Tomotherapy is a groundbreaking advancement in radiation therapy, offering unprecedented precision in targeting tumours while protecting healthy tissue. Dr Harpreet Singh, senior consultant, radiation oncology, talks to Manav Mander about the technology and how it integrates advanced imaging and radiation delivery. As cancer cases rise globally, technologies like tomotherapy are playing a crucial role in offering patients safe and effective care.What is tomotherapy?Tomotherapy is an advanced form of image-guided and intensity-modulated radiation therapy (IG-IMRT), combined with computed tomography scanning, using a single machine. The name comes from Greek word “tomo”, meaning slice. It reflects how radiation is delivered layer by layer to the tumour. Unlike traditional radiation methods, it delivers radiation in a helical and spiral pattern as the patient moves through the device, mimicking a CT scan. The system allows for continuous adjustment of radiation intensity, shaping the dose to precisely match the tumour’s three-dimensional contours.How does it work?Treatment begins with detailed CT or MRI scans to map the tumour and the surrounding organs. Radiation oncologists and medical physicists use the advanced software to generate a customised plan, optimising radiation angles and doses to maximise tumour coverage while minimising exposure to healthy areas. During sessions, the patient lies on a rotating couch that advances slowly through the machine. The radiation source spins 360 degrees. Binary multi-leaf collimators adjust thousands of times per rotation for sub-millimetre accuracy. This level of precision is important when tumours are located near sensitive organs, such as the brain, spinal cord, lungs and kidneys, among others. By minimising radiation exposure to surrounding tissue, tomotherapy helps reduce the risk of complications and long-term side effects.How was the technology developed?Tomotherapy originated at the University of Wisconsin-Madison in the early 1990s, pioneered by Thomas Rockwell Mackie and Paul Reckwerdt. Their goal was to merge diagnostic imaging with therapy, eliminating legacy constraints of conventional linear accelerators. The first commercial system launched in 2003. In Punjab, the current Radixact platform is only available at Mohandai Oswal Hospital here. Today, thousands of systems worldwide treat diverse forms of cancer, supported by extensive research.What are its advantages over traditional radiation?Tomotherapy delivers highly conformal doses, shaping radiation to complex tumours with better precision than traditional methods. It reduces side-effects by cutting radiation to nearby organs by 30 per cent to 50 per cent and offers adaptive planning during treatment.What are its potential drawbacks and side effects?No technology is perfect. Longer session times may pose challenges for claustrophobic patients and higher upfront costs limit access in low-resource areas. Some studies note the integral dose is slightly higher due to low-dose bath around targets. Common side effects mirror radiation fatigue and skin redness, but are milder. Acute risks like mucositis or cystitis occur less frequently. Long-term and secondary cancers are a minimal concern, outweighed by benefits.