Maziar Soltani Emir Medic BEE 04:14, pp. 33. TEK/avd. för signalbehandling, 2005.
Since the end of the 1900th century ionized radiation, foremost X-ray radiation,
have been used, with great success, within the medical field as a method for
diagnostics as well as for therapeutically treatments. When it comes to X- ray
diagnostics, the analogue film, detector and display medium have, in principle,
been used the whole time. This is now rapidly changing, in a way that makes
digital detectors dominate instead.
Within the area of medical treatment, this means that methods must progress and
be developed to measure and secure the quality of the imaging systems in a quick,
easy and accurate way.
The ability of the imaging system to reproduce the measured objects in a natural
manner can be characterized by a number of different parameters such as; ESF
(Edge spread function), LSF (Line spread function), MTF (Modulation transfer
function), NPS (Noise power spectrum), and DQE (Detective quantum
efficiency). These parameters can be received for each detector through
experimental measurements of a sharp edge.
The starting point of the project is the suggestions that are stated in the standard
form IEC (622 20-1) determination of detective quantum efficiency, which was
published by the end of 2003.
Purpose of the project:
• Construct a test object (phantom) that can generate a sharp edge in the X-
• Develop a program code in the high-level language MATLAB for
determination of earlier mentioned parameters, MTF and DQE in
• Work out radiation geometry, suitable for the purpose.
• Verify the usability through practical measurements on already existing
clinical equipment at the hospital in Blekinge.
• Study the effect of radiation energy, dose of radiation, detector direction,
spatial frequency, variation of sampling of the edge spread function (ESF),
• Compare gained results with relevant literature.
The practical meaning of the present case project is to:
• Make a clinically usable method for the quality safety of digital, medical
X- ray equipment available at the hospital in Blekinge.
• Transfer, from the hospital in Blekinge to the Blekinge Institute of
Technology, competence within medical radiation physics and medical
technology, which could be interesting since the University is considering
increasing their commitment within this area.
• The method can be spread within the informal co-operation, concerning
medical radiation physics that is present within the hospitals outside the
University districts in the southern region.