Dedicated cone-beam breast CT using laterally-shifted detector geometry: Quantitative analysis of feasibility for clinical translation.

ABSTRACT:

Background

High-resolution, low-noise detectors with minimal dead-space at chest-wall could improve posterior coverage and microcalcification visibility in the dedicated cone-beam breast CT (CBBCT). However, the smaller field-of-view necessitates laterally-shifted detector geometry to enable optimizing the air-gap for x-ray scatter rejection.

Objective

To evaluate laterally-shifted detector geometry for CBBCT with clinical projection datasets that provide for anatomical structures and lesions.

Methods

CBBCT projection datasets (n?=?17 breasts) acquired with a 40×30?cm detector (1024×768-pixels, 0.388-mm pixels) were truncated along the fan-angle to emulate 20.3×30?cm, 22.2×30?cm and 24.1×30?cm detector formats and correspond to 20, 120, 220 pixels overlap in conjugate views, respectively. Feldkamp-Davis-Kress (FDK) algorithm with 3 different weighting schemes were used for reconstruction. Visual analysis for artifacts and quantitative analysis of root-mean-squared-error (RMSE), absolute difference between truncated and 40×30?cm reconstructions (Diff), and its power spectrum (PSDiff) were performed.

Results

Artifacts were observed for 20.3×30?cm, but not for other formats. The 24.1×30?cm provided the best quantitative results with RMSE and Diff (both in units of ?, cm-1) of 4.39×10-3±1.98×10-3 and 4.95×10-4±1.34×10-4, respectively. The PSDiff (>0.3 cycles/mm) was in the order of 10-14?2mm3 and was spatial-frequency independent.

Conclusions

Laterally-shifted detector CBBCT with at least 220 pixels overlap in conjugate views (24.1×30?cm detector format) provides quantitatively accurate and artifact-free image reconstruction.

SUBMITTER: Vedantham S 

PROVIDER: S-EPMC7347391 | biostudies-literature | 2020

REPOSITORIES: biostudies-literature