Averaged tissue blood oxygen saturation measurements for benign tumors, malignant tumors, and normal reference tissues. x axis, number of patients; y axis, averaged tissue blood oxygen saturation ([StO2]) measurements. Pink bars, [StO2] measurements on the suspicious breast lesions (tumor); blue bars, [StO2] measurements on the normal surrounding breast parenchyma (reference). Patients 1–22 were diagnosed with benign tumors (patients 1 and 2, atypical intraductal papilloma; patients 3–5, fibrocystic changes; patient 6, fibrocystic changes with radial scar; patients 7–15, fibroadenoma; patient 16, fibroadenoma with lactational change; patient 17, intraductal papilloma; patients 18–21, ruptured cyst and fat necrosis; and patient 22, sclerosing adenosis). Patients 23–36 were diagnosed with malignant tumors (patient 23, intracystic papillary carcinoma; patient 24–35, invasive ductual carcinoma; and patient 36, medullary carcinoma). For each patient, averaged [StO2] values were calculated on both the tumor tissue and the reference tissue based on [StO2] measurements by the P-Scan probe.