Modifications of Depth Dose Curves of High Energy X-Ray and Electron Beams by Interposed Bone

Radiology ◽  
1956 ◽  
Vol 66 (1) ◽  
pp. 102-104 ◽  
Author(s):  
Lewis L. Haas ◽  
Glen H. Sandberg
Keyword(s):  
Electron Beams ◽  
High Energy ◽  
X Ray ◽  
Depth Dose

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 Radiosensitization Effect of Gold Nanoparticles in Proton Therapy

2021 ◽  
Vol 9 ◽  
Author(s):  
Charnay Cunningham ◽  
Maryna de Kock ◽  
Monique Engelbrecht ◽  
Xanthene Miles ◽  
Jacobus Slabbert ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Proton Beam ◽  
Proton Therapy ◽  
Metallic Nanoparticles ◽  
Combined Treatment ◽  
Experimental Studies ◽  
High Energy ◽  
Proton Beams ◽  
X Ray ◽  
Depth Dose

The number of proton therapy facilities and the clinical usage of high energy proton beams for cancer treatment has substantially increased over the last decade. This is mainly due to the superior dose distribution of proton beams resulting in a reduction of side effects and a lower integral dose compared to conventional X-ray radiotherapy. More recently, the usage of metallic nanoparticles as radiosensitizers to enhance radiotherapy is receiving growing attention. While this strategy was originally intended for X-ray radiotherapy, there is currently a small number of experimental studies indicating promising results for proton therapy. However, most of these studies used low proton energies, which are less applicable to clinical practice; and very small gold nanoparticles (AuNPs). Therefore, this proof of principle study evaluates the radiosensitization effect of larger AuNPs in combination with a 200 MeV proton beam. CHO-K1 cells were exposed to a concentration of 10 μg/ml of 50 nm AuNPs for 4 hours before irradiation with a clinical proton beam at NRF iThemba LABS. AuNP internalization was confirmed by inductively coupled mass spectrometry and transmission electron microscopy, showing a random distribution of AuNPs throughout the cytoplasm of the cells and even some close localization to the nuclear membrane. The combined exposure to AuNPs and protons resulted in an increase in cell killing, which was 27.1% at 2 Gy and 43.8% at 6 Gy, compared to proton irradiation alone, illustrating the radiosensitizing potential of AuNPs. Additionally, cells were irradiated at different positions along the proton depth-dose curve to investigate the LET-dependence of AuNP radiosensitization. An increase in cytogenetic damage was observed at all depths for the combined treatment compared to protons alone, but no incremental increase with LET could be determined. In conclusion, this study confirms the potential of 50 nm AuNPs to increase the therapeutic efficacy of proton therapy.

Dosimetric evaluation of a novel electron–photon mixed beam, produced by a medical linear accelerator

2018 ◽  
Vol 17 (3) ◽  
pp. 319-331
Author(s):  
Navid Khaledi ◽  
Dariush Sardari ◽  
Mohammad Mohammadi ◽  
Ahmad Ameri ◽  
Nick Reynaert
Keyword(s):  
Electron Beams ◽  
High Energy ◽  
Primary Electron ◽  
Linear Accelerators ◽  
Ion Chamber ◽  
Depth Dose ◽  
Mixed Beam ◽  
Small Fields ◽  
Lead Layer ◽  
Electron Photon

AbstractAimThis study deals with the characteristics of simultaneous photon and electron beams in homogenous and inhomogeneous phantoms by experimental and Monte Carlo dosimetry, for therapeutic purposes. Materials and methods: Both 16 and 20 MeV high-energy electron beams were used as the original beam to strike perforated lead sheets to produce the mixed beam. The dosimetry results were achieved by measurement in an ion chamber in a water phantom and film dosimetry in a Perspex nasal phantom, and then compared with those calculated through a simulation approach. To evaluate two-dimensional dose distribution in the inhomogeneous medium, the dose–area histogram was obtained.ResultsThe highest percentage of photon contribution in mixed beam was found to be 36% for 2-mm thickness of lead layer with holes diameter of 0·2 cm for a 20 MeV primary electron energy. For small fields, the percentage depth dose parameters variations were found to be similar to pure electron beam within ±2%. The most feasible flatness in beam profile was 11% for pure electron and 7% for the mixed beam. Penumbra changes as function of depth was about ten times better than in pure electron field.ConclusionsThe results present some dosimetric advantages that can make this study a platform for the production of simultaneous mixed beams in future linear accelerators (LINACs), which through redesign of the LINAC head, which could lead to setup error reduction and a decrease of intra-fractional tumour cells repair.

PERCENTAGE DEPTH DOSE FOR HIGH ENERGY X-RAY BEAMS IN RADIOTHERAPY

1973 ◽  
Vol 118 (4) ◽  
pp. 919-922 ◽  
Author(s):  
J. A. RAWLINSON ◽  
H. E. JOHNS
Keyword(s):  
High Energy ◽  
X Ray ◽  
Percentage Depth Dose ◽  
Depth Dose

A comparison of chemical and ionization dosimetry for high-energy x-ray and electron beams

1981 ◽  
Vol 8 (2) ◽  
pp. 197-202 ◽  
Author(s):  
J. J. G. Durocher ◽  
H. Boese ◽  
D. V. Cormack ◽  
A. F. Holloway
Keyword(s):  
Electron Beams ◽  
High Energy ◽  
X Ray

scholarly journals Microcoulomb (0.7 ± $$\frac{0.4}{0.2}$$ μC) laser plasma accelerator on OMEGA EP

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
J. L. Shaw ◽  
M. A. Romo-Gonzalez ◽  
N. Lemos ◽  
P. M. King ◽  
G. Bruhaug ◽  
...  
Keyword(s):  
Laser Plasma ◽  
Electron Beams ◽  
Laser Energy ◽  
Short Pulse ◽  
Lawrence Livermore National Laboratory ◽  
National Laboratory ◽  
High Energy ◽  
High Energy Density ◽  
X Ray ◽  
Omega Laser

AbstractLaser-plasma accelerators (LPAs) driven by picosecond-scale, kilojoule-class lasers can generate particle beams and x-ray sources that could be utilized in experiments driven by multi-kilojoule, high-energy-density science (HEDS) drivers such as the OMEGA laser at the Laboratory for Laser Energetics (LLE) or the National Ignition Facility at Lawrence Livermore National Laboratory. This paper reports on the development of the first LPA driven by a short-pulse, kilojoule-class laser (OMEGA EP) connected to a multi-kilojoule HEDS driver (OMEGA). In experiments, electron beams were produced with electron energies greater than 200 MeV, divergences as low as 32 mrad, charge greater than 700 nC, and conversion efficiencies from laser energy to electron energy up to 11%. The electron beam charge scales with both the normalized vector potential and plasma density. These electron beams show promise as a method to generate MeV-class radiography sources and improved-flux broadband x-ray sources at HEDS drivers.

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