Biomedical subjects

S Mattsson

Publications and source records attributed to S Mattsson.

At least 55 records · Page 3Linked to original sources

PubMed2000

The prognostic value of body protein in patients with lung cancer.

Lung cancer is a major cause of death in many countries. To improve the results of treatment, more individualized therapy is necessary; for this, it is necessary to identify new prognostic factors. In 21 patients with lung cancer (17 with non-small-cell lung cancer and 4 with small-cell lung cancer) that had received radiation treatment, the amount of body protein was estimated with in vivo neutron activation analysis. Patients in whom body protein decreased had recurrences of the disease earlier and a poorer survival than patients whose body protein increased. A clear relationship was seen between changes in the body's protein content and recurrence-free survival. To better evaluate the prognostic value of body protein content in patients with lung cancer, a larger number of patients and a longer follow-up period are needed.

Aged↗

PubMed2000

The influence of different technique factors on image quality of lumbar spine radiographs as evaluated by established CEC image criteria.

In this study we have investigated the image quality of lumbar spine radiographs taken after recording technical and physical parameters. Two technical parameters were altered, tube voltage (70 kV and 90 kV for the anteroposterior (AP) projection and 77 kV and 95 kV for the lateral projection) and sensitivity of the film-screen system (sensitivity class 400 and 600). In total, 85 images were included in the study. Entrance surface dose (ESD) was measured using thermoluminescent dosemeters. The mean value of ESD for the different technique groups varied between 1.9 mGy (90 kV, sensitivity class 400) and 4.6 mGy (70 kV, sensitivity class 400) for the AP projection, and between 6.4 mGy (95 kV, sensitivity class 600) and 20.4 mGy (70 kV, sensitivity class 400) for the lateral projection. Image criteria given in the "European Guidelines on Quality Criteria for Radiographic Images" were used to assess image quality. Two evaluation methods have been employed. A straightforward scoring of fulfilled image criteria, and visual grading analysis using the structures defined in the image criteria. The latter method provided a sharper distinction between groups of images taken using different radiographic techniques. The average number of fulfilled image criteria for the AP projections varied between 0.74 (90 kV, sensitivity class 400) and 0.87 (70 kV, sensitivity class 400). For the lateral projection this number varied between 0.79 (95 kV, sensitivity class 600) and 0.84 (77 kV, sensitivity class 600). This study shows that image criteria are useful tools in clinical studies of image quality.

Adolescent↗

PubMed1999

Chelated lead in relation to lead in bone and ALAD genotype.

In order to assess whether lead in bone is available for chelation by 2,3 meso-dimercaptosuccinic acid (DMSA), 21 workers (10 active and 11 retired) from a secondary lead smeltery were studied. A morning urine sample was obtained from all participants, followed by ingestion of 10 mg per kg body weight of the chelating agent DMSA. All urine produced during the following 24 h was collected in consecutive 6- and 18-h portions. Concentrations of lead in blood (B-Pb) and urine were determined by flameless atomic absorption spectrometry (AAS), in plasma (P-Pb) by inductively coupled plasma mass spectrometry (ICP-MS), and in finger bone (Bone-Pb) by K X-ray fluorescence technique (XRF). DMSA-chelatable lead excreted in the 24-h portion correlated well with the excretion in the 6-h portion (U-Pb6h; rs=0.95; P<0.001). U-Pb6h showed a non-linear relationship to B-Pb (rs=0.84; P<0.001) and linear relationships to P-Pb (rs=0. 91; P<0.001) and lead in morning urine (rs=0.95; P<0.001). In active workers, but not in retired ones, P-Pb and U-Pb6h showed some relationship to Bone-Pb. In alternative multiple regression models B-Pb or P-Pb were both significant predictors of U-Pb6h, while Bone-Pb did not significantly improve the models. It can, thus, be concluded that DMSA-chelatable lead mainly reflects lead concentrations in blood, soft tissues, and possibly also trabecular bone. It is not a good index of total body burden and long-term exposure. For such estimations cortical Bone-Pb is more valid, as it contains the major fraction of long-term accumulated lead in the body. Further, the mobilization test did not give better information than measurements of lead levels in blood, plasma, or urine without chelation.

Age Factors↗

PubMed1999

Biokinetics and radiation doses for carbon-14 urea in adults and children undergoing the Helicobacter pylori breath test.

The long-term biokinetics and dosimetry of carbon-14 were studied in nine adults and eight children undergoing carbon-14 urea breath test for Helicobacter pylori (HP) infection. The elimination of 14C via exhaled air and urine was measured with the liquid scintillation counting technique and with accelerator mass spectrometry. After the subjects had been given 110 kBq 14C-urea (children: 55 kBq) orally, samples of exhaled air were taken up to 180 days after administration and samples of urine were collected up to 40 days. Sixteen of the subjects were found to be HP-negative. In these subjects a total of 91.1%+/-3.9% (mean of adults and children +/- standard error of the mean) of the administered 14C activity was recovered. The majority of the administered activity, 88.3%+/-6.2% in adults and 87.7%+/-5.0% in children, was excreted via the urine within 72 h after administration. A smaller fraction was exhaled. In adults 4.6%+/-0.6% of the activity was exhaled within 20 days and in children 2.6%+/-0.3%. Uncertainties in the biokinetic results are mainly due to assumptions concerning endogenous CO2 production and urinary excretion rate and are estimated to be less than 30%. The absorbed dose to various organs and the effective dose were calculated using the ICRP model for urea and CO2. The urinary bladder received the highest absorbed dose: in adults, 0.15+/-0.01 mGy/MBq and in children of various ages (7-14 years), 0.14-0.36 mGy/MBq. The findings indicate that an investigation with 14C-urea gives an effective dose to adults of 2.1+/-0.1 microSv (for 110 kBq) and to children of 0.9-2.5 microSv (for 55 kBq). From a radiation protection point of view, there is thus no reason for restrictions on even repeated screening investigations with 14C-urea in whole families, including children.

Adolescent↗

PubMed1999

Urinary excretion measurements for the assessment of body burden of radiocaesium in man: differences between potassium and creatinine normalisation.

Relationships between 24-h urinary excretion and body burden of 137Cs obtained in a south-Swedish population, together with data from the literature, were applied to urine samples collected in 1994-95 from adult subjects living in Russia, in order to estimate their average body burden of 137Cs. Estimates obtained through creatinine normalisation of the 137Cs content in the Russian urine were a factor of 2 higher than estimates obtained through potassium normalisation. The accuracy of both these normalisation methods is discussed, as well as the influence of the difference in dietary habits between the two populations.

Adult↗

PubMed1999

Absorbed doses to patients from 191Pt-, 193mPt- and 195mPt-cisplatin.

Cisplatin, a chemotherapeutic drug, can be synthesized using radioactive platinum and then used for pharmacokinetic studies and tumor imaging. We have calculated the absorbed doses to various organs and tissues as well as the effective doses from 191Pt-, 193mPt- and 195mPt-cisplatin after administration to humans for diagnostic purposes. Liver was the organ that received the highest absorbed dose. The effective dose from 191Pt-, 193mPt- and 195mPt-cisplatin was 0.10 +/- 0.02, 0.17 +/- 0.04 and 0.23 +/- 0.05 mSv/MBq respectively.

Absorption↗

PubMed1999

Gamma camera imaging of platinum in tumours and tissues of patients after administration of 191Pt-cisplatin.

The aim of this study was to visualize non-invasively the uptake of platinum in tumours and tissues after treatment with cisplatin. 191Pt-cisplatin was synthesized from 191PtCl4 with rigorous pharmaceutical quality control. The uptake of platinum by both tumorous and healthy tissues was studied by gamma camera imaging in 14 patients, 5 of whom showed a clear uptake of platinum in regions corresponding to known tumour sites. Maximum concentrations of platinum in the tumours were on average 4.9+/-1.0 microg/g, when normalized to an administered amount of 180 mg cisplatin. In all the patients, the liver was the organ that showed the highest uptake. Platinum uptake was also seen in the spleen, gall bladder, gastrointestinal tract, bladder, kidneys, ureter, neck and mediastinum and urogenital region. By using in-house production of 191Pt-cisplatin, it was possible to monitor the uptake of platinum in tumorous tissues and healthy organs.

Adult↗

PubMed1999

A 252Cf-based instrument for in vivo body protein monitoring in cancer patients.

A hospital-based facility for in vivo prompt gamma neutron activation analysis of nitrogen for body protein determination is described. The patient is laid on a movable couch and is scanned with a vertically collimated neutron beam from a 252Cf neutron source (the amount of Cf varying from 120 to 40 microg due to the physical decay) positioned below the patient. Four large NaI(Tl) detectors are used to measure the 10.8 MeV gamma-rays from nitrogen. To check the long-term stability of the system, a solid phantom simulating the geometry of the adult human trunk, having similar elemental composition as tissue, was constructed. Repeated phantom measurements over 6 months gave a reproducibility in nitrogen determination of 2.9% (1 SD). Duplicate patient measurements carried out within a week showed a reproducibility of 5% (1 SD). A calibration method for absolute protein measurements in patients is presented. Patients are normally measured for 40 min; giving a mean whole-body equivalent dose of 0.25 mSv. Results from measurements on 13 cancer patients are presented.

Adult↗

PubMed1999

A gamma camera for measurements of internal contamination after a radiological accident.

After a radiological accident with the release of large amounts of radionuclides into the environment, measurements of the external and internal exposure of the public will be urgently required. The aim of this study was to investigate the properties of a gamma camera with regard to measurements of internal contamination. The gamma camera was used as a detector without any imaging function. The lowest minimum detectable activity, 100 Bq 131I in thyroid measured over the neck and 400 Bq 137Cs in the whole body measured over the trunk (1 min measuring time), was found when using the lowest (50 keV-450 keV) energy interval among the three investigated (also 550-750 keV and 450-550 keV), in measurements without a collimator. The mechanical difficulties in handling a gamma camera without a collimator may also have to be considered. It is essential to pay attention to the influence of body size on both background and sensitivity. Provided proper calibrations are carried out and routines for measurements are established, a gamma camera is useful for fast identification and quantification of internal contamination with gamma-emitting radionuclides down to levels so low that in most situations they give a low contribution to the effective dose.

Adult↗

PubMed1999

Administered activity of 99Tcm-MAG3 for gamma camera renography in children.

A method of calculating the activity of 99Tcm-MAG3 to be administered to children of different ages has been developed and evaluated. The suggested administered activity schedule is only valid for estimation of split renal function. The activity required to obtain the same count rate over the kidneys for all ages was calculated as a fraction of the activity administered to an adult by using a biokinetic model and taking attenuation effects into account. The activity schedule is based on the age of the child and was tested using renograms from patients of different ages. Statistical noise was added to the smoothed renograms simulating an injected activity corresponding to 45 MBq for an adult. The precision in the determination of split renal function calculated with four different methods was determined for 500 simulated renograms. The precision was approximately the same for all ages, but varied with the method used. The activity to be administered to a very small child is 90% of the adult activity, decreases to less than 50% between 2 and 5 years of age, and then slowly increases to 100% as the child grows to adulthood.

Adolescent↗

PubMed1999

Survival of mammalian cells exposed to ultrahigh dose rates from a laser-produced plasma x-ray source.

PURPOSE: To determine whether intense laser-produced x rays have an increased radiation hazard. MATERIALS AND METHODS: Mammalian cells were exposed to x rays from a laser-produced plasma that produced ultrahigh peak absorbed dose rates, up to a factor of 10(10) higher than those produced by conventional x rays used in imaging. The cell survival was studied as a function of the absorbed dose. The survival of mammalian cells exposed to high peak absorbed dose rates with laser-produced x rays was compared with the survival of cells exposed to standard absorbed dose rates with conventional x-ray sources. Comparative survival studies were performed by using a conventional x-ray tube and a cobalt 60 source. The absorbed doses in the irradiation field were measured with thermoluminescent dosimeters. RESULTS: Cell survival following irradiation by filtered, laser-produced x rays with a high dose rate was not markedly different from the survival following irradiation by conventional sources. There was, however, a notable difference between the survival after exposure to filtered, laser-produced x rays and the survival after exposure to unfiltered laser-produced x rays. CONCLUSION: Exposure to filtered, laser-produced x rays with a high dose rate does not lead to increased harm to mammalian cells exposed in vitro compared with the harm from exposure to x rays from conventional sources, which indicates that the use of high-power laser facilities for medical imaging is justified.

Animals↗

PubMed1998

Humoral immune responses to Mycoplasma hyopneumoniae in sows and offspring following an outbreak of mycoplasmosis.

Previously healthy sows, seropositive to Mycoplasma hyopneumoniae, developed clinical signs of mycoplasmosis, as well as increasing amounts of antibodies to M. hyopneumoniae during an outbreak of the disease in a herd. During the early phase of the outbreak, young piglets (2 weeks) with maternal antibodies remained healthy while older seronegative piglets (4-7 weeks) developed the disease. The duration of the maternal antibodies to M. hyopneumoniae varied between litters and was related to the amount of antibodies in the serum of the dam. In sows, the level of serum antibodies decreased continuously from 4 weeks ante partum to partus, and the level of antibodies in the whey of colostrum was comparable to that in serum 4 weeks ante partum. After loss of maternal antibodies to M. hyopneumoniae, seropositive animals were not found among piglets younger than 9 weeks. Therefore peripheral blood mononuclear cells (PBMC) were collected from various age categories of piglets in order to measure the ability to produce antibodies to M. hyopneumoniae in vitro. PBMC obtained from piglets aged 1 and 3 weeks produced few antibodies to M. hyopneumoniae. Significantly higher levels of antibodies to M. hyopneumoniae were produced by PBMC obtained from pigs aged 5-9 weeks. Thus, the ability of PBMC to produce antibodies to M. hyopneumoniae in vitro seemed to be age-dependent.

Animals↗

PubMed1998

Effects of triptorelin versus placebo on the symptoms of endometriosis.

OBJECTIVE: To compare the effect of a GnRH-agonist, triptorelin, versus placebo on the symptoms of endometriosis. DESIGN: A prospective, randomized, double-blind study of 6 months of treatment followed by 12 months of follow-up. SETTING: Departments of Obstetrics and Gynecology at two universities and one general hospital. PATIENT(S): Forty-nine women with symptoms of laparoscopically verified endometriosis. INTERVENTION(S): Triptorelin depot or placebo was given every 4 weeks. Clinical evaluation, including the Duration Intensity Behavior Scale and Visual Analogue Scale for pain, was performed before the injections and up to 12 months after treatment. A control laparoscopy was performed 4-6 weeks after the last injection. MAIN OUTCOME MEASURE(S): Quantitation of pain. RESULT(S): Twenty-four patients had active treatment and 25 received placebo. Pain symptoms according to both scales were significantly more reduced after 2 months of triptorelin treatment compared to placebo. The extent of endometriotic lesions was reduced 50% during triptorelin treatment and increased 17% during placebo. The average area of endometriotic lesions was reduced 45% during triptorelin treatment but was unchanged during placebo. Side effects, mainly hot flushes, were experienced by 80% of the actively treated group but also by 33% of patients in the placebo group. Because of recurrent symptoms, only five patients could be observed for 12 months after completion of treatment. CONCLUSION(S): Triptorelin reduces endometriotic lesions and pain to a significantly higher degree than placebo.

Adult↗

PubMed1998

Verification of single beam treatment planning using a ferrous dosimeter gel and MRI (FeMRI).

A method for analysing and comparing treatment planning system (TPS) data and ferrous dosimeter gel measurements evaluated with MRI (FeMRI) was developed, including image processing to final absorbed dose images. Measurements were analysed according to this method and FeMRI data were thereby compared with the TPS-calculated dose distribution. For photons, differences between FeMRI- and TPS dose data were mainly within +/- 2%. Minor shortcomings found in both the FeMRI system and the TPS are explained and discussed. For electron beams, there was an overall good agreement. It was found that the TPS underestimates the lateral scattering dose outside the primary beam, but the reported dose difference corresponds to a small spatial deviation (less than 2 mm). It is important to consider this single beam data comparison when the method is extended to more complicated situations, for example when using several beams.

Ferrous Compounds↗

PubMed1998

Improvements in absorbed dose measurements for external radiation therapy using ferrous dosimeter gel and MR imaging (FeMRI).

A ferrous gel, based on ferrous (Fe) sulphate and agarose, was used with a clinical magnetic resonance imaging (MRI) scanner to obtain relative dose distribution data from therapeutic photon and electron beams. The FeMRI gel was scanned using a new MRI acquisition protocol optimized for T1 measurements. Thorough comparisons with silicon semiconductor detector and ionization chamber measurements, as well as with Monte Carlo calculations, were performed in order to quantify the improvements obtained using FeMRI for dose estimations. Most of the relative doses measured with FeMRI were within 2% of the doses measured with other methods. The larger discrepancies (2-4%) found at shallow depths are discussed. The uncertainty in relative dose measurements using FeMRI was significantly improved compared with previously reported results (5-10%, one standard deviation, 1 SD), and is today between 1.6% and 3.3% (depending on dose level, 2 SD). This corresponds to an improvement in the minimum detectable dose (3 SD above background) from approximately 2 Gy to better than 0.6 Gy. The results obtained in this study emphasize the importance of obtaining basic FeMRI dose data before the method is extended to complicated treatment regimes.

Electrons↗

PubMed1998

Thyroid burdens of 125I in hospital laboratory workers during a 20-y period.

The 125I content in the thyroids of staff members working with 125I at Malmo University Hospital has been measured regularly during a period of 20 y. The measurements were made with a specially designed NaI(Tl) detector, 1.5 mm thick and 124 mm in diameter. Four categories of personnel have been studied: chemists performing routine labeling of mainly proteins and hormones with 125I and using high activities (up to 74 MBq per single labeling); laboratory staff working with in vitro techniques (e.g., radioimmunoassay) using low activities of 125I (approximately 1 kBq in each sample); nuclear medicine staff working with intravenous injections of 125I-labeled radiopharmaceuticals (up to 4 MBq per injection) in patients; administrative staff working in the same department as the above categories, but not handling 125I. Staff from another department, not working with 125I, were used as a control group. During the period 1977-1990, the chemists had a mean 125I activity of 1.5 kBq in their thyroids, giving a yearly absorbed dose of 10 mGy to this organ. An individual value of 7.4 kBq (53 mGy y(-1)) was recorded at one occasion. The mean value of the activity for personnel working with in vitro techniques, mainly radioimmunoassay, was 140 Bq, with an individual value of 4 kBq recorded in this group. The nuclear medicine staff exhibited 30 Bq 125I in their thyroids, on average. Staff members not working with 125I, but working in the same department as someone in the categories above, had up to 25 Bq, indicating diffuse, low-level contamination of 125I in the department. Control subjects from the hospital, not working in any department handling 125I, showed no measurable amount of 125I in their thyroids (<2 Bq). There is a trend towards decreasing internal contamination with time during the period 1977-1990 in spite of the constant use of 125I. This is supposed to be an effect of improved working conditions and active radiation protection information. The further decrease of internal contamination from 1991 to 1996 is due to a decreased use of 125I.

Body Burden↗

PubMed1998

Administered activity of 99Tcm-DMSA for kidney scintigraphy in children.

Kidney scintigraphy using 99Tcm-dimercaptosuccinic acid (DMSA) is a common gamma camera investigation in paediatric patients. The present study deals with methods of calculating the activity to be administered to children. Our aim is to find a method of calculation which gives the same count density in the gamma camera images for all ages. Four different methods, based on body weight, height, body surface area and a theoretical model, are compared. The count density in the images of the kidneys was studied retrospectively in 85 patients aged between 3 weeks and 19.5 years. Fourteen young adults aged 22.0-31.9 years were also studied. Two of the calculation methods, based on body surface area and the theoretical model, showed no apparent age dependency (i.e. a constant count density was observed for all ages). The variation between individuals was similar with both methods, but only the body surface area method gave a count density comparable to that for the young adults. As the method based on body surface area is also easy to implement, this method is recommended.

Adolescent↗

PubMed1998

Radioiodine treatment of hyperthyroidism in a pregnant women.

UNLABELLED: We describe the effects of radioiodine treatment of a pregnant thyrotoxic woman. METHODS: The woman received 500 MBq of (131)I in her 20th gestational week. The pregnancy was discovered 10 days after radioiodine administration. A gamma camera examination of the abdomen at that time showed a distinct focus of activity, which was interpreted as the fetal thyroid. Gamma camera examinations of the mother and fetus were performed at 10, 11, 12, 13 and 18 days after administration of the therapeutic activity and were the basis of dose calculations. The child was examined by hormone tests and mental performance tests, up to 8 yr after birth. RESULTS: The uptake at 24 hr postadministration was calculated to be 10 MBq (2%) in the fetal thyroid gland. The effective half-life was 2.5 days, giving a calculated absorbed dose to the fetal thyroid gland of 600 Gy, which is considered to be an ablative dose. The calculated absorbed dose to the fetal body, including brain, was about 100 mGy, and 40 mGy to the fetal gonads. Doses were estimated taking contributions from radioiodine in the mother, the fetal body and the fetal thyroid into consideration. The woman was encouraged to continue her pregnancy and received levothyroxine in a dose to render her slightly thyrotoxic. At full term, an apparently healthy boy, having markedly raised cord blood serum thyroid-stimulating hormone concentration and subnormal thyroxine (T4) and low-normal triiodothyronine (T3) concentrations, was born. Treatment with thyroxine was initiated from the age of 14 days, when the somatosensoric evoked potential latency time increased to a pathological value and hormonal laboratory tests repeatedly confirmed the hypothyroid state. At 8 yr of age, the child attends regular school. A neuropsychological pediatric examination showed that the mental performance was within normal limits, but with an uneven profile. He has a low attention score and displays evidently subnormal capacity regarding figurative memory. CONCLUSION: Radioiodine treatment in pregnancy in the 20th gestational week does not give a total absorbed dose to the fetal body that justifies termination of pregnancy. A high absorbed dose to the fetal thyroid, however, should be the basis of the management of the pregnancy and offspring.

Adult↗