Developing low-dose C-arm CT imaging for temporomandibular joint (TMJ) disorder in interventional radiology

Manufacturers have provided C-arm CT imaging technologies for applications in interventional radiology in recent years. However, clinical imaging protocols and radiation doses have not been well studied or reported.

The purpose of this study is to develop low-dose settings for clinically acceptable CT imaging of temporomandibular joint in interventional radiology suites, using a C-arm imaging angiography system.

CT scans were performed with a flat-panel digital C-arm angiographic system on a 5-year-old anthropomorphic phantom. The CTDI was determined for various rotation times, dose settings and Cu filter selections. The CTDI values were compared with those of conventional low-dose CT for the same phantom. The effectiveness of using Cu filters to reduce dose was also investigated. Images were reviewed by a senior radiologist for clinical acceptance.

The manufacturer's default setting gave an equivalent CTDI of 4.8 mGy. Optimizing the dose settings and adding copper filtration reduced the radiation dose by 94%. This represents a 50% reduction from conventional CT.

Use of Cu filters and low-dose settings significantly reduced radiation dose from that of standard settings. This phantom study process successfully guided the clinical implementation of low-dose studies for all ages at our institution.