Displaying publications 241 - 260 of 298 in total

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  1. Lim WTH, Ooi EH, Foo JJ, Ng KH, Wong JHD, Leong SS
    PMID: 39075679 DOI: 10.1002/cnm.3857
    Renal anisotropy is a complex property of the kidney and often poses a challenge in obtaining consistent measurements when using shear wave elastography to detect chronic kidney disease. To circumvent the challenge posed by renal anisotropy in clinical settings, a dimensionless biomarker termed the 'anisotropic ratio' was introduced to establish a correlation between changes in degree of renal anisotropy and progression of chronic kidney disease through an in silico perspective. To achieve this, an efficient model reduction approach was developed to model the anisotropic property of kidneys. Good agreement between the numerical and experimental data were obtained, as percentage errors of less than 5.5% were reported when compared against experimental phantom measurement from the literature. To demonstrate the applicability of the model to clinical measurements, the anisotropic ratio of sheep kidneys was quantified, with both numerical and derived experimental results reporting a value of .667. Analysis of the anisotropic ratio with progression of chronic kidney disease demonstrated that patients with normal kidneys would have a lower anisotropic ratio of .872 as opposed to patients suffering from renal impairment, in which the anisotropic ratio may increase to .904, as determined from this study. The findings demonstrate the potential of the anisotropic ratio in improving the detection of chronic kidney disease using shear wave elastography.
  2. Ab Mumin N, Ramli Hamid MT, Wong JHD, Chiew SF, Rahmat K, Ng KH
    PLoS One, 2024;19(8):e0309131.
    PMID: 39208284 DOI: 10.1371/journal.pone.0309131
    OBJECTIVES: Accurate subtyping of breast cancer is crucial for its diagnosis, management, and prognostication. This study aimed to determine the association of magnetic resonance imaging (MRI) breast features with the molecular subtype and aggressiveness of breast cancer in a multi-ethnic population.

    METHODS: Treatment-naive patients with invasive breast carcinoma were included in this retrospective study. Breast MRI features were recorded based on the American College of Radiology-Breast Imaging Reporting and Data System (ACR-BIRADS) criteria, with tumour size, and apparent diffusion coefficient value (ADC). The statistical association was tested with Pearson Chi-Square Test of Independence for categorical data or the Kruskal-Wallis/ Mann Whitney U test for numerical data between the MRI features and molecular subtype, receptor status, tumour grade, lymphovascular infiltration (LVI) and axillary lymph node (ALN). Multinomial logistic regression was used to test the predictive likelihood of the significant features. The breast cancer subtypes were determined via immunohistochemistry (IHC) and dual-color dual-hapten in-situ hybridization (D-DISH). The expression statuses of ER, PR, and HER-2, LVI, and ALN were obtained from the histopathology report. The ER / PR / HER-2 was evaluated according to the American Society of Clinical Oncology / College of American Pathologists.

    RESULTS: The study included 194 patients; 41.8% (n = 81) Chinese, 40.7% (n = 79) Malay, and 17.5% (n = 34) Indian, involving 71.6%(n = 139) luminal-like, 12.9%(n = 25) HER-2 enriched, and 15.5%(n = 30) Triple-negative breast cancer (TNBC). TNBC was associated with rim enhancement (p = 0.002) and peritumoral oedema (p = 0.004). HER-2 enriched tumour was associated with larger tumour size (p = 0.041). Luminal-like cancer was associated with irregular shape (p = 0.005) with circumscribed margin (p = 0.003). Other associations were ER-negative tumour with circumscribed margin (p = 0.002) and PR-negative with round shape (p = 0.001). Tumour sizes were larger in ER-negative (p = 0.044) and PR-negative (p = 0.022). Rim enhancement was significantly associated with higher grade (p = 0.001), and moderate peritumoral oedema with positive axillary lymph node (p = 0.002).

    CONCLUSION: Certain MRI features can be applied to differentiate breast cancer molecular subtypes, receptor status and aggressiveness, even in a multi-ethnic population.

  3. Mohd Haniff NS, Ng KH, Kamal I, Mohd Zain N, Abdul Karim MK
    Heliyon, 2024 Aug 30;10(16):e36313.
    PMID: 39253167 DOI: 10.1016/j.heliyon.2024.e36313
    The aim of this systematic review and meta-analysis is to evaluate the performance of classification metrics of machine learning-driven radiomics in diagnosing hepatocellular carcinoma (HCC). Following the PRISMA guidelines, a comprehensive search was conducted across three major scientific databases-PubMed, ScienceDirect, and Scopus-from 2018 to 2022. The search yielded a total of 436 articles pertinent to the application of machine learning and deep learning for HCC prediction. These studies collectively reflect the burgeoning interest and rapid advancements in employing artificial intelligence (AI)-driven radiomics for enhanced HCC diagnostic capabilities. After the screening process, 34 of these articles were chosen for the study. The area under curve (AUC), accuracy, specificity, and sensitivity of the proposed and basic models were assessed in each of the studies. Jamovi (version 1.1.9.0) was utilised to carry out a meta-analysis of 12 cohort studies to evaluate the classification accuracy rate. The risk of bias was estimated, and Logistic Regression was found to be the most suitable classifier for binary problems, with least absolute shrinkage and selection operator (LASSO) as the feature selector. The pooled proportion for HCC prediction classification was high for all performance metrics, with an AUC value of 0.86 (95 % CI: 0.83-0.88), accuracy of 0.83 (95 % CI: 0.78-0.88), sensitivity of 0.80 (95 % CI: 0.75-0.84) and specificity of 0.84 (95 % CI: 0.80-0.88). The performance of feature selectors, classifiers, and input features in detecting HCC and related factors was evaluated and it was observed that radiomics features extracted from medical images were adequate for AI to accurately distinguish the condition. HCC based radiomics has favourable predictive performance especially with addition of clinical features that may serve as tool that support clinical decision-making.
  4. Hariyanto AP, Mugni FF, Khumaira L, Sensusiati AD, Nursela AL, Suprijanto, et al.
    Radiography (Lond), 2024 Dec 11;31(1):254-263.
    PMID: 39667263 DOI: 10.1016/j.radi.2024.11.023
    INTRODUCTION: Phantom materials with tissue-equivalent physical properties that require regular evaluation using patented phantoms are essential for medical device quality assurance programs. This study evaluated phantom materials for tissue equivalence and their use in image quality assessment for breast ultrasound scanner performance testing using two custom-made phantoms.

    METHODS: Two types of phantoms were developed: phantoms A and B. Phantom A was made from a base material consisting of polyvinyl chloride-plastisol with the addition of glycerol, whereas phantom B consisted of polyvinyl chloride-plastisol with the addition of graphite. Each phantom had a stiff and soft lesion shaped like a sphere, with a diameter of 1.4 cm. The phantoms were cuboids with dimensions of 10 × 10 cm2 and a thickness of 5 cm. A series of phantom evaluations was performed, consisting of density, elasticity, acoustic properties, B-mode ultrasound images, and strain ratio.

    RESULTS: The characterisation results show that background A closely resembles fibroglandular tissue in terms of density and acoustic properties (<5% variation); background B only resembles fibroglandular tissue in terms of density (-1.8% variation). In terms of elasticity, both backgrounds were close to the minimum value of fibroglandular tissue elasticity. The soft lesion on the phantom had a slightly lower density and elasticity than the carcinoma, whereas its acoustic properties (speed of sound and attenuation coefficient) were slightly higher than those of the reference carcinoma. Both phantoms were consistent with the literature in terms of strain ratio, geometric accuracy, lesion detection, and mean pixel value and showed good potential stability over one year.

    CONCLUSION: This study successfully described the fabrication and evaluation sequence of a phantom equivalent to breast fibroglandular tissue and its evaluation via ultrasound imaging.

    IMPLICATIONS FOR PRACTICE: This study offers proprietary information essential for the fabrication of phantoms that can be used for quality assurance and control in ultrasound imaging.

  5. Ng KH, Fong CY, Kamarudzaman MFS, Lo WH, Khalid F, Chong LA
    Brain Dev, 2025 Feb;47(1):104308.
    PMID: 39675180 DOI: 10.1016/j.braindev.2024.104308
    OBJECTIVES: Children with cerebral palsy (CP) can experience a substantial amount of pain. Effective pain management hinges on precise and prompt assessment. We designed a mobile-based application NeuroPAIN app to monitor pain among children with CP. NeuroPAIN app allowed parents to record pain symptoms, pain duration, and rate the perceived pain their child was facing. We evaluated the usefulness of NeuroPAIN app in pain recognition and monitoring among Malaysian parents of children with bilateral CP.

    METHOD: Prospective cohort study of all parents of children with bilateral non-ambulant CP who owned Android devices. NeuroPAIN app was installed in all participants. At 3-month follow-up, data of the NeuroPAIN app was analyzed and participants were given a feedback questionnaire to complete.

    RESULTS: Total of 60 parents participated in the study (child's median age 7 years, interquartile range 4-8.75 years). The vast majority (95 %) of parents reported pain in their children. Children with assisted tube feeding was associated with reported increased pain frequency. Majority (77 %) felt it was easy to navigate the NeuroPAIN app. Two-thirds regularly tracked their child's pain using the app over a 2-month period. Parents of children with prolonged periods of pain ≥25 s were associated with reduced app usage.

    CONCLUSION: Majority of Malaysian children with bilateral CP often experience pain particularly among those with assisted tube feeding highlighting the importance for clinicians to be vigilant in monitoring pain among these children. Prolonged pain periods among children with CP may lead to parental fatigue in monitoring pain through the NeuoPAIN app.

  6. Eturajulu RC, Tan MP, Zakaria MI, Chinna K, Ng KH
    Singapore Med J, 2025 Jan 01;66(1):33-40.
    PMID: 36751846 DOI: 10.4103/singaporemedj.SMJ-2021-254
    INTRODUCTION: Medical errors commonly occur in medical imaging departments. These errors are frequently influenced by patient safety culture. This study aimed to develop a suitable patient safety culture assessment tool for medical imaging departments.

    METHODS: Staff members of a teaching hospital medical imaging department were invited to complete the generic short version of the Safety Attitude Questionnaire (SAQ). Internal consistency and reliability were evaluated using Cronbach's α. Confirmatory factor analysis (CFA) was conducted to examine model fit. A cut-off of 60% was used to define the percentage positive responses (PPR). PPR values were compared between occupational groups.

    RESULTS: A total of 300 complete responses were received and the response rate was 75.4%. In reliability analysis, the Cronbach's α for the original 32-item SAQ was 0.941. Six subscales did not demonstrate good fit with CFA. A modified five-subscale, 22-item model (SAQ-MI) showed better fit (goodness-to-fit index ≥0.9, comparative fit index ≥ 0.9, Tucker-Lewis index ≥0.9 and root mean square error of approximation ≤0.08). The Cronbach's α for the 22 items was 0.921. The final five subscales were safety and teamwork climate, job satisfaction, stress recognition, perception of management and working condition, with PPR of 62%, 68%, 57%, 61% and 60%, respectively. Statistically significant differences in PPR were observed between radiographers, doctors and others occupational groups.

    CONCLUSION: The modified five-factor, 22-item SAQ-MI is a suitable tool for the evaluation of patient safety culture in a medical imaging department. Differences in patient safety culture exist between occupation groups, which will inform future intervention studies.

  7. Ng KH, Hamza M, Lai SY, Imanuella N, Tan LS, Liu CL, et al.
    Environ Res, 2025 Mar 19;275:121402.
    PMID: 40118320 DOI: 10.1016/j.envres.2025.121402
    MoS2 is frequently reported as an effective photocatalytic promoter; however, its explicit roles in improving photo-activity are rarely discussed. In this regard, current study aims to unravel the promotional roles of MoS2, specifically to ZnCdS in degrading tetracycline (TC) under visible light irradiation. ZnCdS/MoS2 derived from photo-deposition approach manifested a large interface with ZnCdS-encapsulating-MoS2 architecture. Alongside MoS2-deposition, the photocatalytically-inert oxide phases of ZnCdS were concurrently eliminated, enabling better photo-responsiveness to visible light. This comes with the closure of energy gap of ZnCdS (evidenced experimentally and theoretically); however, did not weaken its reductive capability due to its unaltered conduction band position. On the other hand, though the valence band of ZnCdS would slightly elevate with MoS2-embedment, its oxidative power is still adequate for direct oxidation of TC. This, therefore, explains TC removal which predominantly assisted by photo-holes and •OH radical (produced from O2-reductive pathway). Electronically-speaking, MoS2 embedment helps in lowering the impedance of ZnCdS, facilitating charges separation while lengthening their lifetimes in photoreaction. Meanwhile, MoS2-modification could also improve TC adsorption onto ZnCdS; this helps in improving utilization of photo-charges while facilitate TC degradation. These benefitting attributes of MoS2, therefore, permitted 458% activity improvements to ZnCdS, realizing 40.93 × 10-5 ppm min-1 TC removal under visible light.
  8. Zaman ZK, Ung NM, Malik RA, Ho GF, Phua VC, Jamalludin Z, et al.
    Phys Med, 2014 Dec;30(8):980-4.
    PMID: 25086486 DOI: 10.1016/j.ejmp.2014.07.002
    Cobalt-60 (Co-60) is a relatively new source for the application of high-dose rate (HDR) brachytherapy. Radiation dose to the rectum is often a limiting factor in achieving the full prescribed dose to the target during brachytherapy of cervical cancer. The aim of this study was to measure radiation doses to the rectum in-vivo during HDR Co-60 brachytherapy. A total of eleven HDR brachytherapy treatments of cervical cancer were recruited in this study. A series of diodes incorporated in a rectal probe was inserted into the patient's rectum during each brachytherapy procedure. Real-time measured rectal doses were compared to calculated doses by the treatment planning system (TPS). The differences between calculated and measured dose ranged from 8.5% to 41.2%. This corresponds to absolute dose differences ranging from 0.3 Gy to 1.5 Gy. A linear relationship was observed between calculated and measured doses with linear regression R(2) value of 0.88, indicating close association between the measured and calculated doses. In general, absorbed doses for the rectum as calculated by TPS were observed to be higher than the doses measured using the diode probe. In-vivo dosimetry is an important quality assurance method for HDR brachytherapy of cervical cancer. It provides information that can contribute to the reduction of errors and discrepancies in dose delivery. Our study has shown that in-vivo dosimetry is feasible and can be performed to estimate the dose to the rectum during HDR brachytherapy using Co-60.
  9. Tan SL, Rahmat K, Rozalli FI, Mohd-Shah MN, Aziz YF, Yip CH, et al.
    Clin Radiol, 2014 Jan;69(1):63-71.
    PMID: 24156797 DOI: 10.1016/j.crad.2013.08.007
    To investigate the capability and diagnostic accuracy of diffusion-weighted imaging (DWI) in differentiating benign from malignant breast lesions using 3 T magnetic resonance imaging (MRI).
  10. 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.
  11. Yeong CH, Abdullah BJ, Ng KH, Chung LY, Goh KL, Sarji SA, et al.
    Nucl Med Commun, 2011 Dec;32(12):1256-60.
    PMID: 21934547 DOI: 10.1097/MNM.0b013e32834b3ac8
    Nuclear medicine techniques are well established for the investigation of gastrointestinal (GI) motility and transit. Ion-exchange resins radiolabelled with ⁹⁹mTc and ¹¹¹In are widely used as nonabsorbable radiopharmaceutical markers, with ¹¹¹In being preferred for whole-gut transit studies. This radionuclide, however, is not produced in many countries and may be expensive when obtained through international shipment. This study describes the use of neutron-activated ¹⁵³Sm-resin as an alternative tracer for use in GI scintigraphic investigation. A measure of 50 mg of stable samarium-152 chloride (¹⁵²SmCl₃) was incorporated into 100 mg of cation-exchange resin and irradiated in a neutron flux of 1 × 10¹³ cm⁻² s⁻¹ for 100 s to achieve an activity of 5 MBq after 66 h. Aliquots of ¹¹¹In-radiolabelled resin (5 MBq) were prepared for comparison of labelling and stability. Radiolabelling efficiencies were obtained by washing resin with distilled water, and the activity lost was measured. The radiolabelled resins were immersed in simulated gastric and intestinal fluid environments, and the retention of ¹⁵³Sm³⁺ and ¹¹¹In³⁺ was measured over a 24 h period. At 66 h after production, 91.15 ± 12.42% of ¹⁵³Sm was bound to the resin after washing in distilled water, whereas radiolabelling with ¹¹¹In achieved 99.96 ± 0.02% efficiency. Both radiolabelled resins demonstrated almost 100% stability in simulated intestinal fluid and >90% stability in artificial gastric juice over 24 h. The performance of neutron-activated ¹⁵³Sm-resin is similar to that of ¹¹¹In-resin and can be used as an alternative tracer for GI transit studies when In is not available.
  12. Hashikin NA, Yeong CH, Abdullah BJ, Ng KH, Chung LY, Dahalan R, et al.
    PLoS One, 2015;10(9):e0138106.
    PMID: 26382059 DOI: 10.1371/journal.pone.0138106
    Samarium-153 (153Sm) styrene divinylbenzene microparticles were developed as a surrogate for Yttrium-90 (90Y) microspheres in liver radioembolization therapy. Unlike the pure beta emitter 90Y, 153Sm possess both therapeutic beta and diagnostic gamma radiations, making it possible for post-procedure imaging following therapy.
  13. Yusof FH, Ung NM, Wong JH, Jong WL, Ath V, Phua VC, et al.
    PLoS One, 2015;10(6):e0128544.
    PMID: 26052690 DOI: 10.1371/journal.pone.0128544
    This study was carried out to investigate the suitability of using the optically stimulated luminescence dosimeter (OSLD) in measuring surface dose during radiotherapy. The water equivalent depth (WED) of the OSLD was first determined by comparing the surface dose measured using the OSLD with the percentage depth dose at the buildup region measured using a Markus ionization chamber. Surface doses were measured on a solid water phantom using the OSLD and compared against the Markus ionization chamber and Gafchromic EBT3 film measurements. The effect of incident beam angles on surface dose was also studied. The OSLD was subsequently used to measure surface dose during tangential breast radiotherapy treatments in a phantom study and in the clinical measurement of 10 patients. Surface dose to the treated breast or chest wall, and on the contralateral breast were measured. The WED of the OSLD was found to be at 0.4 mm. For surface dose measurement on a solid water phantom, the Markus ionization chamber measured 15.95% for 6 MV photon beam and 12.64% for 10 MV photon beam followed by EBT3 film (23.79% and 17.14%) and OSLD (37.77% and 25.38%). Surface dose increased with the increase of the incident beam angle. For phantom and patient breast surface dose measurement, the response of the OSLD was higher than EBT3 film. The in-vivo measurements were also compared with the treatment planning system predicted dose. The OSLD measured higher dose values compared to dose at the surface (Hp(0.0)) by a factor of 2.37 for 6 MV and 2.01 for 10 MV photon beams, respectively. The measurement of absorbed dose at the skin depth of 0.4 mm by the OSLD can still be a useful tool to assess radiation effects on the skin dermis layer. This knowledge can be used to prevent and manage potential acute skin reaction and late skin toxicity from radiotherapy treatments.
  14. Safari MJ, Wong JH, Kadir KA, Thorpe NK, Cutajar DL, Petasecca M, et al.
    Eur Radiol, 2016 Jan;26(1):79-86.
    PMID: 26002131 DOI: 10.1007/s00330-015-3818-9
    OBJECTIVES: To develop a real-time dose-monitoring system to measure the patient's eye lens dose during neuro-interventional procedures.

    METHODS: Radiation dose received at left outer canthus (LOC) and left eyelid (LE) were measured using Metal-Oxide-Semiconductor Field-Effect Transistor dosimeters on 35 patients who underwent diagnostic or cerebral embolization procedures.

    RESULTS: The radiation dose received at the LOC region was significantly higher than the dose received by the LE. The maximum eye lens dose of 1492 mGy was measured at LOC region for an AVM case, followed by 907 mGy for an aneurysm case and 665 mGy for a diagnostic angiography procedure. Strong correlations (shown as R(2)) were observed between kerma-area-product and measured eye doses (LOC: 0.78, LE: 0.68). Lateral and frontal air-kerma showed strong correlations with measured dose at LOC (AKL: 0.93, AKF: 0.78) and a weak correlation with measured dose at LE. A moderate correlation was observed between fluoroscopic time and dose measured at LE and LOC regions.

    CONCLUSIONS: The MOSkin dose-monitoring system represents a new tool enabling real-time monitoring of eye lens dose during neuro-interventional procedures. This system can provide interventionalists with information needed to adjust the clinical procedure to control the patient's dose.

    KEY POINTS: Real-time patient dose monitoring helps interventionalists to monitor doses. Strong correlation was observed between kerma-area-product and measured eye doses. Radiation dose at left outer canthus was higher than at left eyelid.

  15. Charles A, Khan MR, Ng KH, Wu TY, Lim JW, Wongsakulphasatch S, et al.
    Sci Total Environ, 2019 Apr 15;661:522-530.
    PMID: 30682605 DOI: 10.1016/j.scitotenv.2019.01.195
    In this paper, a facile synthesis method for CaFe2O4 is introduced that produces a catalyst capable of significant photocatalytic degradation of POME under visible light irradiation. The co-precipitation method was used to produce two catalysts at calcination temperatures of 550 °C and 700 °C dubbed CP550 and CP700. CP550 demonstrated the maximum COD removal of 69.0% at 0.75 g/L catalyst loading after 8 h of visible light irradiation which dropped to 61.0% after three consecutive cycles. SEM images indicated that the higher calcination temperature of CP700 led to annealing which reduced the pore volume (0.025 cm3/g) and pore diameter (10.3 nm) while simultaneously creating a smoother and more spherical surface with lower SBET (9.73 m2/g). In comparison, CP550 had a rough hair-like surface with higher SBET (27.28 m2/g) and pore volume (0.077 cm3/g) as evidenced by BET analysis. XRD data indicated the presence of CaFe5O7 in the CP550 composition which was not present in CP700. The presence of Wustite-like FeO structures in CaFe5O7 are likely the cause for lower photoluminescence intensity profile and hence better charge separation of CP550 as these structures in CaFe2O4 have been known to increase resistivity and electron localization. The COD removal of CP550 dropped from 69.0% to just 7.0% upon adding a small quantity of isopropanol into the reaction mixture indicating hydroxyl radicals as the primary reactive oxidative species.
  16. Tan SK, Ng KH, Yeong CH, Raja Aman RRA, Mohamed Sani F, Abdul Aziz YF, et al.
    Quant Imaging Med Surg, 2019 Apr;9(4):552-564.
    PMID: 31143647 DOI: 10.21037/qims.2019.03.13
    Background: High delivery rate is an important factor in optimizing contrast medium administration in coronary computed tomography angiography (CCTA). A personalized contrast volume calculation algorithm incorporating high iodine delivery rate (IDR) can reduce total iodine dose (TID) and produce optimal vessel contrast enhancement (VCE) in low tube voltage CCTA. In this study, we developed and validated an algorithm for calculating the volume of contrast medium delivered at a high rate for patients undergoing retrospectively ECG-gated CCTA with low tube voltage protocol.

    Methods: The algorithm for an IDR of 2.22 gI·s-1 was developed based on the relationship between VCE and contrast volume in 141 patients; test bolus parameters and characteristics in 75 patients; and, tube voltage in a phantom study. The algorithm was retrospectively tested in 45 patients who underwent retrospectively ECG-gated CCTA with a 100 kVp protocol. Image quality, TID and radiation dose exposure were compared with those produced using the 120 kVp and routine contrast protocols.

    Results: Age, sex, body surface area (BSA) and peak contrast enhancement (PCE) were significant predictors for VCE (P<0.05). A strong linear correlation was observed between VCE and contrast volume (r=0.97, P<0.05). The 100-to-120 kVp contrast enhancement conversion factor (Ec) was calculated at 0.81. Optimal VCE (250 to 450 HU) and diagnostic image quality were obtained with significant reductions in TID (32.1%) and radiation dose (38.5%) when using 100 kVp and personalized contrast volume calculation algorithm compared with 120 kVp and routine contrast protocols (P<0.05).

    Conclusions: The proposed algorithm could significantly reduce TID and radiation exposure while maintaining optimal VCE and image quality in CCTA with 100 kVp protocol.

  17. Teoh LY, Lai LL, Hanim Aa A, Teh MS, Jamaris S, Yahya A, et al.
    Breast J, 2020 11;26(11):2208-2212.
    PMID: 32996224 DOI: 10.1111/tbj.14060
    Oncoplastic breast surgery (OBS) improves margin clearance and produces good esthetic outcome in breast cancer treatment. This study evaluates the complications and outcome of OBS in a multiracial patient cohort. Data of 421 patients between 2011 and 2018 were analyzed. The majority were Malays (41.8%), followed by Chinese (39.7%) and Indians (16.8%). Low local complications were noted, with no significant differences in disease-free survival (P = .927) and overall survival (P = .719) between low and high OBS levels. Shared decision-making in offering OBS for Asian women has potential to become a practical option in breast cancer treatment.
  18. Leong SS, Wong JHD, Md Shah MN, Vijayananthan A, Jalalonmuhali M, Mohd Sharif NH, et al.
    Ultrasound Med Biol, 2020 01;46(1):34-45.
    PMID: 31594681 DOI: 10.1016/j.ultrasmedbio.2019.08.011
    Tissue elasticity is related to the pathologic state of kidneys and can be measured using shear wave elastography (SWE). However, SWE quantification has not been rigorously validated. The aim of this study was to evaluate the accuracy of SWE-measured stiffness and the effect of tissue anisotropy on SWE measurements. Point SWE (pSWE), 2-D SWE and dynamic mechanical analysis (DMA) were used to measure stiffness and evaluate the effect of tissue anisotropy on the measurements. SWE and DMA were performed on phantoms of different gelatin concentrations. In the tissue anisotropy study, SWE and DMA were performed on the outer cortex of sheep kidneys. In the in vivo study, 15 patients with different levels of interstitial fibrosis were recruited for pSWE measurements. Another 10 healthy volunteers were recruited for tissue anisotropy studies. SWE imaging revealed a non-linear increase with gelatin concentration. There was a significant correlation between pSWE and 2-D SWE, leading to the establishment of a linear regression equation between the two SWE ultrasound measurements. In the anisotropy study, the median difference in stiffness between shear waves oriented at 0° and 90° towards the pyramid axis was significant. In the in vivo study, there was a strong positive linear correlation between pSWE and the percentage of interstitial fibrosis. There was a significant difference in the Young's modulus (YM) between severities of fibrosis. The mean YM values were lower in control patients than in patients with mild, moderate and severe fibrosis. YM values were also significantly higher when shear waves were oriented at 0° toward the pyramid axis. Tissue stiffness and anisotropy affects SWE measurements. These factors should be recognized before applying SWE for the interpretation of measured values.
  19. Jong WL, Wong JH, Ung NM, Ng KH, Ho GF, Cutajar DL, et al.
    J Appl Clin Med Phys, 2014 Sep 08;15(5):4869.
    PMID: 25207573 DOI: 10.1120/jacmp.v15i5.4869
    In vivo dosimetry is important during radiotherapy to ensure the accuracy of the dose delivered to the treatment volume. A dosimeter should be characterized based on its application before it is used for in vivo dosimetry. In this study, we characterize a new MOSFET-based detector, the MOSkin detector, on surface for in vivo skin dosimetry. The advantages of the MOSkin detector are its water equivalent depth of measurement of 0.07 mm, small physical size with submicron dosimetric volume, and the ability to provide real-time readout. A MOSkin detector was calibrated and the reproducibility, linearity, and response over a large dose range to different threshold voltages were determined. Surface dose on solid water phantom was measured using MOSkin detector and compared with Markus ionization chamber and GAFCHROMIC EBT2 film measurements. Dependence in the response of the MOSkin detector on the surface of solid water phantom was also tested for different (i) source to surface distances (SSDs); (ii) field sizes; (iii) surface dose; (iv) radiation incident angles; and (v) wedges. The MOSkin detector showed excellent reproducibility and linearity for dose range of 50 cGy to 300 cGy. The MOSkin detector showed reliable response to different SSDs, field sizes, surface, radiation incident angles, and wedges. The MOSkin detector is suitable for in vivo skin dosimetry.
  20. Ismail UN, Azlan CA, Khairullah S, Azman RR, Omar NF, Md Shah MN, et al.
    J Magn Reson Imaging, 2021 01;53(1):190-198.
    PMID: 33237616 DOI: 10.1002/jmri.27294
    BACKGROUND: β-thalassemia is a genetic disease that causes abnormal production of red blood cells (ineffective erythropoiesis, IE). IE is a condition known to change bone marrow composition.

    PURPOSE: To evaluate the effect of IE on the marrow fat content and fat unsaturation levels in the proximal femur using 1 H-MRS.

    STUDY TYPE: Prospective.

    SUBJECTS: Twenty-three subjects were included in this study, seven control and 16 β-thalassemia subjects.

    FIELD STRENGTH/SEQUENCE: 3.0T; stimulated echo acquisition Mode (STEAM); magnetic resonance spectroscopy (MRS) sequence.

    ASSESSMENT: Multiecho MRS scans were performed in four regions of the proximal left femur of each subject, that is, diaphysis, femoral neck, femoral head, and greater trochanter. The examined regions were grouped into red (diaphysis and femoral neck) and yellow marrow regions (femoral head and greater trochanter).

    STATISTICAL TESTS: The Jonckheere-Terpstra test was used to evaluate the impact of increasing disease severity on bone marrow fat fraction (BMFF), marrow conversion index, and fat unsaturation index (UI). Pairwise comparison analysis was performed when a significant trend (P 

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