SU-E-T-102: Measurement of Absorbed Dose-To-Water for An HDR Ir-192 Source with a Farmer Ionization Chamber in a Sandwich Setup

2013 ◽  
Vol 40 (6Part12) ◽  
pp. 227-227
Author(s):  
F Araki ◽  
T Kouno ◽  
T Ohno ◽  
S Kawamura ◽  
K Kakei
Keyword(s):  
Ionization Chamber ◽  
Absorbed Dose ◽  
Absorbed Dose To Water

scholarly journals Calibration of Therapy Level Ionization Chamber at 60Co Teletherapy Beam Used for Radiation Therapy

2018 ◽  
Vol 79 ◽  
pp. 1-8
Author(s):  
Md. Ali Reza ◽  
Md. Rakibul Islam ◽  
Md. Shakilur Rahman ◽  
Md. Shamsuzzaman ◽  
Md. Rashedur Rahman ◽  
...  
Keyword(s):  
Ionization Chamber ◽  
Absorbed Dose ◽  
Critical Issue ◽  
Calibration Factor ◽  
Ionization Chambers ◽  
Depth Dose ◽  
Output Factors ◽  
Absorbed Dose To Water ◽  
Radiotherapy Dosimetry ◽  
Water Measurement

The accuracy and traceability of absorbed dose to water measurement of radiotherapy beam is a critical issue to achieve the curative outcome of cancer patients. The current dosimetry protocols for radiotherapy beams TRS-398, TG-51 and DIN-6800-2 are based on the calibration factor of ionization chamber in terms of absorbed dose to water for 60Co beam. The accuracy of the calibration factor of ionization chamber as well as output of radiotherapy beam is the primary requirements of precisional dose deliver to the tumor which is the QA part of radiotherapy dosimetry. In the present study, we have calibrated 9 different ionization chambers (8 thimbles and 1 parallel plate) of various active volumes for 60Co beam against reference standard NE2571 and compared with manufacturer’s values. The Percentage Depth Dose (PDD) and Output Factors (OF) of two cobalt units were measured with standard calibration system by following IAEA dosimetry protocol TRS-398 and compare with 6 MV photon beam from medical linear accelerator. The traceability of the dosimetry was verified by the participation of postal dose IAEA/WHO intercomparison program. The aim of the participation was to investigate uncertainties involved in the calibration of Ionization Chamber (IC) and absorbed dose measurement. The percentage of deviation relative to IAEA mean dose was found to be -0.2% (traceable limit ±5%), which shows an excellent agreement of calibration of beam as well as ionization chamber with international standard. The deviation of factors of ionization chambers between the measured and manufacturer’s values were found within 0.07-2.81% with an uncertainty of ±1.5% (k=1).

Performance evaluation of graphite pancake ionization chamber by comparing the absorbed dose to water calibration

2006 ◽  
Vol 41 (3) ◽  
pp. 306-316 ◽  
Author(s):  
J.H. Lee ◽  
C.Y. Lin ◽  
C.F. Wang ◽  
D.J. Butler ◽  
D.V. Webb ◽  
...  
Keyword(s):  
Performance Evaluation ◽  
Ionization Chamber ◽  
Absorbed Dose ◽  
Absorbed Dose To Water

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

2001 ◽  
Vol 1 (1) ◽  
pp. 8-8 ◽  
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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