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Poster ‐ 55: Active Breathing Coordinator Based Treatment of Liver SBRT Patients
Author(s) -
Karotki Aliaksandr,
Erler Darby,
Chu William,
Chung Hans T.
Publication year - 2016
Publication title -
medical physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.473
H-Index - 180
eISSN - 2473-4209
pISSN - 0094-2405
DOI - 10.1118/1.4961829
Subject(s) - breathing , medicine , fluoroscopy , diaphragm (acoustics) , nuclear medicine , radiology , anesthesia , physics , acoustics , loudspeaker
Purpose: Accuracy of treatment delivery for liver SBRT patients can be compromised by breathing induced motion. Recently we started using active breathing coordinator (ABC) to “freeze” the breathing motion. This work describes our initial experience with ABC based treatment of liver SBRT patients. Methods: Patients are treated in maximum exhale state with a minimum required breath hold time of 20 s. Fluoroscopy is used to assess diaphragm stability before both simulation and treatment. Depending on the proximity of organs at risk, 30–60 Gy are given in five fractions every other day and delivered via VMAT. CBCT is used for patient setup verification with robotic couch compensating for translations/rotations. An additional CBCT is acquired after every fraction to confirm patient's stability during treatment. Results: Six patients have successfully been treated using the ABC protocol so far with an approximate treatment time of 1 h. CBCT acquired after the treatment suggests that patients are stable and the liver position, when locked by ABC, is reproducible throughout the treatment (average deviation 1.9 mm). The major immediate benefit of using ABC is a drastic improvement in image quality of the CT simulation as well as CBCT images. Conclusions: ABC eliminates breathing motion and, as such, substantially improves the quality of the images acquired at CT simulation as well as CBCT images leading to more reliable dose delivery. The position of the liver remains stable for the duration of treatment when using the ABC system. The treatment is well tolerated by the patients.