Whole-body counters

Badjin VI, Molokanov AA. 1998. Application of the recent ICRP models for estimating the intake of 241Pu from 241 Am whole-body counter measurements. Radiat Prot Dosim 79(1-4) 141-144. 

Figure 9.3 The whole-body counter of University Medical Centre, Utrecht, The Netherlands. The counter has a mobile shadow shield with two Nal(Tl) scintillation detectors (4x6 in) placed at opposite sites of the subject. The lead shielding is 100 cm long with a diameter of 90 cm. The scanner moves on rails over a distance of 240 cm with an adjustable speed. Extreme variations in geometry yield practically the same value for 59Fe activity. The equipment can be used for measurements in man and small animals.

Gamma Rays (Nuclear-decay y-Rays, 0.5-m.e.v. Photons from Annihilation of Positrons or X-rays). The development of large sodium iodide crystal 7-ray spectrometers (13) has made possible high detection efficiencies (close to 100% for some 7-ray energies). Also, whole-body counters utilizing large cylindrical liquid scintillators provide a detection efficiency of 15% for the 7-rays emitted from potassium-40 in the human body (23). 

U. S. Atomic Energy Commission Division of Technical Information Extension, Whole Body Counters, in Understanding the Atom, Oak Ridge, Tenn. 

Exposure to radium can be determined by use of a whole body counter to measure the presence of gamma radiation emitted by radium (Toohey et al. 1983). Radium levels can also be measured in urine, feces, and other biological media by means of gamma-ray spectroscopy (Lloyd et al. 1983). 

Biomarkers of Exposure and Effect. Currently, human exposure to radium can be assessed by the presence of radioactivity in the body as measured by a whole body counter and in biological fluids such as blood or urine by gamma spectroscopy. 

The distribution of chromium(III) in humans was analyzed using a whole-body scintillation scanner, whole-body counter, and plasma counting. Six individuals given an intravenous injection of 51chromium(III) as chromium trichloride had >50% of the blood plasma chromium(ni) distributed to various body organs within hours of administration. The liver and spleen contained the highest levels. After 3 months, the liver contained half of the total body burden of chromium. The study results indicated a three-compartment model for whole-body accumulation and clearance of chromium(III). The half-lives were 0.5-12 hours for the fast component, 1-14 days for the medium component, and 3-12 months for the slow component (Lim et al. 1983). 

The meals were prepared in advance, extrinsically labelled and measured in the whole body counter. 

Uranium can enter the human body through inhalation, ingestion, or penetration through the skin. Measurement of the quantifies of uranium in the body can be performed by two primary methods, in vivo measurements and in vitro measurements. These types of measurements are called bioassays. In vivo techniques measure the quantifies of internally deposited uranium directly using a whole body counter while in vitro techniques permit estimation of internally deposited uranium by analysis of body fluids, excreta, or (in rare instances) tissues obtained through biopsy or postmortem tissue sectioning (NCRP 1987) (USUTR 1999). Some of these analytical methods are summarized in Table 6-1. 

In vivo or direct measurements of uranium in the body are made with radiation detector systems and associated electronics called whole body counters that measure radiation as it leaves the body from internally deposited uranium. In vivo assays are the most direct method of quantifying internally deposited radioactive materials. However, not all radionuclides emit radiations than may be detected... 

In vitro uranium analyses are routinely performed in support of a personnel monitoring program, or in cases where the size of an operation does not justify the cost of whole body counter facilities. These analyses are usually done on urine samples, but other types of body materials may also be used (e.g., feces or blood). Urinalysis is effective for analysis of transportable or soluble uranium. A fraction of insoluble uranium also appears in the urine (DOE 1988). 

Whole-body counters consist of a heavily shielded space. The person to be examined is placed inside and surrounded by a large number of scintillation detectors. In this way, y-emitting radionuclides in the body can be detected with high sensitivity and identified. In the absence of contamination by artificial radionuclides, the y radiation from is observed. The uptake of small amounts of artificial y-ray emitters such as Cs can be determined effectively, whereas pure a or p emitters cannot be detected in the body. 

For the supeiwision of the persons working in radiochemical laboratories, pocket dosimeters (generally ionization dosimeters) and film dosimeters are used. The lower detection limits of these dosimeters vary between about 1 and 40 mR. Furthermore, hand foot monitors are installed near the exit of the laboratories, by which external contamination can be detected. In the case of suspected internal contamination, the person is checked by means of a whole-body counter which allows detection of y-ray emitters with high sensitivity. The presence of natural contributes essentially to... 

Waterlow JC, Garrow JS, Millward OH. 1969. The turnover of [75Se] selenomethionine in infants and rats measured in a whole body counter. Clin Sci 36 489-504. 

Soluble radioactive strontium can be detected in urine, blood or feces by liquid scintillation counting. Whole body counters (or chest counters for inhalation exposures) can measure internal radioactive strontium deposited in bone following high level exposures (see Section 7.1.1). Children tend to incorporate strontium more homogenously throughout bone than is the case for adults. 

Radioactive Strontium. Exposures to radioactive strontium can be determined readily by measuring levels of radioactivity in blood or urine by liquid scintillation counting techniques. In addition, whole body counters can determine the level of radiostrontium retained in the skeleton. There appears to be no need for additional biomarkers of exposure to radioactive strontium. 

In vivo techniques measure the quantities of internally deposited radiostrontium directly using a whole body counter, while in vitro techniques permit estimation of internally deposited strontium by analysis of body fluids, excreta, or (in rare instances) tissues obtained through biopsy or postmortem tissue sectioning. 

A volunteer consumes the labelled food as part of the diet under study and the whole body radioactivity is determined in an appropriate whole body counter, and this is repeated after 14 days, by which time all non-absorbed material will have been eliminated in the faeces. The fraction of the original activity retained gives a measure of zinc absorption from that diet. 

Whole-body counters were originally developed for investigation of poisoning by radioactive substances such as radium. They are now used diagnostically and consist of a large scintillation, or semiconductor, detector with the whole system, including the patient, placed in a heavily shielded room. The sensitivity is sufficient to measure natural radioactivity in the human body from such nuclides as... 

The whole-body counter is equipped with six sodium iodide doped with thallium (Nal(Tl)) detectors, combined in two triangular arrays. The upper array consists of three detectors that scan above and the lower array of three detectors that scan below the subject. The upper array is on a moveable arm that can be raised from the bed surface to the roof of the counting chamber. The lower array is in a fixed geometry 12 cm below the bed. 

All subjects were measured in the whole-body counter in a supine position. The first count was a whole-body count with the detectors scanning over the subject. The counts were acquired in MCS mode simultaneously with the normal acquisition in an attempt to determine the location of (other than in the thyroid). The second count was a thyroid count where the subject remained supine, but also extended the neck to raise the thyroid gland above the clavicles. The results from the latter counts were used to determine the retention parameters. 

Radiobioassay is the determination of the kind, quantity, and location of radionuclides in the body by direct measurement (in vivo) or by in vitro analysis of material excreted from the body. Spectral analysis permits rapid analysis of radionuclides that emit gamma rays. Computer systems with data analysis in terms of metabolic models support routine use of bioassay procedures for assessing internally deposited radionuclides. The whole-body counter is an example of an in vivo procedure. 

Hll. Harland, W. A., and Orr, J. S., The whole-body counter and thyroxine turnover. In Further Advances in Thyroid Research (K. Fellinger and R. Hbfer, eds.), pp. 1127-1135. Verlag der Wiener Medizinischen Akademie, Vienna, 1971. 

An extension of the concept of measuring the activity in a single organ is to use a whole-body-counter in a scan of the activity throughout the body, which provides a measurement... 

There are several types of portable instruments used in the HCF. These instruments are used routinely by RCTs to monitor and survey the facility, monitor the movement of materials, and monitor facility personnel. Hand and foot monitors and whole body counters are used to routinely monitor all personnel exiting the facility. 

Application of an Inexpensive, Efficient Liquid Scintillator in the Development of Large Volume Rectangular Detectors Suitable for Use in Clinical Whole-Body Counters T. SMITH... 

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