BODY RADIOACTIVITY MEASUREMENT AS AN AID IN ASSESSING CONTAMINATION BY RADIO-NUCLIDES

Technical Report · Sat Oct 31 04:00:00 EST 1959

OSTI ID:4285872

Rundo, J

Methods which havc been used to measure radioactive materials within the human body are briefly surveyed. Because of the high efficiency of sodium iodide as a detector of gamma -rays, and its powers of energy resolution, an apparatus using crystals of this material was built at AEHE, Harwell. The apparatus consists of a substantial lead shield, and the subject lies on a stretcher for the measurement. Four counters (NaI(Tl) crystals, 4-inches in diameter by 2- inches thick) are disposed about the body in such a way as to minimize thc effects on sensitivity of different subject weights, and of distribution of the activity in the body. The energy spectrum of the amplified pulses from the counters is determined with a multichannel pulse amplitude analyzer. The natural gamma -ray activity of the body limits the sensitivity of measurements of contmninants within thc body. This activity is due to potassium--40 and the current contamination with the fission product cesium -- 137. The mean potassium content of sixteen adult males was 0.21% of body weight with a standard deviation of 0.023%. The mean cesium- 137 content of these subjects, measured between June 1956 and July 1957, was 34.0 mu mu c per g potassium, with a standard deviation of T.6 mu mu c per g potassium. For the assessment of internal contamination with a gamma -ray emitter at about the same level as this natural activity, or with a pure BETA particle emitter via its bremsstrahlung, the background activity must be known or be determinable. Measurements with a phantom have demonstrated the practicability of constructing the shape of the spectrum of the body radiation in particular at low energies. (auth)

• Research Organization: Atomic Energy Research Establishment, Harwell, Berks, Eng.
• NSA Number: NSA-13-006875
• OSTI ID: 4285872
• Report Number(s): A/CONF.15/P/1467
• Country of Publication: Country unknown/Code not available
• Language: English

Related Subjects

AMPLIFIERS
BACKGROUND
BETA PARTICLES
BODY
BREMSSTRAHLUNG
CESIUM 137
CONFIGURATION
CONTAMINATION
CRYSTALS
DISTRIBUTION
EFFICIENCY
ENERGY
ERRORS
GAMMA RADIATION
INSTRUMENTS
LEAD
MAN
MEASURED VALUES
PERFORMANCE
PHYSICS AND MATHEMATICS
PLANNING
POTASSIUM 40
PULSE ANALYZERS
PULSES
QUANTITY RATIO
RADIATION DETECTORS
RADIOACTIVITY
RADIOISOTOPES
RESOLUTION
SCINTILLATION COUNTERS
SENSITIVITY
SHIELDING
SODIUM IODIDES
SPECTRA
WEIGHT