Choosing the right radiotherapy technique depends on many factors: the type of cancer, tumour size and location, your overall health, and treatment goals
Source: Thomson Hospital
Radiotherapy, also known as radiation therapy, plays a vital role in modern cancer treatment. It uses targeted radiation to kill or control cancer cells and can be used alone or alongside other treatments like surgery or chemotherapy. With the advancement of technology, radiotherapy has become more precise, effective, and customisable based on each patient’s condition.
What is Radiotherapy?
Radiotherapy is a treatment that uses high-energy radiation to destroy cancer cells or slow their growth. The radiation damages the deoxyribonucleic acid (DNA) of cancer cells, making it impossible for them to continue dividing. Over time, these damaged cells die off, and the body naturally removes them.
There are two main types of radiotherapy:
- External beam radiation therapy (EBRT): Radiation is delivered from a machine outside the body, directed at the tumour site.
- Internal radiation therapy (brachytherapy): A radioactive source is placed inside or near the tumour.
Types of External Radiotherapy Explained
Not all radiotherapies are the same. Depending on the tumour’s size, shape, and location, oncologists may choose from several EBRT techniques to ensure the best outcome while minimising damage to healthy tissues.\
1. Three-Dimensional Conformal Radiation Therapy (3D-CRT)
3D Conformal Radiation Therapy (3D-CRT) is one of the earliest forms of advanced external beam radiation therapy. It uses detailed imaging such as Computed Tomography (CT), Magnetic Resonance Imaging (MRI), or Positron Emission Tomography (PET) scans to create a three-dimensional map of the tumour and surrounding healthy tissues.
This allows the treatment team to shape the radiation beams in order to match the tumour’s size and shape from multiple angles. Our medical physicists use this data to design a treatment plan that directs radiation precisely to the tumour. Our radiation therapists then deliver the treatment using a linear accelerator, which helps shape the beams and protect nearby healthy tissue.
2. Intensity-Modulated Radiation Therapy (IMRT)
Intensity-Modulated Radiation Therapy (IMRT) is a more advanced form of 3D-CRT. It uses multiple small beams, or “beamlets,” with varying intensities to better match the tumour’s shape, even when it’s irregular. This technique allows for higher precision and reduces radiation exposure to nearby healthy organs. Hence, it becomes possible to deliver higher doses to the tumour, which can lead to improved outcomes.
3. Volumetric Modulated Arc Therapy (VMAT)
Volumetric Modulated Arc Therapy (VMAT) is a type of IMRT in which the radiation is delivered continuously as the machine rotates around the patient. This method requires a shorter treatment time while maintaining a high precision. VMAT is commonly used for prostate, lung, and head & neck cancers.
4. Stereotactic Radiation Therapy (SRS / SRT / SBRT)
Stereotactic Radiation Therapy delivers extremely precise, high doses of radiation in one or a few treatment sessions. It includes:
Stereotactic Radiosurgery (SRS): A non-surgical procedure used to treat brain tumours or other abnormalities in the brain, typically in a single session.
Stereotactic Radiotherapy (SRT): Similar to SRS but delivered over several sessions, often used for brain or spine lesions.
Stereotactic Body Radiation Therapy (SBRT): Used for tumours outside the brain, such as in the lungs, liver, spine, or adrenal glands.
These treatments rely on advanced imaging, meticulous planning, and precise patient positioning. Custom immobilisation devices, like head frames or body moulds, are used to keep the patient perfectly still. Medical physicists ensure accurate dose delivery through rigorous planning and quality checks, while radiation therapists manage the setup and safe execution of each session.
5. Image-Guided Radiation Therapy (IGRT)
Image-Guided Radiation Therapy (IGRT) uses imaging taken just before each treatment session to ensure the radiation is delivered with high accuracy. As tumours and nearby organs can shift slightly between sessions due to breathing or other natural movements, IGRT helps confirm the tumour’s position before treatment begins.
During treatment, imaging tools such as cone-beam CT or X-rays are used to capture real-time visuals of the treatment area. These images are then carefully compared against the reference plan to confirm accuracy. If needed, small adjustments are made to the patient’s position to ensure precise alignment before therapy begins. Behind the scenes, ongoing checks keep the imaging systems reliable, safe, and seamlessly integrated into each session — so every treatment is delivered with accuracy and confidence.
6. Surface-Guided Radiation Therapy (SGRT)
Surface Guided Radiation Therapy (SGRT) uses advanced external surface-tracking technology to guide treatment with precision, without the need for permanent skin markers or tattoos. Cancer patients who undergo other earlier methods before SGRT would usually have permanent tattoos on their skin for accurate targeting during treatment.
However, with SGRT, it is non-invasive, radiation-free, and tattoo-free, so it provides a safer and gentler alternative for treatment setup and monitoring.
When is Radiotherapy Used?
Radiotherapy can be used during the early stages of cancer or after it has started to spread.
Radiotherapy can be used to:
- combined with other therapies for a more effective outcome
- try to completely cure cancer
- reduce the relapse of cancer
- relieve symptoms when a cure is not possible
Common Side Effects of Radiotherapy
Although radiotherapy helps to kill cancer cells, some healthy cells in the area can also be damaged during treatment.
Some of the common side effects of radiotherapy are:
- fatigue
- hair loss
- feeling sick
- loss of appetite
- diarrhoea
Choosing a Suitable Radiation Therapy
Choosing the right radiotherapy technique depends on many factors: the type of cancer, tumour size and location, your overall health, and treatment goals. Our oncologists at Thomson Hospital will guide you through the available options, taking into account the benefits, risks, and expected outcomes.
Radiotherapy technology in Malaysia continues to evolve, making treatment more precise and effective. Whether used as a standalone treatment or part of a combined approach, radiotherapy remains a cornerstone in the fight against cancer, and our radiation therapists are here to help you along your journey.
If you have questions or concerns regarding radiotherapy, please visit our OncoCare centre.
References:
Volumetric Modulated Arc Therapy (VMAT) | Cleveland Clinic
Intensity-modulated radiotherapy—what is it? | PMC
Tattoo-less radiation treatment is the future of cancer care | Northwell Health