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  1. 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.
  2. Yap LM, Jamalludin Z, Ng AH, Ung NM
    Phys Eng Sci Med, 2023 Sep;46(3):1331-1340.
    PMID: 37470929 DOI: 10.1007/s13246-023-01303-x
    The survey is to assess the current state of adaptive radiation therapy (ART) for head and neck (H&N) cases among radiotherapy centers in Malaysia and to identify any implementation limitations. An online questionnaire was sent to all radiotherapy centers in Malaysia. The 24-question questionnaire consists of general information about the center, ART practices, and limitations faced in implementing ART. 28 out of 36 radiotherapy centers responded, resulting in an overall response rate of 78%. About 52% of the responding centers rescanned and replanned less than 5% of their H&N patients. The majority (88.9%) of the respondents reported the use Cone Beam Computed Tomography alone or in combination with other modalities to trigger the ART process. The main reasons cited for adopting ART were weight loss, changes in the immobilization fitting, and anatomical variation. The adaptation process typically occurred during week 3 or week 4 of treatment. More than half of the respondents require three days or more from re-simulation to starting a new treatment plan. Both target and organ at risk delineation on new planning CT relied heavily on manual delineation by physicians and physicists, respectively. All centers perform patient-specific quality assurance for their new adaptive plans. Two main limitations in implementing ART are "limited financial resources or equipment" and "limitation on technical knowledge". There is a need for a common consensus to standardize the practice of ART and address these limitations to improve the implementation of ART in Malaysia.
  3. Ng AH, Clay D, Blackshaw PE, Bugby SL, Morgan PS, Lees JE, et al.
    Nucl Med Commun, 2015 Nov;36(11):1134-42.
    PMID: 26352214 DOI: 10.1097/MNM.0000000000000377
    To develop a method for the assessment of small field of view (SFOV) gamma cameras using a novel phantom designed to simulate the localization of sentinel nodes in the presence of a high-activity injection site.
  4. Ng AH, Blackshaw PE, Alqahtani MS, Jambi LK, Bugby SL, Lees JE, et al.
    Nucl Med Commun, 2017 Sep;38(9):729-736.
    PMID: 28704342 DOI: 10.1097/MNM.0000000000000715
    INTRODUCTION: Hybrid imaging has proven to be a major innovation in nuclear medicine, allowing the fusion of functional information with anatomical detail. In the past, the use of hybrid imaging such as PET-CT, PET-MRI and SPECT-CT has been of great clinical benefit; however, these scanners are relatively large and bulky. We have developed and investigated the clinical application of a compact small field of view hybrid gamma camera (HGC) that is suitable for small-organ imaging at the patient bedside.

    PATIENTS AND METHODS: The HGC - consisting of a CsI(Tl) scintillation crystal coupled to an electron-multiplying charge-coupled device and an optical camera - was used in this study. Eligible patients attending the nuclear medicine clinic at Queen's Medical Centre, Nottingham University Hospitals NHS Trust, Nottingham, UK, were invited to take part in this study. Following the standard injection of either a Tc-labelled or I-labelled radiopharmaceutical, images of the patient were acquired using the HGC and presented in a fused optical-gamma display.

    RESULTS: There were 24 patients enrolled in the study (age range between 30 and 83 years, mean: 58.6 years), images of 18 of whom were successfully acquired. These included patients who were undergoing bone, thyroid, lacrimal drainage, DaTscan and lymphatic imaging. In general, the small field of view system was well suited to small-organ imaging. The uptake could be clearly seen in relation to the patient surface anatomy and showed particular promise for lymphatic, thyroid and lacrimal drainage studies.

    CONCLUSION: This pilot study has demonstrated the first clinical results of hybrid optical-gamma imaging in patients. The use of this system has raised new possibilities for small-organ imaging, in which the localization of radiopharmaceutical uptake can be presented in an anatomical context using optical imaging. The compact nature of the hybrid system offers the potential for bedside investigations and intraoperative use.

  5. Ng AH, Alqahtani MS, Jambi LK, Bugby SL, Lees JE, Perkins AC
    Br J Radiol, 2019 Jun;92(1098):20190020.
    PMID: 30864832 DOI: 10.1259/bjr.20190020
    OBJECTIVE: To examine the imaging capability of a novel small field of view hybrid gamma camera (HGC) using 125I seeds prior to surgical use.

    METHODS: The imaging performance of the camera system was assessed quantitatively and qualitatively at different source depths, source to collimator distances (SCD), activity levels, acquisition times and source separations, utilising bespoke phantoms.

    RESULTS: The system sensitivity and spatial resolution of the HGC for 125I were 0.41 cps/MBq (at SCD 48 mm) and 1.53 ± 0.23 mm (at SCD 10 mm) respectively. The camera was able to detect the 125I seed at a SCD of 63 mm (with no scattering material in place) in images recorded within a 1-min acquisition time. The detection of the seeds beneath scattering material (simulating deep-seated tumours) was limited to depths of less than 20 mm beneath the skin surface with a SCD of 63 mm and seed activity of 2.43 MBq. Subjective assessments of the hybrid images acquired showed the capability of the HGC for localising the 125I seeds.

    CONCLUSION: This preliminary ex vivo study demonstrates that the HGC is capable of detecting 125I seeds and could be a useful tool in radioactive seed localisation with the added benefit of providing hybrid optical γ images for guiding breast conserving surgery.

    ADVANCES IN KNOWLEDGE: The SFOV HGC could provide high resolution fused optical-gamma images of 125I radioactive seeds indicating the potential use in intraoperative surgical procedure such as RSL.

  6. Ng KH, Brady Z, Ng AH, Soh HS, Chou YH, Varma D
    J Med Imaging Radiat Oncol, 2021 Jul;65(4):464-470.
    PMID: 33606359 DOI: 10.1111/1754-9485.13165
    More than half of the world's population live in Asia-Pacific. This region is culturally diverse, with significant disparities in terms of socio-economic status, provision of health care and access to advanced technology. The medical use of ionising radiation is increasing worldwide and similarly within the Asia-Pacific region. In this paper, we highlight the current status in usage of ionising radiation in medicine in the region, and review the legal framework, implementation and activities in radiation protection. Asia-Pacific countries are active in strengthening radiation protection by promoting education and training. Various projects and activities initiated by international organisations such as the IAEA, WHO and ICRP have provided stimulation in the region, but more work is needed to continue to improve protection practices.
  7. Santos JC, Goulart LF, Giansante L, Lin YH, Sirico ACA, Ng AH, et al.
    Phys Med, 2020 Aug;76:337-344.
    PMID: 32759035 DOI: 10.1016/j.ejmp.2020.07.023
    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.
  8. Lapchmanan LM, Hussin DA, Mahat NA, Ng AH, Bani NH, Hisham S, et al.
    BMC Health Serv Res, 2024 Feb 02;24(1):165.
    PMID: 38308291 DOI: 10.1186/s12913-024-10569-0
    BACKGROUND: The Malaysian Allied Health Profession Act (Act 774) regulates the practice of allied health practitioners in Malaysia, with two described professions viz. allied health profession (AHP) and profession of allied health (PAH). While AHPs have been clearly identified by the law, comprehensive implementation of the act requires development of specific criteria in defining any profession as PAH in the Malaysian context. Hence, the research aims to explore and identify the criteria for defining such professions for healthcare policy direction in Malaysia.

    METHODS: This research utilised two methods of qualitative research (document review and focus group discussions (FGDs) involving 25 participants from four stakeholders (higher education providers, employers, associations and regulatory bodies). Both deductive and inductive thematic content analysis were used to explore, develop and define emergent codes, examined along with existing knowledge on the subject matter.

    RESULTS: Sixteen codes emerged from the FGDs, with risk of harm, set of competency and skills, formal qualification, defined scope of practice, relevant training and professional working within the healthcare team being the six most frequent codes. The frequencies for these six codes were 62, 46, 40, 37, 36 and 18, correspondingly. The risk of harm towards patients was directly or indirectly involved with patient handling and also relates to the potential harms that may implicate the practitioners themselves in performing their responsibilities as the important criterion highlighted in the present research, followed by set of competency and skills.

    CONCLUSIONS: For defining the PAH in Malaysia, the emerged criteria appear interrelated and co-exist in milieu, especially for the risk of harm and set of competency and skills, with no single criterion that can define PAH fully. Hence, the integration of all the empirically identified criteria must be considered to adequately define the PAH. As such, the findings must be duly considered by policymakers in performing suitable consolidation of healthcare governance to formulate the appropriate regulations and policies for promoting the enhanced framework of allied health practitioners in Malaysia.

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