MyMedR

A low-cost, high-quality method for remote recording of presentations

Tan LK, Wong JH, Ng KH

AJR Am J Roentgenol, 2006 Mar;186(3):898-901.

The purpose of this article was to develop a low-cost method for high-quality remote capturing and recording of multimedia presentations.

Mammographic breast glandularity in Malaysian women: data derived from radiography

Jamal N, Ng KH, McLean D, Looi LM, Moosa F

AJR Am J Roentgenol, 2004 Mar;182(3):713-7.

PMID: 14975974

This study was undertaken to estimate mammographic breast glandularity in Malaysian women from radiographic data.

Magnetic Resonance Imaging Phenotypes of Breast Cancer Molecular Subtypes: A Systematic Review

Ab Mumin N, Ramli Hamid MT, Wong JHD, Rahmat K, Ng KH

Acad Radiol, 2022 Jan;29 Suppl 1:S89-S106.

PMID: 34481705 DOI: 10.1016/j.acra.2021.07.017

OBJECTIVE: Magnetic resonance imaging (MRI) is the most sensitive imaging modality in detecting breast cancer. The purpose of this systematic review is to investigate the role of human extracted MRI phenotypes in classifying molecular subtypes of breast cancer.

METHODS: We performed a literature search of published articles on the application of MRI phenotypic features in invasive breast cancer molecular subtype classifications by radiologists' interpretation on Medline Complete, Pubmed, and Google scholar from 1st January 2000 to 31st March 2021. Of the 1453 literature identified, 42 fulfilled the inclusion criteria.

RESULTS: All studies were case-controlled, retrospective study and research-based. The majority of the studies assessed the MRI features using American College of Radiology- Breast Imaging Reporting and Data System (ACR-BIRADS) classification and using dynamic contrast-enhanced (DCE) kinetic features, Apparent Diffusion Coefficient (ADC) values, and T2 sequence. Most studies divided invasive breast cancer into 4 main subtypes, luminal A, luminal B, HER2, and triple-negative (TN) cancers, and used 2 readers. We present a summary of the radiologists' extracted breast MRI phenotypical features and their correlating breast cancer subtypes classifications. The characteristic features are morphology, enhancement kinetics, and T2 signal intensity. We found that the TN subtype has the most distinctive MRI features compared to the other subtypes and luminal A and B have many similar features.

CONCLUSION: The MRI features which are predictive of each subtype are the morphology, internal enhancement features, and T2 signal intensity, predominantly between TN and the rest. Radiologists' visual interpretation of some of MRI features may offer insight into the respective invasive breast cancer molecular subtype. However, current evidence are still limited to "suggestive" features instead of a diagnostic standard. Further research is recommended to explore this potential application, for example, by augmentation of radiologists' visual interpretation by artificial intelligence.

Denture hyperplasia and oncocytic metaplasia

Siar CH, Ng KH, Ngui CH

Ann Dent, 1992;51(1):27-8.

PMID: 1632623

A case of denture hyperplasia of the upper labial sulcus with concomitant oncocytic metaplastic changes is described. The patient concerned is an elderly male wearing an ill-fitting upper full denture.

Leiomyoma of the incisive papilla region: a case report

Ng KH, Siar CH, Abdul Latif H

Ann Dent, 1992;51(1):29-31.

PMID: 1632624

Leiomyomas are benign neoplasms of smooth muscle origin. They represent rare entities in the oral cavity. A case arising from the incisive papilla region of a 3-month-old infant is described and the histogenesis as well as the biologic potential of this tumor are discussed.

Kimura's disease: a case report

Ng KH, Siar CH, Loh HT

Ann Dent, 1991;50(2):26-7.

PMID: 1785910

The clinical and histologic features of Kimura's disease are briefly outlined. A case presenting as a subcutaneous nodule in the region of the angle of the right mandible of a 20-year-old male is presented. The relationship of this disease to angiolymphoid hyperplasia with eosinophilia is discussed.

A study on the prevalence of oral habits in 100 cases of squamous cell carcinoma in Malaysia

Ng KH, Siar CH, Ramanathan K, Murugasu P

Ann Dent, 1986;45(2):7-10.

PMID: 3468879

Calcifying odontogenic cysts in peninsular Malaysia. A report of 30 cases

Ng KH, Siar CH, Murugasu P

Ann Dent, 1986;45(2):19-22.

PMID: 3468872

Odontogenic keratocyst: a study of 53 cases in Malaysia

Siar CH, Ng KH, Murugasu P

Ann Dent, 1986;45(2):15-8.

PMID: 3468871

Adenomatoid odontogenic tumor: a survey of 44 new cases in Malaysia

Siar CH, Ng KH

Ann Dent, 1986;45(2):11-4.

PMID: 3468870

Ameloblastoma in Malaysia--a 25-year review

Siar CH, Ng KH

Ann Acad Med Singap, 1993 Nov;22(6):856-60.

PMID: 8129343

Four hundred and one cases of ameloblastoma of the jaw diagnosed in the Division of Stomatology, Institute for Medical Research, Kuala Lumpur, between 1967 and 1991 have been analysed. There were 214 males and 187 females. Of these, 50.1% were Malays, 34.7% Chinese, 8.2% Indians and 7.0% other races. Seventy-two percent of patients were in the second, third and fourth decades of life (mean age: 30.8 years). Ninety-three percent of tumours occurred in the mandible and 6.5% in the maxilla. There were 337 cases of conventional ameloblastoma, 49 cases of the unicystic variant and four cases of peripheral ameloblastoma. The predominant histologic patterns were plexiform (34.2%), follicular (16.5%) and mixture of both (17.7%). Majority of the cases were conservatively treated by enucleation. Fifty-nine cases presented with recurrences. Present findings were generally compatible with regional serial studies reported from Thailand, Singapore and Japan.

Induction of labour with prostaglandin E2 and amniotomy--a multicentre, three dose schedule study in 1533 patients

Karim SM, Lim SM, Ilancheran A, Ratnam SS, Ang LT, Ng KH, et al.

Ann Acad Med Singap, 1982 Oct;11(4):503-7.

PMID: 7165271

Prostaglandin E2 administered orally and combined with amniotomy was used for induction of labour at or near term in 1533 patients. The study was carried out as a collaborative project between the University Departments of Obstetrics and Gynaecology in Singapore, Medan (Indonesia) and Kuala Lumpur (Malaysia). The overall success rates for Medan, Kuala Lumpur and Singapore were 95.6%, 88.1% and 84.7% respectively.

Internal radiation dosimetry of orally administered radiotracers for the assessment of gastrointestinal motility

Yeong CH, Ng KH, Abdullah BJJ, Chung LY, Goh KL, Perkins AC

Appl Radiat Isot, 2014 Dec;94:216-220.

PMID: 25222875 DOI: 10.1016/j.apradiso.2014.08.009

Radionuclide imaging using (111)In, (99m)Tc and (153)Sm is commonly undertaken for the clinical investigation of gastric emptying, intestinal motility and whole gut transit. However the documented evidence concerning internal radiation dosimetry for such studies is not readily available. This communication documents the internal radiation dosimetry for whole gastrointestinal transit studies using (111)In, (99m)Tc and (153)Sm labeled formulations. The findings were compared to the diagnostic reference levels recommended by the United Kingdom Administration of Radioactive Substances Advisory Committee, for gastrointestinal transit studies.

Production and first use of 153SmCl3-ion exchange resin capsule formulation for assessing gastrointestinal motility

Yeong CH, Abdullah BJ, Ng KH, Chung LY, Goh KL, Sarji SA, et al.

Appl Radiat Isot, 2012 Mar;70(3):450-5.

PMID: 22178699 DOI: 10.1016/j.apradiso.2011.11.056

We produced an enteric-coated gelatine capsule containing neutron-activated (153)Sm-labelled resin beads for use in gastrointestinal motility studies. In vitro test in simulated gastrointestinal environment and in vivo study on volunteers were performed. Scintigraphic images were acquired from ten volunteers over 24h while blood and urine samples were collected to monitor the presence of (153)Sm. All the capsules remained intact in stomach. This proved to be a safe and practical oral capsule formulation for whole gut transit scintigraphy.

Reproducibility of neutron activated Sm-153 oral dose formulations intended for human administration

Yeong CH, Blackshaw PE, Ng KH, Abdullah BJ, Blaauw M, Dansereau RJ, et al.

Appl Radiat Isot, 2011 Sep;69(9):1181-4.

PMID: 21550260 DOI: 10.1016/j.apradiso.2011.04.017

Neutron activation of Sm-152 offers a method of radiolabeling for the in vivo study of oral dose formulations by gamma scintigraphy. Reproducibility measurements are needed to ensure the robustness of clinical studies. 204 enteric-coated guaifenesin core tablets (10mg of Sm(2)O(3)) were irradiated by thermal neutrons to achieve 1 MBq at 48 h. Administered activities were 0.86±0.03 MBq. Good reproducibility (CV=3.5%) was observed over 24 weeks ensuring that volunteer doses were within the dose reference level of 0.8 mSv.

A low-cost phantom for simple routine testing of single photon emission computed tomography (SPECT) cameras

Ng AH, Ng KH, Dharmendra H, Perkins AC

Appl Radiat Isot, 2009 Oct;67(10):1864-8.

PMID: 19049851 DOI: 10.1016/j.apradiso.2008.10.010

A simple sphere test phantom has been developed for routine performance testing of SPECT systems in situations where expensive commercial phantoms may not be available. The phantom was based on a design with six universal syringe hubs set in the frame to support a circular array of six glass blown spheres of different sizes. The frame was then placed into a water-filled CT abdomen phantom and scanned with a triple head camera system (Philips IRIX, USA). Comparison was made with a commercially available phantom (Deluxe Jaszczak phantom). Whereas the commercial phantom demonstrates cold spot resolution, an important advantage of the sphere test phantom was that hot spot resolution could be easily measured using almost half (370MBq) of the activity recommended for use in the commercial phantom. Results showed that the contrast increased non-linearly with sphere volume and radionuclide concentration. The phantom was found to be suitable as an inexpensive option for daily performance tests.

Evaluating the quality of images produced by soft X-ray units

Bradley DA, Wong CS, Ng KH

Appl Radiat Isot, 2000 9 26;53(4-5):691-7.

PMID: 11003508

For broad-beam soft X-ray sources, assessment of the quality of image produced by such units is made complex by the low penetration capabilities of the radiation. In the present study we have tested the utility of several types of test tool, some of which have been fabricated by us, as part of an effort to evaluate several key image defining parameters. These include the film characteristic, focal-spot size, image resolution and detail detectability. The two sources of X-rays used in present studies were the University of Malaya flash X-ray device (UMFX1) and a more conventional soft X-ray tube (Softex, Tokyo), the latter operating at peak accelerating potentials of 20 kVp. We have established, for thin objects, that both systems produce images of comparable quality and, in particular, objects can be resolved down to better than 45 microm.

Discriminant analysis of normal and malignant breast tissue based upon INAA investigation of elemental concentration

Ng KH, Ong SH, Bradley DA, Looi LM

Appl Radiat Isot, 1997 Jan;48(1):105-9.

PMID: 9022216

Discriminant analysis of six trace element concentrations measured by instrumental neutron activation analysis (INAA) in 26 paired-samples of malignant and histologically normal human breast tissues shows the technique to be a potentially valuable clinical tool for making malignant-normal classification. Nonparametric discriminant analysis is performed for the data obtained. Linear and quadratic discriminant analyses are also carried out for comparison. For this data set a formal analysis shows that the elements which may be useful in distinguishing between malignant and normal tissues are Ca, Rb and Br, providing correct classification for 24 out of 26 normal samples and 22 out of 26 malignant samples.

Treatment of data in the study of elemental concentration of biological materials

Ng KH, Bradley DA, Looi LM

Appl Radiat Isot, 1995 6 1;46(6-7):629-30.

PMID: 7633385

Differentiation of elemental composition of normal and malignant breast tissue by instrumental neutron activation analysis

Ng KH, Bradley DA, Looi LM, Mahmood CS, Wood AK

Appl Radiat Isot, 1993 Mar;44(3):511-6.

PMID: 8472024

Multi-elemental quantitative analyses of 15 paired samples of normal and malignant human breast tissue by instrumental neutron activation analysis are reported. The elements, Al, Br, Ca, Cl, Co, Cs, Fe, K, Na, Rb, Zn were detected. Significantly elevated concentration levels were found for Al, Br, Ca, Cl, Cs, K, Na, Zn in malignant compared to normal tissue. Although the role of elemental composition in breast cancer is unclear, this finding may be of importance as another parameter for differentiating normal from malignant tissue.

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