Inter- and Intrafraction Target Motion in Highly Focused Single Vocal Cord Irradiation of T1a Larynx Cancer Patients
| Autor: | Peter C. Levendag, Abrahim Al-Mamgani, Sarah O.S. Osman, S.L.S. Kwa, Ben J.M. Heijmen, Anne Gangsaas |
|---|---|
| Přispěvatelé: | Radiation Oncology |
| Rok vydání: | 2015 |
| Předmět: |
Organs at Risk
Larynx Glottis Cancer Research Cone beam computed tomography Cord Movement medicine.medical_treatment Vocal Cords Radiotherapy Setup Errors Patient Positioning SDG 3 - Good Health and Well-being medicine Humans Radiology Nuclear Medicine and imaging Irradiation Radiation Injuries Laryngeal Neoplasms Neoplasm Staging Radiation business.industry Radiotherapy Planning Computer-Assisted Larynx tumors Cone-Beam Computed Tomography Thyroid cartilage Radiation therapy medicine.anatomical_structure Oncology Feasibility Studies Dose Fractionation Radiation Radiotherapy Intensity-Modulated Tomography Nuclear medicine business |
| Zdroj: | International Journal of Radiation Oncology Biology Physics, 93(1), 190-195. Elsevier Inc. |
| ISSN: | 1879-355X 0360-3016 |
| DOI: | 10.1016/j.ijrobp.2015.04.049 |
| Popis: | Purpose: The purpose of this study was to verify clinical target volume-planning target volume (CTV-PTV) margins in single vocal cord irradiation (SVCI) of T1a larynx tumors and characterize inter-and intrafraction target motion. Methods and Materials: For 42 patients, a single vocal cord was irradiated using intensity modulated radiation therapy at a total dose of 58.1 Gy (16 fractions x 3.63 Gy). A daily cone beam computed tomography (CBCT) scan was performed to online correct the setup of the thyroid cartilage after patient positioning with in-room lasers (interfraction motion correction). To monitor intrafraction motion, CBCT scans were also acquired just after patient repositioning and after dose delivery. A mixed online-offline setup correction protocol ("O2 protocol") was designed to compensate for both inter-and intrafraction motion. Results: Observed interfraction, systematic (Sigma), and random (sigma) setup errors in left-right (LR), craniocaudal (CC), and anteroposterior (AP) directions were 0.9, 2.0, and 1.1 mm and 1.0, 1.6, and 1.0 mm, respectively. After correction of these errors, the following intrafraction movements derived from the CBCT acquired after dose delivery were: Sigma = 0.4, 1.3, and 0.7 mm, and sigma = 0.8, 1.4, and 0.8 mm. More than half of the patients showed a systematic non-zero intrafraction shift in target position, (ie, the mean intrafraction displacement over the treatment fractions was statistically significantly different from zero; P |
| Databáze: | OpenAIRE |
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