Averaged total hemoglobin concentration measurements for benign tumors, malignant tumors, and their normal reference tissues. x axis, number of patients; y axis, averaged total hemoglobin concentration ([Hbt]) measurements. Pink bars, [Hbt] measurements on the suspicious breast lesions (tumor); blue bars, [Hbt] measurements on the normal surrounding breast parenchyma (reference). Patients 1–22 were diagnosed with benign tumors (patients 1 and 2, intraductal papilloma with mild atypia; 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; patients 24–35, invasive ductual carcinoma; and patient 36, medullary carcinoma). For each patient, averaged [Hbt] values were calculated on both the tumor tissue and the reference tissue based on [Hbt] measurements by the P-Scan probe.