Search PubMed⌕ Search

Biomedical subjects

S Mattsson

Publications and source records attributed to S Mattsson.

At least 109 records · Page 6Linked to original sources
PubMed1989

In vivo measurements of bone lead--a comparison of two x-ray fluorescence techniques used at three different bone sites.

In vivo bone lead measurements have been made on a group of about 120 people, most of whom were lead exposed workers. Two different x-ray fluorescence (XRF) techniques were used to make measurements at three bone sites. Finger lead was measured using 57Co sources, and lead measurements were made in both tibia and calcaneus with a technique based on 109Cd sources. The results of the bone lead measurements correlated strongly with each other and with the index of cumulative exposure, thus confirming the value and reliability of these in vivo measurements as a tool in the study of chronic lead exposure. Measurement precision, +/- 1 standard deviation, was highest for tibia +/- 7.4 micrograms (g bone mineral)-1, +/- 16.6 micrograms (g bone mineral)-1 for the calcaneus and lowest for phalangeal lead +/- 25.0 micrograms (g bone mineral)-1. Maximum absorbed doses to the skin were comparable for all three measurements (1-3 mGy). The mean whole body dose equivalents were all low, but that for the finger measurement, 0.1 microSv, was significantly less than for the calcaneus and tibia measurements 3-5 microSv.

Bone and Bones↗
PubMed1989

Kinetics of radioiodinated monoclonal antibodies in the rat. Influence of tumour growth and reticuloendothelial system host modulation.

This experimental study in rats examines the influence of tumour growth and RES function modulation on the kinetics of iodinated MAb IgG1 C241. The study was designed to investigate unspecific accumulation in liver and blood. C241 is raised against human colon adenocarcinoma COLO 205 and reacts with SiLea tumour-associated antigen, also known as tumour-associated antigen 19-9. In 26 rats, 2 micrograms 125I MAb C241 (lodobead labelling method) was given i.v. Blood, organ and tumour content was measured at 0.5, 24, 72 and 144 h. In 61 rats, 10 micrograms 131I MAb C241 (lodogen labelling method) was given i.v. The rats were divided into a non-tumour and a tumour-bearing group and subjected to RES function modulation with Zymosan stimulation or methyl palmitate depression. A syngeneic nitrosoguanidine-induced colonic carcinoma--mean 11 g--was growing in back subcutaneous tissue and hind leg musculature. Serum content of tumour-associated antigen was not found on IRMA testing and tumour content of SiLea ganglioside antigen was found only on lipid binding phase assay. The half-time in blood of iodinated MAb C241 was three days. In-vivo release of iodine was tested by plasma separation on a gel column. More than 90% of the iodine was in the IgG fraction. The activity distribution was almost in equilibrium after 24 h. A tumour/blood activity concentration ratio of 0.5 and liver/blood ratio of 0.3 remained at 72 h and 144 h. Radionuclide accumulation was equally low in the macrophage-rich liver and the kidneys. Tumour-bearing animals had significantly lower blood content (0.37 versus 0.99% g-1) and liver content (0.09 versus 0.31% g-1) at 144 h than non-tumour-bearing rats. The whole body content at 144 h was also lower (24% versus 35% of administered activity) (p = 0.10). Modulation of RES function had no significant influence on the whole body, blood or liver content of 131I MAb C241 activity in non-tumour-bearing animals. In tumour-bearing animals, RES stimulation with Zymosan increased the whole body, liver and blood content of 131I activity. The two tested methods of iodination gave similar results.

Adenocarcinoma↗
PubMed1989

Digital chest radiography with a large image intensifier. An ROC study with an anthropomorphic phantom.

The diagnostic performance of two systems for chest radiography was studied. One system was based on a large image intensifier, the other was a conventional film-screen system. The images from the image intensifier were studied either on a digital TV screen or on 100 mm photofluorograms. Receiver operating characteristic curve analysis was performed on images of an anthropomorphic chest phantom. Low-contrast MMAP (methyl methacrylate polymer) nodules and simulated vessels were positioned over the parenchymal and the mediastinal region of the phantom. Five observers assessed the digital monitor images, photofluorograms, and conventional full-size radiograms. The results showed a significantly superior detectability for the full-size radiograms over the digital monitor images both in the parenchyma and in the mediastinum. No significant difference was found between photofluorograms and digital images.

Humans↗
PubMed1988

Repeated quantitative bone scintigraphy in patients with prostatic carcinoma treated with orchiectomy.

Bone scintigraphy was performed in 16 men with newly diagnosed prostatic carcinoma before orchiectomy as well as 2 weeks and 2 months after operation. The uptake in the lower thoracic and lumbar vertebrae was registered up to 240 min after injection of 99mTc-MDP and was then calculated for each patient and vertebra. The relative standard deviation in measured uptake due to measuring technique was estimated to be +/- 7%. In eight patients, who had normal bone scintigraphies before orchiectomy, there were no changes in the uptake values after operation. The remaining eight patients had widespread metastatic involvement prior to treatment. Six of these patients showed a so called "flare phenomenon" in the abnormal vertebrae which means an initial increase in uptake after operation followed by a decreased uptake in response to therapy. One patient had a continuously increased uptake in all the abnormal vertebrae which correlated well with the clinical progression of the disease, while in another patient both reactions were seen. Thus, repeated quantitative bone scintigraphies using 99mTc-MDP can be made in a reproducible way and can be a useful tool to follow a patient's response to treatment.

Aged↗
PubMed1988

A method for in vivo analysis of platinum after chemotherapy with cisplatin.

A method to quantify the concentration of platinum in vivo by x-ray fluorescence (XRF) analysis is described. The measurement system consists of a roentgen apparatus, operated at 155 kV and 25 mA, and a high-purity germanium detector. In order to reduce the amount of scattered radiation in the detector the connecting links between the roentgen tube and scatterer, scatterer and patient, patient and detector, are arranged in a three-axial geometry with mutually orthogonal directions. With this system, quantification of platinum can be achieved with a minimum detectable concentration of 8 micrograms/g, for a measuring time of 30 min and an organ depth of 4 cm. The method can be used to follow the uptake and retention of platinum in patients treated with cisplatin, a frequently used cytostatic agent for tumour therapy.

Cisplatin↗
PubMed1987

Cadmium concentration in the kidney cortex of occupationally exposed workers measured in vivo using X-ray fluorescence analysis.

A method for in vivo X-ray fluorescence analysis of the cadmium concentration in the kidney cortex has been improved and tested in 20 selected male occupationally cadmium-exposed workers (duration of exposure 7-39 years). The concentration of cadmium in kidney cortex ranged from 47 to 317 (median 141) micrograms/g. The concentration of cadmium in blood was 32-160 (median 64) nmole/liter, cadmium in urine was 2.5-13 (median 5.4) nmole/mmole creatinine, and beta 2-microglobulin in urine was 3.3-68 (median 14) micrograms/mmole creatinine. In individuals, the relationship between duration of exposure, time-integrated exposure, and cadmium level in urine on the one hand and cadmium level in the kidney on the other varied considerably. Direct in vivo analysis of the concentration of cadmium in the kidney cortex is therefore valuable as a complement to the other tests when monitoring cadmium exposure. Our method is sensitive, practically free from risk, and can b performed by routine at low costs.

Adult↗
PubMed1985

Excretion of radionuclides in human breast milk after the administration of radiopharmaceuticals.

The fraction of injected activity that was excreted through the breast milk of nursing mothers at different times after the injection of various radiopharmaceuticals has been measured in 21 patients. For 99mTc-labeled radiopharmaceuticals the total excreted fraction was 10% for pertechnetate and 1.5-3% for MAA, plasmin, diethylenetriaminepentaacetic acid (DTPA), and methylene diphosphonate (MDP). For [125I]hippuran and [131I]hippuran the corresponding value was 3%. For the above mentioned radiopharmaceuticals the activity concentration in the milk decreased exponentially with an effective half-life of approximately 4 hr. For chromium-51 ethylenediaminetetraacetic acid ([51Cr]EDTA) and [99mTc]RBC, much smaller amounts were excreted in the breast milk. The absorbed dose to various organs of the baby has been calculated. We conclude that when [99mTc]pertechnetate, [99mTc]MAA, [99mTc]plasmin, [125I]hippuran, or [131I]hippuran are used the child should be fed just before the administration of the radionuclide to the mother and the next three milk fractions should not be used. For [99mTc]DTPA and [99mTc]MDP as well as [51Cr]EDTA, only the first fraction should not be used. According to our earlier investigations breast feeding has to be stopped for at least 3 wk after investigations with [125I]fibrinogen.

Breast Feeding↗
PubMed1984

Lead in finger-bone analysed in vivo in active and retired lead workers.

In 75 active lead workers the median lead level in finger-bone (bone-Pb), as determined in vivo by an X-ray fluorescence method, was 43 micrograms/g (range less than 20-122). In 32 retired workers the median level was even higher, 59 micrograms/g (range less than 20-135), which indicates a slow turnover rate of lead in finger-bone. This was confirmed in 18 of the "active" workers, in whom bone-Pb was studied in connection with an exposure-free period. In spite of a significant decrease in blood-lead levels (B-Pb), no systematic change of bone-Pb occurred. There was an increase of bone-Pb with time of employment, but with a large interindividual variation. No association was found between bone-Pb and present B-Pb in the active lead workers. However, in the retired ones, B-Pb rose with increasing bone-Pb. The bone-lead pool thus causes an "internal" lead exposure.

Adult↗
PubMed1984

Effective dose equivalent from radiopharmaceuticals.

The concept of "effective dose equivalent", which was introduced by the International Commission on Radiological Protection (ICRP) for occupationally exposed workers, has also created the possibility of expressing by means of a single figure, the radiation risk to patients undergoing different medical radiodiagnostic procedures. In this study, we present the effective dose equivalent for various nuclear-medicine investigations. The figures given are primarily based on a review of data contained in the literature on the mean absorbed dose to various organs. In many cases, however, our own calculations, using biokinetic data derived from the literature, have been used. It was found that for the different radiopharmaceuticals, the effective dose equivalent per activity unit administered extends over an interval of five orders of magnitude, from 0.00015 to 20 mSv/MBq. For the technetium-labelled compounds, the absorbed dose for 90% of the substances lies within the narrower interval between 0.0060 and 0.025 mSv/MBq. With the aid of the figures presented, each nuclear medicine department will be able to estimate the effective dose equivalent and, hence, the risk to patients undergoing different investigations.

Adult↗
PubMed1983

Depth localization of thrombi and dynamic studies of postoperative thrombosis using the 125I-fibrinogen-sum-coincidence method.

Forty-one patients subjected to gynecologic surgery were investigated by means of the 125I-fibrinogen-sum-coincidence (FSC) method, which allows depth determination as well as absolute activity measurements of the thrombi. In 14 patients with postoperative deep venous thrombosis there was a good correlation between the depths of thrombi measured on phlebograms and those determined by the FSC test. The new technique allows differentiation between superficial thrombophlebitis and deep venous thrombosis, thereby eliminating the main disadvantage that has limited the use of the original fibrinogen uptake test. The FSC test makes it possible to calculate the absolute net activity of 125I-fibrinogen in a thrombus and to measure its elimination rate. The courses of individual thrombi could be followed up for as long as 1 month after surgery.

Female↗
PubMed1983

Polarised X-rays in XRF-analysis for improved in vivo detectability of cadmium in man.

A technique is described for the in vivo XRF-analysis of cadmium in the kidney cortex of man using plane polarised photons for excitation. The polarised photons are produced by scattering the radiation from an X-ray tube (W anode, 150 kV, 15 mA) in a polymethylmethacrylate disc at a 90 deg angle. The beam paths (X-ray tube to scatterer, scatterer to sample, sample to detector) must represent three mutually orthogonal directions. The minimum detectable concentration for a counting time of 1800 s and a skin-kidney distance of 30 mm is 8 micrograms g-1. This is a factor of 2.5 lower than our earlier method with direct excitation using the 59.5 keV photons from 241Am. The energy imparted has also been lowered from 0.4 to 0.2 mJ. The cadmium concentration in the kidney cortex of six occupationally exposed persons varied between 15 and 170 micrograms g-1.

Cadmium↗
PubMed1981

Cadmium in man measured in vivo by x-ray fluorescence analysis.

The sensitivity and detection limit for measurements of the concentration of cadmium in the kidney cortex of man in vivo have been investigated using the technique of X-ray fluorescence. An 11 GB1 241Am source was used to generate the characteristic K alpha X-rays of cadmium. The variation in the sensitivity for the detection of cadmium at various locations in a kidney has been studied. Because of the pronounced variation in sensitivity with depth in tissue, a measurement could be made selectively in the kidney cortex. The minimum detectable Cd concentration varies between 20 and 40 micrograms g-1 for distances between the skin and the kidney surface of 30 to 40 mm; this distance has a measured uncertainty of +/- 3 mm which gives rise to an uncertainty of +/- 30% in the estimated Cd concentration. The mean absorbed dose to the kidney during such a measurement is about 0.6 mGy. The X-ray fluorescence method is more advantageous than the alternative neutron capture gamma ray analysis technique as far as the total irradiation of the patient is concerned. The cadmium concentrations in the kidneys of five exposed persons were found to lie between 30 and 143 micrograms g-1.

Cadmium↗