The primary objective of this work is to determine if half-dose Molecular Breast Imaging (MBI) performed with 4 mCi Tc-99m sestamibi with or without Wide Beam Reconstruction applied can achieve image quality and diagnostic accuracy non-inferior to that of standard MBI performed with 8 millicurie (mCi) Tc-99m sestamibi.

Recent implementation of dose reduction strategies for Molecular Breast Imaging now allow performance of MBI at an administered dose of 8 mCi Tc-99m sestamibi, which is reduced from the previously used doses of 20-30 mCi. In order to safely introduce MBI as a screening modality, we aim to perform MBI using 4 mCi Tc-99m sestamibi. An image processing algorithm called Wide Beam Reconstruction (WBR) has been tailored for MBI technology with the goal of allowing either the current administered dose or current acquisition time to be reduced by half.

Inclusion Criteria:

Subgroup 1, Patients with breast lesions:

-At least one breast lesion detected by mammogram, ultrasound or breast MRI that measures < 20 mm in greatest dimension, presents as a mass, is considered suspicious or highly suggestive of malignancy according to the Breast Imaging Reporting and Data System Atlas criteria (BIRADS 4 or 5), and is scheduled for core-needle biopsy or surgical biopsy.

OR

-At least one breast lesion that measures between > 10 mm but < 20 mm in greatest dimension, presents as a mass, is biopsy-proven as malignant, and is scheduled for surgical resection.

AND

• Age > 40 years
• Negative pregnancy test, postmenopausal, or surgically sterilized

Subgroup 2, Patients without known breast lesions:

• Negative screening mammogram performed at Mayo Clinic Rochester within 15 months prior to performance of study MBI
• No signs or symptoms of breast disease
• Age > 40 years
• Negative pregnancy test, postmenopausal, or surgically sterilized

Exclusion Criteria:

• Vacuum-assisted or excisional biopsy has been performed prior to the study MBI. Reason: these types of biopsies are more likely to remove all of the tumor
• MBI is performed after biopsy and neo-adjuvant chemotherapy is planned prior to surgery. Reason: true tumor size will not be able to be ascertained from the final pathology findings
• Breast implants. Reason: cases with breast implants will be easily identifiable on blinded interpretation to take place at the study end
• Suspected that breasts will not fit in the MBI field of view. Reason: cases that require tiled views or additional views will be easily identifiable on blinded interpretation to take place at the study end
• Only one breast remaining. Reason: unilateral cases will be easily identifiable on blinded interpretation to take place at the study end; injection timing is designed for bilateral views
• Pregnancy test (if necessary) is not negative, or the patient is unable to complete the pregnancy test
• Physically unable to sit upright and still remain still during two consecutive MBI studies over the course of a 2-hour period.

Day of study participation