Treatment delivery time optimization of respiratory gated radiation therapy by application of audio-visual feedback.
OBJECTIVE
The feasibility to use visually guided voluntary breath-hold with and without audio assistance to reduce the total treatment time was evaluated.


METHODS
Patients referred for gated SBRT received hypofractionation schedules for lung or liver treatments. The patients were treated with the Novalis system (BrainLAB AG, Feldkirchen, Germany) and IGRT was performed with ExacTrac5.0/NovalisBody allowing gated irradiation. Video glasses, used for visual feedback to guide voluntary breath-hold, allowed additional audio assistance during treatment. The technique was applied for 25 patients of whom 9 were treated in free breathing, 7 had only visual feedback and another 9 had both audio and visual feedback.


RESULTS
The delivery time of gated treatment during free breathing had an average value of 1.7 min/100 MU (SD 0.6 min/100 MU). The introduction of visual feedback reduced the average delivery time to 1.4 min/100 MU (SD 0.4 min/100 MU). The treatments with additional audio assistance indicated a significant reduction (p=0.004) of the average delivery time to 0.9 min/100 MU (SD 0.2 min/100 MU).


CONCLUSIONS
The introduction of visually guided voluntary breath-hold with audio assistance led to treatment times for gated radiation therapy approaching conformal beam delivery times, which made gated treatments applicable in conventional treatment time slots.
Radiotherapy Department, Universitair Ziekenhuis Brussel, Belgium. Nadine.linthout@uzbrussel.be
Nadine
N
Linthout
Samuel
S
Bral
Iwein
I
Van de Vondel
Dirk
D
Verellen
Koen
K
Tournel
Thierry
T
Gevaert
Michael
M
Duchateau
Truus
T
Reynders
Guy
G
Storme
D001296:Audiovisual Aids; D019583:Dose Fractionation, Radiation; D005240:Feasibility Studies; D005246:Feedback; D006801:Humans; D008113:Liver Neoplasms / Q000000981:diagnostic imaging / Q000601:surgery*; D008175:Lung Neoplasms / Q000000981:diagnostic imaging / Q000601:surgery*; D009068:Movement; D011187:Posture; D016634:Radiosurgery / Q000295:instrumentation* / Q000379:methods*; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods; D011881:Radiotherapy, Computer-Assisted / Q000295:instrumentation* / Q000379:methods*; D055425:Respiratory-Gated Imaging Techniques; D013997:Time Factors; D014057:Tomography, X-Ray Computed / Q000379:methods; D016896:Treatment Outcome