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Lee C, Leung MC, Tang YK, Ho C, Wan MC, Woo S, Lee ML, Ng KH, So H, Lee MY, Ying SKY, Leung MH, Wong PY, Mok CC. POS0779 STANDARDIZED MORTALITY RATIO AND RISK FACTORS FOR DEATH IN SOUTHERN CHINESE PATIENTS WITH THE ANTIPHOSPHOLIPID SYNDROME (APS). Ann Rheum Dis 2022. [DOI: 10.1136/annrheumdis-2022-eular.4533] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
ObjectivesTo report the mortality rate and risk factors for death in southern Chinese patients with the antiphospholipid syndrome (APS)MethodsThe HKAPS registry was established in early 2020 by the Hong Kong Society of Rheumatology to study the outcomes of Chinese patients with APS treated in public hospitals in Hong Kong. Patients aged ≥18 years were identified by the Hospital Authority Clinical Data retrieval system using the ICD-10 diagnostic code of APS. The medical history and APS diagnosis was verified by sub-investigators in different hospitals using the 2006 modified consensus criteria for the APS. Eligible patients were classified into definite APS or probable APS, which was further categorized into primary (without underlying rheumatic diseases) and secondary types. The treatment and outcome (recurrence and mortality) of the patients was studied by Kaplan-Meier analysis and risk factors for recurrence of thrombosis and mortality were studied by Cox regression.Results428 APS patients were studied - 282 fulfilled the 2006 criteria for APS while 146 patients had probable APS (anti-phospholipid [aPL] antibodies positive once or with non-criteria manifestations). All were ethnic Chinese. The mean age at diagnosis was 44.1±15.6 years and the female to male ratio was 3.4:1. APS was primary in 211 patients and secondary to concomitant rheumatic diseases in 217 patients (SLE in 89.9%). 369(86.4%) patients had thromboembolic manifestations, 85(19.9%) had obstetric morbidities and 20(4.7%) had both. In patients with secondary APS, 23% thrombotic or obstetric manifestations occurred before diagnosis of the rheumatic diseases. Lupus anticoagulant (LAC), moderate/high titers of IgG anticardiolipin and anti-β2glycoprotein-1 antibodies was present in 326(76.1%), 242(56.5%) and 29(6.7%) patients, respectively. 137(32%) patients were double positive while 19(4.4%) patient was triple positive for these aPL antibodies. Among the thromboembolic manifestations, arterial thrombosis (n=201) was more common than venous thrombosis (n=186). The following treatment regimens were used: warfarin (63.6%), aspirin plus subcutaneous heparin (6.8%), aspirin plus warfarin (3%), aspirin alone (17.8%) and direct oral anticoagulant (DOAC) (2.8%). Bleeding complications developed in 77(18%) patients.After a mean follow-up of 8.0±14.1 years, recurrence of thromboembolic or obstetric complications occurred in 83(19.4%) and 14(3.3%) patients, respectively (1 patient had recurrence of both thrombosis and obstetric complications). Cox regression did not reveal any factors significantly associated with recurrence of thrombosis. A total of 67(15.7%) patients succumbed (median time to death 7.3 years). The causes of death were vascular in 29.9% (intracranial haemorrhage [35%], myocardial infarction [30%], limb ischemia [10%], ischemic stroke[10%], bowel ischemia[5%]) and non-vascular in 70.1% of patients (infection [59.6%], malignancy [10.6%], SLE activity [6.4%], pulmonary arterial hypertension [2.1%], organ failure [6.4%] and others). The cumulative risk of mortality over time was 6.4% at 5 years and 11.9% at 10 years. The age and sex adjusted standardized mortality ratio (SMR) of our APS patients relative to the general population was 18.2(14.2-23.0). In patients with thrombotic APS, mortality was associated with older age (≥60 years) (HR 2.57[1.34-4.95]) and the presence of LAC (HR 2.01[1.07-3.75]), adjusted for age, sex and vascular risk factors that included hypertension, diabetes mellitus, dyslipidaemia, smoking and atrial fibrillation.ConclusionAPS in southern Chinese is relatively uncommon and most cases were associated with SLE. In contrast to the Caucasians, venous thrombosis related to APS is less frequent. Over 8 years, recurrence of thrombotic events is uncommon. The mortality of APS in our Chinese patients was increased, with older age and the presence of LAC being independent risk factors.Disclosure of InterestsNone declared
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Santos JC, Goulart LF, Giansante L, Lin YH, Sirico ACA, Ng AH, Tsapaki V, Bezak E, Ng KH. Leadership and mentoring in medical physics: The experience of a medical physics international mentoring program. Phys Med 2020; 76:337-344. [PMID: 32759035 DOI: 10.1016/j.ejmp.2020.07.023] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Revised: 07/09/2020] [Accepted: 07/16/2020] [Indexed: 10/23/2022] Open
Abstract
Mentoring aims to improve careers and create benefits for the participants' personal and professional lives. Mentoring can be an individual or a shared experience for a group, while the mentor's role remains the same in both models. Mentors should increase confidence, teach, inspire, and set examples, helping the mentees to mould their path, contributing to the pursuit of their personal and professional goals. This study aims to report on the experience of early-career medical physics professionals and postgraduate students participating in a global mentoring program and to assess the impact of this activity on their professional development. The objectives of this mentoring program are to develop leadership roles among young medical physicists and to provide guidance and support. An online questionnaire was administered to the mentee participants. The analysis of their responses is reported in this work and the current status of the programme was examined using a SWOT analysis. In general, the mentoring experience had a positive impact on the mentees. The mentors were found especially helpful in the decision-making situations and in other conflicts that may arise with career development. Additionally, the mentees felt that mentoring contributed to the development of leadership skills required for the job market and assist in personal development. This paper concludes that participation of young medical physicists in a mentoring group program is beneficial to their career and therefore should be encouraged.
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Chen HH, Ng KH, Chao WC, Lin CH. SAT0582 RISK OF INTERSTITIAL LUNG DISEASE IN SYSTEMIC AUTOIMMUNE RHEUMATIC DISEASES: A NATIONWIDE, POPULATION-BASED COHORT STUDY. Ann Rheum Dis 2020. [DOI: 10.1136/annrheumdis-2020-eular.205] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
Background:To date, very few studies had investigated the epidemiology of interstitial lung disease (ILD) among patients with systemic autoimmune rheumatic disease (SARD).Objectives:To study the risk of interstitial lung disease (ILD) among patients with various systemic autoimmune rheumatic diseases (SARDs) including rheumatoid arthritis (RA), dermatomyositis (DMtis), polymyositis (PM), systemic sclerosis (SSc), systemic lupus erythematosus (SLE), and primary Sjögren’s syndrome (pSS).Methods:Using 1997–2013 claims data from the Taiwanese National Health Insurance Research Database, we identified 63,277 newly diagnosed patients with various SARDs after excluding those with overlapping SARD diagnoses from 2001-2013 and randomly selected 253,108 non-SARD subjects matching (1:4) SARD patients for SARD diagnosis, age, sex and the year of the index date. We calculated the incidence rates (IRs) of ILD (ICD-9 code 515) in various SARD groups and the corresponding non-SARD comparison groups and estimated the IR ratios (IRRs) with 95% confidence intervals (CI) of ILD development. Using multivariable cox regression analyses, we estimated hazard ratios (HRs) with 95% CIs of ILD in various SARD groups compared with their comparison groups after adjusting for age, sex, Charlson comorbidity index, amiodarone use and methotrexate use. Sensitivity analyses were conducted by using a narrow definition of ILD.Results:As shown in Table 1, the IRs of ILD were greatest in SSc patients (2,523 per 105years), followed by patients with DMtis (2,463 per 105years), PM (1,956 per 105years), SS (601 per 105years), RA (279 per 105years), and SLE (276 per 105years). Multivariable analyses showed that the risks of ILD were significantly increased in patients with SSc (HR, 66.01; 95% CI, 32.73—133.13), DMtis (128.74, 95% CI, 40.19—412.47), PM (HR, 30.39; 95% CI, 11.24—82.15), pSS (HR, 8.76; 95% CI, 7.03—10.90), RA (HR, 4.22; 95% CI, 3.51—5.08), and SLE (HR, 13.98; 95% CI, 9.25—21.14).Conclusion:This nationwide, population-based, matched cohort study demonstrated that the risks of ILD were significantly increased in patients with SARDs.References:[1]Su R, Bennett M, Jacobs S, Hunter T, Bailey C, Krishnan E, et al. An analysis of connective tissue disease-associated interstitial lung disease at a US Tertiary Care Center: better survival in patients with systemic sclerosis. The Journal of rheumatology. 2011;38(4):693-701.[2]Hu Y, Wang LS, Wei YR, Du SS, Du YK, He X, et al. Clinical Characteristics of Connective Tissue Disease-Associated Interstitial Lung Disease in 1,044 Chinese Patients. Chest. 2016;149(1):201-8.Araki T, Putman RK, Hatabu H, Gao W, Dupuis J, Latourelle JC, et al. Development and Progression of Interstitial Lung Abnormalities in the Framingham Heart Study. Am J Respir Crit Care Med 2016;194:1514-1522.Disclosure of Interests:None declared
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Wong JHD, Bakhsh M, Cheah YY, Jong WL, Khor JS, Ng KH. CHARACTERISATION AND EVALUATION OF AL2O3:C-BASED OPTICALLY STIMULATED LUMINESCENT DOSEMETER SYSTEM FOR DIAGNOSTIC X-RAYS: PERSONAL AND IN VIVO DOSIMETRY. RADIATION PROTECTION DOSIMETRY 2019; 187:451-460. [PMID: 31650160 DOI: 10.1093/rpd/ncz186] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2019] [Revised: 07/22/2019] [Accepted: 07/24/2019] [Indexed: 06/10/2023]
Abstract
This study characterises and evaluates an Al2O3:C-based optically stimulated luminescent dosemeter (OSLD) system, commercially known as the nanoDot™ dosemeter and the InLight® microStar reader, for personal and in vivo dose measurements in diagnostic radiology. The system characteristics, such as dose linearity, reader accuracy, reproducibility, batch homogeneity, energy dependence and signal stability, were explored. The suitability of the nanoDot™ dosemeters was evaluated by measuring the depth dose curve, in vivo dose measurement and image perturbation. The nanoDot™ dosemeters were observed to produce a linear dose with ±2.8% coefficient variation. Significant batch inhomogeneity (8.3%) was observed. A slight energy dependence (±6.1%) was observed between 60 and 140 kVp. The InLight® microStar reader demonstrated good accuracy and a reproducibility of ±2%. The depth dose curve measured using nanoDot™ dosemeters showed slightly lower responses than Monte Carlo simulation results. The total uncertainty for a single dose measurement using this system was 11%, but it could be reduced to 9.2% when energy dependence correction was applied.
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Karim MKA, Sabarudin A, Muhammad NA, Ng KH. A comparative study of radiation doses between phantom and patients via CT angiography of the intra-/extra-cranial, pulmonary, and abdominal/pelvic arteries. Radiol Phys Technol 2019; 12:374-381. [PMID: 31468370 DOI: 10.1007/s12194-019-00532-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2019] [Revised: 08/09/2019] [Accepted: 08/10/2019] [Indexed: 10/26/2022]
Abstract
This study aimed to evaluate effective dose and size-specific dose estimate (SSDE) of computed tomography angiography (CTA) examination using an anthropomorphic phantom. We included three CTA examination protocols to evaluate the intra- and extra-cranial arteries, pulmonary artery (CTPA), and abdominal vessels. Patient SSDEs were measured retrospectively to estimate patient dose, relative to the bodyweight of the patient and volume CT dose index (CTDIvol). Our findings revealed that the highest dose was absorbed by the left lobe of the thyroid gland during intra-/extra-cranial CTA and CTPA, that is, 14.11 ± 0.24 mGy and 16.20 ± 3.95 mGy, respectively. However, the highest absorbed dose in abdominal/pelvic CTA was the gonads (8.98 ± 0.30 mGy), while other radiosensitive organs in intra- and extra-cranial CTA, CTPA, and abdominal/pelvic CTA did not demonstrate significant differences between organs/structures with p value 0.88, 0.11, and 0.54, respectively. The estimated effective dose in intra-/extra-cranial CTA was lower in patients (0.80 ± 0.60 mSv) than in the phantom (0.83 mSv), but it was the opposite for CTPA, with the effective dose being higher in patients (7.54 ± 3.09 mSv) than in the phantom (6.68 mSv). Similar to the effective dose, only CTPA SSDEs were significantly higher in men than in women (19.74 ± 4.79 mGy versus 7.9 mGy). Effective dose and SSDE are clinically relevant parameters that can help estimate a more accurate patient dose based on a patient's size.
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Mumin NA, Rahmat K, Fadzli F, Ramli MT, Westerhout CJ, Ramli N, Rozalli FI, Ng KH. Diagnostic Efficacy of Synthesized 2D Digital Breast Tomosynthesis in Multi-ethnic Malaysian Population. Sci Rep 2019; 9:1459. [PMID: 30728394 PMCID: PMC6365555 DOI: 10.1038/s41598-018-37451-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2018] [Accepted: 11/23/2018] [Indexed: 11/11/2022] Open
Abstract
Synthesized 2D images can be reconstructed from tomosynthesis images in breast imaging. This study aims to investigate the diagnostic efficacy of synthesized 2D images (C-View) in comparison to full field digital mammography (FFDM) when used with digital breast tomosynthesis (DBT) in multi-ethnic Malaysian population. FFDM and C-View images (n = 380) were independently evaluated by three readers through Breast Imaging Reporting and Data System (BI-RADS) categorisation, breast density and lesion characterisation. Statistical analysis was done comparing sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of C-View + DBT with FFDM + DBT as standard of reference. Very good interreader agreement in BI-RADS category and density assessment between C-View + DBT and FFDM + DBT, with high sensitivity, specificity, PPV and NPV of C-View + DBT when compared with FFDM + DBT. There was comparable PPV between C-View + DBT and FFDM + DBT, with histopathology as gold standard. High level of interreader agreement in BI-RADS category and density assessment for FFDM + DBT and C-View + DBT. There was good agreement between FFDM + DBT and C-View + DBT in mass characterization, and almost perfect agreement in calcification and asymmetric density. 52.2% lower radiation dose incurred when using C-View + DBT. Hence, synthesized 2D images are comparable to FFDM with reduction in radiation dose within the limits of Malaysian multi-ethnic population.
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Round WH, Ng KH, Rodriguez L, Thayalan K, Tang F, Srivastava R, Fukuda S, Krisanachinda A, Deng X, Han Y. AFOMP policy number 6: code of ethics for medical physicists in AFOMP Countries. AUSTRALASIAN PHYSICAL & ENGINEERING SCIENCES IN MEDICINE 2018; 41:809-810. [PMID: 30406922 DOI: 10.1007/s13246-018-0708-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2018] [Accepted: 10/31/2018] [Indexed: 10/27/2022]
Abstract
This policy statement, which is the sixth of a series of documents prepared by the Asia-Oceania Federation of Organizations for Medical Physics (AFOMP) Professional Development Committee, gives guidance on how medical physicists in AFOMP countries should conduct themselves in an ethical manner in their professional practice (Ng et al. in Australas Phys Eng Sci Med 32:175-179, 2009; Round et al. in Australas Phys Eng Sci Med 33:7-10, 2010; Round et al. in Australas Phys Eng Sci Med 34:303-307, 2011; Round et al. in Australas Phys Eng Sci Med 35:393-398, 2012; Round et al. in Australas Phys Eng Sci Med 38:217-221, 2015). It was developed after the ethics policies and codes of conducts of several medical physics societies and other professional organisations were studied. The policy was adopted at the Annual General Meeting of AFOMP held in Jaipur, India, in November 2017.
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Martin CJ, Vassileva J, Vano E, Mahesh M, Ebdon-Jackson S, Ng KH, Frush DP, Loose R, Damilakis J. Unintended and accidental medical radiation exposures in radiology: guidelines on investigation and prevention. JOURNAL OF RADIOLOGICAL PROTECTION : OFFICIAL JOURNAL OF THE SOCIETY FOR RADIOLOGICAL PROTECTION 2017; 37:883-906. [PMID: 28836506 DOI: 10.1088/1361-6498/aa881e] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
This paper sets out guidelines for managing radiation exposure incidents involving patients in diagnostic and interventional radiology. The work is based on collation of experiences from representatives of international and national organizations for radiologists, medical physicists, radiographers, regulators, and equipment manufacturers, derived from an International Atomic Energy Agency Technical Meeting. More serious overexposures can result in skin doses high enough to produce tissue reactions, in interventional procedures and computed tomography, most notably from perfusion studies. A major factor involved has been deficiencies in training of staff in operation of equipment and optimization techniques. The use of checklists and time outs before procedures commence, and dose alerts when critical levels are reached during procedures, can provide safeguards to reduce the risks of these effects occurring. However, unintended and accidental overexposures resulting in relatively small additional doses can take place in any diagnostic or interventional x-ray procedure and it is important to learn from errors that occur, as these may lead to increased risks of stochastic effects. Such events may involve the wrong examinations, procedural errors, or equipment faults. Guidance is given on prevention, investigation, and dose calculation for radiology exposure incidents within healthcare facilities. Responsibilities should be clearly set out in formal policies, and procedures should be in place to ensure that root causes are identified and deficiencies addressed. When an overexposure of a patient or an unintended exposure of a foetus occurs, the foetal, organ, skin, and/or effective dose may be estimated from exposure data. When doses are very low, generic values for the examination may be sufficient, but a full assessment of doses to all exposed organs and tissues may sometimes be required. The use of general terminology to describe risks from stochastic effects is recommended rather than the calculation of numerical values, as these are misleading when applied to individuals.
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Safari MJ, Wong JHD, Ng KH, Jong WL, Cutajar DL, Rosenfeld AB. Characterization of a MOSkin detector for in vivo skin dose measurements during interventional radiology procedures. Med Phys 2016; 42:2550-8. [PMID: 25979047 DOI: 10.1118/1.4918576] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
PURPOSE The MOSkin is a MOSFET detector designed especially for skin dose measurements. This detector has been characterized for various factors affecting its response for megavoltage photon beams and has been used for patient dose measurements during radiotherapy procedures. However, the characteristics of this detector in kilovoltage photon beams and low dose ranges have not been studied. The purpose of this study was to characterize the MOSkin detector to determine its suitability for in vivo entrance skin dose measurements during interventional radiology procedures. METHODS The calibration and reproducibility of the MOSkin detector and its dependency on different radiation beam qualities were carried out using RQR standard radiation qualities in free-in-air geometry. Studies of the other characterization parameters, such as the dose linearity and dependency on exposure angle, field size, frame rate, depth-dose, and source-to-surface distance (SSD), were carried out using a solid water phantom under a clinical x-ray unit. RESULTS The MOSkin detector showed good reproducibility (94%) and dose linearity (99%) for the dose range of 2 to 213 cGy. The sensitivity did not significantly change with the variation of SSD (± 1%), field size (± 1%), frame rate (± 3%), or beam energy (± 5%). The detector angular dependence was within ± 5% over 360° and the dose recorded by the MOSkin detector in different depths of a solid water phantom was in good agreement with the Markus parallel plate ionization chamber to within ± 3%. CONCLUSIONS The MOSkin detector proved to be reliable when exposed to different field sizes, SSDs, depths in solid water, dose rates, frame rates, and radiation incident angles within a clinical x-ray beam. The MOSkin detector with water equivalent depth equal to 0.07 mm is a suitable detector for in vivo skin dosimetry during interventional radiology procedures.
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Sun ZJ, Ng KH, Liao P, Zhang Y, Ng JL, Liu ID, Tan PH, Chong SSC, Chan YH, Liu J, Davila S, Heng CK, Jordan SC, Soong TW, Yap HK. Genetic Interactions Between TRPC6 and NPHS1 Variants Affect Posttransplant Risk of Recurrent Focal Segmental Glomerulosclerosis. Am J Transplant 2015; 15:3229-38. [PMID: 26147534 DOI: 10.1111/ajt.13378] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2015] [Revised: 04/20/2015] [Accepted: 05/05/2015] [Indexed: 01/25/2023]
Abstract
Individuals with TRPC6 mutations have variable phenotypes, ranging from healthy carrier to focal segmental glomerulosclerosis (FSGS) leading to renal failure. Here, we describe a family where six members had a novel TRPC6 p.R68W (c.202C>T) mutation, two of whom had renal failure from FSGS, and one had proteinuria. One healthy carrier donated a kidney to her sister. Both donor and recipient had no proteinuria at 20 years posttransplant. Two synonymous NPHS1 polymorphisms, rs2285450 (c.294C>T) and rs437168 (c.2289C>T) segregated with renal failure in this family. These variants had higher allele frequencies in 97 unrelated patients with nephrotic syndrome or FSGS compared to 224 controls. Using patch-clamp experiments in HEK293 and podocytes, we showed that the p.R68W mutation increased TRPC6 current amplitudes, which may be explained by enhanced TRPC6 surface expression. Additionally, while wild-type nephrin suppressed TRPC6 currents, this ability was lost in the presence of NPHS1 c.294C>T polymorphism. When cells were transfected according to combined TRPC6 and NPHS1 genotypes in the family, those representing the donor had lower TRPC6 currents than cells representing the recipient, suggesting that interactions between TRPC6 and NPHS1 variants could possibly account for the variable penetrance of TRPC6 mutations and the absence of recurrence in the graft.
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Kron T, Azhari HA, Voon EO, Cheung KY, Ravindran P, Soejoko D, Inamura K, Han Y, Ung NM, TsedenIsh B, Win UM, Srivastava R, Marsh S, Farrukh S, Rodriguez L, Kuo M, Baggarley S, DilipKumara AH, Lee CC, Krisanachinda A, Nguyen XC, Ng KH. Medical physics aspects of cancer care in the Asia Pacific region: 2014 survey results. AUSTRALASIAN PHYSICAL & ENGINEERING SCIENCES IN MEDICINE 2015; 38:493-501. [DOI: 10.1007/s13246-015-0373-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/10/2015] [Accepted: 08/24/2015] [Indexed: 11/29/2022]
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Ng KH, Faust O, Sudarshan V, Chattopadhyay S. Data Overloading in Medical Imaging: Emerging Issues, Challenges and Opportunities in Efficient Data Management. JOURNAL OF MEDICAL IMAGING AND HEALTH INFORMATICS 2015. [DOI: 10.1166/jmihi.2015.1449] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
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Round WH, Stefanoyiannis AP, Ng KH, Rodriguez LV, Thayalan K, Han Y, Tang F, Fukuda S, Srivastava R, Krisanachinda A, Shiau AC, Deng X. AFOMP Policy No 5: career progression for clinical medical physicists in AFOMP countries. AUSTRALASIAN PHYSICAL & ENGINEERING SCIENCES IN MEDICINE 2015; 38:217-21. [DOI: 10.1007/s13246-015-0355-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2015] [Accepted: 03/30/2015] [Indexed: 10/23/2022]
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Ng KH, Ng SM, Parker A. Annual review of children with tuberous sclerosis. Arch Dis Child Educ Pract Ed 2015; 100:114-21. [PMID: 25112285 DOI: 10.1136/archdischild-2013-304948] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/23/2013] [Accepted: 07/21/2014] [Indexed: 12/17/2022]
Abstract
Tuberous sclerosis complex is a complex childhood disorder characterised by the formation of hamartomas in multiple organs. Annual review of this disease is recommended to monitor the development of complications. We aim to provide a concise, evidence-based framework to assist clinicians during this annual review. We focus on the following areas: (A) what questions need to be asked during annual review, (B) which areas need emphasis on examination, (C) when is an investigation required and (D) referral to tertiary specialists and other members of the multidisciplinary team. It should also be noted that there are ongoing debates regarding screening intervals in certain areas. These include the frequency, modality of screening and degree of intervention for astrocytomas and renal angiomyolipomas. This review seeks to summarise the product of the ongoing debates, and provide evidence-based suggestions in light of the uncertainty.
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Saw A, Ng KH. Open Access Publishing in Medicine. Malays Orthop J 2014. [DOI: 10.5704/moj.1403.021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
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Sim GS, Wong JHD, Ng KH. The use of radiochromic EBT2 film for the quality assurance and dosimetric verification of 3D conformal radiotherapy using Microtek ScanMaker 9800XL flatbed scanner. J Appl Clin Med Phys 2013; 14:4182. [PMID: 23835383 PMCID: PMC5714532 DOI: 10.1120/jacmp.v14i4.4182] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2012] [Revised: 03/15/2013] [Accepted: 03/13/2013] [Indexed: 11/23/2022] Open
Abstract
Radiochromic and radiographic films are widely used for radiation dosimetry due to the advantage of high spatial resolution and two‐dimensional dose measurement. Different types of scanners, including various models of flatbed scanners, have been used as part of the dosimetry readout procedure. This paper focuses on the characterization of the EBT2 film response in combination with a Microtek ScanMaker 9800XL scanner and the subsequent use in the dosimetric verification of a 3D conformal radiotherapy treatment. The film reproducibility and scanner uniformity of the Microtek ScanMaker 9800XL was studied. A three‐field 3D conformal radiotherapy treatment was planned on an anthropomorphic phantom and EBT2 film measurements were carried out to verify the treatment. The interfilm reproducibility was found to be 0.25%. Over a period of three months, the films darkened by 1%. The scanner reproducibility was ± 2% and a nonuniformity was ±1.9% along the direction perpendicular to the scan direction. EBT2 measurements showed an underdose of 6.2% at high‐dose region compared to TPS predicted dose. This may be due to the inability of the treatment planning system to predict the correct dose distribution in the presence of tissue inhomogeneities and the uncertainty of the scanner reproducibility and uniformity. The use of EBT2 film in conjunction with the axial CT image of the anthropomorphic phantom allows the evaluation of the anatomical location of dose discrepancies between the EBT2 measured dose distribution and TPS predicted dose distribution. PACS number: 87.55.Qr
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Siu SWK, Law M, Liu RKY, Wong KH, Soong IS, Kwok AOL, Ng KH, Lam PT, Leung TW. Use of methylphenidate for the management of fatigue in Chinese patients with cancer. Am J Hosp Palliat Care 2013; 31:281-6. [PMID: 23650644 DOI: 10.1177/1049909113487022] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
UNLABELLED REASON FOR THE STUDY: Studies on methylphenidate for cancer-related fatigue showed conflicting results. This prospective study aims to determine whether methylphenidate is useful for relieving fatigue in Chinese patients with cancer. Chinese Version of Brief Fatigue Inventory (BFI-C) was administered on days 1, 8, and 29. Methylphenidate dose on day 1 was 5 mg daily then adjusted after day 8 according to response and side effects tolerance. MAIN FINDINGS Only 48% of the 25 recruited patients were on methylphenidate by day 29. Overall, no significant improvement in fatigue level was observed after methylphenidate, though benefits were shown in subgroups with age ≤ 65 and higher baseline BFI-C values. PRINCIPAL CONCLUSIONS Methylphenidate may be useful for management of cancer-related fatigue in selected Chinese patients.
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Sun Z, Choo GH, Ng KH. Coronary CT angiography: current status and continuing challenges. Br J Radiol 2012; 85:495-510. [PMID: 22253353 DOI: 10.1259/bjr/15296170] [Citation(s) in RCA: 102] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Coronary CT angiography has been increasingly used in the diagnosis of coronary artery disease owing to rapid technological developments, which are reflected in the improved spatial and temporal resolution of the images. High diagnostic accuracy has been achieved with multislice CT scanners (64 slice and higher), and in selected patients coronary CT angiography is regarded as a reliable alternative to invasive coronary angiography. With high-quality coronary CT imaging increasingly being performed, patients can benefit from an imaging modality that provides a rapid and accurate diagnosis while avoiding an invasive procedure. Despite the tremendous contributions of coronary CT angiography to cardiac imaging, study results reported in the literature should be interpreted with caution as there are some limitations existing within the study design or related to patient risk factors. In addition, some attention must be given to the potential health risks associated with the ionising radiation received during cardiac CT examinations. Radiation dose associated with coronary CT angiography has raised serious concerns in the literature, as the risk of developing malignancy is not negligible. Various dose-saving strategies have been implemented, with some of the strategies resulting in significant dose reduction. The aim of this review is to present an overview of the role of coronary CT angiography on cardiac imaging, with focus on coronary artery disease in terms of the diagnostic and prognostic value of coronary CT angiography. Various approaches for dose reduction commonly recommended in the literature are discussed. Limitations of coronary CT angiography are identified. Finally, future directions and challenges with the use of coronary CT angiography are highlighted.
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Velayutham P, Govindasamy GK, Raman R, Prepageran N, Ng KH. High-frequency hearing loss among mobile phone users. Indian J Otolaryngol Head Neck Surg 2011; 66:169-72. [PMID: 24533378 DOI: 10.1007/s12070-011-0406-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2011] [Accepted: 11/24/2011] [Indexed: 10/14/2022] Open
Abstract
The objective of this study is to assess high frequency hearing (above 8 kHz) loss among prolonged mobile phone users is a tertiary Referral Center. Prospective single blinded study. This is the first study that used high-frequency audiometry. The wide usage of mobile phone is so profound that we were unable to find enough non-users as a control group. Therefore we compared the non-dominant ear to the dominant ear using audiometric measurements. The study was a blinded study wherein the audiologist did not know which was the dominant ear. A total of 100 subjects were studied. Of the subjects studied 53% were males and 47% females. Mean age was 27. The left ear was dominant in 63%, 22% were dominant in the right ear and 15% did not have a preference. This study showed that there is significant loss in the dominant ear compared to the non-dominant ear (P < 0.05). Chronic usage mobile phone revealed high frequency hearing loss in the dominant ear (mobile phone used) compared to the non dominant ear.
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Siar CH, Yeo KB, Nakano K, Nagatsuka H, Tsujigiwa H, Tomida M, Ng KH, Kawakami T. Strawberry gingivitis as the first presenting sign of Wegener's granulomatosis: report of a case. Eur J Med Res 2011; 16:331-4. [PMID: 21813375 PMCID: PMC3352006 DOI: 10.1186/2047-783x-16-7-331] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
Wegener's granulomatosis is a rare multi-system disease characterized by the classic triad of necrotizing granulomas affecting the upper and lower respiratory tracts, disseminated vasculitis and glomerulonephritis. Oral lesions as a presenting feature are only encountered in 2% of these cases. Hyperplastic gingival lesions or strawberry gingivitis, is a characteristic sign of Wegener's granulomatosis. The latter consists of reddish-purple exophytic gingival swellings with petechial haemorrhages thus resembling strawberries. Recognition of this feature is of utmost importance for timely diagnosis and definitive management of this potentially fatal disease. A case of strawberry gingivitis as the first presenting sign of Wegener's granulomatosis affecting a 50-year-old Malay male is reported here. The differential diagnosis of red lesions that may present in the gingiva is discussed.
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Round WH, Ng KH, Healy B, Rodriguez L, Thayalan K, Tang F, Fukuda S, Srivastava R, Krisanachinda A, Shiau AC, Deng X, Han Y. AFOMP Policy Statement No. 3: recommendations for the education and training of medical physicists in AFOMP countries. AUSTRALASIAN PHYSICAL & ENGINEERING SCIENCES IN MEDICINE 2011; 34:303-7. [PMID: 21809140 DOI: 10.1007/s13246-011-0091-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/02/2011] [Accepted: 07/24/2011] [Indexed: 11/25/2022]
Abstract
AFOMP recognizes that clinical medical physicists should demonstrate that they are competent to practice their profession by obtaining appropriate education, training and supervised experience in the specialties of medical physics in which they practice, as well as having a basic knowledge of other specialties. To help its member countries to achieve this, AFOMP has developed this policy to provide guidance when developing medical physicist education and training programs. The policy is compatible with the standards being promoted by the International Organization for Medical Physics and the International Medical Physics Certification Board.
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Bakkaloglu SA, Borzych D, Soo Ha I, Serdaroglu E, Büscher R, Salas P, Patel H, Drozdz D, Vondrak K, Watanabe A, Villagra J, Yavascan O, Valenzuela M, Gipson D, Ng KH, Warady BA, Schaefer F. Cardiac geometry in children receiving chronic peritoneal dialysis: findings from the International Pediatric Peritoneal Dialysis Network (IPPN) registry. Clin J Am Soc Nephrol 2011; 6:1926-33. [PMID: 21737855 PMCID: PMC3359542 DOI: 10.2215/cjn.05990710] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2010] [Accepted: 04/19/2011] [Indexed: 12/20/2022]
Abstract
BACKGROUND AND OBJECTIVES Left ventricular hypertrophy (LVH) is an independent risk factor and an intermediate end point of dialysis-associated cardiovascular comorbidity. We utilized a global pediatric registry to assess the prevalence, incidence, and predictors of LVH as well as its evolution in the longitudinal follow-up in dialyzed children. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS Cross-sectional echocardiographic, clinical, and biochemical data were evaluated in 507 children on peritoneal dialysis (PD), and longitudinal data were evaluated in 128 patients. The 95(th) percentile of LV mass index relative to height age was used to define LVH. RESULTS The overall LVH prevalence was 48.1%. In the prospective analysis, the incidence of LVH developing de novo in patients with normal baseline LV mass was 29%, and the incidence of regression from LVH to normal LV mass 40% per year on PD. Transformation to and regression from concentric LV geometry occurred in 36% and 28% of the patients, respectively. Hypertension, high body mass index, use of continuous ambulatory peritoneal dialysis, renal disease other than hypo/dysplasia, and hyperparathyroidism were identified as independent predictors of LVH. The use of renin-angiotensin system (RAS) antagonists and high total fluid output (sum of urine and ultrafiltration) were protective from concentric geometry. The risk of LVH at 1 year was increased by higher systolic BP standard deviation score and reduced in children with renal hypo/dysplasia. CONCLUSIONS Using height-adjusted left ventricular mass index reference data, LVH is highly prevalent but less common than previously diagnosed in children on PD. Renal hypo/dysplasia is protective from LVH, likely because of lower BP and polyuria. Hypertension, fluid overload, and hyperparathyroidism are modifiable determinants of LVH.
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Cheung HYS, Ng KH, Leung ALH, Chung CC, Yau KK, Li MKW. Laparoscopic sphincter-preserving total mesorectal excision: 10-year report. Colorectal Dis 2011; 13:627-31. [PMID: 20163425 DOI: 10.1111/j.1463-1318.2010.02235.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
AIM Total mesorectal excision (TME) is currently the gold standard for resection of mid or low rectal cancer and is associated with a low local recurrence rate. However, few studies have reported the long-term oncological outcome following use of a laparoscopic approach. The aim of this study was to evaluate the long-term oncological outcome after laparoscopic sphincter-preserving TME with a median follow up of about 4 years. METHOD Patients with mid or low rectal cancer who underwent laparoscopic sphincter-preserving TME with curative intent between March 1999 and March 2009 were prospectively recruited for analysis. RESULTS During the 10-year study period, 177 patients underwent laparoscopic sphincter-preserving TME with curative intent for rectal cancer. Conversion was required in two (1%) patients. There was no operative mortality. At a median follow-up period of 49 months, local recurrence had occurred in nine (5.1%) patients. The overall metastatic recurrence rate after curative resection was 22%. The overall 5-year survival and 5-year disease-free survival in the present study were 74% and 71%, respectively. CONCLUSION The results of this study show that laparoscopic sphincter-preserving TME is safe with long-term oncological outcomes comparable to those of open surgery.
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Siar CH, Ha KO, Aung LO, Nakano K, Tsujigiwa H, Nagatsuka H, Ng KH, Kawakami T. Immunolocalization of notch signaling protein molecules in a maxillary chondrosarcoma and its recurrent tumor. Eur J Med Res 2011; 15:456-60. [PMID: 21156405 PMCID: PMC3352190 DOI: 10.1186/2047-783x-15-10-456] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Background Notch receptors are critical determinants of cell fate in a variety of organisms. Notch signaling is involved in the chondrogenic specification of neural crest cells. Aberrant Notch activity has been implicated in numerous human diseases including cancers; however its role in chondrogenic tumors has not been clarified. Method Tissue samples from a case of primary chondrosarcoma of the maxilla and its recurrent tumor were examined immunohistochemically for Notch1-4 and their ligands (Jagged1, Jagged2 and Delta1) expression. Results Both primary and recurrent tumors were histopathologically diagnosed as conventional hyaline chondrosarcoma (WHO Grade I). Hypercellular tumor areas strongly expressed Notch3 and Jagged1 in spindle and pleomorphic cells suggesting up-regulation of these protein molecules at sites of tumor proliferation. Expression patterns were distinct with some overlap. Differentiated malignant and atypical chondrocytes demonstrated variable expression levels of Jagged1, and weak to absent staining for Notch1, 4 and Delta1. Protein immunolocalization was largely membranous and cytoplasmic, sometimes outlining the lacunae of malignant chondrocytes. Hyaline cartilage demonstrated a diffuse or granular precipitation of Jagged1 suggesting presence of soluble Jagged1 activity at sites of abnormal chondrogenesis. No immunoreactivity for the other Notch members was observed. Calcified cartilage was consistently Notch-negative indicating down-regulation of Notch with cartilage maturation. Stromal components namely endothelial cells and fibroblasts variably expressed Notch1, 3 and Jagged1 but were mildly or non-reactive for the other members. Conclusions Results indicate that Notch signaling pathway may participate in cellular differentiation and proliferation in chondrosarcoma. Findings implicate Notch3 and Jagged1 as key molecules that influence the differentiation and maturation of cells of chondrogenic lineage.
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Peh WCG, Ng KH. Publication ethics and scientific misconduct. Singapore Med J 2010; 51:908-912. [PMID: 21221494] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
To maintain the readers' trust and to uphold the journal's reputation, it is paramount for the entire research, peer reviewer and publication process to follow ethical principles and decisions. Studies involving humans, animals, medical records and human tissues/organs need to be conducted ethically, and the appropriate approvals obtained. The privacy and confidentiality of patients, authors and reviewers should be respected. When required, rights and permissions should be sought. Common forms of scientific misconduct include misappropriation of ideas, violation of generally accepted research practices, failure to comply with legislative and regulatory requirements, falsification of data, and inappropriate behaviour in relation to misconduct. Authors can expect editorial action to be taken, should duplicate publication, plagiarism and other forms of scientific misconduct be attempted or detected.
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