Audio-visual biofeedback for respiratory-gated radiotherapy: impact of audio instruction and audio-visual biofeedback on respiratory-gated radiotherapy.

Full Abstract

PURPOSE:
Respiratory gating is a commercially available technology for reducing the deleterious effects of motion during imaging and treatment. The efficacy of gating is dependent on the reproducibility within and between respiratory cycles during imaging and treatment. The aim of this study was to determine whether audio-visual biofeedback can improve respiratory reproducibility by decreasing residual motion and therefore increasing the accuracy of gated radiotherapy.

METHODS AND MATERIALS:
A total of 331 respiratory traces were collected from 24 lung cancer patients. The protocol consisted of five breathing training sessions spaced about a week apart. Within each session the patients initially breathed without any instruction (free breathing), with audio instructions and with audio-visual biofeedback. Residual motion was quantified by the standard deviation of the respiratory signal within the gating window.

RESULTS:
Audio-visual biofeedback significantly reduced residual motion compared with free breathing and audio instruction. Displacement-based gating has lower residual motion than phase-based gating. Little reduction in residual motion was found for duty cycles less than 30%; for duty cycles above 50% there was a sharp increase in residual motion.

CONCLUSIONS:
The efficiency and reproducibility of gating can be improved by:
incorporating audio-visual biofeedback, using a 30-50% duty cycle, gating during exhalation, and using displacement-based gating.

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Author information

Author/s: George, Rohini (R); Chung, Theodore D (TD); Vedam, Sastry S (SS); Ramakrishnan, Viswanathan (V); Mohan, Radhe (R); Weiss, Elisabeth (E); Keall, Paul J (PJ);

Affiliation: Department of Radiation Oncology, Virginia Commonwealth University, Richmond, VA, USA.

Grants: R01 CA 93626 (Agency:NCI NIH HHS)

Journal and publication information

Publication Type: Evaluation Studies; Journal Article; Research Support, N.I.H., Extramural

Journal: International journal of radiation oncology, biology, physics (Int J Radiat Oncol Biol Phys), published in United States. (Language: eng)

Reference: 2006-Jul; vol 65 (issue 3) : pp 924-33

Dates: Created 2006/06/05; Completed 2006/07/06; Revised 2007/11/14;

PMID: 16751075, status: MEDLINE (last retrieval date: 12/26/2008)

Sourced from the National Library of Medicine. Abstract text and other information may be subject to copyright.

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MeSH headings (categories)

This article was linked to the MESH Headings shown below.

Adult
Aged
Aged, 80 and over
Audiovisual Aids
Biofeedback (Psychology) - instrumentation; methods
Female
Humans

Humans
Lung Neoplasms - physiopathology; radiotherapy
Male
Middle Aged
Movement
Reproducibility of Results
Respiration

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