This thesis details the measurement and simulation of patient skin doses arising from
X-ray exposure during interventional cardiology procedures. Interventional cardiology
procedures can be long and complex resulting in high skin doses, to the extent that radiation
burns may be produced. Twenty patients were used in the study consisting of 10 coronary
angiogram and 10 coronary angioplasty procedures.
Radiochromic films were used to measure skin dose directly. The Gafchromic® XR-RV2
film was chosen for its suitability for this project. The key characteristics of this film were
experimentally determined including: dose response, energy dependence, polarisation and
post-exposure growth. The dose range was found to be ideally suited for the doses
encountered in this study. Energy dependence was found to be ~14% between 60 and
125 kVp at 1 Gy and introduced an unavoidable uncertainty into dose calculations from
unknown beam energies. Document scanner characteristics were also been investigated and a
scanning protocol is determined.
A mathematical model was created to use the geometry and exposure information encoded
into acquisition files to reconstruct dose and dose distributions. The model requires a set of
study files encoded according to the DICOM format, as well as user input for fluoroscopic
estimations. The output is a dose map and dose summary.
Simulation parameters were varied and results compared with film measurements to
provide the most accurate model. From the data collected the relation between dose area
product, maximum skin dose and fluoroscopic time were also investigated.
The results demonstrated that a model based on acquisition information can accurately
predict maximum skin dose and provide useful geometrical information. The model is
currently being developed into a standalone program for use by the Medical Physics and
Bioengineering department.
| Identifer | oai:union.ndltd.org:canterbury.ac.nz/oai:ir.canterbury.ac.nz:10092/2603 |
| Date | January 2009 |
| Creators | Blair, Andrew Warwick |
| Publisher | University of Canterbury. Medical Physics |
| Source Sets | University of Canterbury |
| Language | English |
| Detected Language | English |
| Type | Text, Electronic thesis or dissertation |
| Rights | Copyright Andrew Warwick Blair, http://library.canterbury.ac.nz/thesis/etheses_copyright.shtml |
| Relation | NZCU |
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