Protecting the Heart: A Practical Approach to Account for the Full Extent of Heart Motion in Radiation Therapy Planning.
Four-Dimensional Computed Tomography
/ methods
Heart
/ diagnostic imaging
Humans
Lung Neoplasms
/ radiotherapy
Observer Variation
Organ Motion
Organs at Risk
/ diagnostic imaging
Radiation Injuries
/ prevention & control
Radiation Tolerance
Radiosurgery
/ methods
Radiotherapy Planning, Computer-Assisted
/ methods
Respiration
Journal
International journal of radiation oncology, biology, physics
ISSN: 1879-355X
Titre abrégé: Int J Radiat Oncol Biol Phys
Pays: United States
ID NLM: 7603616
Informations de publication
Date de publication:
15 11 2020
15 11 2020
Historique:
received:
23
09
2019
revised:
04
05
2020
accepted:
26
06
2020
pubmed:
7
7
2020
medline:
14
4
2021
entrez:
7
7
2020
Statut:
ppublish
Résumé
Emerging evidence suggests that the heart is more radiosensitive than previously assumed; therefore, accounting for heart motion in radiation therapy planning is becoming more critical. In this study, we determined how much heart delineations based on 3-dimensional (3D) computed tomography (CT), 4-dimensional (4D) average projection (AVG), and maximum intensity projection (MIP) images should be extended to represent the full extent of heart motion during 4D imaging acquisition. The 3D and 4D CT scans of 10 lung cancer patients treated with stereotactic ablative radiation therapy were used. Median surfaces were derived from heart delineations of 3 observers on the 3D CT, AVG, MIP, and 25% exhale scans. Per patient, the 25% exhale contour was propagated on every phase of the 4D scan. The union of all 4D phase delineations (U4D) represented the full extent of heart motion during imaging acquisition. Surface distances from U4D to 3D, AVG, and MIP volumes were calculated. Distances in the most extreme surface points (1.5 cm most superoinferior, 10% most right/left/anteroposterior) were used to derive margins accounting only for systematic (delineation) errors. Heart delineations on the MIP were the closest to the full extent of motion, requiring only ≤2.5-mm margins. Delineations on the AVG and 3D scans required margins up to 3.4 and 7.1 mm, respectively. The largest margins were for the inferior, right, and anterior aspects for the delineations on the 3D, AVG, and MIP scans, respectively. Delineations on 3D, AVG, or MIP scans required extensions for representing the heart's full extent of motion, with the MIP requiring the smallest margins. Research including daily imaging to determine the random components for the margins and dosimetric measurements to determine the relevance of creating a planning organ at risk volume of the heart is required.
Identifiants
pubmed: 32629080
pii: S0360-3016(20)31388-2
doi: 10.1016/j.ijrobp.2020.06.068
pii:
doi:
Types de publication
Journal Article
Research Support, Non-U.S. Gov't
Langues
eng
Sous-ensembles de citation
IM
Pagination
1082-1090Subventions
Organisme : Department of Health
Pays : United Kingdom
Informations de copyright
Copyright © 2020 Elsevier Inc. All rights reserved.