TY - JOUR
T1 - Radiation Therapy Workflow and Dosimetric Analysis from a Phase 1/2 Trial of Noninvasive Cardiac Radioablation for Ventricular Tachycardia
AU - Knutson, Nels C.
AU - Samson, Pamela P.
AU - Hugo, Geoffrey D.
AU - Goddu, S. Murty
AU - Reynoso, Francisco J.
AU - Kavanaugh, James A.
AU - Mutic, Sasa
AU - Moore, Kaitlin
AU - Hilliard, Jessica
AU - Cuculich, Phillip S.
AU - Robinson, Clifford G.
N1 - Funding Information:
All financial support was provided by Washington University Departments of Radiation Oncology (C.G.R.) and Medicine, Cardiovascular Division (P.S.C.), or from Barnes-Jewish Hospital Foundation competitive grants (P.S.C.). Support for electrocardiographic imaging processing and analyses were provided by the National Institutes of Health R01 HL033343 (Yoram Rudy). No industry-related support was used.
Publisher Copyright:
© 2019 Elsevier Inc.
PY - 2019/8/1
Y1 - 2019/8/1
N2 - Purpose: A prospective phase 1/2 trial for electrophysiologic guided noninvasive cardiac radioablation treatment of ventricular tachycardia (ENCORE-VT) demonstrating efficacy for arrhythmia control has recently been reported. The treatment workflow, report dose-volume metrics, and overall process improvements are described here. Methods and Materials: Patients receiving 25 Gy in a single fraction to the cardiac ventricular tachycardia substrate (identified on presimulation multimodality imaging) on the phase 1/2 trial were included for analysis. Planning target volume (PTV), R50, monitor unit ratio, and gradient measure values were compared over time using statistical process control. Outlier values in the dose-volume histogram (DVH) for PTV and organs at risk were identified by calculating inner fences based on the interquartile range. Median heart substructure doses are also reported. Results: For the 16 trial patients included, the median target volumes for the gross “target” volumes, internal target volumes, and PTVs were 25.1 cm3 (minimum: 11.5 cm3, maximum: 54.9 cm3), 30.1 cm3 (17.7, 81.6), and 97.9 cm3 (66, 208.5), respectively. On statistical process control analysis, there was a significant decrease in PTV volume among the more recent cohort of cases and mean doses to the nontargeted heart (heart – PTV). Two patients had heart-minus-PTV, esophagus, and stomach DVH data significantly higher than inner fence, and 3 patients had spinal cord DVH data higher than the inner fence, but in all cases the deviations were clinically acceptable. Subjective decreases were seen in the R50, gradient measure, and treatment time from the first to last patient in this series. All plans were verified in phantom with ionization chamber measurements within 2.9% of the expected dose value. Conclusions: Over the duration of this trial, PTV volumes to the cardiac substrate target decreased significantly, and organ-at-risk constraints were met for all cases. Future directions for this clinical process will include incorporating knowledge-based planning techniques and evaluating the need for substructure optimization.
AB - Purpose: A prospective phase 1/2 trial for electrophysiologic guided noninvasive cardiac radioablation treatment of ventricular tachycardia (ENCORE-VT) demonstrating efficacy for arrhythmia control has recently been reported. The treatment workflow, report dose-volume metrics, and overall process improvements are described here. Methods and Materials: Patients receiving 25 Gy in a single fraction to the cardiac ventricular tachycardia substrate (identified on presimulation multimodality imaging) on the phase 1/2 trial were included for analysis. Planning target volume (PTV), R50, monitor unit ratio, and gradient measure values were compared over time using statistical process control. Outlier values in the dose-volume histogram (DVH) for PTV and organs at risk were identified by calculating inner fences based on the interquartile range. Median heart substructure doses are also reported. Results: For the 16 trial patients included, the median target volumes for the gross “target” volumes, internal target volumes, and PTVs were 25.1 cm3 (minimum: 11.5 cm3, maximum: 54.9 cm3), 30.1 cm3 (17.7, 81.6), and 97.9 cm3 (66, 208.5), respectively. On statistical process control analysis, there was a significant decrease in PTV volume among the more recent cohort of cases and mean doses to the nontargeted heart (heart – PTV). Two patients had heart-minus-PTV, esophagus, and stomach DVH data significantly higher than inner fence, and 3 patients had spinal cord DVH data higher than the inner fence, but in all cases the deviations were clinically acceptable. Subjective decreases were seen in the R50, gradient measure, and treatment time from the first to last patient in this series. All plans were verified in phantom with ionization chamber measurements within 2.9% of the expected dose value. Conclusions: Over the duration of this trial, PTV volumes to the cardiac substrate target decreased significantly, and organ-at-risk constraints were met for all cases. Future directions for this clinical process will include incorporating knowledge-based planning techniques and evaluating the need for substructure optimization.
UR - http://www.scopus.com/inward/record.url?scp=85065865141&partnerID=8YFLogxK
U2 - 10.1016/j.ijrobp.2019.04.005
DO - 10.1016/j.ijrobp.2019.04.005
M3 - Article
C2 - 31002942
AN - SCOPUS:85065865141
SN - 0360-3016
VL - 104
SP - 1114
EP - 1123
JO - International Journal of Radiation Oncology Biology Physics
JF - International Journal of Radiation Oncology Biology Physics
IS - 5
ER -