Wei-Kom Chu

Ocular volume measured by CT scans

SummaryNewer CT scans have greatly enhanced oculometric research and made it possible to measure ocular dimensions. With these measurements, ocular volume can be more accurately estimated to understand its relationship with age and sex. One hundred CT orbit scans with presumed normal eyes were used for the data base. The mean values and normal variations of ocular volumes at various ages in both sexes are presented. Rapid growth of the eyeball was noted during the first 24 months of age. It reached its peak between the ages of 18 and 30 years of age, after which there was a reduction. Results may be of help in recognizing eye abnormalities such as microophthalmus and macrophthalmia.

Role of brachytherapy in the management of the skull base meningioma. Treatment of skull base meningiomas.

Background. The treatment of primary and recurrent skull base meningiomas presents a formidable surgical problem.

An examination of radiation exposure to clinical staff from patients implanted with 137Cs and 192Ir for the treatment of gynecologic malignancies.

The treatment of cancers by placement of radioactive materials within or adjacent to a tumor is clinically known as brachytherapy. Although the intracavitary treatment of gynecologic cancers using 137Cs has been in widespread use for nearly a century, interstitial techniques using 192Ir have developed within the last decade. Both procedures are performed as temporary implants and typically require a hospital stay of approximately 48 h. Significant differences in source strengths, loading conditions, and patient care requirements are visible between the intracavitary and interstitial techniques. Facilities that are experienced in the use of intracavitary techniques may lack clinical experience in the use of newer interstitial procedures. An examination of radiation exposure to the radiation oncology staff administering the treatment, exposure rate at frequently occupied points in the patient room, and exposure to the nursing staff will be of value to those institutions considering integration of interstitial brachytherapy techniques into their department.

A microcomputer-based system for MR imaging analysis of brain for hepatic encephalopathy

A microcomputer-based imaging system for acquisition and analysis is discussed. The high-intensity lesions due to hepatic encephalopathy have been demonstrated through the magnetic resonance imaging (MRI) sequences with T1 weighting (TR 600 ms/TE 20 ms) of the brain. Data from 11 patients with clinically proven hepatic encephalopathy, and three sets of normal brain MRI which were identified with no evidence of brain or liver diseases were collected. The histograms followed and generated out of brain MRI slices were composed of two distinguished peaks which were lumped together. After the decomposition and curve fitting procedures, the Gaussian distributions were identified with the mean value and the standard deviation. One was assumed to be gray index region for gray and white matter, the other with higher gray index value was the contribution of hepatic encephalopathy. Once the gray index range of the distribution has been determined, the affected portion could be marked out and highlighted.<<ETX>>

An Image Analysis Study On Thigh Muscles And Cross-sectional Area Determined By MRI

A computerized pattern recognition of magnetic resonance imaging (MRI) which the high quality for use in making quantitative diagnosis based on the histogram analysis and its application is accessible. A histogram shows display information how often pixel runs of a certain length and a certain gray level range are occurred in the image. By carrying out MR scans at forty-two evenly spaced levels along the right thigh of the volunteer, the histogram showing the differences in the distribution of shades within a region of interest (ROI) of in vivo determinations of cross-sectional area (C SA) of individual muscle. This study clearly demonstrates the clinical usefulness of the histogram as a diagnostic tool and the simplicity of measurements of CSA of a personal computer on video images of the MRI. To perform the manipulations and programming one of commercially available software and hardware are outlined.

An analysis of the elements essential in the development of a customized TBI program

Bone marrow transplant, once a procedure carried out at a relatively small number of large medical centers, is being employed at an increasing number of non-academic hospitals. The use of total body photon irradiation for the purpose of marrow ablation and immunosuppression can be expected to accompany the outward growth of bone marrow transplantation at these same hospitals. An analysis of the fundamental physical factors associated with total body photon irradiation (TBI) should be of value to facilities considering the incorporation of a total body irradiation program into an existing radiation oncology department. By examining the existing resources of a radiotherapy center and the clinical objectives of the treatment, a facility considering TBI may determine whether or not their center already fulfills the necessary criteria, in addition to the avoidance of potential pitfalls in project implementation.

MODELLING THE FREQUENCY DEPENDENCY OF THE ACOUSTICAL CHARACTERISTICS OF HUMAN LIVER

In this paper, we present an analytic way to measure the acoustical characteristics of human liver and their dependency on frequency and compare the derived model with others based on the empirical data collected in-vivo. The empirical data suggest a different and highly non-linear relation between the attenuation coefficient and backscattering coefficient with respect to frequency. Since these parameters are dependent on the tissue, we also investigate the feasibility of using these parameters for tissue differentiation. Results showed that the parameter values are closely clustered for normal subjects but widely varying and clearly distinguishable for abnormal subjects.