Gamma | Selection of kVp and mA for low-dose attenuation correction in pediatr…

Gye Hwan Kim1, Soo Mee Kim2, Hyung Jin Lee1, Hong Jae Lee1,

Hyun Joo Kim1, Jae Sung Lee2 and Dong Soo Lee1

+Author Affiliations

1. 1Seoul National University Hospital, Seoul, Republic of Korea

2. 2Seoul National University, Seoul, Republic of Korea

Objectives

The aim of this study is to select the optimized CT acquisition parameters (kVp and mA) for low-dose attenuation correction in pediatric SPECT/CT.

Methods

SPECT scans were acquired through a clinical Lung SPECT (20 sec/view and 120 views)/CT (0.8 sec/view, 108 views, 3.75 mm thickness) protocol for Flangeless Esser PET Phantom. The CT scans were acquired with different tube voltage (kVp of 80, 100 and 130) and current mA (50, 90, 115 and 130). The SPECT/CT scans with different CT parameters were compared in terms of CT absorbed dose (Dose Length Product, DLP), contrasts for hot and cold spheres, and background (BKG) variability.

Results

The increase in kVp and mA did not make a difference in terms of contrast for hot spheres and BKG variability. However, the contrast for cold sphere corresponding to bone material was gradually decreased as the CT parameters were increased. CT dose (DLP) was reduced three times in maximum for CT parameters of 80 kVp and 50 mA.

Conclusions

There was not difference in terms of the SPECT image quality for different CT parameters and CT scan with 80 kVp and 50 mA provided the reasonable attenuation map for low-dose pediatric SPECT/CT