Conditions behind Local Concrete Shielding Bombarded by 650-MeV Protons

Medical Radiology and radiation safety ◽

10.12737/1024-6177-2020-65-5-77-86 ◽

2021 ◽

Vol 65 (5) ◽

pp. 77-86

Author(s):

A Ivanov ◽

A Krylov ◽

A. Molokanov ◽

A. Bushmanov ◽

A. Samoylov

Keyword(s):

Absorbed Dose ◽

High Energy ◽

Laboratory Animals ◽

Diamond Detector ◽

Radiation Fields ◽

The Monte Carlo Method ◽

Direct Measurements ◽

Pass Through ◽

Protective Structures ◽

Dose Measurements

Purpose: To estimate the radiation fields formed after the passage of high-energy protons through the concrete protection for subsequent radiobiological experiments on animals on this model. Material and methods: The results of the calculation of the secondary characteristics of a field of mixed radiation behind the local concrete with thickness 20, 40, and 80 cm, bombarded by a proton beam of 650 MeV at the JINR Phasotron and experimental estimation of the values of the absorbed dose phantoms of mice irradiated for protection during radiobiological experiments. The calculation was performed by the Monte Carlo method according to the MCNPX program for secondary protons, neutrons, π-mesons, and gamma rays. To verify the adequacy of calculations was performed the comparison of calculated and measured in the experiment spatial distribution of activation threshold detectors for aluminum protection, as well as a comparison of the calculated values of absorbed dose for radiation protection with the results of absorbed dose measurements with a diamond detector. Results: The calculations made it possible to obtain the characteristics of the fields of mixed secondary radiation behind local concrete shields of different thickness irradiated with protons with an energy of 650 MeV and to estimate the values of absorbed doses in the irradiation sites of mice in the radiobiological experiment. The reliability of the calculations was confirmed by experimental verification of the activation of aluminum threshold detectors behind a 20 cm thick protection, as well as direct measurements using a diamond detector. Conclusion: The calculated assessment of radiation fields formed after protons pass through the concrete protection and its comparison with the results of radiation dose measurements for the subsequent radiobiological experiment on animals on this model in the interests of designing protective structures on the Moon and other space bodies, as well as biological defenses on charged-particles accelerators.

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The use of ionization chambers for the absorbed dose calibration of high energy electron beam therapy units

The International Journal of Applied Radiation and Isotopes ◽

10.1016/0020-708x(70)90025-6 ◽

1970 ◽

Vol 21 (1) ◽

pp. 1-3 ◽

Cited By ~ 11

Author(s):

P.R. Almond

Keyword(s):

Electron Beam ◽

Absorbed Dose ◽

High Energy ◽

Energy Electron ◽

High Energy Electron ◽

Ionization Chambers ◽

Electron Beam Therapy

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Comparison of ionometric and calorimetric absorbed dose measurements in a 10 MeV electron beam

International Journal of Radiation Oncology*Biology*Physics ◽

10.1016/0360-3016(78)90235-3 ◽

1978 ◽

Vol 4 ◽

pp. 76

Author(s):

J.G. Holt ◽

A. Buffa ◽

R.C. Fleischman ◽

J.C. McDonald ◽

I.C. Ma

Keyword(s):

Electron Beam ◽

Absorbed Dose ◽

Dose Measurements

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Commercial Thimble Chambers for Absorbed Dose Measurements at High Energy Electron Radiation

Acta Radiologica Therapy Physics Biology ◽

10.3109/02841867109130780 ◽

1971 ◽

Vol 10 (5) ◽

pp. 504-512 ◽

Cited By ~ 4

Author(s):

H. Svensson ◽

C. Pettersson ◽

G. Hettinger

Keyword(s):

Absorbed Dose ◽

High Energy ◽

Energy Electron ◽

Electron Radiation ◽

High Energy Electron ◽

Dose Measurements

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Absorbed dose measurements external to thick shielding at a high energy proton accelerator: Comparison with Monte-Carlo calculations

Nuclear Instruments and Methods in Physics Research ◽

10.1016/0167-5087(82)90344-1 ◽

1982 ◽

Vol 197 (2-3) ◽

pp. 465-472 ◽

Cited By ~ 3

Author(s):

J.D. Cossairt ◽

N.V. Mokhov ◽

C.T. Murphy

Keyword(s):

Monte Carlo ◽

Absorbed Dose ◽

High Energy ◽

Proton Accelerator ◽

High Energy Proton ◽

Monte Carlo Calculations ◽

Energy Proton ◽

Dose Measurements

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Review of surface dose detectors in radiotherapy

Journal of Radiotherapy in Practice ◽

10.1017/s1460396903000049 ◽

2003 ◽

Vol 3 (2) ◽

pp. 69-76 ◽

Cited By ~ 7

Author(s):

E. O'Shea ◽

P. McCavana

Keyword(s):

Absorbed Dose ◽

High Energy ◽

Skin Dose ◽

Surface Dose ◽

Radiographic Film ◽

Equilibrium Conditions ◽

Diamond Detector ◽

Thermoluminescent Dosimeters ◽

Absorbed Radiation Dose ◽

Dose Measurements

Several instruments have been used to measure absorbed radiation dose under non-electronic equilibrium conditions, such as in the build-up region or near the interface between two different media, including the surface. Many of these detectors are discussed in this paper. A common method of measuring the absorbed dose distribution and electron contamination in the build-up region of high-energy beams for radiation therapy is by means of parallel-plate ionisation chambers. Thermoluminescent dosimeters (TLDs), diodes and radiographic film have also been used to obtain surface dose measurements. The diamond detector was used recently by the author in an investigation on the effects of beam-modifying devices on skin dose and it is also described in this report.

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