Radiation therapy utilizes high doses of ionizing or particulate radiation to kill cancer cells. It is an integral component of multimodality cancer care. However, the challenge lies in delivering it precisely to the target while sparing surrounding healthy tissues. Technological advancements have revolutionised radiation therapy planning and delivery leaps and bounds. Especially incorporation of axial imaging in treatment planning & computerised algorithm-based radiation planning has emerged as a game changer in the last 2 decades. In the era of precision medicine Image-Guided Radiation Therapy (IGRT) is a powerful ally, placing targeted radiation techniques like Stereotactic radiosurgery (SRS) and Stereotactic body radiation therapy (SBRT) on a high pedestal. These techniques treat tumours with sub millimetric precision and also permit dose escalation to ablative levels for some tumours.
IGRT particularly has improved treatment planning and delivery by enhanced localization-.This permits for real-time visualization of the tumour as well as motion management (targeting tumour in a particular phase of respiration) and also enables clinicians to adapt treatment plans based on the dynamic nature of tumours, accounting for changes in size, shape, and position.
Monitoring treatment response is a critical aspect of precision medicine. Functional imaging facilitates the assessment of how tumors respond to radiation in real-time. Treatment plans can be adapted based on the observed response, either intensifying treatment for resistant tumors or reducing radiation doses for responsive ones. A step ahead in image guidance is MRI Linac – it is a linear accelerator with an in built MRI machine .Inbuilt MRI enhances the ability to visualise the tumour with greater accuracy and also picks up changes early .It is particularly helpful for treating tumours in the pelvic region.
In recent years, significant strides have been made in refining particle beam therapy, addressing longstanding challenges such as high costs, large equipment size, and the need for technological improvements in dosimetry, gantry systems, patient positioning, and image verification. Notably, scattered beams are now being utilized to treat irregular tumors, expanding the therapy’s applicability. Commercially available particle therapies, including proton, hadron, and carbon ion therapy, have not only proven effective in treating recurrent tumors but have also been deployed in clinically challenging scenarios where tumors are situated close to critical areas.
To conclude IGRT offers unprecedented levels of accuracy and customization in cancer treatment. The advantages of IGRT extend beyond enhanced targeting, encompassing improved treatment planning, motion management, response assessment, and the reduction of treatment margins.
