Characterization and preliminary imaging evaluation of a clinical prototype stationary intraoral tomosynthesis system

Christina R. Inscoe, Enrique Platin, Sally M. Mauriello, Angela Broome, Andre Mol, Laurence R. Gaalaas, Michael W. Regan Anderson, Connor Puett, Jianping Lu, Otto Zhou

Research output: Contribution to journalArticlepeer-review

8 Scopus citations

Abstract

Purpose: Technological advancements in dental radiography have improved oral care on many fronts, yet diagnostic efficacy for some of the most common oral conditions, such as caries, dental cracks and fractures, and periodontal disease, remains relatively low. Driven by the clinical need for a better diagnostic yield for these and other dental conditions, we initiated the development of a stationary intraoral tomosynthesis (s-IOT) imaging system using carbon nanotube (CNT) x-ray source array technology. Here, we report the system characterization and preliminary imaging evaluation of a clinical prototype s-IOT system approved for human use. Methods: The clinical prototype s-IOT system is comprised of a multibeam CNT x-ray source array, high voltage generator, control electronics, collimator cone, and dynamic digital intraoral detector. During a tomosynthesis scan, each x-ray source is operated sequentially at fixed, nominal tube current of 7 mA and user-specified pulse width. Images are acquired by a digital intraoral detector and the reconstruction algorithm generates slice information in real time for operator review. In this study, the s-IOT system was characterized for tube output, dosimetry, and spatial resolution. Manufacturer specifications were validated, such as tube current, kVp, and pulse width. Tube current was measured with an oscilloscope on the analog output of the anode power supply. Pulse width, kVp, and peak skin dose were measured with a dosimeter with ion chamber and high voltage accessory. In-plane spatial resolution was evaluated via measurement of MTF and imaging of a line pair phantom. Spatial resolution in the depth direction was evaluated via artifact spread measurement. The size of the collimated radiation field was evaluated for compliance with FDA regulations. A dental phantom and human specimens of varying pathologies were imaged on a clinical 2D intraoral imaging system as well as s-IOT for comparison and to explore potential clinical applications. Results: The measured tube current, kVp, and pulse width values were within 3% of the set values. A cumulative peak skin dose of 1.12 mGy was measured for one complete tomosynthesis scan using a 50-ms pulse per projection view. Projection images and reconstruction slices revealed MTF values ranging from 8.1 to 9.3 cycles/mm. Line pair imaging verified this result. The radiation field was found to meet the FDA requirements for intraoral imaging devices. Tomosynthesis reconstruction slice images of the dental phantom and human specimens provided depth resolution, allowing visibility of anatomical features that cannot be seen in the 2D intraoral images. Conclusions: The clinical prototype s-IOT device was evaluated and found to meet all manufacturer specifications. Though the system capability is higher, initial investigations are targeting a low-dose range comparable to a single 2D radiograph. Preliminary studies indicated that s-IOT provides increased image quality and feature conspicuity at a dose comparable to a single 2D intraoral radiograph.

Original languageEnglish (US)
Pages (from-to)5172-5185
Number of pages14
JournalMedical Physics
Volume45
Issue number11
DOIs
StatePublished - Nov 2018

Bibliographical note

Funding Information:
The authors would like to thank Mark Brueckner, Bradford Taylor, Aaron Gunsalus, and Mike Soles (UNC Department of Environment, Health, and Safety) for assisting in dosimetry characterization, Robert Hilton (UNC Department of Oral and Maxillofacial Radiology) for assistance in measuring the radiation field, and the UNC Be A Maker (BeAM) makerspace for access to their 3D printers. The authors would also like to thank Andrew Tucker, Sarah Boyce, Tim Capo, Julianna Burney, and Jesse Dean of XinVivo for technical support. The project was supported by the Improving Human Health Awards from the NCTraCS which is the academic home of the NIH Clinical and Translational Science Award (CTSA) at UNC (Grant #IHHAR21506), and by XinVivo.

Funding Information:
The authors would like to thank Mark Brueckner, Bradford Taylor, Aaron Gunsalus, and Mike Soles (UNC Department of Environment, Health, and Safety) for assisting in dosimetry characterization, Robert Hilton (UNC Department of Oral and Maxillofacial Radiology) for assistance in measuring the radiation field, and the UNC Be A Maker (BeAM) makerspace for access to their 3D printers. The authors would also like to thank Andrew Tucker, Sarah Boyce, Tim Capo, Julianna Burney, and Jesse Dean of Xin-Vivo for technical support. The project was supported by the Improving Human Health Awards from the NCTraCS which is the academic home of the NIH Clinical and Translational Science Award (CTSA) at UNC (Grant #IHHAR21506), and by XinVivo.

Publisher Copyright:
© 2018 American Association of Physicists in Medicine

Keywords

  • bitewing radiography
  • carbon nanotube x ray
  • intraoral tomosynthesis
  • source array
  • stationary tomosynthesis

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