Recent Survey of Effective Doses of F-18 FDG Torso PET/CT in Korea and the Current Recommendations for CT Protocols of PET/CT / 대한핵의학회잡지

Purpose@#This study aimed to construct a database of the effective doses (ED) from F-18 fluorodeoxyglucose (FDG) torso positron emission tomography/computed tomography (PET/CT) in Korea to provide data that supports the reduction of the CT dose of PET/CT and optimization of PET/CT protocols in Korea. @*Methods@#We investigated data of ED and CT parameters of FDG PET/CT. The data were analyzed by body weight groups. @*Results@#A total of 31 hospitals participated in the survey (99 adults). The mean total EDs (± SD) were 8.77 ± 2.76, 10.93 ± 3.14, and 12.57 ± 3.79 mSv for the 55-, 70-, and 85-kg groups, respectively. The FDG EDs were 4.80 ± 0.98, 6.05 ± 1.15, and 6.89 ± 1.52 mSv, and the CT EDs were 4.00 ± 2.12, 4.88 ± 2.51, and 5.68 ± 2.89 mSv, respectively. Of the enrolled hospitals, 54.5% used ultra-low-dose CT protocols, and their CT ED was significantly lower than low-dose CT group in all groups (2.9 ± 1.0, 3.2 ± 1.1, and 3.3 ± 1.0 mSv vs. 6.6 ± 1.6, 7.2 ± 2.1, and 7.9 ± 2.2 mSv, all p < 0.001, respectively). In the ultra-low-dose CT group, the CT ED with the iterative reconstruction was significantly lower than that of CT without iterative reconstruction in the 55-kg group (2.4 ± 0.9 vs. 3.3 ± 0.9, p = 0.04). @*Conclusions@#These results and current recommendations can be helpful for optimizing PET/CT diagnostic reference level (DRL) and reducing unnecessary PET/CT radiation exposure.

KSNM/KSID/KOSHIC Guidance for Nuclear Medicine Department Against the Coronavirus Disease 2019 (COVID-19) Pandemic / 대한핵의학회잡지

The dramatic spread of Coronavirus Disease 2019 (COVID-19) has profound impacts on every continent and life. Due to humanto-human transmission of COVID-19, nuclear medicine staffs also cannot escape the risk of infection from workplaces. Everystaff in the nuclear medicine department must prepare for and respond to COVID-19 pandemic which tailored to the characteristicsof our profession. This article provided the guidance prepared by the Korean Society of Nuclear Medicine (KSNM) incooperation with the Korean Society of Infectious Disease (KSID) and Korean Society for Healthcare-Associated InfectionControl and Prevention (KOSHIC) in managing the COVID-19 pandemic for the nuclear medicine department.We hope that thisguidance will support every practice in nuclear medicine during this chaotic period.

Prognostic Value of Metabolic Information in Advanced Gastric Cancer Using Preoperative ¹⁸F-FDG PET/CT / 대한핵의학회잡지

PURPOSE: This study evaluated the usefulness of semiquantitative and volumetric PET parameters for predicting prognosis in patients with advanced gastric cancer (AGC).METHODS: We enrolled 213 patients who underwent ¹⁸F-fluoro-2-deoxyglucose positron emission tomography/computed tomography (¹⁸F-FDG PET/CT) prior to curative surgery for AGC. Maximum standardized uptake value (SUVmax) and tumor-to-liver uptake ratio (TLR) were measured in all patients. Metabolic tumor volume (MTV) and total lesion glycolysis were measured in volume-measurable patients. For further quantification of FDG uptake, we developed PET prognostic scores by combining SUVmax and MTV (1: low SUVmax/low MTV; 2: high SUVmax/low MTV; 3: high SUVmax/high MTV). Comparison of PET parameters between recurrence and non-recurrence groups was performed. Univariate and multivariate analyses for recurrence-free survival (RFS) and overall survival (OS) were subsequently performed.RESULTS: The recurrence rate was 32.4% (69/213 patients). Mean SUVmax and mean MTV of the recurrence group were significantly higher than those of the non-recurrence group (p = 0.026 and p = 0.025). TLR showed marginal significance (p = 0.051). In multivariate analysis for RFS including all patients, SUVmax (p = 0.022), TLR (p = 0.010), and PET score (p = 0.003) were independent prognostic factors. In post hoc analysis of PET score, significant differences in RFS were observed between PET scores 2 and 3 as well as scores 1 and 3. No significant difference in RFS was observed between scores 1 and 2. Only PET score was statistically significant for OS in univariate analysis. None of the PET parameters were statistically significant for OS in multivariate analysis.CONCLUSION: High SUVmax and high MTV of the primary tumor suggest a high risk of recurrence for AGC patients. Even if SUVmax is similar, the prognosis may vary depending on MTV. Combining PET parameters results in a better prediction for prognosis.

Prognostic Value of Metabolic Information in Advanced Gastric Cancer Using Preoperative ¹⁸F-FDG PET/CT / 대한핵의학회잡지

PURPOSE@#This study evaluated the usefulness of semiquantitative and volumetric PET parameters for predicting prognosis in patients with advanced gastric cancer (AGC).@*METHODS@#We enrolled 213 patients who underwent ¹⁸F-fluoro-2-deoxyglucose positron emission tomography/computed tomography (¹⁸F-FDG PET/CT) prior to curative surgery for AGC. Maximum standardized uptake value (SUVmax) and tumor-to-liver uptake ratio (TLR) were measured in all patients. Metabolic tumor volume (MTV) and total lesion glycolysis were measured in volume-measurable patients. For further quantification of FDG uptake, we developed PET prognostic scores by combining SUVmax and MTV (1: low SUVmax/low MTV; 2: high SUVmax/low MTV; 3: high SUVmax/high MTV). Comparison of PET parameters between recurrence and non-recurrence groups was performed. Univariate and multivariate analyses for recurrence-free survival (RFS) and overall survival (OS) were subsequently performed.@*RESULTS@#The recurrence rate was 32.4% (69/213 patients). Mean SUVmax and mean MTV of the recurrence group were significantly higher than those of the non-recurrence group (p = 0.026 and p = 0.025). TLR showed marginal significance (p = 0.051). In multivariate analysis for RFS including all patients, SUVmax (p = 0.022), TLR (p = 0.010), and PET score (p = 0.003) were independent prognostic factors. In post hoc analysis of PET score, significant differences in RFS were observed between PET scores 2 and 3 as well as scores 1 and 3. No significant difference in RFS was observed between scores 1 and 2. Only PET score was statistically significant for OS in univariate analysis. None of the PET parameters were statistically significant for OS in multivariate analysis.@*CONCLUSION@#High SUVmax and high MTV of the primary tumor suggest a high risk of recurrence for AGC patients. Even if SUVmax is similar, the prognosis may vary depending on MTV. Combining PET parameters results in a better prediction for prognosis.

Preoperative Nodal ¹⁸F-FDG Avidity Rather than Primary Tumor Avidity Determines the Prognosis of Patients with Advanced Gastric Cancer

PURPOSE: This study investigated whether the metabolic avidity of primary tumors and/or metastatic lymph nodes (LNs) measured by 18F-fluorodeoxyglucose (18F-FDG) positron emission tomography/computed tomography (PET/CT) was related to survival after surgery in patients with advanced gastric cancer (AGC). MATERIALS AND METHODS: One hundred sixty-eight patients with AGC who underwent preoperative 18F-FDG PET/CT and curative resection were included. The 18F-FDG avidity of the primary gastric tumor and LNs was determined quantitatively and qualitatively. The diagnostic performance of 18F-FDG PET/CT was calculated, and the prognostic significance of 18F-FDG avidity for recurrence-free survival (RFS) and overall survival (OS) was assessed. RESULTS: In all, 51 (30.4%) patients experienced recurrence, and 32 (19.0%) died during follow-up (median follow-up duration, 35 months; range, 3–81 months); 119 (70.8%) and 33 (19.6%) patients showed 18F-FDG-avid primary tumors and LNs, respectively. 18F-FDG PET/CT showed high sensitivity (73.8%) for the detection of advanced pathologic T (pT ≥3) stage and high specificity (92.2%) for the detection of advanced pN (≥2) stage. 18F-FDG avidity of LNs was significantly associated with RFS (P=0.012), whereas that of primary tumors did not show significance (P=0.532). Univariate and multivariate analyses revealed that 18F-FDG avidity of LNs was an independent prognostic factor for RFS (hazard ratio=2.068; P=0.029). CONCLUSIONS: 18F-FDG avidity of LNs is an independent prognostic factor for predicting RFS. Preoperative 18F-FDG PET/CT can be used to determine the risk and prognosis of patients with AGC after curative resection.

Predictive Value of Preoperative Volume-Based 18F-2-Fluoro-2-Deoxy-D-Glucose Positron Emission Tomography/Computed Tomography Parameters in Patients with Resectable Lung Adenocarcinoma / 대한핵의학회잡지

PURPOSE: This study aimed to investigate the prognostic value of metabolic tumor volume (MTV) and total lesion glycolysis (TLG), which are volume-based PET parameters, using 18F-2-fluoro-2-deoxy-D-glucose positron emission tomography/computed tomography (¹⁸F-FDG PET/CT) in patients with surgically resectable lung adenocarcinoma.METHODS: We retrospectively evaluated 149 patients with lung adenocarcinoma who underwent 18F-FDG PET/CT before surgical resection. Maximum standardized uptake value (SUVmax), MTV, and TLG of the primary tumor with threshold value of SUVmax 30, 40, and 50% were calculated, respectively. To compare the predictive performance of volume-based PET parameters, recurrence-free survival was assessed using the Kaplan-Meier method.RESULTS: The study included 70 males and 79 females with an average age of 65.8 years. The median follow-up time was 45.4 months. Recurrence was observed in 53 patients (35.6%). The mean ± SD SUVmax, MTV30%, and TLG(30%) of the entire cohort were 4.79 ± 2.94, 19.45 ± 24.85, and 56.43 ± 101.88, respectively. The cut-off values of MTV30% and TLG(30%) for recurrence were 11.07 ad 30.56, respectively. The 1-year recurrence-free survival (RFS) rate was 96.5% in low-MTV30% patients compared with 86.2% in high-MTV30% patients (p = 0.018) and 96.0% in low-TLG(30%) patients compared with 88.5% in high-TLG(30%) patients (p < 0.001). On univariate and multivariate analysis, TLG(30%) (HR, 2.828, p < 0.001; HR, 2.738, p < 0.001, respectively) was an independent prognostic factor for predicting recurrence-free survival (RFS).CONCLUSION: TLG(30%) value was observed to be a significant prognostic factor for RFS in patients with lung adenocarcinoma treated by surgical resection.

Predictive Value of Preoperative Volume-Based 18F-2-Fluoro-2-Deoxy-D-Glucose Positron Emission Tomography/Computed Tomography Parameters in Patients with Resectable Lung Adenocarcinoma / 대한핵의학회잡지

PURPOSE@#This study aimed to investigate the prognostic value of metabolic tumor volume (MTV) and total lesion glycolysis (TLG), which are volume-based PET parameters, using 18F-2-fluoro-2-deoxy-D-glucose positron emission tomography/computed tomography (¹⁸F-FDG PET/CT) in patients with surgically resectable lung adenocarcinoma.@*METHODS@#We retrospectively evaluated 149 patients with lung adenocarcinoma who underwent 18F-FDG PET/CT before surgical resection. Maximum standardized uptake value (SUVmax), MTV, and TLG of the primary tumor with threshold value of SUVmax 30, 40, and 50% were calculated, respectively. To compare the predictive performance of volume-based PET parameters, recurrence-free survival was assessed using the Kaplan-Meier method.@*RESULTS@#The study included 70 males and 79 females with an average age of 65.8 years. The median follow-up time was 45.4 months. Recurrence was observed in 53 patients (35.6%). The mean ± SD SUVmax, MTV30%, and TLG(30%) of the entire cohort were 4.79 ± 2.94, 19.45 ± 24.85, and 56.43 ± 101.88, respectively. The cut-off values of MTV30% and TLG(30%) for recurrence were 11.07 ad 30.56, respectively. The 1-year recurrence-free survival (RFS) rate was 96.5% in low-MTV30% patients compared with 86.2% in high-MTV30% patients (p = 0.018) and 96.0% in low-TLG(30%) patients compared with 88.5% in high-TLG(30%) patients (p < 0.001). On univariate and multivariate analysis, TLG(30%) (HR, 2.828, p < 0.001; HR, 2.738, p < 0.001, respectively) was an independent prognostic factor for predicting recurrence-free survival (RFS).@*CONCLUSION@#TLG(30%) value was observed to be a significant prognostic factor for RFS in patients with lung adenocarcinoma treated by surgical resection.

FDG Whole-Body PET/MRI in Oncology: a Systematic Review / 대한핵의학회잡지

The recent advance in hybrid imaging techniques enables offering simultaneous positron emission tomography (PET)/magnetic resonance imaging (MRI) in various clinical fields. ¹⁸F-fluorodeoxyglucose (FDG) PET has been widely used for diagnosis and evaluation of oncologic patients. The growing evidence from research and clinical experiences demonstrated that PET/MRI with FDG can provide comparable or superior diagnostic performance more than conventional radiological imaging such as computed tomography (CT), MRI or PET/CT in various cancers. Combined analysis using structural information and functional/molecular information of tumors can draw additional diagnostic information based on PET/MRI. Further studies including determination of the diagnostic efficacy, optimizing the examination protocol, and analysis of the hybrid imaging results is necessary for extending the FDG PET/MRI application in clinical oncology.

Effectiveness of Intraluminal Air Decompression on Postcolonoscopic Pain According to Reinsertion Site / 가정의학회지

BACKGROUND: Colonoscopy is a very effective and essential examination to diagnose colorectal cancer; however, many patients experience discomfort due to post-examination abdominal pain, which reduces colonoscopy compliance. This study was conducted to determine methods for reducing post-colonoscopic abdominal pain. METHODS: We conducted a randomized controlled study of 405 male and female adults who visited Hana General Hospital in Cheongju. We surveyed general characteristics, history of colonoscopy, and other related factors, then categorized examinees into 5 groups (0-5) according to the site of scope reinsertion. Pain was measured using a numeric rating scale (NRS). RESULTS: The mean age of examinees in this study was 47.8 years, and 210 participants had prior experience of colonoscopy. No significant difference was observed between variables, with the exception of reinsertion duration (P=0.005). Pain scores were different between performing physicians (P=0.006), and were higher when the subjective level of procedure difficulty was low (P=0.026) in univariate analysis. Pain scores decreased as the reinsertion site became closer to the proximal colon (P<0.001), but there was no significant difference between groups 3 and 4. The results of multiple logistic regression analysis, including univariate analysis, showed that group 1 had 0.48 times, group 2 had 0.38 times, group 3 had 0.09 times, and group 4 had 0.03 times odds ratio (moderate-to-severe pain, NRS ≥4) than control group 0. CONCLUSION: Air decompression by scope reinsertion is an effective way to reduce abdominal pain after colonoscopy. Removing air when the reinserted scope approaches the hepatic flexure seems to be the most effective method to reduce post-colonoscopic pain.

Radiation Dose from Whole-Body F-18 Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography: Nationwide Survey in Korea

The purpose of this study was to estimate average radiation exposure from 18F-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) examinations and to analyze possible factors affecting the radiation dose. A nation-wide questionnaire survey was conducted involving all institutions that operate PET/CT scanners in Korea. From the response, radiation doses from injected FDG and CT examination were calculated. A total of 105 PET/CT scanners in 73 institutions were included in the analysis (response rate of 62.4%). The average FDG injected activity was 310 +/- 77 MBq and 5.11 +/- 1.19 MBq/kg. The average effective dose from FDG was estimated to be 5.89 +/- 1.46 mSv. The average CT dose index and dose-length product were 4.60 +/- 2.47 mGy and 429.2 +/- 227.6 mGycm, which corresponded to 6.26 +/- 3.06 mSv. The radiation doses from FDG and CT were significantly lower in case of newer scanners than older ones (P < 0.001). Advanced PET technologies such as time-of-flight acquisition and point-spread function recovery were also related to low radiation dose (P < 0.001). In conclusion, the average radiation dose from FDG PET/CT is estimated to be 12.2 mSv. The radiation dose from FDG PET/CT is reduced with more recent scanners equipped with image-enhancing algorithms.

Preoperative 18FFDG PET/CT predicts recurrence in patients with epithelial ovarian cancer / 부인종양

OBJECTIVE: To determine whether [18F]FDG uptake on PET/CT imaging before surgical staging has prognostic significance in patients with epithelial ovarian cancer (EOC). METHODS: Patients with EOC were imaged with integrated PET/CT before surgical staging. Hypermetabolic lesions were measured as the standardized uptake value (SUV) in primary and metastatic tumors. SUV distribution was divided into two regions at the level of umbilicus, and the impact of the ratio between above and below umbilicus (SUVlocation ratio) on progression-free survival (PFS) was examined using Cox proportional hazards regression. RESULTS: Between January 2004 and December 2009, 55 patients with EOC underwent preoperative PET/CT. The median duration of PFS was 11 months (range, 3 to 43 months), and twenty (36.4%) patients experienced recurrence. In univariate analysis, high SUVlocation ratio (p=0.002; hazard ratio [HR], 1.974; 95% confidence interval [CI], 1.286 to 3.031) was significantly associated with recurrence. Malignant mixed mullerian tumor compared with endometrioid histology was also shown to have significance. In multivariate analysis, high SUVlocation ratio (p=0.005; HR, 2.418; 95% CI, 1.1315 to 4.447) and histology (serous, mucinous, and malignant mixed mullerian tumor compared with endometrioid type) were significantly associated with recurrence. Patients were categorized into two groups according to SUVlocation ratio ( or =0.3934), and the Kaplan-Meier survival graph showed a significant difference in PFS between the groups (p=0.0021; HR, 9.47, log-rank test). CONCLUSION: SUV distribution showed a significant association with recurrence in patients with EOC, and may be a useful predictor of recurrence.