[Visualization of the female breast in bone scintigraphy]

Breast cancer incidence rates in Japan have more than doubled in the decade between 1975 and 1985 due to a well-established and affluent Western life-style. One hundred patients having breast cancer, 107 patients having mastectomies, and 243 patients having no breast cancer were reviewed for whole body and spot views of bone scintigraphy with 99mTc-MDP. The frequency of positive breast uptake in patients with no breast cancer showed a maximum in those patients between the ages of 30 and 40, with a progressive rise and fall before and after the peak, respectively. Patients between the ages of 50 and 60 with breast cancer showed a maximum uptake of 83%, while those patients between the ages of 70 and 80 with breast cancer showed an uptake higher than 50%. There was a markedly higher breast uptake ratio in the breast cancer group compared to the breast cancer free group. Although this scanning agent was of no value in recognition of tumor localization from breast uptake, we have to suspect a high incidence of cancer existence whenever there was unilateral increased breast activity. Even though the mechanism of 99mTc-MDP uptake by breast tissue is unknown, breast concentration of 99mTc-MDP appears to be influenced by hormones, especially estrogen.