MARCH 9 — When dentist Dr Loo Yie Jin was told that his pancreatic cancer had spread to his liver, the news was devastating. 

He had already undergone surgery and chemotherapy, but the disease had progressed. 

Multiple new tumours had appeared in his liver, and conventional treatment options were becoming limited.

Today, however, Dr Loo is back at his dental clinic in Sungai Petani, seeing patients again and slowly returning to the rhythms of daily life. 

His recovery was made possible through a highly precise form of radiation therapy performed at Pusat Kanser Tun Abdullah Ahmad Badawi (PKTAAB), Universiti Sains Malaysia, in Kepala Batas, Penang.

The treatment is known as 3D interstitial high-dose-rate brachytherapy, a technique that delivers radiation directly inside the tumour rather than from outside the body. 

In contrast to conventional radiation therapy, where beams must pass through layers of healthy tissue to reach the tumour, brachytherapy places the radiation source precisely where it is needed. 

For patients with complex liver tumours, this difference can be crucial.

Liver cancer presents unique challenges for doctors. The organ moves constantly as we breathe, shifting position several millimetres with each cycle. 

It also sits close to other sensitive structures such as the stomach and intestines. 

Delivering a high dose of radiation to a tumour while protecting these surrounding organs requires an extraordinary level of precision.

Interstitial brachytherapy addresses this problem by placing thin catheters directly into the tumour under CT guidance. 

Through these temporary channels, a tiny radioactive source travels to carefully calculated positions, stopping briefly to deliver radiation before moving on to the next point. 

Once the treatment is completed, the source is fully withdrawn, and no radiation remains in the patient’s body.

This approach allows doctors to deliver what is known as an “ablative” radiation dose, strong enough to destroy tumour cells while minimising exposure to healthy tissue nearby. For certain patients, the treatment can be completed in just one or a few sessions, rather than requiring weeks of daily visits.

The liver is also a challenging organ because of its complex blood supply. Heat-based treatments such as radiofrequency ablation can sometimes be less effective near large blood vessels, where flowing blood dissipates heat. 

Radiation therapy, however, is not affected by this “heat sink” effect, allowing tumours in difficult locations to be treated more effectively.

Behind the scenes, medical physicists play a crucial role in ensuring that such treatments are delivered safely and accurately. 

Using advanced treatment planning systems, we create a three-dimensional model of the patient’s internal anatomy. 

This digital representation allows us to map the tumour and nearby organs with millimetre precision, calculating exactly how long the radioactive source should pause at each position within the catheter.

These calculations may appear abstract, but they translate directly into patient outcomes. Every second of radiation delivery is carefully planned to maximise tumour control while protecting the surrounding liver.

Dr Loo’s case illustrates what this precision can achieve. Over the course of nine months, our multidisciplinary team treated 15 liver tumours across seven treatment sessions. 

Such cases are rare, and the experience has drawn international attention from professional platforms such as BrachyAcademy and AboutBrachytherapy.com. 

Today, Dr Loo continues to share his story with other patients, demonstrating that even complex diagnoses can still have meaningful treatment options.

At PKTAAB, these advances are the result of close collaboration between radiation oncologists, medical physicists, radiologists and specialised nursing teams. 

Together, we work to develop treatment protocols that improve both survival and quality of life for patients.

The centre has also become an international educational and research hub for brachytherapy, helping to train clinicians and physicists from across the region. 

Our team recently presented a hybrid brachytherapy technique known as HyBIRT at the 2025 Asian Oncology Society Congress in Seoul, where it received the Best Oral Presentation Award.

Such recognition is encouraging, but the real impact is felt in the clinic. Many of the patients referred to us arrive after being told that their tumours are too complex for surgery or other treatments. In these situations, precision radiation therapy can sometimes provide a valuable alternative.

Looking ahead, the field continues to evolve. Researchers are exploring the use of artificial intelligence to assist treatment planning, as well as 3D-printed templates that can further improve the accuracy of catheter placement. These innovations aim to make complex procedures safer, faster and more accessible to patients.

For those of us working in medical physics, the goal is simple. Radiation is a powerful tool, but it must always be guided with care and precision. 

By bringing the source of treatment directly inside the tumour, brachytherapy allows us to target cancer more effectively while preserving as much healthy tissue as possible.

Dr Loo’s experience is a reminder that a cancer diagnosis is not always the end of the road. With advances in technology, teamwork and clinical expertise, we are learning how to fight certain cancers from the inside out.

* Dr Mohd Zahri Abdul Aziz is an Associate Professor and a Medical Physicist at Pusat Kanser Tun Abdullah Ahmad Badawi (PKTAAB), Universiti Sains Malaysia (USM), and may be reached at mohdzahri@usm.my 

** This is the personal opinion of the writer or publication and does not necessarily represent the views of Malay Mail.