Illustration of the radiotherapy room and the occlusion downside confronted by ceiling-mounted cameras on this utility.
What was the subject of your PhD analysis and why was it an fascinating space?
My subject of analysis was growing an optical tactile sensor to trace head movement throughout radiotherapy. I labored on each the {hardware} and software program growth of this sensor, although my focus was totally on the software program aspect. Its significance comes from the truth that throughout radiotherapy, sufferers present process head and neck most cancers remedy are sometimes immobilised. That is normally performed utilizing a thermoplastic masks, which may really feel very claustrophobic, or a stereotactic body. Frames are extra frequent for mind cancers, however they should be surgically inserted into the affected person’s cranium utilizing pins. Both of those immobilisation instruments could also be used relying on the scenario. When sufferers are uncomfortable, they’re extra more likely to transfer, which impacts the accuracy of remedy, particularly with thermoplastic masks.
One other main concern is that present programs use ceiling-mounted cameras to file affected person movement. These cameras can’t be positioned too near the affected person due to the electromagnetic setting across the gear. Their view can be steadily occluded as a result of the affected person strikes right into a tunnel to obtain the ionising beams, which makes it tough to seize rotational movement.
One various is an infrared digital camera with a nostril marker, however this solely captures translational movement. Presently, when a nostril tracker detects motion past a sure threshold, remedy is paused, the affected person is repositioned, and remedy resumes. It’s tough to adapt this technique to reliably measure the rotational movement of the affected person’s head within the radiotherapy setting.
That is the place the Movement Seize Pillow (MCP) is available in, which incorporates the optical tactile sensor I developed. The purpose with this technique is much like the nostril tracker, however with extra correct rotational suggestions for the radiographer. It may be positioned beneath the affected person’s head and connected to the remedy mattress. It estimates how a lot the affected person’s neck is rotating and improves affected person consolation. Radiographers can obtain real-time suggestions on each translational and rotational motion. Some great benefits of this technique are that there are not any occlusions, as a result of the pillow is in direct contact with the affected person’s head, and it’s extra appropriate with radiotherapy environments as a result of the sensor is non-ferromagnetic. Its premise is to take care of affected person consolation, keep compact and simple to combine into the pre-existing programs for radiotherapy, while enhancing the accuracy of the remedy by way of real-time head monitoring.
Labelled diagram of the Movement Seize Pillow – Optical tactile sensor for head monitoring throughout radiotherapy. The pneumatic pillow is a deformable rubber-like sheet with embedded white markers, held in its convex form utilizing air strain. The fibrescope represents a non-ferromagnetic fibre optic bundle used as a lens extension to an space scan digital camera. The digital camera is ferromagnetic and would require protected positioning and fixation.
What had been the principle contributions of your work?
There have been 4 essential contributions to my work. The first contribution centered on making the system extra non-ferromagnetic and enhancing the imaging and monitoring strategy. Earlier work used a webcam and binary picture processing inside the optical tactile sensor to trace marker displacement. I finally determined to make use of a fibrescope, optical circulate monitoring algorithm, and grayscale imaging as an alternative, which improved the sensor’s monitoring means.
The second contribution centered on optimising marker density. The optical tactile sensor consists of an array of markers on a deformable rubber-like sheet, resembling a pillow. The deformation of those markers is captured by the digital camera. I investigated how dense the marker array wanted to be by adjusting the spacing between markers to find out what labored finest for this utility.
The third contribution concerned sensor fusion to enhance reliability and robustness. To do that, I built-in a gyroscope and used Kalman filtering to fuse information from the gyroscope and the MCP. This was necessary for Gamma Knife programs, that are radiosurgery platforms used for mind cancers. They have an inclination to have increased accuracy necessities than linear accelerators, that are generally used for head and neck cancers, and decrease constraints on using ferromagnetic parts.
The ultimate contribution was a participatory design research carried out in collaboration with clinicians and the social sciences division. We explored how the MCP could possibly be built-in into hospital workflows and assessed its feasibility.
How possible is it to combine this sensor into hospital workflows?
Clinicians did appear to be very on board with it, however the research was extra qualitative than quantitative. Whereas they felt the thought had advantage, there have been reservations about adopting new expertise and the related studying curve.
They had been additionally involved about accuracy. Enhancing accuracy and reliability is crucial for clinicians to really feel assured utilizing the system. At current, additional growth is required earlier than it may be broadly applied.
What future work is deliberate on this space?
One space to analyze is the variations between the model and participant information. The pillow form is managed by a pneumatic system with a strain sensor and air pump. When the affected person or model strikes, strain modifications happen. The system compensates to take care of a set strain, however this introduces errors within the movement readings. The model produced extra errors than the participant information. It might not precisely simulate human movement on the pillow, and the testing setup could introduce discrepancies that don’t replicate real-world behaviour.
So, future work contains stabilising and refining the strain management system to enhance reliability. If mandatory, reconsidering using gel on the sensors could possibly be an choice. Gel had been used beforehand however was deserted on account of clinician considerations about attenuation of ionising beams. Nonetheless, if avoiding gel considerably compromises sensor efficiency, revisiting this strategy could also be worthwhile.
As well as, extra participant information assortment is required. Not all beforehand collected information could possibly be used on account of ground-truth measurements being partially occluded within the experimental setup. Extra participant research would offer a clearer understanding of efficiency throughout totally different people. One other precedence is enhancing the fibrescope’s decision and angle to higher visualise high-density marker arrays. {Hardware} upgrades would assist guarantee a clearer discipline of view and enhance total system efficiency.
About Bhoomika
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Bhoomika Gandhi is a latest PhD graduate from the College of Sheffield Medical Robotics group. Her undergraduate diploma was in Bioengineering – Medical Gadgets and Devices, with management engineering and robotics being the important thing themes. |
Ella Scallan
is Assistant Editor for AIhub