Lesion detection in conventional gamma camera, SPECT and SPECT / CT systems: Phantom study

Objective: It was aimed to create special phantom to be used for benchmarking the lesion detectability of planar, SPECT and SPECT / CT systems by computing the corresponding contrast (C) and contrast / noise ratio (CNR) of the lesions with different activity concentrations. Method: In the study, the phantom was equiped with with four lesions filled with radioiodine (131I). The phantom’s planar images were acquired by two different gamma cameras with small field of view (SFOV) and large field of view (LFOV). Tomographic images were obtained from SPECT and SPECT / CT scans. Contrast (C) and contrast-to-noise ratio (CNR) were calculated by delineating areas of interest (ROI) over the tubes and background with different activity concentrations in the phantom. Results: As the camera’s field of view increased, the related contrast and CNR values increased partially. Contrast and CNR values of SPECT and SPECT / CT images were significantly higher than planer images. Conclusions: It was found that the superior lesion detectability might be achieved by SPECT or SPECT / CT (AC) imaging techniques