Assessment and validation of glottic motion using cone-beam CT and real-time cine MRI

© 2024. The Author(s)..

PURPOSE: This study aimed to assess the margin for the planning target volume (PTV) using the Van Herk formula. We then validated the proposed margin by real-time magnetic resonance imaging (MRI).

METHODS: An analysis of cone-beam computed tomography (CBCT) data from early glottic cancer patients was performed to evaluate organ motion. Deformed clinical target volumes (CTV) after rigid registration were acquired using the Velocity program (Varian Medical Systems, Palo Alto, CA, USA). Systematic (Σ) and random errors (σ) were evaluated. The margin for the PTV was defined as 2.5 Σ + 0.7 σ according to the Van Herk formula. To validate this margin, we accrued healthy volunteers. Sagittal real-time cine MRI was conducted using the ViewRay system (ViewRay Inc., Oakwood Village, OH, USA). Within the obtained sagittal images, the vocal cord was delineated. The movement of the vocal cord was summed up and considered as the internal target volume (ITV). We then assessed the degree of overlap between the ITV and the PTV (vocal cord plus margins) by calculating the volume overlap ratio, represented as (ITV∩PTV)/ITV.

RESULTS: CBCTs of 17 early glottic patients were analyzed. Σ and σ were 0.55 and 0.57 for left-right (LR), 0.70 and 0.60 for anterior-posterior (AP), and 1.84 and 1.04 for superior-inferior (SI), respectively. The calculated margin was 1.8 mm (LR), 2.2 mm (AP), and 5.3 mm (SI). Four healthy volunteers participated for validation. A margin of 3 mm (AP) and 5 mm (SI) was applied to the vocal cord as the PTV. The average volume overlap ratio between ITV and PTV was 0.92 (range 0.85-0.99) without swallowing and 0.77 (range 0.70-0.88) with swallowing.

CONCLUSION: By evaluating organ motion by using CBCT, the margin was 1.8 (LR), 2.2 (AP), and 5.3 mm (SI). The margin acquired using CBCT fitted well in real-time cine MRI. Given that swallowing during radiotherapy can result in a substantial displacement, it is crucial to consider strategies aimed at minimizing swallowing and related motion.

Medienart:

E-Artikel

Erscheinungsjahr:

2024

Erschienen:

2024

Enthalten in:

Zur Gesamtaufnahme - volume:200

Enthalten in:

Strahlentherapie und Onkologie : Organ der Deutschen Rontgengesellschaft ... [et al - 200(2024), 5 vom: 01. Apr., Seite 418-424

Sprache:

Englisch

Beteiligte Personen:

Chun, Seok-Joo [VerfasserIn]
Son, Jaeman [VerfasserIn]
Kang, Seonghee [VerfasserIn]
Choi, Chang Heon [VerfasserIn]
Kim, Jung-In [VerfasserIn]
Kim, Young-Il [VerfasserIn]
Lee, Joo Ho [VerfasserIn]
Kim, Jin Ho [VerfasserIn]
Wu, Hong-Gyun [VerfasserIn]

Links:

Volltext

Themen:

Cone-beam CT
Glottic cancer
Journal Article
PTV margin
Radiotherapy
Validation Study
ViewRay
Vocal cord

Anmerkungen:

Date Completed 23.04.2024

Date Revised 26.04.2024

published: Print-Electronic

Citation Status MEDLINE

doi:

10.1007/s00066-024-02204-y

funding:

Förderinstitution / Projekttitel:

PPN (Katalog-ID):

NLM369785851