Kazuho Maeda

The Whole-Body (Human) Counter of the University of Tokyo: Its Structure and Performance

A description is given of the design and performance of a whole-body counter at the University of Tokyo. The apparatus is intended for use in medical research and as control measure for radiation protection. Three types of detectors are installed for whole body counting of the human subject: (a) 5″ Nal(Tl) scintillation probe, (b) 2.5″ Nal(Tl) scintillation probes, and (c) large plastic scintillation probes. Output signals from the detectors are analyzed in a 400-channel pulse height analyzer. The subject is measured either on: (a) stretcher, (b) chair, or (c) V-bottom bed. In using the plastic scintillation probes, counting for a period of 15 min suffices to detect 150 g of potassium in the body, allowing for a statistical counting error of 2.2%. Spectra from some human subjects are presented.

A Survey of Indoor Pollution by Volatile Organohalogen Compounds in Katsushika, Tokyo, Japan

A survey of indoor and outdoor pollution by 10 volatile organohalogen compounds (VOHCs) was performed in Katsushika Ward, Tokyo, Japan. Thirteen houses in Feb ruary and 30 houses in July were sampled. Four consec utive 24-hour samples were collected by passive sam pling from living room, kitchen, bedroom, bathroom and outdoors in February and July 1995. Indoor concentra tions of carbon tetrachloride and trichloroethylene were at nearly the same as outdoor concentrations; therefore, it was concluded that indoor pollution by these com pounds was primarily due to penetration of outdoor pol lutants. Indoor concentrations of some VOHCs were con siderably higher than outdoor concentrations and they varied widely between households. The list included: p- dichlorobenzene, tetrachloroethylene and trihalometh anes, for which emission sources were insect repellents, dry-cleaned clothes, and tap water, showers and bathtub water, respectively. Indoor concentrations of these com pounds were higher in reinforced concrete houses than in wooden houses or wooden houses with mortar walls. This suggests that airtightness of the rooms is responsi ble for high indoor VOHC concentrations.

The Whole-Body (Human) Counter of the University of Tokyo

A description is given of the design and performance of a whole-body counter at the University of Tokyo. The apparatus is intended for use in medical research and as control measure for radiation protection. Three types of detectors are installed for whole body counting of the human subject: (a) 5″ Nal(Tl) scintillation probe, (b) 2.5″ Nal(Tl) scintillation probes, and (c) large plastic scintillation probes. Output signals from the detectors are analyzed in a 400-channel pulse height analyzer. The subject is measured either on: (a) stretcher, (b) chair, or (c) V-bottom bed. In using the plastic scintillation probes, counting for a period of 15 min suffices to detect 150 g of potassium in the body, allowing for a statistical counting error of 2.2%. Spectra from some human subjects are presented.