Targets coupled to the diaphragm
Upper-abdominal targets move with respiration more than most lung targets, and the organs around them — duodenum, stomach, bowel, kidneys — set the dose constraints. The smaller and more stable the target volume, the easier those constraints are to meet.
A vacuum cushion reproduces the patient's shape. It does not give a compression plate anything rigid to push against, and it does not stop the body rolling or sliding over a long fraction. AerFrame adds both: a rigid U-shaped base around the bag, and a compression arch mounted on the frame's own rails.
Compression with a fixed reference
Negoro IJROBP 2001 (n=10) · Heinzerling IJROBP 2008 (n=10) · comparable rigid frame systems; benefit varies by patient and tumor location.
The compression plate sits on the abdomen; the arch slides onto the rails to a recorded position and the screw turns down to the prescribed depth. Because the arch is referenced to the frame rather than to the couch or the bag, the same two numbers reproduce the same compression at every fraction.
Built for adaptive abdominal workflows
Online adaptive radiotherapy is used widely for pancreatic and other abdominal targets, where day-to-day anatomy changes the plan. Adaptive replans on the patient's anatomy alone and never sees the immobilization hardware, so the hardware has to be negligible. AerFrame measures under 2% single-beam attenuation at 6, 10 and 15 MV away from the side rails and renders at −928 HU on the planning scan. The attenuation measurements →
For MR simulation and MR-guided workflows, the frame, head rest and the MR Safe black compression arch go into the MR suite; the coordinate arch, laser box and blue arch stay out. AerFrame is MR Conditional per labeling. MR environments →
Data on file, Stabilix. Available on request.
Every fraction, learned once
- Place. Frame and the patient's own vacuum-bag cradle onto the couch. Patient into the bag.
- Verify the marks. Coordinate arch and laser box to the registration position. The two dots land on the patient's marks; shift the patient in the frame if they don't.
- Frame to the room. Arch to the isocenter position on the rail. Move the frame until the room lasers meet X, Y and Z on the arch.
- Remove and verify. Arch off. Image guidance confirms the alignment before every fraction, as the IFU requires.
Questions
Which abdominal sites is AerFrame used for?
Liver, pancreas, kidney and adrenal SBRT with restraint and compression, and prostate and spine with restraint alone. These are common sites, not a limit; AerFrame is cleared for photon-based immobilization.
How much does compression reduce liver tumor motion?
In a published rigid-frame series, mean lung and liver tumor motion fell from 13.6 mm without compression to 7.2 mm with high compression (Heinzerling, IJROBP 2008, n=10). The figure combines lung and liver patients and comes from a comparable rigid frame system; the benefit varies by patient and tumor location.
How is the compression depth reproduced?
The arch position on the rail and the screw setting are recorded on the worksheet at simulation. At each fraction the arch goes to the same rail position and the screw to the same depth.
Can the patient be imaged in the frame?
Yes. The coordinate arch and laser box come off before imaging; the frame and compression arch stay on for CBCT and treatment. In the MR suite the MR Safe black arch is used in place of the blue one.
Does the frame change the dose to the duodenum or bowel?
The frame itself contributes a measured mean D95 loss of 1.1% across eleven patients, with every patient inside 3%, away from the side rails. Organ doses are set by the plan; the attenuation data package has the measurements your physicist will want.