Effect of adjacent cavity on ionization-chamber measurements in a phantom for 1.25-MeV to 25-MV photon beams

1974 ◽  
Vol 1 (2) ◽  
pp. 79-79
Author(s):  
Robert Golden ◽  
Dale E. Starchman
Keyword(s):  
Ionization Chamber ◽  
Photon Beams ◽  
Chamber Measurements

Khảo sát một số đặc tính bức xạ của buồng ion hóa CC13 và diode bán dẫn razor đối với các chùm photon kích thước nhỏ trên máy gia tốc tuyến tính xạ trị Clinac IX

2020 ◽  
Author(s):  
Tu Vu Ngoc
Keyword(s):  
Radiation Field ◽  
Dose Response ◽  
Dose Distribution ◽  
Ionization Chamber ◽  
Field Size ◽  
Photon Beams ◽  
Silicon Diode ◽  
Depth Dose ◽  
The Difference

Purpose: Compare percent depth dose (PDD) and off-center ratio (OCR) measured by the CC13 ionization chamber and the RAZOR silicon diode in small photon beams. Method and Materials: Some dosimetric characteristics, such as PDD, OCR, penumbra and radiation field size, were considered in this study for 2x2, 3x3, and 4x4 cm2 field sizes. We used the CC13 ionization chamber and the RAZOR silicon diode to measure dose distribution with depth along the axis and off-center of the beam. From the results obtained, the team investigated the differences in radiation parameters measured by the two types of probes above. Results: There are significant differences in the radiation parameters investigated for the CC13 ionization chamber and the RAZOR silicon diode, especially the width of penumbra. For PDD curves, the difference is less than 5% from dmax to 30 cm, however the difference becomes greater in the build-up region, which reaches to 33% at the water phatom surface. The width of penumbra measured by CC13 is always larger than that of RAZOR, the ratio of the penumbra width between two detectors is 1.8 and 1.3 for energies of 6 MV and 15 MV, respectively. Conclusion: The RAZOR silicon diode has better dose response than the CC13 ionization chamber for measuring the PDD and the OCR in small photon beams.

Cable-induced effects on plane-parallel ionization chamber measurements in large clinical electron beams

1994 ◽  
Vol 19 (2) ◽  
pp. 73-76 ◽  
Author(s):  
Claudio Fiorino ◽  
Giovanni Mauro Cattaneo ◽  
Antonella Del Vecchio ◽  
Marcello Fusca ◽  
Barbara Longobardi ◽  
...  
Keyword(s):  
Ionization Chamber ◽  
Electron Beams ◽  
Plane Parallel ◽  
Chamber Measurements
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