심근 관류 SPECT에서 핵종에 따른 Uniformity correction map 설정을 통한 영상의 질 비교

The difference of image quality using other radioactive isotope in uniformity correction map of myocardial perfusion SPECT

Purpose When the patients takes myocardial perfusion SPECT using ²⁰¹Tl, the operator gives the patients an injection of ²⁰¹Tl. But the uniformity correction map in SPECT uses ⁹⁹ᵐTc uniformity correction map. Thus, we want to compare the image quality when it uses ⁹⁹ᵐTc uniformity correction map and when it uses ²⁰¹Tl uniformity correction map. Materials and Methods Phantom study is performed. We take the data by Asan medical center daily QC condition with flood phantom including ²⁰¹Tl 21.3 kBq/mL. After postprocessing with this data, we analyze CFOV integral uniformity(I.U) and differential uniformity(D.U). And we take the data with Jaszczak ECT Phantom by American college of radiology accreditation program instruction including ²⁰¹Tl 33.4 kBq/mL. After post processing with this data, we analyze spatial Resolution, Integral Uniformity(I.U), coefficient of variation(C.V) and Contrast with Interactive data language program. Results In the flood phantom test, when it uses ⁹⁹ᵐTc uniformity correction map, Flood I.U is 3.6% and D.U is 3.0%. When it uses ²⁰¹Tl uniformity correction map, Flood I.U is 3.8% and D.U is 2.1%. The flood I.U is worsen about 5%, but the D.U is improved about 30% inversely. In the Jaszczak ECT phantom test, when it uses ⁹⁹ᵐTc uniformity correction map, SPECT I.U, C.V and contrast is 13.99%, 4.89% and 0.69. When it uses ²⁰¹Tl uniformity correction map, SPECT I.U, C.V and contrast is 11.37%, 4.79% and 0.78. All of data are improved about 18%, 2%, 13% The spatial resolution was no significant changes. Conclusion In the flood phantom test, Flood I.U is worsen but Flood D.U is improved. Therefore, it’s uncertain that an image quality is improved with flood phantom test. On the other hand, SPECT I.U, C.V, Contrast are improved about 18%, 2%, 13% in the Jaszczak ECT phantom test. This study has limitations that we can’t take all variables into account and study with two phantoms. We need think about things that it has a good effect when doctors decipher the nuclear medicine image and it’s possible to improve the image quality using the uniformity correction map of other radionuclides other than ⁹⁹ᵐTc, ²⁰¹Tl when we make other nuclear medicine examinations.