If you are rotating the patient won’t they move more?

Most of us don’t like change, it is human behaviour to resist or question the reasoning behind it. Here at Leo Cancer Care we understand we are making a significant change to the way radiotherapy will be delivered and therefore we want to answer all concerns fully with data and research.

One of the biggest questions we get asked is; if you are rotating the patient won’t they move more? 

We have spent the last few months starting to answer this question across our channels, sharing existing data, papers and educational videos. In this blog, we are going to summarise the findings.

What do we already know about motion upright?

There is evidence to suggest that when we are upright our organs move less, we will share the top papers on this subject in this blog. These papers really convinced us to set out on this journey, to be the more human way to deliver radiation therapy in the upright orientation.

Interfractional and Intrafractional Motion

Interfractional motion is everything that changes or moves between treatments, for example; weight loss, patient setup or repositioning. 

Intrafractional is the change that takes place during treatment inside the body i.e. organ movement or tumour changes.

Interfractional Motion Upright

The key is patient set-up reproducibility, achieving the same position at each treatment fraction. 

Working with our research partners at Centre Léon Bérard we are currently gathering data on this subject. We will soon have data to share from patients that have been set up in our technology directly after receiving treatment on a conventional supine solution. So watch this space.

Immobilisation devices used for Upright Radiotherapy

As an industry we strive for submillimetre accuracy to target a tumour, motion is the enemy and our bodies are designed to move.

Therefore, immobilisation has always been a tool to reduce motion. Upright is no different and the devices used are not a far cry from what the industry uses in supine treatments.

To learn about the standard immobilisation devices used for upright radiotherapy watch the video below we recorded at ESTRO in Copenhagen, with our partners from CIVCO Radiotherapy.

Optical Guidance for setup reproducibility

Optical guidance cameras are becoming increasingly popular to ensure the patient is repositioned as accurately as possible and to detect irregular motion during treatment.

At Leo Cancer Care are currently using optical guidance cameras to measure the setup reproducibility with our partners in Centre Léon Bérard, results will be available soon.

In addition, we want the cameras to offer another opportunity for patients to participate in their setup and treatment. With a screen positioned at the start position of the patient positioning system, patients will be able to reposition themselves based on previous setup images. 

Intrafractional Motion

As previously mentioned there are multiple papers supporting the reduced motion in upright compared to supine. Let’s go through a few of them here:

Our lungs are on average 50% greater in volume upright compared to supine

Most intrafactional motion comes from our lungs and diaphragm, a study carried out by a group lead by Laurence Court at MD Anderson, showed that upright our lungs are on average 50% greater in volume compared to when we are laying down. This means for a given tidal volume the motion is reduced on average by 5mm. 

Bigger lungs and less motion will mean a more targeted treatment with less radiation delivered to healthy tissue or surrounding organs.

Did you know that our liver drifts up to 35 minutes when we lay down?

A study carried out by a team at the Paul Scherrer Institute, investigated what happens to the liver when we go from being upright to laying down. The results were enlightening, showing that our liver can move for up to 35 mins, moving in the order of centimetres. 

With such movement, the PTV could quickly become out of the field during treatment and healthy tissue irradiated. Our hypothesis is that if we remain upright, the liver drift will not take place with such magnitude. This is something that we are keen to prove with data from our solutions in the near future. 

Our very own whitepaper - Anatomical Changes in the Male Pelvis Between the Supine and Upright Positions

Niek Schrueder, our Chief Scientific Officer and the team at Leo Cancer Care carried out a study investigating  the position of the prostate in the upright compared to supine.

The results showed that the position of the prostate favoured the upright position, potentially reducing damage to surrounding organs. Furthermore, the team discovered that full bladder filling may not be as necessary upright.

Summary

Ultimately, data is what will help prove to the industry that motion is reduced upright and we are on a mission to provide that information. 

We feel the evidence is there and as we collect more data, we are more confident that upright we will reduce motion and therefore, more importantly deliver more accurate treatments with fewer side effects, a more human way to treat with radiation therapy.

*The Leo Cancer Care technology does not currently have a CE mark in the EU, or an FDA 510k clearance in the US, but Leo Cancer Care is in the process of acquiring those regulatory approvals.