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.
Child ; Child, Preschool ; Fluorodeoxyglucose F18/chemistry ; Humans ; Infant ; *Positron-Emission Tomography ; *Radiation Dosage ; Surveys and Questionnaires ; *Tomography, X-Ray Computed ; *Whole Body Imaging

BACKGROUND AND OBJECTIVES: Early glottic cancer can be effectively treated with conservation laryngeal surgery, radiation therapy, and endoscopic laser surgery. The aim of this study was to compare the clinical results between laser cordectomy and radiation therapy for early glottic cancer and to evaluate the role of laser cordectomy. MATERIALS AND METHOD: From 1988 to 1998, 89 patients with T1-T2/N0 glottic cancer were treated initially with radiation therapy or laser cordectomy. There were 67 T1 and 22 T2 tumors. Fifty-two patients were treated by radiation therapy (RT), and thirty-seven patients were treated by endoscopic laser cordectomy. The method of primary treatment, local control rate, survival rate and larynx preservation were retrospectively evaluated. RESULTS: With the median follow-up period of 48.2 months, the local control rates in laser cordectomy and radiation therapy were 88.9%, 89.7% for T1, and 90.0% and 61.5% for T2 tumors, respectively. The 3-year survival rate was 88.9% and 87.2% for T1 and 80.0% and 61.5% for T2. Larynx preservation rate was 83.4% in T1 and 70.0% in T2 patients. These results of laser cordectomy were superior to those treated by radiation therapy. CONCLUSION: In T1b glottic cancer, radiation therapy gave better results than laser cordectomy, whereas for T2 glottic cancer, laser cordectomy was superior to radiation therapy in initial control of tumor. Compared with radiation therapy, laser cordectomy afforded a greater likelihood of larynx preservation and more options for further treatment in case of failure. We conclude that the laser cordectomy is a good surgical alternative for properly selected early glottic cancer.
Follow-Up Studies ; Humans ; Larynx ; Laser Therapy ; Retrospective Studies ; Survival Rate