There are no reports of quantitative evaluation of metabolic changes in the mammary gland after radiation therapy. The purpose of this study was to investigate metabolic changes in the ipsilateral mammary gland after radiation therapy and to evaluate the late radiation effects.
Patients and methods
Metabolic changes of the ipsilateral and contralateral mammary glands were retrospectively evaluated by F-18 fluorodeoxyglucose (FDG) PET/CT after whole breast irradiation following lumpectomy in five breast cancer patients. The maximum standardized uptake values (SUVmax) of the ipsilateral mammary gland (S1) and the contralateral mammary gland (S0) were measured. The relative SUVmax (= S1/S0) was measured immediately before, one year after, three years after, and five years after radiation therapy.
The SUVmax of the ipsilateral mammary gland decreased gradually, but there was no decrease in the SUVmax of the contralateral mammary gland. Relative SUVmax values before, 1, 3, and 5 years after radiation therapy were 1.33 ± 0.20, 1.13 ± 0.35, 0.99 ± 0.26 and 0.62 ± 0.10, respectively. Relative SUVmax value at 5 years was significantly lower than before radiation therapy (P < 0.01).
18F-FDG PET/CT may be useful in assessing mammary gland function and predict lactation disorders in advance.
Calcium-suppressed imaging with dual-energy CT can visualize subtle cellular changes in the bone marrow. The purpose of this study was to investigate the application value of calcium-suppressed images in the evaluation of cancellous bone metastasis treated by stereotactic ablative radiotherapy (SABR).
Patients and methods
Dual-energy CT was performed before and after SABR in 10 patients with cancellous bone metastasis from breast cancer. Signal intensities of cancellous bone metastases to skeletal muscle were compared using calcium-suppressed images.
The relative signal intensity of cancellous bone metastasis before SABR was 0.99 ± 0.02, while after SABR it was 0.95 ± 0.06 (P < 0.05). Visual assessment of the signal intensity of cancellous bone metastases showed a decrease in signal intensity in all cases.
Calcium-suppressed imaging with dual-energy CT may be able to evaluate cancellous bone metastases treated by SABR.