Image quality and dose evaluation of MVCT TomoTherapy acquisitions: A phantom study
| Autor: | E. Miglietta, I. Abdi Osman, Federica Cattani, Cristina Garibaldi, M.C. Leonardi, Daniela Origgi, Raffaella Cambria, F. Castellini, P. De Marco, Rosalinda Ricotti, Barbara Alicja Jereczek-Fossa |
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| Rok vydání: | 2019 |
| Předmět: |
Quality Control
Image quality medicine.medical_treatment Biophysics General Physics and Astronomy Radiation Dosage Imaging phantom Tomotherapy 030218 nuclear medicine & medical imaging 03 medical and health sciences 0302 clinical medicine Optical transfer function medicine Radiology Nuclear Medicine and imaging Image resolution Mathematics Phantoms Imaging business.industry Radiotherapy Dosage General Medicine Noise 030220 oncology & carcinogenesis Ionization chamber Tomography X-Ray Computed business Quality assurance Radiotherapy Image-Guided Biomedical engineering |
| Zdroj: | Physica Medica. 57:200-206 |
| ISSN: | 1120-1797 |
| DOI: | 10.1016/j.ejmp.2019.01.009 |
| Popis: | Background The aim of this study is to evaluate the dose delivered and the image quality of pre-treatment MVCT images with Hi-Art TomoTherapy system, varying acquisition and reconstruction parameters. Materials and methods Catphan 500 MVCT images were acquired with all acquisition pitch and reconstruction intervals; image quality was evaluated in terms of noise, uniformity, contrast linearity, contrast-to-noise ratio (CNR) and spatial resolution with the Modulation Transfer Function (MTF). Dose was evaluated as Multi Slice Average Dose (MSADw) and measurements were performed with the Standard TomoTherapy® Quality Assurance Kit composed by the TomoTherapy Phantom, the Exradin A1SL ion chamber and TomoElectrometer. For each pitch-reconstruction interval, acquisitions were repeated 5 times. Results Differences in noise and uniformity, though statistically significant in some cases, were very small: noise ranged from 2.3% for Coarse – 3 mm to 2.4% for Coarse – 6 mm, while uniformity passed from 99.5% for Coarse – 6 mm to 99.8% for Normal – 4 mm. No differences at all were found for CNR for high and low density inserts, while MTF was higher for pitch Coarse, even if no differences in spatial resolution were observed visually (spatial resolution was up to 4 lp/cm for all combinations of pitch and reconstruction interval). Dose was dependent on pitch, being 1.0 cGy for Coarse, 1.5 cGy for Normal and 2.85 cGy for Fine. Conclusions We observed negligible differences in image quality among different pitch and reconstruction interval, thus, considerations regarding pre-treatment imaging modalities should be based only on dose delivered and on the desired resolution along the cranio-caudal axis for image-guided radiotherapy and adaptive radiotherapy purposes. |
| Databáze: | OpenAIRE |
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