A group of Indian scientists have developed a novel and cheap 3D robotic motion phantom that can reproduce human lung motion during breathing which can be used to check if the radiation is being correctly focussed on a moving target, the Department of Science and Technology (DST) said on Monday.
The phantom is placed inside a CT scanner on the bed in the human’s place, and it emulates human lung motion as it is irradiated during therapy.
Ashish Dutta, Professor at IIT Kanpur, along with K J Maria Das, Professor at Sanjay Gandhi Postgraduate Institute of Medical Sciences (SGPGIMS), Lucknow, developed the programmable robotic motion, the platform for quality assurance of respiratory motion management techniques in radiation therapy.
Breathing motion is a hurdle for delivering focused radiation dose to the cancer tumour attached to upper abdomen and thoracic regions. The motion exposes an area larger than the tumour to radiation during treatment, thus affecting tissues surrounding the targeted tumour.
A focused radiation for a patient could be customised by simulating the lung movement of the particular patient and then orienting the radiation’s delivery so that it can be effective with minimal dosage. Before this is done on a human, its effectiveness needs to be checked on a robotic phantom.
Recent technological developments have resulted in state-of-the-art motion management techniques like-gating and tracking. Though there is incremental development in radiation therapy delivery of respiratory moving targets, the quality assurance (QA) tools have not been developed in parallel.
For quantitative determination of the absorbed dose in an organ in the patient for a specific type of treatment procedure accuracy of respiratory motion management techniques, additional respiratory motion phantoms are required.
During irradiation, consistently high-quality images of advanced 4D radiation therapy treatments are obtained with minimum exposure of the patients and workers. Before the targeted radiation is delivered to a human subject, its effectiveness in focusing only on the tumour is checked with this phantom.
The major part of the phantom is a dynamic platform over which any dosimetric or imaging quality assurance devices can be placed, and the platform can mimic 3D tumour motion by using three independent stepper-motor systems.
This platform is placed on the bed where the patient lays down during radiation therapy. As phantom emulates the lung movement, a moving or gating window is used to focus the radiation from the radiation machine on the moving tumour. Detectors placed in the phantom help detect whether the radiation is localised on the tumour.
The dose effectiveness is checked during therapy. The researchers are in the process of testing the system on a phantom. Once done, they will test it on human beings.
This is the first time in India for manufacturing this type of robotic phantoms, and it is more affordable than other imported products available in the market as the program can be changed to produce different types of lung motion.
The technology developed with support from the Advanced Manufacturing Technologies programme of the DST, and aligned with the ‘Make in India’ initiative is currently under final testing in SGPGIMS, Lucknow.
The innovators are further trying to commercialise the product, which can be used in place of the overseas model that is much more expensive and does not give access to the control software, it added.