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Development and application of a real‐time monitoring and feedback system for deep inspiration breath hold based on external marker tracking
Author(s) -
Stock Markus,
Kontrisova Kristina,
Dieckmann Karin,
Bogner Joachim,
Poetter Richard,
Georg Dietmar
Publication year - 2006
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 - 10.1118/1.2219775
Subject(s) - reproducibility , breathing , medicine , tracking (education) , medical imaging , computer science , nuclear medicine , radiology , mathematics , psychology , pedagogy , statistics , anatomy
Respiration can cause tumor movements in thoracic regions of up to 3 cm . To minimize motion effects several approaches, such as gating and deep inspiration breath hold (DIBH), are still under development. The goal of our study was to develop and evaluate a noninvasive system for gated DIBH (GDIBH) based on external markers. DIBH monitoring was based on an infrared tracking system and an in‐house‐developed software. The in‐house software provided the breathing curve in real time and was used as on‐line information for a prototype of a feedback device. Reproducibility and stability of the breath holds were evaluated without and with feedback. Thirty‐five patients undergoing stereotactic body radiotherapy (SBRT) performed DIBH maneuvers after each treatment. For 16 patients dynamic imaging sequences on a multislice CT were used to determine the correlation between tumor and external markers. The relative reproducibility of DIBH maneuvers was improved with the feedback device ( 74.5 % ± 17.1 % without versus 93.0 % ± 4.4 % with feedback). The correlation between tumor and marker was good (Pearson correlation coefficient 0.83 ± 0.17 ). The regression slopes showed great intersubject variability but on average the internal margin in a DIBH treatment situation could be theoretically reduced by 3 mm with the feedback device. DIBH monitoring could be realized in a noninvasive manner through external marker tracking. We conclude that reduction of internal margins can be achieved with a feedback system but should be performed with great care due to the individual behavior of target motion.