Biomedical subjects
Kwan-Hoong Ng
Publications and source records attributed to Kwan-Hoong Ng.
Global quality control perspective for the physical and technical aspects of screen-film mammography--image quality and radiation dose.
The systematic monitoring of image quality and radiation dose is an ultimate solution to ensuring the continuously high quality of mammography examination. At present several protocols exist around the world, and different test objects are used for quality control (QC) of the physical and technical aspects of screen-film mammography. This situation may lead to differences in radiation image quality and dose reported. This article reviews the global QC perspective for the physical and technical aspects of screen-film mammography with regard to image quality and radiation dose. It points out issues that must be resolved in terms of radiation dose and that also affect the comparison.
A low-cost, high-quality method for remote recording of presentations.
OBJECTIVE: The purpose of this article was to develop a low-cost method for high-quality remote capturing and recording of multimedia presentations. CONCLUSION: The method for making high-quality digital recordings of presentations by using the mix of freely available software presented in this article offers great potential for institutions on a budget as well as others seeking viable alternatives to current methods of presentation recording.
Mammographic breast glandularity in Malaysian women: data derived from radiography.
OBJECTIVE: This study was undertaken to estimate mammographic breast glandularity in Malaysian women from radiographic data. MATERIALS AND METHODS: A mammography X-ray unit was used to expose different thicknesses of phantom material of varying glandular and adipose composition at 27 kV. A least squares method was then used to fit the combined data of phantom glandularity, thickness, and milliampere-seconds. The subsequent fitted equation was then applied to calculate breast glandularity for 705 women who underwent diagnostic mammography, who were drawn equally from the three major ethnic groups of Malaysia: Malay, Chinese, and Indian. The difference in breast glandularity among ethnic groups was tested for significance using the nonparametric Kruskal-Wallis test. RESULTS: The fitted equation gave an absolute error of less than or equal to +/- 8% when applied to the data from phantom exposure. The average breast glandularity of the study sample was 48.9% +/- 18.7%. Breast glandularity was found to decrease with breast thickness and age. CONCLUSION: No significant difference was seen in breast glandularity among the ethnic groups (p > 0.05, Kruskal-Wallis test).
A model for online interactive remote education for medical physics using the Internet.
BACKGROUND: Medical physics is a relatively small community but it spans great geographical distances, usually with a scarcity of experts whose expertise could greatly benefit students entering into the field. In addition there are many software systems for which an interactive education method would be most advantageous. OBJECTIVE: To develop a process to optimally use the Internet for real-time interactive remote education of medical physics and to present the experience of the study. METHODS: The project is a collaboration of the Department of Medical Physics at the Toronto-Sunnybrook Regional Cancer Centre in Canada and the Department of Radiology at the University of Malaya in Malaysia. A class of medical-physics graduate students at the University of Malaya attended lectures provided by lecturers in Toronto, using the Internet as the main tool of communication. RESULTS: The different methods that can be used to provide the real-time interactive remote education were explored, and various topics-including traditional classroom lectures as well as hands-on workshops-were also delivered. CONCLUSIONS: The concept of real-time interactive remote education is viable and holds promise for providing economical and practical tele-education to the medical physics community, but depends heavily on the availability of the Internet in many developing countries.