Biomedical subjects
Publications and source records attributed to I Crooks.
The lecturer-practitioner role can be a means of supporting students and making education relevant to practice. The professional credibility--and skills--of the post-holder can be enhanced by this link with practice. It is vital to ensure that the clinical aspects of the post are not neglected.
The application of NMR Fricke-gelatin dosimetry to the imaging of dose distributions around high dose rate (HDR) radioactive Ir-192 seeds in brachytherapy is presented. The duration of the irradiations required to give changes of the Fricke-gelatin NMR characteristics, which were readily detected by the magnetic resonance imager, typically ranged from 4 to 25 min for single source and multiple source (33 source positions distributed among three catheters) geometries, respectively. A fast approach for determining radiation dose from MR image intensity using a calibration curve is described. NMR Fricke-gel dosimetry is shown to be a viable means of verifying the dose distributions from brachytherapy sources.
A 2-day video-based workshop developed for teaching psychiatrists was used to instruct learner psychiatric nurses in the conversational model of psychotherapy. A small evaluation was carried out to assess the effects of the teaching on the performance of these nurses in interviewing other learner nurses who role-played people with common emotional difficulties. A randomized groups design was used comparing the interview behaviour of experimental and control groups before and after the workshops, and at 3 months follow-up. Considered as a pilot the study was instructive, although only one significant result emerged. The conversational model of psychotherapy and the teaching workshops devised and used previously with psychiatrists can be used by nurses, including those still in training.
A novel algorithm, histogram shifting (HS) is presented, which performs edge detection or edge enhancement with the choice of two parameters. The histogram of a region surrounding each pixel is found and translated toward the origin, resulting in the new pixel value. Images from a variety of medical imaging modalities were processed with HS to perform detection and enhancement of edges. Comparison with results obtained from conventional edge detection (e.g., Sobel) and with conventional edge-enhancement algorithms is discussed. HS appears to perform the edge-detection operation without introducing "double-edge" effects often obtained with conventional edge-detection algorithms. HS also appears to perform edge enhancement without introducing extensive noise artifacts, which may be noticeable with many edge-enhancement algorithms.
Because of the high energy of the treatment beam, contrast of portal verification films is very poor. A simple contrast enhancement technique is described which we have labeled selective histogram equalization (SHE), to improve visualization of double-exposure portal images and this facilitate the beam verification process. The technique performs separate histogram equalization on the treatment- and open-field sections of double-exposure portal images. Delineation of the treatment field edge and separation into two regions is performed automatically for off-line portal radiographs by a strategic combination of Sobel filtration and morphological processes. Analyses of images processed by SHE and other adaptive histogram equalization techniques indicate that SHE produces improved contrast enhancement with minimal addition of noise or artifacts, thus simplifying the beam verification procedure. The simple implementation of an automatic SHE process with on-line portal systems is also discussed.