Thesis
Comparative study of dosimetry in two cone beam CT devices: I-CAT FLX and CS9000
University of Iowa
Master of Science (MS), University of Iowa
Spring 2018
DOI: 10.17077/etd.kv5isxho
Abstract
<p>Introduction: Increasing the imaging demand in the dental field has lead to a dramatic increase in the number of CBCT machines in the U.S. market with a variety of new models and features, as well as different radiation exposures. These differences in exposure among the different CBCT machines and the potential for radiation accumulation over a life time are major concerns for aiming for a reduction in patients’ radiation exposure. Most of the studies have aimed to measure the radiation dose in different CBCT units with different field of views. Up to date, few studies have aimed to measure the radiation dose in different CBCT devices with similar fields of view. The aim of the study was to compare the dosimetry levels with relatively small FOV in different scan protocols in two CBCT units.</p>
<p>Materials and methods: A 16-cm diameter PMMA phantom with 10-cm pencil ionization chamber were used to measure the radiation exposure from two CBCT devices: i-CAT FLX and CS9000. A smallest FOV in both CBCT (8 x 8 cm in the i-CAT FLX and 5 x 3.7 cm in the CS9000) was selected at different scan protocols. The scan settings included in the i-CAT FLX HD (120 kVp; 5 mA; 7.4 sec; 0.125, 0.250, 0.200 mm voxel sizes; 360° rotation) Quick HD (120 kVp; 5 mA; 4.1 sec; 0.200, 0.250 mm voxel sizes; 180° rotation), Quick+ (90 kVp; 3 mA; 2 sec; 0.300, 0.400 mm voxel sizes; 180° rotation) , Quick (120 kVp; 5 mA; 2 sec; 0.300, 0.400 mm voxel sizes; 180° rotation), and standard scans (120 kVp; 5 mA; 3.7 sec; 0.300, 0.400 mm voxel sizes; 360° rotation). In the CS9000 scan settings included voxel sizes (CS9000: 0.076 mm, 0.100 mm, and 0.200 mm), 80 kVp, 10 mA, 10.8 sec, and 360° rotation. The phantom was exposed three times at the same position to calculate the average measurement of dose by the ionization chamber. All the radiation exposure doses were read by one examiner.</p>
<p>Results: The radiation exposure of the phantom slots in different resolutions and scan protocols in the both CBCT units ranged from 4.31 to 60.73 mR. There were statistically significant differences in radiation value between i-CAT FLX and CS9000 due to voxel size (P < 0.001). Each voxel size was significantly different from the other in both scanners, except between CS9000 0.076 and HD 0.125; CS9000 0.200 and HD 0.125; and CS9000 0.100 and HD 0.200. Also, there were no statistically significant differences between the voxel size within the same scan protocols in the i-CAT FLX, especially the Quick HD, Quick+, Quick, and Standard scans.</p>
<p>Conclusion: The selection of x-ray parameters (mainly scan time), voxel size, and rotation angle have a significant radiation expsoure reduction in both the i-CAT FLX and CS9000 units and hence should be appropriately selected to minimize the radiation dose.</p>
Details
- Title: Subtitle
- Comparative study of dosimetry in two cone beam CT devices: I-CAT FLX and CS9000
- Creators
- Daniah Mansour Alhazmi - University of Iowa
- Contributors
- Saulo Leonardo Sousa Melo (Advisor)Eric A. Hoffman (Committee Member)Bruno das Neves Cavalcanti (Committee Member)Veeratrishul Allareddy (Committee Member)
- Resource Type
- Thesis
- Degree Awarded
- Master of Science (MS), University of Iowa
- Degree in
- Oral Science
- Date degree season
- Spring 2018
- DOI
- 10.17077/etd.kv5isxho
- Publisher
- University of Iowa
- Number of pages
- ix, 34 pages
- Copyright
- Copyright © 2018 Daniah Mansour Alhazmi
- Language
- English
- Date submitted
- 09/04/2018
- Description illustrations
- color illustrations
- Description bibliographic
- Includes bibliographical references (pages 24-27).
- Public Abstract (ETD)
Cone beam computed tomography (CBCT) has been widely used as an advanced imaging technique in dentistry. With increasing demand, the number of CBCT scanners have dramatically raised, and these machines have varied settings, including the possibility of different radiation exposures. These differences in exposure among the various CBCT machines and the potential for radiation accumulation over a life time are major concerns when aiming for a reduction in patients’ radiation exposure. Many of the previous studies have evaluated the radiation exposure among multiple CBCT units with various scan settings and scan volume sizes. However, comparison of similar small scan volumes in various scans in different CBCT units have not been previously addressed. In this study, we aimed to compare the radiation exposure of smallest scan volumes in two CBCT devices with different scan settings. An object of 16 cm in diameter and a radiation measuring device were used to measure the radiation exposure from the 8 x 8 cm scan volume in the i-CAT FLX scanner and the 5 cm x 3.7 cm scan volume in the CS9000 at various scan settings including time, current, voltage, and resolution. The object was exposed three times at the same position to calculate a mean measurement of dose exposure. All the radiation doses were read by one examiner. Based on the results from the present study, the selection of scan settings, especially time and resolution, have a high impact on reducing the patient’s radiation exposure in CBCT units.
- Academic Unit
- Oral Pathology, Radiology and Medicine
- Record Identifier
- 9983777153502771
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