x-Ray fluorescence (XRF) analysis and neutron activation analysis (NAA) are the two main methods for non-invasive in vivo determination of heavy metal concentrations in man. This paper describes various XRF-techniques developed for the measurements of cadmium, mercury and lead, primarily in occupationally exposed persons. Measurements have revealed cadmium concentrations close to 400 micrograms/g in the kidneys of exposed workers. Today, the technique can also be used for measuring kidney cadmium levels in the general population. Significantly different cadmium concentrations between groups of smokers and non-smokers have been observed. For workers with current lead exposure, there is no correlation between lead in finger bone and lead in blood. However, for retired lead workers, there is a relation between these levels, due to the endogenous excretion of lead from the skeleton. From a longitudinal study of retired lead workers, the biological half-time for bone lead was estimated to about 16 yr. Recently, the XRF-technique was shown to be capable of measuring mercury in vivo. On a group of chloralkali workers, we found kidney mercury concentrations ranging from non-detectable to over 50 micrograms/g.

Cadmium↗

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In vivo XRF as a means to evaluate the risk of kidney effects in lead and cadmium exposed smelter workers.

The effect on kidney function was studied in 22 smelter workers with concomitant exposure to lead and cadmium. One active and five retired workers showed early signs of kidney dysfunction. They all had a long-term and high lead exposure, while their kidney cadmium concentrations measured in vivo by XRF techniques were low to moderate. Thus, the exposure to lead has been a greater risk, although an interaction between lead and cadmium could not be excluded.

Acetylglucosaminidase↗

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Only a temporary increase of the amount of body protein during long-term treatment with growth-hormone (GH) of adults with GH-deficiency (GHD).

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Absorptiometry, Photon↗

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Trace element concentrations studied in vivo using X-ray fluorescence analysis.

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Body Composition↗

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Decrease of skeletal lead levels in man after end of occupational exposure.

Lead levels in finger bone were monitored using an in vivo X-ray fluorescence technique in retired lead workers. Eight subjects followed for 2-5 yr directly after end of exposure all displayed a decrease. Their average half-time was 7 (range 3-15) yr. In a second group of six persons, followed from year 7 to year 13 after finishing lead work, a decrease was seen in all but one. The average half-time for this group was 8 (range 2 infinity) yr. The mean value for both groups was 7 yr. The results show that there is a decrease of lead in bone after the end of exposure and that it is considerably faster than estimated earlier from various data on lead metabolism.

Adult↗

PubMedDate not supplied

Lead in fingerbone: a tool for retrospective exposure assessment.

Exposure to inorganic lead may cause many adverse health effects. When absorbed, lead is accumulated in large part in bone. In this study, we investigated the relationship between lead concentration in fingerbone, exposure time, and lead in blood. We also sought to design a model that made it possible to use fingerbone lead as an indicator of earlier exposure. The study comprised 137 active workers from a secondary lead smeltery. Workers had undergone regular determinations of blood lead (i.e., up to 6 times/y) for up to 24 y. In addition, during the period 1979-1992, workers underwent up to four fingerbone lead assessments via noninvasive x-ray fluorescence. We calculated cumulative blood lead, adjusted for time-related reduction of bone lead according to a transfer of lead from bone to blood, for each worker. We obtained the best fit of bone lead to cumulative adjusted blood lead when we assumed a 14-y half-time for the transfer coefficient. This half-time was similar to the terminal half-time for lead in bone in retired smelters, whom we studied earlier by longitudinal in vivo measurements. We described models for the accumulation of bone lead on blood lead and exposure time. The combined data on bone lead and exposure time may be used to estimate a mean blood lead during previous exposure. Such estimates will be valuable in epidemiological studies aimed at evaluating the toxic effects of long-term lead exposure in lead workers for whom data on previous blood lead levels are lacking.

Adolescent↗

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Digital chest radiography with a large image intensifier. Evaluation of diagnostic performance and patient exposure.

A digital system for chest radiography based on a large image intensifier was compared with a conventional film-screen system. The diagnostic performance was evaluated with special reference to the digital monitor images with a modified version of receiver operating characteristic (ROC) analysis--free response ROC (FROC) analysis--on a chest equivalent phantom. Measurements of spatial resolution and energy imparted were also performed. The detectability of low-contrast objects as well as spatial resolution was better for the full-size film-screen radiographs than for both the digital monitor images and the 100 mm photofluorograms. The image-intensifier system has a potential for considerable dose savings in relation to the conventional technique provided that fluoroscopy is excluded in the positioning of the patients.

Energy Transfer↗

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Radiation dose to patients and personnel during fluoroscopy at percutaneous renal stone extraction.

The radiation dose to patients and personnel was estimated during 11 percutaneous renal stone extractions. For the patients the energy imparted, the mean absorbed dose to various organs, and the effective dose equivalent were estimated. For different personnel categories some organ doses and the effective dose equivalent were also estimated. Large differences in the radiation dose between patients were observed. The mean effective dose equivalent to the patient was 4.2 (range 0.6-8.3) mSv, and the energy imparted 285 (range 50-500) mJ. These figures are comparable to those reported for routine colon examination and urography. For the personnel there were also large differences between individuals and categories. The highest radiation dose was received by the radiologist. It was estimated that a radiologist who performs 150 percutaneous renal stone extractions per year will receive a yearly contribution to his/her effective dose equivalent of 2.4 mSv. Even when the contribution from other diagnostic and interventional radiologic procedures is added, the total effective dose equivalent hardly exceeds 5 mSv or 1/10 of the present dose limit for persons engaged in radiologic work. For the hands of the radiologist there is a risk of doses closer to the present limit for single organs or tissues of 500 mSv/year.

Aged↗

PubMedDate not supplied

Patient exposure when using 99Tcm-DTPA for evaluation of cerebrospinal fluid shunt patency.

The absorbed dose from 99Tcm-DTPA was estimated from 12 investigations in 9 patients who were evaluated for the patency of ventriculo-peritoneal shunts. The distribution of 99Tcm-DTPA in the ventricles, urinary bladder and peritoneal cavity was determined in regions of interest from repeated static gamma camera images. The effective dose equivalent was calculated to be less than 0.10 mSv for an injected activity of 15 MBq.

Cerebrospinal Fluid Shunts↗

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The reversibility of disuse osteoporosis. Fluoride treatment and bone strength.

The biomechanical strength of femur of adult rats was tested after immobilization for 9 weeks and remobilization for 12 weeks of 1 hind leg. Some rats were also given a fluoride supplement of 200 ppm in the drinking water. As reflected in the ultimate torque and stiffness there was a decrease in bone strength due to immobilization. After 12 weeks of remobilization the stiffness remained lower than in normal animals of the same age. Fluoride supplement partially counteracted the effect of immobilization but after the remobilization period no positive effect of the fluoride supplement was observed. Remobilization per se is of much more significance than fluoride in restoration of bone strength.

Animals↗

PubMedDate not supplied

Noninvasive estimation of kidney function by x-ray fluorescence analysis. Elimination rate and clearance of contrast media injected for urography in man.

A noninvasive method for the estimation of kidney function is described. The use of radioactive tracers and the sampling of plasma and urine are omitted. The method has been used in patients referred for urography and who had therefore been injected with routine amounts of iodine-containing urographic contrast medium. After urography, the elimination rates of urographic contrast medium from both serum and finger tissue were determined and compared during a 2-hour period that began two hours after injection of contrast medium. The elimination of iodine in finger tissue was measured noninvasively using x-ray fluorescence analysis. A strong degree of correlation was found between the elimination rates from serum and finger tissue and between the total clearances calculated from the serum and finger measurements. Thus, after urography estimation of kidney function may be obtained as a fringe benefit by x-ray fluorescence measurements of the elimination rate of an iodine-containing contrast medium from tissue or from serum.

Adolescent↗