Performance Evaluation and X-ray Dose Quantification for Various Scanning Protocols of the GE eXplore 120 Micro-CT

The aim of this paper was to evaluate the performance of the General Electric eXplore 120 micro-CT regarding image quality and delivered dose of several protocols. Image quality (resolution, linearity, uniformity, and geometric accuracy) was assessed using the vmCT phantom developed for the GE eXplore Ultra, the QRM low contrast, and the QRM Bar Pattern Phantom. All dose measurements were performed using a mobileMOSFET dose verification system, and the CTDI100 and the multiple-scan average dose (MSAD) were determined with a custom-built PMMA phantom. Additionally, in vivo scans in sacrificed rats with different weights were acquired to assess dose, contrast, and resolution variation due to X-ray absorption in surrounding tissue. The spatial resolution was determined as between 95 and 138 μm with a geometric accuracy of 0.1%. The system has a highly linear response to the iodine concentrations (0.937-30 mg/ml) for all protocols. The calculated CTDI100 ranged from 20.15 to 56.79 mGy, and the MSAD from 27.98 to 77.45 mGy. The results were confirmed by in vivo scans in rats with different weights, and no impact of body weight on delivered dose could be observed. However, body weight had a slight impact on image contrast and resolution.