Program Information
Impact On Clinical Workflow of Volume Modulated Arc Stereotactic Body Radiation Therapy (VMAT-SBRT)
B Lewis1*, E Fields2 , S Kim1 , T Kim1 , (1) Virginia Commonwealth University, Richmond, VA, (2) Virginia Commonwealth University Health, Richmond, Virginia
Presentations
SU-I-GPD-T-615 (Sunday, July 30, 2017) 3:00 PM - 6:00 PM Room: Exhibit Hall
Purpose: To evaluate the changes to clinical workflow of volume modulated arc stereotactic body radiation therapy (VMAT-SBRT) without or with the use of an active breathing coordinator (ABC) system for deep inspiration breath hold (DIBH).
Methods: 31 SBRT patients were observed during treatment, totaling 116 individual fractions. Ten of these patients were treated using the ABC system for DIBH, for 42 individual fractions. Each fraction was timed, as well as a subset of timepoints throughout each treatment fraction. Patients were positioned using in room lasers and markings on the personal immobilization equipment. The AlignRT surface tracking system was used to make fine corrections to patient roll and position, matching to the surface DICOM image from the simulation CT. They then received orthogonal 2D kV images, and a cone beam CT (CBCT) scan before beginning treatment. Patient shift distances were recorded in addition to treatment time points.
Results: Patients spent an average of 27.2±7.8 minutes, and 42.4±10.4 minutes for non-ABC and ABC patients, respectively. ABC patients required an average of 16 breath holds per fraction. The average time from the start of beam on time, to the end of the final beam was 2.5±1.2 minutes, and 7.0±4.4 minutes for non-ABC patients and ABC patients, respectively. Superior-inferior (S-I) shifts were -1.39±4.42 mm and -0.17±4.42 mm, anterior-posterior (A-P) shifts were -1.29±4.10 mm and -2.20±4.51 mm, and left-right (L-R) shifts were -0.22±4.26 mm and 0.15±4.22 mm for non-ABC and ABC patients respectively.
Conclusion: The addition of the ABC system during SBRT results in longer average treatment times. It is recommended to increase allotted appointment time by at least 15 minutes. This increased treatment time, however, is justified by the improved setup accuracy, and reduced target motion, reported by previous studies.
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