PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “Strontium Radioisotopes”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 37 records · Page 2Linked to original sources
PubMed2004

Toxicity to Tradescantia of technogenic radionuclides and their mixture with heavy metals.

The genotoxic effects on Tradescantia of (137)Cs, (90)Sr, and (236, 242)Pu, a heavy metal mixture [Cd, Cr(VI), Cu, Mn(II), Ni, Pb, Zn] and of a complex mixture of these toxicants were determined. The impact of radionuclides on plants subjected to ionizing radiation exposure was estimated. The number of somatic mutations and the quantity of nonviable stamen hairs were used as end points in the testing. An increase in the quantity of nonviable stamen hairs was observed with increasing internal exposure to (137)Cs, (90)Sr, and (236, 242)Pu; however, the number of somatic mutations was not observed to be dependent on ionizing radiation. The internal dose of individual radionuclides necessary to decrease the quantity of viable stamen hairs in Tradescantia by 50% can be arranged in the following sequence: (236, 242)Pu > (137)Cs > (90)Sr. Tradescantia died in the mixture of the radionuclides (90)Sr, (137)Cs, and (236)Pu (5 x 10(-2), 7 x 10(-5), and 4 x 10(-10) Gy, respectively) after 14 days, whereas the heavy metal mixture caused somatic mutations in 3% of the Tradescantia and nonviable stamen hairs in 7% but no mortality. However, the Tradescantia died in a combined mixture of these heavy metals and the radionuclides after 14 days. On the basis of all these observations, it can be concluded that the toxic effect of radionuclides was more significant than that of heavy metals.

Cesium Radioisotopes↗
PubMed1975

Influence of perfusion pressure and heart rate on local myocardial flow in the collateralized heart with chronic coronary occlusion.

We studied the influence of controlled changes in perfusion pressure and heart rate on the regional distribution of myocardial flow in normal dogs and in dogs with multiple chronic coronary artery occlusions but without infarctions. Local myocardial blood flow was determined with the tracer microsphere technique. By stepwise altering of systemic blood pressure during maximal vasodilation classical pressure flow relations were obtained. One week after complete chronic occlusion a functionally and anatomically well-defined compartmentation of blood flow was found. The dilatory reserve is clearly compromised not only in the collateral-dependent myocardium but also in the apparently normal myocardium which delivers collateral flow. An "arterio-arterial shunting" mechanism is shown to exist. Several months after coronary occlusion, regional mycoardial flow is still nonhomogeneous. Although the coronary dilatory capacity of the collateralized myocardium is nearly normal, that of the normal myocardium is found to be higher than normal. Vessel growth in both areas is discussed as being responsible for this phenomenon. Right ventricular pacing during maximal vasodilation produces a flow decrease to the endocardial muscle layers in normal dogs, while the epicardial flow is unchanged. One week after complete chronic coronary occlusion pacing during maximal vasocilation reduces the dilatory capacity in the collateralized areas to such an extent that the supplementary increase in myocardial oxygen demand will induce ischemia because of the compromised oxygen supply.

Animals↗
PubMed2006

Anthropogenic radionuclides in sediment in the Japan Sea: distribution and transport processes of particulate radionuclides.

Distributions of anthropogenic radionuclides ((90)Sr, (137)Cs and (239+240)Pu) in seabed sediment in the Japan Sea were collected during the period 1998-2002. Concentration of (90)Sr, (137)Cs and (239+240)Pu in seabed sediment was 0.07-1.6 Bq kg(-1), 0.4-9.1 Bq kg(-1) and 0.002-1.9 Bq kg(-1), respectively. In the northern basin of the sea (Japan Basin), (239+240)Pu/(137)Cs ratios in seabed sediment were higher and their variation was smaller compared to that in the southeastern regions of the sea. The higher (239+240)Pu/(137)Cs ratios throughout the Japan Basin were considered to reflect production of Pu-enriched particles in the surface layer and substantial sinking of particulate materials in this region. In the southern regions of the Japan Sea (<38 degrees N), both inventories and (239+240)Pu/(137)Cs ratios in sediment were larger than those in the other regions. In the southern Japan Sea, observations suggested that supply of particulate radionuclides by the Tsushima Warm Current mainly enhanced accumulation of the radionuclides in this region.

Cesium Radioisotopes↗
PubMed1979

Radioisotope therapy in bone and joint disease.

The short range tissue destruction of beta-emitting radioisotopes can be utilized in painful metastatic disease of the skeleton by employing a radionuclide that is specifically metabolized in or adjacent to these lesions. Sodium phosphate P 32 has been used for this purpose for the past 25 yr. It uptake in skeletal tumor and in osteoblastic new bone adjacent to tumor can be markedly increased by pharmacologic stimulation using androgenic steroids, or during rebound deposition after a course of parathyroid hormone. Although efficacy in terms of subjective pain relief is high, more objective signs of success are often lacking, and survival, while more confortable, is not prolonged. Marrow depression is the most significant side effect. A beta-emitting, bone-seeking isotope, 89Sr, may have a better therapeutic/toxic ratio, and should receive further trial. Radiation-induced necrosis has also been applied, though more hesitantly, to the proliferative, destructive, but nonmalignant synovium in rheumatoid disease. Here, a number of colloidal preparations, most commonly 198Au, have been employed. Again, relief of symptoms, particularly recurrent joint effusions, is quite high, although the basic disease process is not reversed. The major hazard here appears to be leakage of material to regional lymph nodes, resulting in irradiation of circulating lymphocytes. Although chromosomal damage can be detected when such cells are then cultured, the actual consequences of this, if any, are not presently known. Both shorter-lived (165Dy) and longer-lived (32P) larger-size colloids are being evaluated, which may prove safer in this regard than 198Au.

Bone Marrow↗
PubMed1999

Sedimentary fluxes of 90Sr, 137Cs, 239,240Pu and 210Pb in the East Sea (Sea of Japan).

Sediment cores collected from the deep basins of the East Sea (Sea of Japan) provide an ongoing and historical record of artificial radionuclides contamination into one of the most highly publicized radioactive waste dumping areas in the world ocean. The depth distributions of 90Sr, 137Cs and 239,240Pu in sediment cores were investigated with the aid of 210Pb-derived sediment accumulation and mixing rates in the deep basins of the East Sea (Sea of Japan). Five box core samples were collected from the northern Yamato Ridge, Korea Plateau, Ulleung and Japan Basins below 1000-m depth. Sediment inventories of 137Cs and 239,240Pu are inversely correlated with water depth and linearly correlated with sediment accumulation rates. The inventories of these nuclides are linearly correlated with the accumulation rates of organic carbon in sediments. The 238Pu/239,240Pu activity ratios in sediments are 0.036 +/- 0.009 suggesting that most of the Pu to the study area is derived from the global fallout. The activity ratios of 239,240Pu/137Cs, and 90Sr/137Cs in bottom sediments are much lower than those of global fallout due to the differences of particle affinity and biological uptake of these nuclides. Sediment inventories of 90Sr and 137Cs constitute < 4% of the anticipated inventories from the global fallout, while those of 239,240Pu constitute 30-150% of the anticipated inventories from the global fallout. The residence time of the dissolved 239,240Pu in the study area is estimated to be 200-400 years based on the sediment inventory and/or sediment accumulation rate, and water column inventory.

Cesium↗
PubMed2002

A general methodology for structuring models to predict the long-term migration of radionuclides from catchments.

In the present paper a generic model for predicting the long-term migration of radionuclides and heavy metals from catchments is described. The model subdivides the catchment into a number of homogeneous, infinitesimal sub-catchments and integrates the radionuclide contributions from such sub-catchments to calculate the total flux of contaminant. It relates the radionuclide behaviour to the statistical distribution of the pollutant partition coefficient on the "ensemble" of sub-catchments. The methodology was validated for 90Sr and 137Cs by using data for water contamination in some European rivers. Values of migration parameters for Pu, Tc, I and Cd isotopes were obtained.

Cesium Radioisotopes↗
PubMed2002

Translocation studies of 137Cs and 90Sr in bean plants (Phaseolus vulgaris): simulation of fallout.

In case of an accident at a nuclear power plant with liberation of radioactive material into the atmosphere, knowledge about the behavior of plant species when in contact with radionuclides is indispensable for safety reasons. The leaf-fruit translocation is an important route through which agricultural products are contaminated by radionuclides. To quantify the leaf-fruit translocation factors for 137Cs and 90Sr in common beans (Phaseolus vulgaris) an experiment was carried out in a greenhouse with a randomized block design. 137Cs activity was determined by gamma-ray spectrometry, while chemical separation followed by beta counting of 90Y was used for 90Sr determination. The model applied for translocation indicated functional dependence between the moment of tracer application and the physiological development of the bean plant. Translocation factors obtained for 137Cs and 90Sr were 0.16 and less than 0.005, respectively.

Cesium Radioisotopes↗
PubMed2002

Improvement of nuclide leaching resistance of paraffin waste form with low density polyethylene.

Low-level liquid borate wastes have been immobilized with paraffin wax using a concentrate waste drying system (CWDS) in Korean nuclear power plants. The possibility for improving chemical durability of paraffin waste form was suggested in this study. A small amount of low density polyethylene (LDPE) was added to increase the leaching resistance of the existing paraffin waste form. The influence of LDPE on the leaching behavior of waste form was investigated by performing leaching test according to ANSI/ANS-16.1 procedure during 325 days. It was observed that the leaching of nuclides immobilized within paraffin waste form made a marked reduction although little content of LDPE was added to waste form. The acceptance criteria of paraffin waste form associated with leachability index (LI) and compressive strength after the leaching test were fully satisfied with the help of LDPE.

Cesium Radioisotopes↗
PubMed1976

The dosimetry of radioisotopes incorporated in bone using cavity ionization theory.

Cavity ionization theory is applied to the dosimetry of bones incorporating beta- and gamma-emitting radioactive isotopes. The assumptions inherent in different theoretical approaches to bone dosimetry are reviewed and compared with those adopted in cavity theory. In presenting the theory attention is given to the effects of electron and photon attenuation and to the absence of electronic equilibrium which may occur in bone. The mean marrow dose is calculated for a range of cavity size and gamma-ray energies and for a beta-ray emitter. The mean marrow dose and the mean endosteal dose are calculated for a human lumbar vertebra and some comparisons made with the results of other workers. It is concluded that cavity theory provides a useful approach to the dosimetry problems of bone-seeking beta- and gamma-ray radioactive isotopes.

Adult↗
PubMed1976

Calculated beta-ray dose factors for trabecular bone.

Mean dose factors have been calculated for those tissues in bone that are relevant to the induction of late irradiation effects; namely, red bone marrow and endosteal tissues lining trabecular bone surfaces. The calculations are based on a Monte Carlo computer method for beta-emitting radionuclides which are distributed uniformly throughout the volume of mineralized bone. Results are given for the radionuclides 14C, 45Ca, 22Na, 18F, 32P, 90Y and 90Sr+90Y (all considered for this purpose as volume-seekers) for seven bones from the adult human skeleton and calculations are also presented of average skeletal dose factors. Where possible, results are compared with those derived from other methods based on simple geometrical models.

Adult↗
PubMed2007

Precision-controlled elution of a 82Sr/82Rb generator for cardiac perfusion imaging with positron emission tomography.

A rubidium-82 ((82)Rb) elution system is described for use with positron emission tomography. Due to the short half-life of (82)Rb (76 s), the system physics must be modelled precisely to account for transport delay and the associated activity decay and dispersion. Saline flow is switched between a (82)Sr/(82)Rb generator and a bypass line to achieve a constant-activity elution of (82)Rb. Pulse width modulation (PWM) of a solenoid valve is compared to simple threshold control as a means to simulate a proportional valve. A predictive-corrective control (PCC) algorithm is developed which produces a constant-activity elution within the constraints of long feedback delay and short elution time. The system model parameters are adjusted through a self-tuning algorithm to minimize error versus the requested time-activity profile. The system is self-calibrating with 2.5% repeatability, independent of generator activity and elution flow rate. Accurate 30 s constant-activity elutions of 10-70% of the total generator activity are achieved using both control methods. The combined PWM-PCC method provides significant improvement in precision and accuracy of the requested elution profiles. The (82)Rb elution system produces accurate and reproducible constant-activity elution profiles of (82)Rb activity, independent of parent (82)Sr activity in the generator. More reproducible elution profiles may improve the quality of clinical and research PET perfusion studies using (82)Rb.

Algorithms↗
PubMed1986

The single-passage extraction of 18F in rabbit bone.

The only clinically applicable method for the quantitative measurement of blood flow to the skeleton which has so far been developed rests on the assumption that the initial extraction of the bone-seeking isotope 18F from blood by bone is known and constant. Previous work to measure the single-passage extraction ratio of this isotope in rabbit bone has been criticised, so a novel technique has been developed in which isotope recirculation cannot occur. In addition, the post mortem uptake of isotope from surrounding tissues and the vascular tracer content of the bone can be monitored. The apparent extraction ratios of two bone-seeking isotopes, 85Sr and 18F, were measured in nine animals, and extrapolated to the time of death from both the time at which dissection of the bones began (giving a maximum value) and the time at which it ended (giving a minimum). Mean blood flow to the femur was 0.562 ml min-1 (SD = 0.170, n = 15) and mean blood flow to the tibia was 0.290 ml min-1 (SD = 0.140, n = 12). Statistical analysis of the results showed that there were significant differences in the extrapolated ratio between animals and significantly higher extraction of isotope in the tibia than in the femur. There was no significant difference between the extraction of 85Sr and that of 18F. The best estimate of the single-passage extraction ratio of 85Sr and 18F which can be made, therefore, is that in rabbit femur it is 0.88 (SE 0.04) and in the rabbit tibia it is 1.08 (SE 0.04). Post mortem uptake of isotope increases the apparent extraction ratio by about 1% per minute.

Animals↗