Our Doctors

Dr Looi Wen Shen is an experienced proton therapy radiation oncologist
Dr Looi is an experienced proton therapy radiation oncologist

Dr Looi Wenshen

MBBS (SIN), FRCR (Clinical Oncology, UK), FAMS (Radiation Oncology)

Head & Consultant
Radiation Oncologist
Proton Therapy SG
Singapore Institute of Advanced Medicine

Visiting Consultant Radiation Oncologist
KK Women’s and Children’s Hospital, Singapore

Visiting Consultant Radiation Oncologist
National Cancer Centre Singapore

Conditions Treated:

  • Proton therapy- UFPTI fellowship trained)
  • Paediatric- fellowship trained; Children’s Oncology Group Member Representative for NCCS
  • Urologic- prostate and kidney
  • Sarcomas
  • Head and neck
  • Liver cancer



Enquiries: WhatsApp +65 9297 5542 or email wenshen.looi@proton.sg.


Dr Looi Wen Shen is a radiation oncologist at Proton Therapy SG, Singapore Institute of Advanced Medicine. He graduated from Yong Loo Lin School of Medicine, National University of Singapore in 2008, and went on to complete his residency training in National Cancer Centre Singapore (NCCS), before receiving specialist accreditation in radiation oncology by the Specialist Accreditation Board. He worked as a Consultant in the Division of Radiation Oncology, National Cancer Centre Singapore; Clinical Assistant Professor in Duke-NUS medical school; and Clinical Teacher in the Lee Kong Chian School of Medicine. During his time in public service in NCCS, Dr Looi oversaw the creation of a comprehensive paediatric radiation oncology program that integrated allied healthcare to improve patient satisfaction and experience. As an educator to the younger generation of doctors, Dr Looi obtained a certificate for Essential Skills in Medical Education (ESME) for this.

Dr Looi is a radiation oncologist with practical overseas experience in proton therapy, having practised at the University of Florida Proton Therapy Institute, USA, where he completed subspecialty fellowship training in proton therapy and paediatric radiotherapy as an Adjunct Clinical Post-Doctoral Associate. He also received further proton therapy training at the Taiwan Medical University Hospital Proton Centre for regionally endemic diseases such as liver cancer and nasopharyngeal cancer. He is adept at 3D conformal radiotherapy (3DCRT), intensity modulated radiotherapy (IMRT), volumetric modulated arc therapy (VMAT), stereotactic body radiotherapy (SBRT), and intensity modulated proton therapy (IMPT).

Dr Looi is proud to have been able to kick start the paediatric proton program at National Cancer Centre Singapore. Today, Dr Looi continues to contribute to public healthcare as a Visiting Consultant in KK Women’s and Children’s Hospital and National Cancer Centre Singapore. Dr Looi is one of the few regional radiation oncologist members of the Children’s Oncology Group (COG). Additionally, he is listed in the Chordoma Foundation Directory (Wen Shen Looi). He is also a member of several other professional societies including the American Society for Radiation Oncology (ASTRO), Academy of Medicine, Singapore (AMS), Royal College of Radiology (RCR) (UK), Children’s Cancer and Leukaemia Group (CCLG) (UK), and the Paediatric Radiation Oncology Society (PROS).

While in NCCS, his research was published in journals such as the International Journal of Radiation Oncology Biology and Physics, and Medical Physics, Pediatric Blood and Cancer, and the Archives of Disease in Childhood. Through his research, Dr Looi endeavours to decrease the acute and late side effects of radiation in patients, thus improving their quality of life. Dr Looi will continue his research in the Singapore Institute of Advanced Medicine (SAM), focusing on the clinical outcomes of proton therapy. SAM’s plans for incorporation of FLASH proton therapy will also add an exciting dimension to the local proton research and clinical scene.

Education And Training

2020 – 2021Postdoctoral Fellowship- Paediatric and Adult Proton Therapy at the University of Florida Health Proton Therapy Institute (UFPTI)
2020United States Medical Licensing Examination (USMLE)
2017Fellow, Academy of Medicine, Singapore (FAMS)
2017Fellow of the Royal College of Radiologists (FRCR Clinical Oncology)
2013 – 2017Residency- Radiation Oncology, National Cancer Centre, Singapore
2003 – 2008Bachelor of Medicine, Bachelor of Surgery (M.B.B.S)- Yong Loo Lin, School of Medicine, National University of Singapore


2020—2022Florida Board of Medicine
2020Standard Certificate for United States Medical Licencing Examination (USMLE)- Education Commission for Foreign Medical Graduates (ECFMG)  
2019Essential Skills in Medical Education Certificate (ESME)- Association for Medical Education in Europe (AMEE)
2017Certificate of Specialist Accreditation, Radiation Oncology- Specialist Accreditation Board, Singapore
2017Certificate of Specialist Registration, Radiation Oncology, Singapore Medical Council
2008Certificate of Medical Registration, Radiation Oncology, Singapore Medical Council

Past And Present Appointments

2023Consultant, Proton Therapy Singapore, Singapore Institute of Advanced Medicine
2021 –Clinical Assistant Professor, Duke-NUS
2021 – 2023Clinical Teacher, Lee Kong Chian, School of Medicine
2020 – 2021Adjunct Clinical Postdoctoral Associate, University of Florida College of Medicine
2019 –           Visiting Consultant, Hematology/Oncology Service, KKH, Singapore.
2019 – 2021Clinical Instructor at Duke-NUS Medical School
2017 – 2023Consultant, Radiation Oncology, National Cancer Centre, Singapore

Professional Licensure

2008 –Practicing Certificate, Singapore Medical Council
2017 –Radiation Oncology Specialty Certificate, Specialist Accreditation Board of Singapore
2020 – 2022Registration for Resident / House Physician, Florida Board of Medicine

Professional Memberships

2021 –Children’s Cancer and Leukaemia Group, International Member
2021 –Children’s Oncology Group, International Associate Member
2021 –VIVA Asia Brain and Solid Tumour Working Group Member
2020 –American Society for Radiation Oncology
2019 –Paediatric Radiation Oncology Society, Member
2018 – 2019Singapore Radiological Society, Executive Committee Member (co-opted)
2017 –Royal College of Radiology (Clinical Oncology), Fellow (FRCR)
2017 –Academy of Medicine Singapore, Fellow (FAMS)
2008 – 2014Singapore Medical Association

Previous Grants:

  • Development of a Virtual/Mixed Reality Proton Gantry Room prototype to aid paediatric patient counselling, FY2021.
  • Kids, adolescent and young adult (KAYA) electronic patient-reported outcomes for Quality of Life metric measurements following radiotherapy, FY2023.
  • Improving comfort in Kids, Adolescent and Young adults during radiotherapy: Open-face masks in paediatric patients for immobilisation, FY2023.


Please see Google Scholar

  1. Tan AJL, Tey ML, Seow WT, Low DCY, Chang KTE, Ng LP, Looi WS, Wong RX, Tan EEK, Low SYY. Intraoperative Fluorescein Sodium in Pediatric Neurosurgery: A Preliminary Case Series from a Singapore Children’s Hospital. NeuroSci. 2023; 4(1):54-64. https://doi.org/10.3390/neurosci4010007
  2. Liu KX, Indelicato DJ, Paulino AC, Looi WS, Catalano PJ, Chintagumpala MM, Gallotto SL, Marcus KJ, Haas-Kogan DA, Tarbell NJ, MacDonald SM, Mahajan A, Yock TI. Multi-institutional Characterization of Outcomes for Pediatric and Young Adult Patients With High-Risk Myxopapillary Ependymoma After Radiation Therapy. Int J Radiat Oncol Biol Phys. 2023 Jul 10:S0360-3016(23)04708-9. doi: 10.1016/j.ijrobp.2023.06.2293. Epub ahead of print. PMID: 37437812.
  3. Lim YG, Tan EE, Looi WS, Wong RX, Chang KT, Low DC, Seow WT, Low SY. Biopsy of paediatric brainstem intrinsic tumours: Experience from a Singapore Children’s Hospital. J Clin Neurosci. 2022 Oct 10;106:8-13. doi: 10.1016/j.jocn.2022.09.021. Epub ahead of print. PMID: 36228504.
  4. Hong KT, Han JW, Fuji H, Byun HK, Koh KN, Wong RX, Lee HL, Yoon HI, Lee JH, Phi JH, Kim SK, Kim DS, Lyu CJ, Choi JY, Kang HJ, Chen YW, Lee YY, Im HJ, Ra YS, Do Ahn S, Low SYY, Looi WS, Park HJ, Suh YG, Suh CO, Wang KC, Tan EEK, Wong TT, Kim JY. Outcomes of intracranial non-germinomatous germ cell tumors: a retrospective Asian multinational study on treatment strategies and prognostic factors. J Neurooncol. 2022 Aug 31. doi: 10.1007/s11060-022-04100-w. Epub ahead of print. PMID: 36045266.
  5. Lim JX, Tan EEK, Ng LP, Seow WT, Chang KTE, Wong RX, Looi WS, Low DCY, Low SYY. Monomodality versus Combined Therapy in Optic Pathway Gliomas-20-Year Experience from a Singapore Children’s Hospital. Front Surg. 2022 May 2;9:827675. doi: 10.3389/fsurg.2022.827675. PMID: 35586500; PMCID: PMC9108767.
  6. Li Y, Ong WS, Shwe MTT, Yit NLF, Quek SZH, Pang EPP, Looi WS, Nei WL, Wang MLC, Chua MLK, Tan TWK, Chua ET, Ng CT, Tuan JKL. Cardiovascular toxicities of androgen deprivation therapy in Asian men with localized prostate cancer after curative radiotherapy: a registry-based observational study. Cardiooncology. 2022 Mar 14;8(1):4. doi: 10.1186/s40959-022-00131-4. PMID: 35287756.
  7. Koh KN, Wong RX, Lee DE, Han JW, Byun HK, Yoon HI, Kim DS, Lyu CJ, Kang HJ, Hong KT, Lee JH, Kim IH, Phi JH, Kim SK, Wong TT, Lee HL, Lai IC, Kang YM, Ra YS, Ahn SD, Im HJ, Looi WS, Low SYY, Tan EEK, Park HJ, Shin SH, Fuji H, Suh CO, Chen YW, Kim JY. Outcomes of intracranial germinoma-a retrospective multinational Asian study on effect of clinical presentation and differential treatment strategies. Neuro Oncol. 2021 Dec 22:noab295. doi: 10.1093/neuonc/noab295. Epub ahead of print. PMID: 34935949.
  8. Yen Sin Koh, Jason Yongsheng Chan, Wen Shen Looi, Mohamad Farid, N Gopalakrishna Iyer, Ci-An Gerald Tay, Kiattisa Sommat, Ru Xin Wong. Outcomes of head and neck angiosarcoma with different treatment modalities: a 20-year single institutional experience. Precision Cancer Medicine 2022 March.
  9. Valerie Ting Lim, Angelie Cabe Gacasan, Jeffrey Kit Loong Tuan, Terence Wee Kiat Tan, Youquan Li, Wen Long Nei, Wen Shen Looi, Xinying Lin, Hong Qi Tan, Eric Chern-Pin Chua, Eric Pei Ping Pang. Evaluation of inter- and intra-observer variations in prostate gland delineation using CT-alone versus CT/TPUS. Rep Pract Oncol Radiother 2022;27(1):97-103. DOI: 10.5603/RPOR.a2022.0004
  10. Hyperfractionated-Accelerated Reirradiation with Proton Therapy for Radiation-Associated Breast Angiosarcoma. Wen Shen Looi, MBBS, FRCR; Julie A. Bradley, MD; Xiaoying Liang, PhD; Christiana M. Shaw, MD; Mark Leyngold, MD; Raymond B. Mailhot Vega, MD, MPH; Eric D. Brooks, MD; Michael S. Rutenberg, MD, PhD; Lisa R. Spiguel, MD; Fantine Giap, MD; Nancy P. Mendenhall, MD. International Journal of Particle Therapy. https://doi.org/10.14338/IJPT-21-00031.1 2022/1/18
  11. Li Y, Chan Kong Ngai T, Zhou S, Yap Haw Hwong J, Pang Pei Ping E, Ong Li Kuan A, Wang Lian Chek M, Chua Lee Kiang M, Looi WS, Nei WL, Chua ET, On WLK, Tan Wee Kiat T, Yuen Shyi Peng J, Tuan Kit Loong J. A comparative analysis between low-dose-rate brachytherapy and external beam radiation therapy for low- and intermediate-risk prostate cancer in Asian men. Acta Oncol. 2021 Jul 14:1-5. doi: 10.1080/0284186X.2021.1950921. Epub ahead of print. PMID: 34259123.
  12. Looi WS, Indelicato DJ, Rutenberg MS. The Role of Radiation Therapy for Symptomatic Desmoid Tumors. Curr Treat Options Oncol. 2021 Mar 1;22(4):34. doi: 10.1007/s11864-021-00831-6. PMID: 33649873.
  13. Bte Syed Sulaiman N, Kuick CH, Chang KTE, Wan KR, Looi WS, Low DCY, Seow WT, Low SYY. Cytokines in Pediatric Pilocytic Astrocytomas: A Clinico-Pathological Study. NeuroSci. 2021; 2(1):95-108. https://doi.org/10.3390/neurosci2010006
  14. Indelicato DJ, Bates JE, Mailhot Vega RB, Rotondo RL, Hoppe BS, Morris CG, Looi WS, Sandler ES, Aldana PR, Bradley JA. Second tumor risk in children treated with proton therapy. Pediatr Blood Cancer. 2021 Feb 9:e28941. doi: 10.1002/pbc.28941. Epub ahead of print. PMID: 33565257.
  15. Indelicato DJ, Rotondo RL, Mailhot Vega RB, Holtzman AL, Looi WS, Morris CG, Sandler ES, Aldana PR, Bradley JA. Local Control Following Proton Therapy for Pediatric Chordoma. Int J Radiat Oncol Biol Phys. 2020 Nov 27:S0360-3016(20)34591-0. doi: 10.1016/j.ijrobp.2020.11.051. Epub ahead of print. PMID: 33253819.
  16. Looi WS, Indelicato DJ, Mailhot Vega RB, Morris CG, Sandler E, Aldana PR, Bradley JA. Outcomes following limited-volume proton therapy for multifocal spinal myxopapillary ependymoma. Pediatr Blood Cancer. 2020 Nov 23:e28820. doi: 10.1002/pbc.28820. Epub ahead of print. PMID: 33226179.
  17. Low SYY, Bte Syed Sulaiman N, Tan EEK, Ng LP, Kuick CH, Chang KTE, Tang PH, Wong RX, Looi WS, Low DCY, Seow WT. Cerebrospinal fluid cytokines in metastatic group 3 and 4 medulloblastoma. BMC Cancer. 2020 Jun 15;20(1):554. doi: 10.1186/s12885-020-07048-0. PMID: 32539808; PMCID: PMC7296667.
  18. Pang EPP, Knight K, Park SY, Lian W, Master Z, Baird M, Chan JWX, Wang MLC, Tan TWK, Chua MLK, Chua ET, Looi WS, Nei WL, Tuan JKL. Duration-dependent margins for prostate radiotherapy-a practical motion mitigation strategy. Strahlenther Onkol. 2020 Jul;196(7):657-663. doi: 10.1007/s00066-019-01558-y. Epub 2020 Jan 13. PMID: 31932995.
  19. Looi WS, Goh SH, Tan CJ, Yeoh KW, Seng MS. Adolescent with facial swelling. Arch Dis Child Educ Pract Ed. 2019 Oct 22:edpract-2019-317654. doi: 10.1136/archdischild-2019-317654. Epub ahead of print. PMID: 31641021.
  20. Looi WS, Low DCY, Low SYY, Goh SH. Neonatal orbital swelling due to intracranial teratoma. Arch Dis Child Fetal Neonatal Ed. 2019 Jul;104(4):F365. doi: 10.1136/archdischild-2018-316337. Epub 2018 Dec 14. PMID: 30552092.

Dr Shaun Ho Zhirui

MBBS, MRCS, FRCR (Clinical Oncology), Grad Dip (Palliative Medicine), FAMS (Radiation Oncology)

Consultant Radiation Oncologist

Proton Therapy SG

Contact: shaun.ho@proton.sg


Dr. Shaun Ho is an experienced senior radiation oncologist at Proton Therapy Singapore. He specialises in the use of advanced radiotherapy techniques to improve patient outcomes while minimizing treatment side effects. This encompasses proton beam therapy (PBT), stereotactic body radiotherapy (SBRT), stereotactic radiosurgery (SRS), as well as intensity modulated/volumetric modulated arc radiotherapy (IMRT/VMAT).

Prior to joining Proton Therapy Singapore, Dr. Ho was the head and Clinical Director of Radiation Oncology at Raffles Hospital. He also previously served as a Consultant and Clinical Assistant Professor at the National Cancer Centre Singapore (NCCS) and Duke-NUS Graduate Medical School.

Dr. Ho is an MOH accredited specialist in Radiation Oncology and a Fellow of the Academy of Medicine Singapore. He is also a Fellow of the UK Royal College of Radiologists (Clinical Oncology) and a Member of the Royal College of Surgeons of Edinburgh. Additionally, he holds a Graduate Diploma in Palliative Medicine.

He underwent radiation oncology residency at NCCS and subsequently completed a fellowship in Clinical Oncology at University College London Hospital (UCLH) in the UK. During his fellowship, he treated patients at UCH Macmillan Cancer Centre, the National Hospital for Neurology and Neurosurgery (NHNN), and was part of the London Sarcoma Service, one of the largest sarcoma services in Europe. His subspecialty training was in gastrointestinal oncology, neuro-oncology, sarcomas and lymphomas. He also underwent further training in proton beam therapy (PBT) at Kobe Proton Therapy Center in Japan, and at Taipei Medical University in Taiwan.

Dr. Ho served as a Consultant Radiation Oncologist at the National Cancer Centre Singapore (NCCS), specialising in gastrointestinal oncology, sarcomas, and lymphomas. During his time in public service, he received the SingHealth 10-year long service award in recognition of his contributions to patient care.

In 2020, Dr. Ho took on the role of Clinical Director of Radiation Oncology Services at Raffles Hospital. There, he established and operationalised their first radiotherapy services, which included techniques such as Stereotactic Body Radiotherapy (SBRT) for lung and bone tumours, Stereotactic Radiosurgery (SRS) for brain metastases, Deep Inspiratory Breath-hold (DIBH) Radiotherapy for breast cancer, and Volumetric Modulated Arc Therapy (VMAT) for cancers in the head and neck, lung, and prostate.

To advance the radiation oncology specialty in Singapore, Dr. Ho served on the Executive Committees of the Chapter of Radiation Oncologists, College of Radiologists Singapore, and the Singapore Radiological Society. He is also a member of the International Society for Radiosurgery.

Dr Ho treats patients for a wide range of conditions. He also has deep expertise and interest in the treatment of head & neck cancers, colorectal cancer, esophagus, liver and pancreatic cancers, lung cancer, breast cancer, , prostate cancer, sarcomas, lymphomas, and brain tumours.

Dr Wong Ru Xin

MBBS (Singapore), FRCR (Clinical Oncology)

Senior consultant 

Singapore Institute of Advanced Medicine Holdings

Radiation Oncologist



Dr Wong Ru Xin graduated from the National University of Singapore on the Dean’s list in 2009 and started residency training shortly after. Soon after, she became a Fellow of the Royal College of Radiologist (UK) (clinical oncology).

Work experience:

Dr Wong worked at the National Cancer Center of Singapore for more than 10 years before leaving for private practice. As part of her training in proton therapy, she received the Ministry of Health Manpower Development Program to spend time at St. Jude Children’s Research Hospital and observed at Provision Cares Proton Center, and Kobe Proton Center. She continues to serve the public as a visiting consultant in NCC Singapore and KK Hospital.

Specialised areas:

Her practice includes radiation therapy technology and the treatment of breast, head and neck, paediatric, brain, skin cancer and sarcoma. Dr Wong is skilled in the use of electrons, 3D, IGRT, VMAT, SBRT and Proton Beam Therapy in treating cancer.

Training courses:

She has attended relevant courses like Winter School in Particle Therapy, ESTRO Particle Therapy, ESTRO Radiobiology and physics, ESTRO lung, ESTRO Head and Neck, and ESTRO Stereotactic Radiosurgery. 


Dr Wong was the principal investigator in a few clinical trials and studies while in public institutions. 

Dr Wong has published local and regional papers on cancer prognostication, outcomes, and using novel techniques. Dr Wong concluded a clinical trial using hypo-fractionated radiotherapy in sarcomas. She also received grants to implement open-faced masks and silicon grip rings for patient comfort, electronic patient-reported outcomes, and study repeat MRI for adaptive radiotherapy in intracranial malignancies. While in National Cancer Center Singapore, she implemented new clinical technologies like pulsed low dose rate radiotherapy and collaborated with her colleagues to implement paediatric interstitial brachytherapy for rhabdomyosarcoma.

Dr Wong hopes to bring proton and advanced photon radiotherapy to Singapore and the region. Dr Wong is leveraging SAM network on the FLASH therapy consortium and A*STAR to investigate new technologies. 

She published papers on multi-national outcomes of intra-cranial germ cell tumours, head and neck sarcomas, retroperitoneal sarcomas, brain tumours, proton beam therapy for whole-lung irradiation, dyspnea at the end of life, breast phyllodes tumours, breast cancer prognostication and breast cancer socio-demographics and mammogram screening patterns, Human Papilloma Virus vaccination knowledge, attitudes and practice amongst teenagers in Singapore etc.  

See google scholar for more research publications.

Grants obtained:

  1. Duke-NUS Singhealth Academic Grant Proton Beam Therapy $50, 000 for short-course neoadjuvant radiotherapy in retroperitoneal liposarcomas with margins at risk.
  2. Onco-ACP Pediatric Research Grant Proton Beam Therapy $100,000 to utilise electronic patient reported outcomes.
  3. Duke-NUS Pediatric Cancer Charity Grant $40,000 to implement open-faced masks, silicon grip rings and investigate adaptive radiotherapy by repeating MRI for brain cancers.



She also taught medical students and residents and continues to teach oncology nurses. She has organised various webinars and symposiums in the past for local and international faculty.

Memberships & Affiliates:

  1. Singapore Radiological Society (SRS)
  2. Royal College of Radiologists UK (FRCR)
  3. Southeast Asia Radiation Oncology Group (SEAROG)
  4. European Society Radiation Oncology ( ESTRO)
  5. Pediatric Radiation Oncology Society (PROS)

Awards & Honours:

Dean’s list 2009 NUS

ENT book prize, General surgery book prize

Human Manpower Development Program 2018

Long service award (10 years) Singhealth

Singhealth-Duke NUS Academic Research Grant 2021, 2022