The effect of the time interval between the last breastfeeding and Tc-99m MIBI injection on the intensity of Tc-99m MIBI uptake in breast tissue

In this case report, we present a 36-year-old lactating woman, 10 months after delivery, who was referred to our clinic for a myocardial perfusion scintigraphy (MPS) due to chest pain. A scintigraphic procedure was performed according to the two-day protocol. On the first day, dipyridamole pharmacological stress Tc-99m MIBI MPS was performed, and on the second day, the same test was repeated while in a resting state without the administration of any pharmacological agent. The stress scan, compared to the rest scan, presented a higher uptake of Tc-99m MIBI in the breast tissue. The patient query revealed that the last breastfeeding was 12 hours before the stress scan and she did not breastfeed or express breast milk prior to the rest scan. Our findings suggest that ceasing the emptying of the mammary glands prior to the Tc-99m MIBI injection might be appropriate to decrease the radiation exposure of the mammary glands and the breast-fed baby.