Physicist Mr S Somanesan took the nuclear option to harness the science of radiation to save lives. Radionuclides added to drugs can be used to diagnose and treat some cancers and other illnesses.


At 5.30am every day, Singapore General Hospital (SGH) Senior Principal Medical Physicist Mr S Somanesan dutifully checks in on one of his ‘children’ — the hulking, silent 20-year-old giant cyclotron.

A massive machine that manufactures radionuclides, or radioactive materials, for use in pharmaceuticals to diagnose some cancers and other illnesses, the cyclotron holds a special place in Mr Somanesan’s heart. He had singlehandedly managed the procurement of the machine to make SGH the first medical cyclotron facility in Singapore and Southeast Asia in 2003.

Even with an honour’s degree in physics from the National University of Singapore (NUS), he had no idea what radiation physicist or medical physics — the job he applied for in 1989 — was as the discipline was so new and rare. Today, Mr Somanesan leads a team at the Department of Nuclear Medicine and Molecular Imaging, and at the Division of Radiological Sciences, looking after safety and quality management of the hospital’s radiation-related equipment. Hence, the daily check on the cyclotron.

“It was a steep learning curve. I had to learn from the doctors, engineers, nurses and radiographers. Also, there wasn’t the Internet at the time, so I learnt a lot from books and journals,” said Mr Somanesan. “The beauty of my profession is that I see the clinical application of physics I learnt back in university as well as through continual education. It’s so fulfilling to see how the science of gamma rays and x-rays are utilised in the healthcare sector to diagnose and even save lives. This field is never static. It is always evolving with new discoveries and applications. This keeps me excited.”

Mr Somanesan has been the SGH Radiation Safety Officer since 1999, and oversees radiation safety in laboratories, radiology services, research units, animal facilities, and nuclear medicine services on SGH Campus, as well as emergency planning for radiological incidents and accidents. Medical physicists, he said, develop procedures to ensure the safe and effective use of radiation in medicine. “As we harness radiation, we are also mindful of its ill effects. So, we work closely with the doctors and radiographers to ensure that only the optimal dosage of radiation is administered to patients.”

That safety aspect extends to staff, including couriers, nurses and healthcare attendants who come into contact with radioactivity to ensure their radiation exposure is kept to a minimum. Radiographers have to carry a TLD (thermoluminescent dosimeter), which measures the amount of radiation they are exposed to at all times.

Teaching and training prospective medical physicists have also been an important part of his job from the start. That has evolved to include evening classes at the Singapore Institute of Technology (where he was appointed as an Adjunct Associate Professor), Nanyang Technological University (NTU), and NUS. Clearly passionate about his work and the field of physics, Mr Somanesan said: “I find joy in making the physics come alive, to make the textbook come alive, to explain to them so that they can understand it better after I explain to them. The teaching component gives me the most pleasure — whether I’m teaching the nuclear med residents, radiology residents, or the student radiographers. I don’t say ‘no’ to work.”

Medical physics is no longer the exotic field that Mr Somanesan first stumbled upon. “It’s now taught at even ‘O’ levels through to university. At NTU, students can do a module on medical physics, where students learn about proton therapy, nuclear medicine, ultrasound and MRI (magnetic resonance imaging),” he said.

The years of learning and practice have earned Mr Somanesan recognition as an expert by the International Atomic Energy Agency (IAEA). Indeed, his humble demeanour hides the reputation he has acquired in the field. A colleague realised that just about everyone at an IAEA course in Sydney, Australia, knew him well. Impressed, she told him that he was a superstar, to which Mr Somanesan replied: “I’ve been around the block. I’m a very old man.”

To find out more about PET and CT scans, click here to watch a LinkedIn video.

Get the latest updates about Singapore Health in your mailbox! Click here to subscribe.