ASMR

Case example

Incident description: During weekly off-line check of the patient’s CBCT the physicist noticed that the patient (H&N) lost weight / experienced tumour shrinkage in the treatment area. There is 8-10 mm air under the immobilisation net, on both right and left side. By analysing older CBCTs, it was discovered, that the loss of tissue already occurred 1-2 weeks earlier, but without reactions.

Incident consequences: Uncertain setup, uncertainty in the delivered dose distribution

Assumed cause of incident: Image guidance was not performed satisfactorily

Suggestion to avoid repeating the incident: Better/more detailed information to the RTT’s to observe the images for potential weight loss resulting in air under the immobilisation mask. Better/more detailed information t the physicists to evaluate the images (during off-line controls) as a whole and not only focusing on the matching structures. Quicker actions required when observing anatomical changes.

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