@article {Hamill1377, author = {James Hamill and Robert Eisner and James Streeter and Randolph Patterson}, title = {Accuracy of cardiac PET with ultra-low-dose CT/AC}, volume = {51}, number = {supplement 2}, pages = {1377--1377}, year = {2010}, publisher = {Society of Nuclear Medicine}, abstract = {1377 Objectives Rb-82 PET/CT studies of the heart include low-dose CT scans for PET attenuation correction (CT/AC), with the X ray generator set at 120 kV. The dose of ionizing radiation from CT/AC, already small compared to other nuclear medicine procedures, can be further reduced by using an 80 kV setting. Since low-kV imaging can cause quantitative mu-map errors, it is of interest to compare PET results with the two kV settings. Methods Data were obtained from randomly selected patients undergoing rest/stress Rb-82 myocardial perfusion studies with a Siemens Biograph-64 PET/CT system. One 80 kV and two 120 kV CT/AC scans of the chest followed dipyridamole stress imaging. 41 cases (21 females) were selected in which 80 and 120 kV were well aligned with each other and with the PET image of the myocardium. Average CT numbers were compared at 80 and 120 kV in regions including the LV, liver, and breasts in female patients. PET data were processed with the semi-automatic 4D-MSPECT program to generate polar maps and to compare regional values against a normal file based on 34 patient cases with low probability of disease. Summed Stress Scores were generated. SSS greater than or equal to 4 was considered abnormal. Average counts were compared in 5 myocardial segments. Results Patient BMI ranged from 14.8 to 48.7. X-ray dose per scan was 0.14 mSv at 80 kV and 0.32 mSv at 120 kV. CT numbers differed by as much as 100 HU, with largest differences in females. Normalized polar map raw values differed by (0.40 +/- 3.2)\% with a range of -14\% to 9\%. Based on the SSS criteria, the same 34 normal and 7 abnormal findings resulted with 80 and 120 kV AC. Polar map differences had no apparent effect on the clinical interpretation. Conclusions The use of 80 kV rather than 120 kV CT/AC reduced radiation dose by 60\%. Even with a large range of patient BMI, identical clinical diagnoses were found in all cases}, issn = {0161-5505}, URL = {https://jnm.snmjournals.org/content/51/supplement_2/1377}, eprint = {https://jnm.snmjournals.org/content}, journal = {Journal of Nuclear Medicine} }