What is Radiation Therapy?

Radiation therapy (or radiotherapy) is a form of cancer treatment that damages or kills cancer cells by ionizing radiation, high-energy particles or waves, usually X-rays. Radiation works through direct and indirect damage to the genes that control cancer cells’ growth and division.

The goal of radiotherapy is to limit the spread of cancer cells while minimizing harm to nearby healthy tissue. It can be used to shrink tumors, reduce pressure, and treat other symptoms of cancer.

About 4 out of 10 patients with cancer receive some type of radiation therapy in their prescribed treatment plan. This can be an effective treatment by itself, but other types of cancer are best treated through a combination of procedures, which may include surgery, chemotherapy and immunotherapy.

Radiotherapy can be administered in a number of ways, from external machines, to the insertion of radioactive material. Refer below for the list of radiation therapy treatment techniques commonly used in Asian Alliance Radiation & Oncology.

Side Effects of Radiation Therapy

There are common side effects associated with undergoing Radiation Therapy treatment. For more information on Radiation Therapy side effects, click here.

Our Cancer Specialists


Dr. Jonathan Teh Yi Hui

Medical Director (CSR) & Senior Radiation Oncologist

Stereotactic Radiosurgery (SRS/SBRT), Head & Neck, Pediatric, Urologic, Gastrointestinal Cancers & Sarcoma


Dr Daniel Tan Yat Harn

Director & Senior Radiation Oncologist

Stereotactic Radiosurgery (SRS/SBRT), Brain and Spine, Breast and Prostate Cancers


Dr David Tan Boon Harn

Medical Director (AARO) & Senior Radiation Oncologist

Stereotactic Radiosurgery (SRS/SBRT), Gynaecological, Gastrointestinal & Lung Cancers


Dr Michelle Tseng Shu Fen

Women's & Children Program Director & Consultant Radiation Oncologist

Women’s & Children’s Cancer, Breast and Gynae-oncology and Paediatric