Due to the size(s) of the energy source, the detector(s) size, and other second-order factors, a specific-shaped Line Spread Function (LSF), or blurred Edge Response Function (ERF) in the image domain is obtained from a Delta Function or Step Function (SF) in the object domain. This specific-shaped LSF or `blurred’ ERF varies from edge position to edge position. Mathematically, the ERF can be derived by the convolution of the LSF with the SF. Experimentally, we can derive the “local” LSF from the ERF by a...
Material and methods
(A) Animal tissue and Phantoms were used for initial studies and calibrations, and patient field-trial examples were subsequently followed to study the merits of the methodology and to overcome certain problem features. (1) Animal tissue (Lamb Kidney) was examined with a MR Scanner using a Gradient-Echo sequence (TE: 26ms, TR:1160ms); 5mm slice. (2) A New York Catphan 500 and a Star-Burst phantom were examined with CT systems using technique factors of 120kVp, 300mA, 4 secs., 10mm slice and 120kVp, 130mA, 2.24 sec., 1mm slice respectively....
(A) Animal Tissue and Phantom Studies and Calibrations - (1) MR Animal tissues – Measurements and Discussions - The key Figures 2 & 3 were obtained from the tissue scan. In Figure 2, the `step-shape’ feature of the original digital data of the ERF of the animal tissue MR scan was reduced to the `smooth’ feature of the LSF by the effective Running Filter; And the averaging effect of the mid-point of the FWHM also contributed to both the sensitivity and accuracy. The length of...
The ERF-blurring or ”penumbral-spread” can not be overcome by current digital enhancement. This deconvolution technique permits sensitive and accurate edge-profile detection and enhancement to overcome the "penumbral-spread" problem. As a result, the definitive method to make accurate quantitative measurements in radiology may have been found. Potential applications are in radiological diagnosis, oncological response, microsurgery, and radiotherapy treatment planning.
Reference 1 - Judy P.F., Med. Phys. Vol. 3, No. 4, Jul/Aug 1976, pp.233-236). Reference 2 – `Accurate Measurements using a new algorithm in a patient with hepatic metastases from colon cancer’; by Chui S.L, Chui K.M., Stanfield D.B. Eurorad Case Report 2242, www.eurorad.org; 2003.10.02.
For any further enquiries, please do not hesitate to contact Dr. Kui M. Chui, E-mail: [email protected]
(or via http://www.iet.org.uk/ )