Improve the diagnostic accuracy of CBCT for oral lesions

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ABSTRACT Oral cancer accounts for 2.5% of all cancers in the United States. It has one of the lowest five-year survival rates among the major cancer types. Early diagnosis and treatment are critical to improve the prognosis of oral cancer patients. Contrast enhanced computed tomography (CT) and magnetic resonance imaging (MRI) are currently the most widely accepted imaging modalities for diagnosis and staging of oral cancer. However, because of their high cost, high patient radiation exposure (CT), and large footprint, CT and MRI are not the standard imaging modalities used in dental clinics. In addition, oral lesions in the CT images are frequently obscured by metal artifacts caused by dental prostheses, reducing the sensitivity and increasing false diagnosis. CT is known to have a high specificity but low sensitivity for detection of oral cancers. Cone beam CT (CBCT) reduces the radiation exposure to the patient, the cost to purchase and to operate, as well as the footprint, compared to CT. It has found wide applications in dentistry. However, CBCT’s role in oral cancer imaging and staging is currently limited, despite its wide availability. This is primarily due to its poor soft tissue contrast resolution, which makes it difficult to visualize the tumor mass, and neoplastic processes are frequently overlooked. The role of CBCT in preoperative assessment of bone invasion from oral cancer has been evaluated in only a few studies with inconsistent results. The presence of strong metal artifacts also degrades the quality of the CBCT images, as in the case of CT. We propose a multisource spectral volumetric CT (mSCT) technology to 1) increase the soft tissue contrast of dental CBCT; 2) reduce the image metal artifacts; and 3) improve the tumor delineation in contrasted CT imaging. These will be achieved by 1) retrofitting the conventional CBCT with a unique carbon nanotube (CNT) x-ray source array invented by our team; and 2) incorporating dual energy CT (DECT) and virtual monoenergetic image (VMI) capabilities at low cost. The device maintains all the clinical functionality and utility of CBCT and its desirable attributes. The technology has the potential to not only enable precision imaging of oral lesions using the widely available CBCT after modification, reducing the cost and patient radiation exposure compared to the current clinical practice, but also improve earlier detection of oral cancer through either screening or/and opportunistic imaging. The Specific Aims are: 1) Optimizing mSCT to achieve high soft tissue contrast resolution; 2) Reducing metal artifacts and improving tumor delineation by incorporating spectral filter based dual-energy and virtual monoenergetic imaging; 3) Constructing a prototype mSCT scanner and characterizing its system performance; and 4) Demonstrating increased soft tissue contrast, reduced metal artifact and improved oral lesion delineation in mSCT compared to CBCT.