Poster - Wed Eve-18: Investigating Responses of Three Commercial p-Type Silicon Diodes on Percentage Depth Dose (PDD) Distributions of Megavoltage LINAC Photon Beams

2009 ◽  
Vol 36 (9Part2) ◽  
pp. 4307-4307
Author(s):  
E Sham
Keyword(s):  
Photon Beams ◽  
Percentage Depth Dose ◽  
Type Silicon ◽  
Depth Dose ◽  
P Type

Percentage depth dose fragmentation for investigating and assessing the photon beam dosimetry quality

2018 ◽  
Vol 18 (03) ◽  
pp. 280-284 ◽  
Author(s):  
Mohamed Bencheikh ◽  
Abdelmajid Maghnouj ◽  
Jaouad Tajmouati
Keyword(s):  
Exponential Decay ◽  
Target Volume ◽  
Photon Beam ◽  
Field Size ◽  
Photon Beams ◽  
Energy Agency ◽  
Percentage Depth Dose ◽  
Depth Dose ◽  
Beam Dosimetry

AbstractAimThe purpose of this study is to introduce a new approach to assess the dosimetry quality of photon beam with energy and irradiation field size. This approach is based on percentage depth dose (PDD) fragmentation for investigating the dosimetry quality.Materials and methodsFor the investigation of the dosimetry quality of 6 and 18 MV photon beams, we have proceeded to fragment the PDD at different field sizes. This approach checks the overall PDD and is not restricted to the exponential decay regions, as per the International Atomic Energy Agency Technical Reports Series No 398 and the American Association of Physicist in Medicine Task Group 51 recommendations.Results and discussionThe 6 MV photon beam deposited more energy in the target volume than the 18 MV photon beam. The dose delivered by the 6 MV beam is greater by a factor of 1·5 than that delivered by the 18 MV beam in the build-up region and the dose delivered by the 6 MV beam is greater by a factor of 2·6 than that delivered by the 18 MV beam in the electronic equilibrium and the exponential decay regions.ConclusionThe dose measured at different points of the beam is higher for 6 MV than for 18 MV photon beam. Therefore, the 6 MV beam is more dosimetrically efficient than the 18 MV beam. Using the proposed approach, we can assess the dosimetry quality by taking into account overall PDD not only in the exponential decay region but also in the field.

scholarly journals Applications and benefits of using gradient percentage depth dose instead of percentage depth dose for electron and photon beams in radiotherapy

2021 ◽  
Vol 27 (1) ◽  
pp. 25-29
Author(s):  
Labinot Kastrati ◽  
Gezim Hodolli ◽  
Sehad Kadiri ◽  
Elvin Demirel ◽  
Lutfi Istrefi ◽  
...  
Keyword(s):  
Electron Beams ◽  
Published Data ◽  
Photon Beams ◽  
Data Set ◽  
Percentage Depth Dose ◽  
Depth Dose ◽  
Electron And Photon

Abstract Introduction: The aim of this study is to analyze the gradient of percentage depth dose for photon and electron beams of LINACs and to simplify the data set. Materials and Methods: Dosimetry measurements were performed in accordance with Technical Reports Series No. 398 IAEA. Results and discussion: The gradient of percentage depth dose was calculated and compared with the available published data. Conclusion: Instead of percentage depth dose for increasing and decreasing parts, the findings suggest using only two numbers for specific gradient of dose, separately. In this way, they can replace the whole set of the percentage depth dose (PDD).

scholarly journals A modified formula for defining tissue phantom ratio of photon beams

2008 ◽  
Vol 33 (3) ◽  
pp. 92-97
Author(s):  
M Jahangir Alam ◽  
KS Rabbani ◽  
GA Zakaria ◽  
SM Akram Hussain ◽  
Adnan Kiber ◽  
...  
Keyword(s):  
Linear Accelerator ◽  
Measured Data ◽  
German Cancer Research ◽  
Photon Beams ◽  
Data Set ◽  
Surface Distance ◽  
Percentage Depth Dose ◽  
Depth Dose ◽  
Tissue Phantom ◽  
Modified Formula

Tissue phantom ratio (TPR), for square fields of various dimensions has been determined at varying depths in water. The dose in water has been measured at a fixed source-to-surface distance (SSD) of 100 cm and reference depth of 5 cm for 6 MV photon beam of Siemens Linear Accelerator Primus II in German Cancer Research Center (DKFZ), Heidelberg, Germany. A modified formula has been developed to calculate the TPR value for isocentric treatment. The present article describes the conversion of the measured data values into a comprehensive and consistent data set by the modified formula, that gives the TPR from Percentage Depth Dose (PDD) with depth as a function of field sizes from 10 mm x 10 mm up to 300 mm x 300 mm) and depth (from 0 mm to 300 mm).DOI = 10.3329/bmrcb.v33i3.1140Bangladesh Med Res Counc Bull 2007; 33: 92-97

scholarly journals Can Gafchromic EBT3 films effectively characterize small fields of 6 MV unflattened photon beams of Cyberknife system?

2018 ◽  
Vol 24 (4) ◽  
pp. 181-187
Author(s):  
Jerrin Amalraj ◽  
Ramasubramanian Velayudham ◽  
Pichandi Anchineyan
Keyword(s):  
Silicon Detectors ◽  
Photon Beams ◽  
Output Factor ◽  
Percentage Depth Dose ◽  
Depth Dose ◽  
Gamma Analysis ◽  
Small Fields ◽  
Output Factors ◽  
Dose Measurements ◽  
Dose Difference

Abstract Shielded silicon diodes are commonly employed in commissioning of Cyberknife 6 MV photon beams. This study aims to measure output factors, off centered ratio (OCR), percentage depth dose (PDD) of 6 MV photons using shielded and unshielded diodes and to compare with Gafchromic EBT3 film measurements to investigate whether EBT3 could effectively characterize small 6 MV photon beams. Output factors, OCR and PDD were measured with shielded and unshielded silicon detectors in a radiation field analyzer system at reference condition. Water equivalent solid phantom were used while irradiating EBT3 films. From multiuser data, diodes underestimated output factor by 3% for collimator fields ≤ 10 mm, while EBT3 underestimated the output factor by 3.9% for 5 mm collimator. 1D Gamma analysis of OCR between diode and film, results in gamma ≤ 1 for all measured points with 1 mm distance to agreement (DTA) and 1% relative dose difference (DD). Dose at surface is overestimated with diodes compared to EBT3. PDD results were within 2% relative dose values between diode and EBT3 except for 5 mm collimator. Except for small collimator fields of up to 10 mm, results of output factor, OCR, PDD of all detectors used in this study exhibited similar results. Relative dose measurements with Gafchromic EBT3 in this work show that EBT3 films can be used effectively as an independent tool to verify commissioning beam data of small fields only after careful verification of methodology for any systematic errors with appropriate readout procedure.

scholarly journals Analysis of Tissue Phantom Ratio of the Megavoltage Photon Beams

2018 ◽  
Vol 5 (2) ◽  
pp. 61-68
Author(s):  
M. A. Rahman ◽  
M. Jahangir Alam
Keyword(s):  
General Hospital ◽  
Source Surface ◽  
Photon Beams ◽  
Surface Distance ◽  
Mean Error ◽  
Percentage Depth Dose ◽  
Depth Dose ◽  
Tissue Phantom ◽  
Phantom Tissue ◽  
Good Agreement

Iso-centric beam data, phantom tissue ratios (TPR) are a dosimetric quantity commonly used to describe the change in dose with depth in tissue. Measurement of this is time-consuming and has the possibility of lose the consistency. The value of this quantity of any filed size in any depth is possible to calculate conveniently by the newly developed formula using only percentage depth dose (PDD) data of two fields. PDD for square fields ranging from 2 to 30 cm and various depths in increment of 0.4 cm up to maximum 30 cm have been measured in water at a fixed source surface distance (SSD) of 90 cm for 4, 6 and 15 MV photon beams in Ahsania Mission Cancer & General Hospital (AMCGH), Dhaka, Bangladesh. TPR values calculating for these energies of the same field sizes, depths and SSD by using the developed formula compared with those determined from the measured PDD data using a standard formula and had the good agreement. Mean error less than 1% observed between these TPR values.  

Development of a fibre-optic dosemeter to measure the skin dose and percentage depth dose in thebuild-up region of therapeutic photon beams

2012 ◽  
Vol 153 (3) ◽  
pp. 294-299 ◽  
Author(s):  
K.- A. Kim ◽  
W. J. Yoo ◽  
K. W. Jang ◽  
J. Moon ◽  
K.- T. Han ◽  
...  
Keyword(s):  
Skin Dose ◽  
Fibre Optic ◽  
Photon Beams ◽  
Percentage Depth Dose ◽  
Depth Dose ◽  
Therapeutic Photon Beams

scholarly journals Determination of piezo-resistive coefficient π44 in p-type silicon by comparing simulation and measurement of pressure sensors

AIP Advances ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 085005
Author(s):  
Kevin Lauer ◽  
Geert Brokmann ◽  
Mario Bähr ◽  
Thomas Ortlepp
Keyword(s):  
Pressure Sensors ◽  
Type Silicon ◽  
P Type
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