# A shared registry comparing upright and lying-down radiotherapy

Source: https://onco.cc/ideas/idea-mach-upright-versus-supine-registry/  
OnCo record `idea-mach-upright-versus-supine-registry` (Idea). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

Upright proton machines are being installed, cleared mainly for the head, neck and upper chest, without any head-to-head comparison with lying down. A proposal: every centre records set-up accuracy, comfort and side effects the same way so the comparison exists.

## Summary

Upright positioning removes the proton gantry and is now cleared in the United States and Europe (P-Cure 2023, Leo Cancer Care Marie 2025, Mevion S250-FIT 2025), with the S250-FIT limited to sites above the mid-chest when fully seated. OnCo found no randomised or matched comparison of upright and supine treatment. This proposal, which no source makes in these words, is a common registry across upright sites recording daily set-up error, replanning rate, patient-reported comfort and acute toxicity, matched to supine patients at the same centres.

## Fields

- Kind: Idea
- Last checked: 2026-11-04
- Tags: machines-wave3; proposal
- Hypothesis: For head, neck and upper thoracic targets, upright treatment gives set-up reproducibility within the margins used for supine treatment and better patient-reported comfort in people who find lying flat difficult.
- Rationale: The clearances define where upright treatment may be used but not how it compares; the number of installations is small enough that a shared registry from the start is feasible.
- Proposed test: Pool set-up, imaging and patient-reported data from the first upright centres for two years and compare with matched supine patients; publish the protocol before the data.
- Maturity: early-clinical
- Actor: clinic

## Sources

- FDA 510(k) K250986: Mevion S250-FIT, seated indication limits: https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfpmn/pmn.cfm?ID=K250986
- FDA 510(k) K250970: Leo Cancer Care Marie: https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfpmn/pmn.cfm?ID=K250970

## Connected records

- fronts: [Radiation Therapy](https://onco.cc/fronts/radiation/)
- technologies: [Proton therapy machines: cyclotrons, synchrotrons and single-room systems](https://onco.cc/technologies/proton-therapy-systems/), [Upright radiotherapy positioning (Leo Cancer Care Marie, P-Cure, Mevion S250-FIT)](https://onco.cc/technologies/upright-radiotherapy-positioning/)
- companies: [Leo Cancer Care](https://onco.cc/companies/leo-cancer-care/), [Mevion Medical Systems](https://onco.cc/companies/mevion/), [P-Cure](https://onco.cc/companies/p-cure/)
- institutions: [Stanford Health Care / Stanford Cancer Institute](https://onco.cc/institutions/stanford/)
- bottlenecks: [Surgery and radiotherapy cure most, get least](https://onco.cc/bottlenecks/b-surgery-radiation-innovation/), [Trial design, endpoints and cost](https://onco.cc/bottlenecks/b-trial-design/)
- roadmaps: [Particle therapy machines: from Loma Linda to proton rooms in a linac vault, carbon gantries and FLASH](https://onco.cc/roadmaps/particle-therapy-machines-roadmap/)

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