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4D cone-beam computed tomography (CBCT) using a moving blocker for simultaneous radiation dose reduction and scatter correction
- Source :
- Physics in Medicine & Biology. 63:115007
- Publication Year :
- 2018
- Publisher :
- IOP Publishing, 2018.
-
Abstract
- Four-dimensional (4D) x-ray cone-beam computed tomography (CBCT) is important for a precise radiation therapy for lung cancer. Due to the repeated use and 4D acquisition over a course of radiotherapy, the radiation dose becomes a concern. Meanwhile, the scatter contamination in CBCT deteriorates image quality for treatment tasks. In this work, we propose the use of a moving blocker (MB) during the 4D CBCT acquisition ('4D MB') and to combine motion-compensated reconstruction to address these two issues simultaneously. In 4D MB CBCT, the moving blocker reduces the x-ray flux passing through the patient and collects the scatter information in the blocked region at the same time. The scatter signal is estimated from the blocked region for correction. Even though the number of projection views and projection data in each view are not complete for conventional reconstruction, 4D reconstruction with a total-variation (TV) constraint and a motion-compensated temporal constraint can utilize both spatial gradient sparsity and temporal correlations among different phases to overcome the missing data problem. The feasibility simulation studies using the 4D NCAT phantom showed that 4D MB with motion-compensated reconstruction with 1/3 imaging dose reduction could produce satisfactory images and achieve 37% improvement on structural similarity (SSIM) index and 55% improvement on root mean square error (RMSE), compared to 4D reconstruction at the regular imaging dose without scatter correction. For the same 4D MB data, 4D reconstruction outperformed 3D TV reconstruction by 28% on SSIM and 34% on RMSE. A study of synthetic patient data also demonstrated the potential of 4D MB to reduce the radiation dose by 1/3 without compromising the image quality. This work paves the way for more comprehensive studies to investigate the dose reduction limit offered by this novel 4D MB method using physical phantom experiments and real patient data based on clinical relevant metrics.
- Subjects :
- Cone beam computed tomography
Lung Neoplasms
Image quality
Computer science
Movement
medicine.medical_treatment
Computed tomography
Image processing
Radiation Dosage
Article
Imaging phantom
030218 nuclear medicine & medical imaging
Reduction (complexity)
03 medical and health sciences
0302 clinical medicine
Image Processing, Computer-Assisted
medicine
Humans
Scattering, Radiation
Radiology, Nuclear Medicine and imaging
Computer vision
Four-Dimensional Computed Tomography
Lung cancer
Projection (set theory)
Radiological and Ultrasound Technology
medicine.diagnostic_test
Phantoms, Imaging
business.industry
Radiation dose
Cone-Beam Computed Tomography
medicine.disease
Radiation therapy
030220 oncology & carcinogenesis
Dose reduction
Artificial intelligence
business
Algorithms
Subjects
Details
- ISSN :
- 13616560
- Volume :
- 63
- Database :
- OpenAIRE
- Journal :
- Physics in Medicine & Biology
- Accession number :
- edsair.doi.dedup.....6d31104801f1e018c2c6f975714d52d2