TY - JOUR T1 - Whole breast quantification with dedicated SPECT-CT JF - Journal of Nuclear Medicine JO - J Nucl Med SP - 1350 LP - 1350 VL - 51 IS - supplement 2 AU - Kristy Perez AU - Spencer Culter AU - Priti Madhav AU - Martin Tornai Y1 - 2010/05/01 UR - http://jnm.snmjournals.org/content/51/supplement_2/1350.abstract N2 - 1350 Objectives Metabolic SPECT imaging with 99mTc-labelled compounds can potentially be used to determine if malignant breast changes are occurring. This study assesses the ability of our dedicated breast SPECT-CT system to obtain accurate activity concentrations of the whole breast (WB) for a variety of activity concentrations and breast sizes. WB quantification could provide a stratification of normal, atypical and pre-malignant status in high-risk women. Ultimately, the activity concentration from pooled patient data could be used to obtain a normal threshold to indicate presence of disease. Methods Various breast phantoms were filled with 470, 935 and 1060mL aqueous 99mTc-pertechnetate and imaged with a cone beam CT system and a CZT-based SPECT system. The initial breast activity concentration was 0.3µCi/mL and SPECT images were acquired every 3 hours, decaying to 0.03µCi/mL. A torso phantom containing heart and liver was filled at clinical concentration ratios to simulate background activity. Data corrections were applied to provide quantitative images. Mean values from WB volumes of interest generated from fused SPECT-CT data were compared with dose calibrator values. Three sequential scans were acquired with complex acquisition trajectories to evaluate image variability at different activity concentrations. Additionally, WB quantification was retrospectively applied to patient data. Results Compared with the time-decayed dose calibrator values, the measured data have mean squared errors of 0.004, 0.007 and 0.003 for the various sized phantoms, respectively. The measured versus known activity concentration R2 values for linear fits are 0.986, 0.967 and 0.997 with slopes of 1.00, 1.09 and 0.87 for each breast phantom, respectively. Measured WB activity concentration in one subject was 0.04µCi/mL, corroborating others’ published ranges. Conclusions This SPECT-CT quantification approach is accurate for low level WB activity concentrations in a variety of breast shapes and sizes, giving this approach the potential for discerning minute changes in broad-breast tracer distributions ER -