ABSTRACT
Objective To estimate effective and organ doses to prostate cancer patients result ing from the whole-body 18F-Choline,11C-Choline and 68Ga-PSMA PET-CT examinations.Methods A total of 150 prostate cancer patients who underwent PET-CT scanning from May 2017 to June 2018 were retrospectively analyzed.They were divided into three groups,each with 50 patients,according to the type of positron radiopharmaceuticals injected.All patients used the same PET-CT scan protocol.PET component dose was calculated by using OLINDA/EXM (version 1.1) software which was based on the MIRD method.The CTDI values were measured by the standard CT phantoms and computed by ImPACT (version 1.0.4) CT,and ImPACT was used for dose calculation from CT.The tissue weighting factors according to ICRP Report 103 were used for effective dose calculation.Results The effective dose and organ equivalent dose from 18F/11C-Choline and 68Ga-PSMA PET/CT examinations were estimated.The voltage and current of Topogram scan were 120 kV and 35 mA,respectively,as well as 120 kV and (135.6±9.4) mA for low-dose CT scan.The injected activity of 18 F-Choline,11 C-Choline and68Ga-PSMA was (279.2±13.2),(350.2±39.9) and (186.8±19.4) MBq,respectively.The effective dose was (5.0±0.2),(1.6±0.2) and (3.0±0.3) mSv,respectively (F=837.0,P＜0.001).The CT effective dose was (11.4±0.2) mSv.The total effective dose for three groups were (16.4±0.3),(13.0±0.3) and (14.4±0.4) mSv,respectively.The mean organ equivalent doses were statistically significantly different among groups (F=381.2-1 637.7,P＜0.001).The highest organ equivalent dose was to kidney for18F-Choline and68 Ga-PSMA PET/CT scans and thyroid for11 C-Choline PET/CT scan.Conclusions The effective dose to the prostate cancer patients who underwent PET-CT scanning was from 13.0 to 16.4 mSv,with vast majority of these doses coming from CT scans.The lowest radiation dose to the patients was caused by 11C-Choline PET-CT examination,suggesting that it would be a potential prostate cancer PET radiotracer.
ABSTRACT
Objective: To explore the diagnostic value and efficiency of using whole body bone scintigraphy (WBS) combined with the levels of tumor markers to evaluate non-small cell lung cancer (NSCLC) patients with bone metastases. Methods: One-hundred and eighty-five cases of NSCLC, confirmed by pathology or cytological examination from January 2014 to June 2016, were emrolled from the Affiliated Tumor Hospital of Guangxi Medical University. WBS and test results of tumor markers, such as serum carcinoembryonic antigen (CEA), serum carbohydrate antigen (CA125), and cytokeratin CK19 (CYFRA21-1), were analyzed. WBS results were assessed by the Soloway classification criteria and divided into four grades: Correlations between WBS classification and the levels of tumor mark-ers were determined with Spearman correlation analyses. Results: Seventy-eight of the 185 NSCLC patients had bone metastases (a rate of 42.16%). The sensitivity and specificity of WBS were 91.02%(71/78) and 85.98%(92/107), respectively. The CEA, CA125, and CYFRA21-1 levels in bone metastases patients were higher than those in NSCLC patients without bone metastases (P＜0.05). In the 78 patients with bone metastases, there were seven cases of EOD0 (8.98%), 39 cases of EOD1 (50%), 17 cases of EOD2 (21.8%), and 15 cases of EOD3 (19.2%). The correlations between WBS grade and CEA, CA125, and CYFRA21-1 levels were: rs=0.579, 0.274, and 0.327, respectively (P＜0.05). The combined WBS and tumor marker diagnostic performance was significantly better than either alone (AUC=0.922), and their sensitivity and specificity increased (92.3%and 86.0%, respectively). Conclusions: WBS shows high clinical efficacy in the diagnosis of NSCLC with bone metastases. Furthermore, it can be used as a screening test for bone metastases of NSCLC, which has important clinical implications. WBS combined with CEA, CA125, and CYFRA21-1 examination improves the detection rate of NSCLC bone metastases, thereby enhancing its clinical utility.