Student Number : 8802466H -
MSc research report -
School of Physics -
Faculty of Science / Medical ionising radiation sources give by far the largest contribution to the
population dose from man-made sources. About 90% of this contribution is
due to x-ray diagnostic procedures. Doses from diagnostic radiology
procedures are nevertheless small and usually do not approach thresholds
for deterministic effects. However, they must be accurately determined in
order to maintain a reasonable balance between image quality and patient
exposure. There is, thus, a need to establish quality assurance for
diagnostic procedures that will provide the required clinical information in its
optimal form and with minimum dose to the patient. In order to achieve this,
dose measurements must be reproducible and the uncertainties associated
with that measurement should be known. One of key factors for ensuring
that appropriate levels of accuracy and long-term reproducibility of dose
measurements are maintained is a calibration of the measuring
equipment.
The IEC (International Electrotechnical Commission) issued a standard
IEC 61267 that deals with methods for generating radiation beams with
radiation conditions which can be used under test conditions typically
found in test laboratories for the determination of characteristics of medical
diagnostic X-ray equipment. The document is currently being revised and
publication of the new version is expected soon.
Standard radiation qualities were established at a laboratory following the
new IEC 61267 standard. Radiation qualities that characterize radiation
beams emerging from the X-ray target (RQR qualities) were established.
They were further filtered by Copper to obtain RQT beam qualities that
simulate those used in Computed Tomography (CT). The spatial uniformity
of a commercial CT dosimeter was then determined.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:wits/oai:wiredspace.wits.ac.za:10539/1691 |
| Date | 14 November 2006 |
| Creators | Msimang, Zakithi Lungile Mpumelelo |
| Source Sets | South African National ETD Portal |
| Language | English |
| Detected Language | English |
| Type | Thesis |
| Format | 309812 bytes, application/pdf, application/pdf |
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