ABSTRACT
Objective:To compare and analyze the differences of common dose indicators before and after operation of 3D-printing template assisted by CT-guided 125I seed implantation in the treatment of bone metastases to guide clinical application. Methods:A retrospective analysis of 12 lesions in the 10 patients (9 males and 1 female, median age 65 years), who underwent seed implantation surgery for bone metastases in the Tianjin Third Central Hospital from June 2019 to January 2021, was conducted. All the lesions were adopted for 3D-printing template to guide seed implantation and the prescribed dose was 120-140 Gy. The differences of common dose indicators between preoperative treatment plan and postoperative verification plan were compared, including D90 (dose received by 90% of the target volume), D100 (dose received by 100% of the target volume), V90 (the volume percent for tumor target volume receiving 90% of the prescribed dose), V100 (the volume percent for tumor target volume receiving 100% of the prescribed dose), V150 (the volume percent for tumor target volume receiving 150 % of the prescribed dose), as well as the quantity of seeds planned and actually used. The paired t-test was performed to compare and analyze those parameters. Results:There was no statistically significant difference in pre- and postoperative D90, D100, V90, V100, V150 ( P > 0.05). The actual quantity of seeds used after operation was more than that of the preoperative planned quantity and the difference was statistically significant ( t=-2.930, P < 0.05). Conclusions:The clinical use of 3D-printing template assisted by CT-guided 125I seed implantation for bone metastasis should be promoted since the dose is accurate and the requirements of preoperative plan can be achieved.
ABSTRACT
Objective To assess the patient effective dose during SPECT/CT imaging.Methods A total of 157 patients (85 males,72 females;mean age:(60.46±13.44) years,range:24-88 years) who underwent SPECT/CT from April 2013 to September 2014 were retrospectively analyzed.They were divided into 3 groups:99Tcm-MDP bone scan group (n=113),99Tcm-MIBI parathyroid imaging group (n=23) and 99Tcm-MAA pulmonary perfusion imaging group (n=21).The injection dose (MBq) was recorded and the effective dose (mSv) was estimated according to the International Commission on Radiological Protection (ICRP) guideline.The volume-weighted computed tomography dose index (CTDIvol) and dose length product (DLP) of CT were also recorded and the effective dose (mSv) due to CT was calculated.The effective doses among different groups were statistically compared by Kruskal-Wallis rank sum test and Wilcoxon rank sum test.Results The effective dose from radiopharmaceuticals were (4.02±0.35) mSv for 99Tcm-MDP bone scan,(6.13±0.53) mSv for 99Tcm-MIBI parathyroid imaging and (1.66±0.13) mSv for 99Tcm-MAA pulmonary perfusion imaging (x2=96.853;Z =7.533,7.262 and 5.676;all P＜ 0.05).The effective dose due to CT were (3.84±1.98),(1.04±0.19),(4.05±0.47) mSv respectively (x2 =41.225,P＜0.05),and there were significant differences between 99Tcm-MIBI parathyroid imaging group and 99Tcm-MDP bone scan group,99Tcm-MAA pulmonary perfusion imaging group(Z=6.046 and 5.672,both P＜0.05).The total effective dose during SPECT/CT imaging were (7.86± 1.98),(7.21±0.81) and (5.71±0.45) mSv (x2 =28.988,P＜ 0.05).There were significant differences between 99Tcm-MAA pulmonary perfusion imaging group and 99Tcm-MDP bone scan group,99Tcm-MIBI parathyroid imaging group(Z=4.967 and 4.994,both P＜0.05).Conclusions The increase in effective dose due to spiral CT during SPECT/CT examination should be concerned.Appropriate utilization and optimization of SPECT/CT is needed.