2024 Volume 15 Issue 1 Pages 1-8
Objective: Thallium-201 chloride single-photon emission computed tomography (201TlCl SPECT) has been widely used in brain tumor studies. This study aimed to estimate 201Tl abnormal uptake, frequency of abnormal uptake, and retention indices with 201TlCl SPECT for patients with gliomas.
Materials and Methods: Each patient was intravenously injected with 74—148 Mbq of 201Tl-chloride, and SPECT images were obtained
after 20 min (early imaging) and 4 h (delayed imaging). In the hospital system, 51 patients (54 cases) between January 2015 and August 2019 were enrolled and grouped into three: low-grade glioma (grade II) in 11 patients (12 cases), anaplastic (grade III) in 9 patients (9 cases), and grade IV in 31 patients (33 cases).
Grade classification was classified according to the 2016 World Heath Organization (WHO).
Radiologists placed the region of interest (ROI) on the abnormal uptake on early images, which were drawn on corresponding areas on delayed images. This was evaluated using three different 201Tl uptake and retention indices according to the previous report1).
(1) average early 201Tl uptake=Avg.Le/Avg.BRe; (2) 201Tl retention A=Avg.Ld/Avg.Le; and (3) 201Tl retention B=(Avg.Ld/Avg.BRd)/(Avg.Le/Avg.BRe) where Avg.Le is the average count for lesions, Avg.BRe and Avg.BRd are the average early and delayed counts for contralateral normal brains, and Avg.Ld is the average delayed counts for lesions.
Results: Abnormal uptake was seen in 44/55 cases. Grade II were seen in 6/12, Grade III, were seen in 7/9 Grade IV was seen in 30/33. (Table 2) The average early 201Tl uptake of grade IV was higher than that of grade II (P＜0.05), The retention B of grade II was higher than that of grade IV. (Table 3)
Conclusion: When there was abnormal uptake, high grade was likely.
In cases with abnormal uptake, if both average early and retention B were high, glioblastoma was considered. If retention B was high, and average early was not, grade II may be considered based on anatomical images.
