Comparative Diagnostic Utility of Low‐Dose Breast‐Specific Gamma Imaging to Current Clinical Standard

To retrospectively compare low‐dose (7–10 mCi) to high‐dose (15–30 mCi) breast‐specific gamma imaging (BSGI) in the detection of breast cancer. A retrospective review of 223 consecutive women who underwent BSGI exam between February 2011 and August 2013 with subsequent pathologic analysis was performed. Women were divided into low‐dose and high‐dose groups. The results of BSGI and pathology were compared, and the sensitivity, positive predictive value (PPV), and negative predictive value (NPV) were determined. A subgroup analysis was performed to evaluate specificity using benign follow‐up imaging to establish true‐negative results. There were 223 women who met inclusion criteria with 109 patients with 153 lesions in the low‐dose group and 114 patients with 145 lesions in the high‐dose group. Pathologic correlation demonstrates sensitivities of 97.6% (95% CI = 90.9–99.6%) and 94.6% (95% CI = 84.2–98.6%; p = 0.093), PPVs of 62.1% (95% CI = 53.2–70.3%) and 50.5% (95% CI = 40.6–60.3%, p = 0.089), and NPVs of 90.5% (95% CI = 68.2–98.3%) and 92.5% (95% CI = 78.5–98.0%, p = 0.781) in the low‐dose and high‐dose groups, respectively. Subgroup analysis included 72 patients with 98 lesions in the low‐dose group and 116 patients with 132 lesions in the high‐dose group, with a specificity of 53.7% (95% CI = 39.7–67.1%) and 66.3% (95% CI = 56.2–75.2%%, p = 0.143), respectively. Low‐dose BSGI demonstrated high sensitivity and NPV in the detection of breast cancer comparable to the current standard dose BSGI, with moderate specificity and PPV in a limited subgroup analysis, which was associated with a substantial number of false‐positives.