Feasibility of markerless 3D position monitoring of the central airways using kilovoltage projection images: Managing the risks of central lung stereotactic radiotherapy.
Radiother Oncol
; 129(2): 234-241, 2018 11.
Article
en En
| MEDLINE
| ID: mdl-30172457
ABSTRACT
BACKGROUND AND PURPOSE:
Central lung stereotactic body radiotherapy (SBRT) can cause proximal bronchial tree (PBT) toxicity. Information on PBT position relative to the high-dose could aid risk management. We investigated template matchingâ¯+â¯triangulation for high-frequency markerless 3D PBT position monitoring. MATERIALS ANDMETHODS:
Kilovoltage projections of a moving phantom (full-fan cone-beam CT [CBCT, 15 frames/second] without MV irradiation 889 images/datasetâ¯+â¯CBCT and 7 frames/second fluoroscopy with MV irradiation) and ten patients undergoing free-breathing stereotactic/hypofractionated lung irradiation (full-fan CBCT without MV irradiation, 470-500 images/dataset) were retrospectively analyzed. 2D PBT reference templates (1 filtered digitally reconstructed radiograph/°) were created from planning CT data. Using normalized cross-correlation, templates were matched to projection images for 2D position. Multiple registrations were triangulated for 3D position.RESULTS:
For the phantom, 2D right/left PBT position could be determined in 86.6/75.1% of the CBCT dataset without MV irradiation, and 3D position (excluding first 20° due to the minimum triangulation angle) in 84.7/72.7%. With MV irradiation, this was up to 2% less. For right/left PBT, root-mean-square errors of measured versus "known" position were 0.5/0.8, 0.4-0.5/0.7, and 0.4/0.5-0.6â¯mm for left-right, superior-inferior, and anterior-posterior directions, respectively. 2D PBT position was determined in, on average, 89.8% of each patient dataset (range 79.4-99.2%), and 3D position (excluding first 20°) in 85.1% (range 67.9-99.6%). Motion was mainly superior-inferior (range 4.5-13.6â¯mm, average 8.5â¯mm).CONCLUSIONS:
High-frequency 3D PBT position verification during free-breathing is technically feasible using markerless template matchingâ¯+â¯triangulation of kilovoltage projection images acquired during gantry rotation. Applications include organ-at-risk position monitoring during central lung SBRT.Palabras clave
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Radiocirugia
/
Neoplasias Pulmonares
Tipo de estudio:
Etiology_studies
/
Evaluation_studies
/
Observational_studies
Límite:
Humans
Idioma:
En
Revista:
Radiother Oncol
Año:
2018
Tipo del documento:
Article