Comment on “Calculated absorbed-dose ratios, TG51/TG21, for most widely used cylindrical and parallel-plate ion chambers over a range of photon and electron energies” [Med. Phys.29, 1464-1472 (2002)]

2003 ◽  
Vol 30 (3) ◽  
pp. 473-477 ◽  
Author(s):  
M. Saiful Huq
Keyword(s):  
Parallel Plate ◽  
Absorbed Dose ◽  
Ion Chambers

scholarly journals EP-1446: Can parallel plate ion chambers be used for PDD measurements in FFF beams?

2017 ◽  
Vol 123 ◽  
pp. S771-S772
Author(s):  
S. Vargas Castrillón ◽  
F. Cutanda
Keyword(s):  
Parallel Plate ◽  
Ion Chambers

Response of Parallel‐Plate Ion Chambers to Radiation Pulses

1964 ◽  
Vol 35 (8) ◽  
pp. 2341-2348
Author(s):  
Peter M. Livingston
Keyword(s):  
Parallel Plate ◽  
Ion Chambers

scholarly journals Measurement with electret ion chambers of absorbed dose outside the treated volume, during external-photon radiation therapy

2021 ◽  
pp. 15-15
Author(s):  
Alexandros Clouvas ◽  
Anna Makridou ◽  
Michalis Chatzimarkou
Keyword(s):  
Radiation Therapy ◽  
Treatment Planning ◽  
Absorbed Dose ◽  
Planning System ◽  
Photon Radiation ◽  
Treatment Planning System ◽  
Low Doses ◽  
Prescription Dose ◽  
Ion Chambers ◽  
Leakage Radiation

The capabilities of electret ion chambers to measure non-target absorbed dose for distances greater than 20 cm from the irradiated volume during radiotherapy treatment was investigated for the first time. During radiotherapy, nontarget doses can be classified as one of three approximate dose levels: high doses, intermediate doses and low doses. Low doses (<5 % of the prescription dose) are not generally considered during treatment planning, due to the fact that is difficult to measure, characterize, or model them in the planning system. In this work were performed measurements with electret ion chambers of absorbed dose outside the treated volume (<5 % of the prescription dose), during external photon radiation therapy in an Elekta Infinity Linear Accelerator of ?Theagenio? Cancer Hospital of Thessaloniki, Greece. The absorbed dose values for distances greater than 20 cm from the irradiated volume varied from 0.3 to 17 mGy which corresponds to 0.01% up to 0.6% of the prescription dose (2660 mGy). Near the irradiation volume the absorbed dose values were greater than the upper detection limit of the electret ion chambers (threshold 40 mGy). The results are compared with the calculated ones by the Monaco Treatment Planning System (Elekta Monaco 5.11.03). In the non-target radiation region where Monaco Treatment Planning System calculates rather precisely (within uncertainties of less than 10%) the absorbed dose, measured and calculated doses are the same within experimental uncertainties. On the contrary, when leakage radiation becomes the dominant source of out-of-field dose the differences are up to 31%.

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