What is the best method for ensuring that vaginal cuff cylinder is in proper position at each fraction?

The best method depends on local context and what tech is available.

For imaging, one can: re-CT each treatment, use fluoro (we have a C-arm), use the kV or MV imager on a Linac with an orthogonal pair or a CBCT. There are other methods also. Some practices don’t image verify (makes me nervous).

For immobilization: stretch net/mesh underwear, leg strap available from each vendor, brachy transfer boards with a built-in immobilizer, or Martin-style articulating arm that can rigidly hold the cylind...

We do not have fluoroscopy available in our clinic. I insert the cylinder in CT sim, secure it using a stabilizer board, and obtain AP and lateral scout films to compare to the prior imaging. We then move the patient by stretcher to the HDR unit. Our therapists put reference marks on the patient to confirm stability when the patient is moved.

If your HDR unit is in the same room as your linac, kV imaging may be another option.

From the ABS guidelines (@Dr. First Last et al. PMID 22265439): "When...

I do a CT scan with stabilizing arm in place (as necessary based on patient anatomy) every fraction. Insertion is done on the CT simulation cylinder table, usually in frog-leg position.

The treatment is planned after 1st scan. Subsequent scans are only to confirm positioning looks the same as the first scan, and then treated with the same plan as day 1, time-adjusted for differences in source strength.

Whenever the patient has the CT scan done, where the distal end of the connecting tube is loca...