Objective: We aimed to preserve sternal vascularity better by harvesting only midsegment of the right internal thoracic artery (RITA) than using conventional bilateral internal thoracic artery (BITA) harvesting method, and we evaluated the sternal vascularity with single photon emission computed tomography (SPECT). Methods: In this prospective clinical randomized investigation, 135 patients undergoing coronary artery bypass surgery (CABG) were divided into three groups: Full-RITA group who had a full length of both ITA as a graft for CABG (n=45); mid-RITA group - a midsegment of RITA and left internal thoracic artery (LITA) (n=45); and non-RITA group who had only LITA (n=45). Before and after surgery, all patients underwent a bone scan with single photon emission computed tomography (SPECT) to evaluate the sternal vascular activity. Comparisons of variables were performed by Chi-square, ANOVA, Tukey HSD and paired t test as appropriate. The Bonferroni correction was applied for multiple comparisons. Results: Postoperative early scans (6.9±0.9 days) showed a reduction of blood flow in the both sides of the sternum compared with the preoperative scans (p<0.001). In full-RITA group, there was no significant difference between left and right hemi-sternum (0.56±0.04 and 0.55±0.02 respectively). However, in mid-RITA and non-RITA groups, right hemi-sternum showed significantly better vascularity than left hemi-sternum in the early postoperative period (p<0.001). Three patients (6.6%) with diabetes mellitus in full-RITA group had sternal infection; one of them was deep sternal infection with dehiscence. In mid-RITA group, there was only two patients who had superficial infection (4.4%) and in non-RITA group there was no infection (p=0.234). Conclusion: Mid-RITA harvesting technique can be preferred to preserve sternal vascularity better than conventional technique. By improving new techniques and methods, more acceptable sternal complications could be achieved than full-RITA technique.