Gamma | Comparison of image uniformity due to position shifting in COR on myoc…

1Hyun Jin Lim, 2JoongHyunKim,1JaeIlKim,1JungJinLim,1JinEuiKim,1HyunJooKim,

1,2Jae Sung Lee , 1,2DongSooLee

1Dept. of Nuclear Medicine, SeoulNationalUniv.Hospital

2Dept. of Nuclear Medicine, Seoul National U

Purpose It is important to acquire accurate data because the SPECT Scan affected

by various physical factors. The aim of this study was to compare the uniformity

when both centers were matched or mismatched differed from position of heart in

COR.

Materials and methods The images were acquired with cylindrical Uniform phantom

(6.7 cm diameter, 9 cm length) and heart insert phantom using Cardio MD SPECT

system (Philips, U.S.A). The phantoms were positioned on COR as well as four

different points which were 10 cm above, below, left and right side from the COR.

The counts from the both edge of cylindrical uniform phantom and those from the

both wall of heart insert phantom were compared by using vertical and horizontal line

profile. In addition, the qualitative evaluation was performed with heart insert phantom

images and volunteer test.

Result The differences of counts were 1.1%, 4.1%, 4.9%, 2.2% and 0.9% at COR,

10cm above, below, left and right side from COR in order for cylindrical uniform

phantom and 0.8%, 14.4%, 4.5%, 7.3% and 7.2% for heart insert phantom. For

qualitative evaluation, the images at COR were the most uniform for both of heart

insert phantom and volunteer test, whereas other four positions showed somewhat

distorted images.

Conclusion It showed the most uniform images when COR is matched with the heart.

Therefore, we can expect that distortion which increased or decreased of myocardial

perfusion will be prevented by matching the heart and COR when positioning.

Furthermore, the accuracy of diagnosis will be improved as well.