title: [Investigation of radioactivity measurement of medical radioactive waste].
abstract: To explore the possibility of which medical radioactive wastes could be disposed as general wastes after keeping them a certain period of time and confirming that their radioactivity reach a background level (BGL), we made a survey of these wastes in several nuclear medicine facilities. The radioactive wastes were collected for one week, packed in a box according to its half-life, and measured its radioactivity by scintillation survey meter with time. Some wastes could reach a BGL within 10 times of half-life, but 19% of the short half-life group (group 1) including 99mTc and 123I, and 8% of the middle half-life group (group 2) including 67Ga, (111)In, and 201Tl did not reach a BGL within 20 times of half-life. A reason for delaying the time of reaching a BGL might be partially attributed to high initial radiation dose rate or heavy package weight. However, mixing with the nuclides of longer half-life was estimated to be the biggest factor affecting this result. When disposing medical radioactive wastes as general wastes, it is necessary to avoid mixing with radionuclide of longer half-life and confirm that it reaches a BGL by actual measurement.
authors.affiliation: Tokyo Medical University Hachioji Medical Center. kkoi@tokyo-med.ac.jp
authors.forename: Kiyoshi
authors.initials: K
authors.lastname: Koizumi
authors.forename: Kazutaka
authors.initials: K
authors.lastname: Masuda
authors.forename: Kiyoko
authors.initials: K
authors.lastname: Kusakabe
authors.forename: Fujimi
authors.initials: F
authors.lastname: Kinoshita
authors.forename: Kazumi
authors.initials: K
authors.lastname: Kobayashi
authors.forename: Tetsuo
authors.initials: T
authors.lastname: Yamamoto
authors.forename: Shinichi
authors.initials: S
authors.lastname: Kanaya
authors.forename: Tetsuo
authors.initials: T
authors.lastname: Kida
authors.forename: Masamichi
authors.initials: M
authors.lastname: Yanagisawa
authors.forename: Tetsuo
authors.initials: T
authors.lastname: Iwanaga
authors.forename: Hideharu
authors.initials: H
authors.lastname: Ikebuchi
authors.forename: Keiji
authors.initials: K
authors.lastname: Kusama
authors.forename: Nobuo
authors.initials: N
authors.lastname: Namiki
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Okuma
authors.forename: Yoko
authors.initials: Y
authors.lastname: Fujimura
authors.forename: Akiko
authors.initials: A
authors.lastname: Horikoshi
authors.forename: Mamoru
authors.initials: M
authors.lastname: Tanaka
mesh_terms: D006207:Half-Life; D008506:Medical Waste; D011829:Radiation Dosage; D011850:Radioactive Waste; D011874:Radiometry / Q000379:methods*
chemical_list: D008506:Medical Waste; D011850:Radioactive Waste