Measurement of ki using ionization chamber and gafchromic films for mobile x-ray machine
The aim of this study is to determine the incident air kerma (Ki) for mobile unit x-ray by using ionization chamber and Gafchromic films based on TRS457. Examination of abdomen and chest had been chosen in this study. Exposure parameters that had been used was 83kVp/ 12.5 mAs, 85kVp/32.0 mAs and 85...
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| Format: | Monograph |
| Language: | English |
| Published: |
Universiti Sains Malaysia
2016
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| Online Access: | http://eprints.usm.my/62323/ http://eprints.usm.my/62323/1/NURUL%20AISHAH%20MOHD%20NASIR%20-%20e.pdf |
| Summary: | The aim of this study is to determine the incident air kerma (Ki) for mobile unit x-ray by using ionization chamber and Gafchromic films based on TRS457. Examination of abdomen and chest had been chosen in this study. Exposure parameters
that had been used was 83kVp/ 12.5 mAs, 85kVp/32.0 mAs and 85kVp/ 40mAs for
abdomen examination, while for chest was 120kVp/ 5mAs, 125kVp/1.0 mAs and
125kVp/1.6mAs. The first objective was to study the dose response of the Gafchromic
XR-QA2 and XR-RV3 films. The films irradiated with 70, 80, 90 and lOOkVp for
20mAs. The films were scanned by using Epson 10000XL flatbed scanner after 24hours
irradiation, to obtain the pixel value of the films. Then, the pixel value had to be
changed to optical density to plot the linearly dose response graph. The study showed
linear relationship for Gafchromic XR-QA2 film, but not for XR-RV3 films since the
Gafchromic XR-RV3 films was fluoroscopic-guided favour. The study was preceded by
obtaining of calibration curve for Gafchromic XR-QA2 films to get the dose from the
films. The cross-checked dose obtained from IC and calibration curve used for the
calculation for measurement of Ki. The result showed Ki for films was higher than IC
due to the difference of sensitivity. Large variation was displayed in term of percentage
difference (%) for abdomen was 34% to 108%, while for chest was 32% to 350%. The
reasons why the large variation of percentage difference were due to the usage of
parameter that contributed to out of range dose, properties of films and mishandling of
the films. As a conclusion, the variation of percentage difference is not significantly
different between IC and Gafchromic films if the dose in range applied in this study. |
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