99mTc-MIBI myocardial perfusion scintigraphy for assessment of myocardial damage after radiotherapy in patients with breast cancer.
OBJECTIVE
After radiation therapy (RT) to the thorax, cardiac injuries may be induced involving the myocardial capillaries and causing myocardial fibrosis. The aim of this study was to assess the role of 99mTc-MIBI myocardial perfusion scintigraphy (MPS) for mapping the RT-induced cardiac injuries.


METHODS
The study involved 56 patients: 46 with left-sided(study group) and 10 with right-sided (control group) breast cancer who, after breast surgery, received postoperative RT. In the cases of the study group, the anterior wall of the myocardium was included in the target field. All of the patients were asymptomatic and without risk factors concerning heart. 99m Tc-MIBI MPS was performed using Siemens Diacam gamma camera. 555 MBq of tracer was injected in each occasion. MPS was performed 30-60 min after injection and the images were analyzed using a semi quantitative four-point system.


RESULTS
MPS was normal in all patients of the control group and in 33 (76%) patients of the study group. In 11 (24%) of the patients in the study group MPS indicated moderately reduced perfusion: 7 of the patients had hypo-perfusion of the anterior wall segments, 4 had hypoperfused septum and apex. Comparison of the 2 groups showed statistically significant difference (p<0.001).


CONCLUSIONS
Cardiac injury after irradiation of the thorax is not rare and its early detection may minimize severe cardiac damage. MPS may be a feasible method to that purpose.
Tzonevska
A
A
Department of Nuclear Medicine, National Oncological Hospital, Sofia, Bulgaria. dr.tzonevska@gmail.com
Tzvetkov
K
K
Parvanova
V
V
Dimitrova
M
M
D001943:Breast Neoplasms / Q000532:radiotherapy*; D003327:Coronary Disease / Q000000981:diagnostic imaging*; D004562:Electrocardiography; D005260:Female; D006801:Humans; D009203:Myocardial Infarction / Q000000981:diagnostic imaging*; D015425:Myocardial Reperfusion; D011379:Prognosis; D011832:Radiation Injuries / Q000000981:diagnostic imaging*; D019275:Radiopharmaceuticals / Q000493:pharmacokinetics; D017256:Technetium Tc 99m Sestamibi / Q000493:pharmacokinetics; D015899:Tomography, Emission-Computed, Single-Photon
D019275:Radiopharmaceuticals; D017256:Technetium Tc 99m Sestamibi