A new tomotherapy machine with a fully integrated treatment planning and delivery system allows doctors to deliver radiotherapy more accurately and effectively.
Radiation therapy, or radiotherapy, is one of the main treatments for cancer. High-energy beams from a linear accelerator are directed at precise points in the body to safely and effectively treat both malignant and benign tumours by killing cancer cells or halting their growth.
With continuing advancement in radiation therapy over the years, the delivery of radiation has become faster, more precise and safer. This enables doctors to customise the treatment to be more targeted while minimising the unnecessary effects of radiation on surrounding healthy tissues and cells by modulating the radiation dose received by the tumour and its surrounding normal tissues.
One of the latest forms of linear accelerator-based radiotherapy is helical tomotherapy, which uses intensity-modulated radiation therapy (IMRT) to treat tumours. A built-in CT scanner first confirms the shape and location of a tumour before customised radiation beams are directed precisely onto the diseased tissues.
Recent advancements have been seen in the use of tomotherapy. A new next-generation platform that helps doctors to treat patients more efficiently and effectively is the Radixact Treatment Delivery System (Radixact System), a machine that has the ability to scan, then deliver the treatment slice by slice to achieve great conformity to the shape of the tumour while sparing normal tissues by creating steep dose gradients between tissues.
The system provides rotational (helical) and non-rotational radiation therapy using intensity-modulated and non-intensity-modulated (3D conformal) radiation therapy. As it is equipped with built-in true CT detectors, it can deliver image-guided and adaptive radiation therapy.
With this machine, doctors can take a CT scan immediately before each treatment. The CT image allows them to verify the position of the tumour so that they can adjust the patient’s treatment position just before beam on and thus ensure that the radiation can be delivered precisely.
The delivery itself is done by directing beamlets of radiation from 360 degrees around the patient, who is moved through the machine at a slow, calibrated speed. Each beamlet contains an optimised dose of radiation, and contributes to the total radiation dose as they come together in the tumour. This unique method of delivering radiation makes the radiation very targeted, customised and precise, thus further reducing the impact of radiotherapy on surrounding normal tissue and organs.
Each treatment session generally takes about 10 to 20 minutes.
Doctors and patients alike have given the Radixact System a thumbs-up. Doctors have found that the machine allows them to treat complex tumours that are hard to reach. They have also been able to treat cancers that have recurred and previously would not have been treatable with radiation.
Dr Lee Kim Shang, a Senior Consultant in Radiation Oncology at Parkway Cancer Centre, said that as it is a fully integrated treatment planning and delivery system, the Radixact System simplifies the workflow and enables precise treatment delivery to more patients. “This treatment planning system is more advanced and allows for quick generation of treatment plans, thus reducing waiting time,” he said. “The Radixact System is able to treat multiple tumours in the body at the same time.”