title: Radiation safety issues in y-90 microsphere selective hepatic radioembolization therapy: possible radiation exposure from the patients.
abstract: OBJECTIVE
  The purpose of this study was to estimate the possible external radiation dose to other individuals from patients treated with Y-90 resin microspheres for unresectable hepatocellular carcinoma.
  
  
  METHODS
  We designed the study prospectively to estimate the possible radiation dose to other individuals from patients who had been treated with Y-90 microspheres for unresectable hepatocellular carcinoma. We estimated the total effective dose equivalent (TEDE) using two methods: 'theoretical' TEDEs according to the administered activity and 'measured' TEDE based on the 'measured' ambient radiation exposure rate. We compared the results from each method to determine when we can release patients from confinement at the earliest time complying with the patient release criteria.
  
  
  RESULTS
  A total of 20 administrations of Y-90 resin microspheres were done in 18 patients. The average administered activity was 1.2 ± 0.77 (0.28-2.97) GBq. The 'theoretical' TEDEs were in the range of 0.8-10 μSv. The 'measured' TEDEs were in the range of 2.31-185 μSv. The measured TEDEs tend to be higher than the theoretical TEDEs. The values of theoretical and measured TEDE were both far less than 1 mSv, the upper limit at which the licensee can release a patient without any written documents.
  
  
  CONCLUSIONS
  The effective dose equivalent caused by the Y-90 microsphere administered patient is very low. It is safe in terms of radiation safety to the other individuals when Y-90 microsphere radioembolization therapy is done with dose less than 3 GBq. Because the measured TEDE tends to be higher than the theoretical TEDE, it is recommended to use 'measured' TEDE for determining patient release.
authors.affiliation: Department of Nuclear Medicine, Korea University Anam Hospital, 126-1 Anam-dong 5-Ga, Seongbuk-Gu, Seoul 136-705 Republic of Korea.
authors.forename: Young-Chul
authors.initials: YC
authors.lastname: Kim
authors.affiliation: Department of Diagnostic Radiology, Korea University Anam Hospital, 126-1 Anam-dong 5-Ga, Seongbuk-Gu, Seoul 136-705 Republic of Korea.
authors.forename: Yun-Hwan
authors.initials: YH
authors.lastname: Kim
authors.affiliation: Department of Internal Medicine (Gastroenterology), Korea University Anam Hospital, 126-1 Anam-dong 5-Ga, Seongbuk-Gu, Seoul 136-705 Republic of Korea.
authors.forename: Soon-Ho
authors.initials: SH
authors.lastname: Uhm
authors.affiliation: Department of Internal Medicine (Gastroenterology), Korea University Anam Hospital, 126-1 Anam-dong 5-Ga, Seongbuk-Gu, Seoul 136-705 Republic of Korea.
authors.forename: Yeon Seok
authors.initials: YS
authors.lastname: Seo
authors.affiliation: Department of Nuclear Medicine, Korea University Anam Hospital, 126-1 Anam-dong 5-Ga, Seongbuk-Gu, Seoul 136-705 Republic of Korea.
authors.forename: Eun-Kyung
authors.initials: EK
authors.lastname: Park
authors.affiliation: Department of Nuclear Medicine, Korea University Anam Hospital, 126-1 Anam-dong 5-Ga, Seongbuk-Gu, Seoul 136-705 Republic of Korea.
authors.forename: Sun-Young
authors.initials: SY
authors.lastname: Oh
authors.affiliation: Department of Nuclear Medicine, Korea University Anam Hospital, 126-1 Anam-dong 5-Ga, Seongbuk-Gu, Seoul 136-705 Republic of Korea.
authors.forename: Eugene
authors.initials: E
authors.lastname: Jeong
authors.affiliation: Department of Nuclear Medicine, Korea University Anam Hospital, 126-1 Anam-dong 5-Ga, Seongbuk-Gu, Seoul 136-705 Republic of Korea.
authors.forename: Sinae
authors.initials: S
authors.lastname: Lee
authors.affiliation: Department of Nuclear Medicine, Korea University Anam Hospital, 126-1 Anam-dong 5-Ga, Seongbuk-Gu, Seoul 136-705 Republic of Korea.
authors.forename: Jae-Gol
authors.initials: JG
authors.lastname: Choe
keywords: Hepatocellular carcinoma; Liver tumor; Radiation safety; Selective hepatic radio-embolization therapy; Y-90 microsphere