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At least 829 records · Page 46Linked to original sources
PubMed1998

[Radiation protection in the use of tracers in radioguided breast surgery].

PURPOSE: Recent techniques in nuclear medicine have permitted to implement new procedures useful in surgery. Among these, the procedures for locating sentinel lymph nodes and nonpalpable breast lesions are of great interest. The protocols for the location of the sentinel lymph node and for the radioguided location of occult lesions developed at the European Institute of Oncology (IEO, Milan) are based on the administration of radiopharmaceuticals labelled with Technetium-99m (99mTc). We evaluated the dosimetric data relative to patients and hospital personnel to assess whether specific radiation protection procedures are needed. MATERIAL AND METHODS: Fifty patients with nonpalpable breast lesions and 50 patients with suspected lymph node involvement were enrolled in this study. All the patients underwent surgery the day after in-loco administration of the radiopharmaceutical (11 MBq of 99mTc). The absorbed dose to the hospital personnel was estimated from the air kerma rate measured by ionization chamber at different distances from the patients at 0 and 16 hours after the radiopharmaceutical administration. In order to evaluate radiation protection for patients, absorbed doses were measured positioning thermoluminescent dosimeters on the patient's skin for about 16 hours. In the operating room, activity was measured on some excised tissues (lymph nodes and tumors) and on surgical instruments. RESULTS: Absorbed doses were very low for the clinical staff also in case of prolonged patient assistance. After 100 cases, the surgeon mean absorbed dose to the hands and mean effective dose were .45 mGy and .09 mGy, respectively. These values correspond to 1% of the annual dose limit to the hands and to 10% of the annual equivalent effective dose recommended for the population (ICRP 60 and law by decree 230/95). The absorbed dose to healthy tissues of the patients were lower than 1 mGy (mean values: contralateral breast: .9 mGy; abdomen .45 mGy). The mean activity detected in the excised tissues was 9 kBq and 900 kBq in the sentinel lymph nodes and in the tumor lesions (injection site), respectively. The activity detected on the surgical instruments, higher on gauzes (< 100 kBq), was negligible. CONCLUSIONS: From the radiation protection point of view, the data support the validity of our protocols. Absorbed doses to the hospital personnel are low and require neither a radiation protection control nor a classification of exposed workers as classes A or B. Special containers for radioactive wastes are necessary in the administration room but not in the operating room, where the levels of possible contamination are negligible.

Breast Neoplasms↗
PubMed2001

On depleted uranium: gulf war and Balkan syndrome.

The complex clinical symptomatology of chronic illnesses, commonly described as Gulf War Syndrome, remains a poorly understood disease entity with diversified theories of its etiology and pathogenesis. Several causative factors have been postulated, with a particular emphasis on low level chemical warfare agents, oil fires, multiple vaccines, desert sand (Al-Eskan disease), botulism, Aspergillus flavus, Mycoplasma, aflatoxins, and others, contributing to the broad scope of clinical manifestations. Among several hundred thousand veterans deployed in the Operation Desert Storm, 15-20% have reported sick and about 25,000 died. Depleted uranium (DU), a low-level radioactive waste product of the enrichment of natural uranium with U-235 for the reactor fuel or nuclear weapons, has been considered a possible causative agent in the genesis of Gulf War Syndrome. It was used in the Gulf and Balkan wars as an armor-penetrating ammunition. In the operation Desert Storm, over 350 metric tons of DU was used, with an estimate of 3-6 million grams released in the atmosphere. Internal contamination with inhaled DU has been demonstrated by the elevated excretion of uranium isotopes in the urine of the exposed veterans 10 years after the Gulf war and causes concern because of its chemical and radiological toxicity and mutagenic and carcinogenic properties. Polarized views of different interest groups maintain an area of sustained controversy more in the environment of the public media than in the scientific community, partly for the reason of being less than sufficiently addressed by a meaningful objective interdisciplinary research.

Adult↗
PubMedDate not supplied

[Technetium-99m production for use in nuclear medicine].

INTRODUCTION: Technetium-99m is the most important radioisotope used in nuclear medicine. Its routine application is ensured by introduction of 99Mo/99mTc generators. This paper reviews the present status and perspectives of different types of generators. Novelties in the production of either 99Mo for generators or directly 99mTc by using accelerators are also included. PRODUCTION OF 99MO IN NUCLEAR REACTORS AND 99MO/99MTC TYPES OF GENERATORS: The main source of 99Mo is a nuclear reactor. Nuclear reaction 99Mo(n, gamma)99Mo is rather simple, but the main disadvantage is a low specific activity of 99Mo. For routine production the nuclear reaction 235U(n,f)99Mo is used. It gives high yields of 99Mo of very high specific activity. However, its main disadvantages are high costs and generation of large quantities of highly radioactive waste. Depending on the separation method several types of generators were developed. The predominant is the chromatographic generator based on fission-produced 99Mo. Due to the disadvantages of (n,f)99Mo production, the alternatives based on (n, gamma)99Mo were developed. However, sublimation (except low temperature sublimation) and extraction generators at the present stage have no perspective. Only gel generators are promising. PRODUCTION OF 99MO AND 99MTC IN ACCELERATORS: Several nuclear reactions are considered. 100Mo(gamma, n)99Mo gives 99Mo of low specific activity. So it could be used in production by sublimation generators. The reaction 100Mo(p,pn)99Mo was also investigated but it seems not to be suitable for routine production of 99Mo. 99mTc can be directly produced by 98Mo(p, gamma)99mTc and 100Mo(p,2n)99mTc nuclear reactions. It seems that the latter could serve as an auxilliary source of 99mTc. CONCLUSION: At present chromatographic generators based on fission-produced 99Mo seem to have no real alternative. Gel and in lesser extent sublimation generators are prosperous, but still not suitable for large scale production of 99mTc. The accelerators offer good possibilities but a real alternative to fission 99Mo has not been found yet.

Molybdenum↗
PubMed1975

Tritiated thymidine uptake in pig skin. Comparison of in vivo and in vitro techniques.

Tritiated thymidine (3HT) was used in one of three ways to label deoxyribonucleic acid replication in epidermal cells of miniature swine: (1) the radioactive material was injected intracutaneously in vivo; (2) the radioactive material was injected intracutaneously into biopsy specimens and the specimens incubated in vitro in Eagle's medium, or (3) uninjected biopsy specimens were incubated in Eagle's medium with added 3HT. The first two methods yielded the same proportions of labeled cells with uniform distribution of labeled cells. The third method resulted in labeling of cells mainly at the periphery of the biopsy specimens. The advantages of the in vitro over the in vivo technique of injection of 3HT includes the fact that injecting a biopsy specimen avoids the problems of large amounts of radioactive waste disposal in animal studies or the legal and ethical problems of tracer studies in humans.

Animals↗
PubMed2001

[Problems with radiation protection for adjuvant radiotherapy of thyroid cancer].

Ablative treatment of thyroid cancer with 131I is associated with the exposure to ionizing radiation of not only the target cells but also other cells and organs in the patient's body. Thermoluminescent dosimetry showed that the mean dose equivalent in ovaries equaled to several dozen mSv when the mean therapeutic dose was 2.8 GBq of 131I. In the treated young women the performed ovulation tests revealed no dysfunction of the ovaries. The highest dose equivalent in the clinic staff would not exceed 20 mSv per year. Accordingly, the dose equivalents to the public would not exceed the threshold limit of 1 mSv per year. In order to fulfill the requirements of regulations for disposal of radioactive waste and the necessity to store the waste for as long as 80 days it is obligatory to utilize setting tanks of very large capacity.

Environmental Exposure↗
PubMed2003

[Characteristics of water-gas two-phase CO2 transport in unsaturated zone].

The migration of CO2 in soil was simulated through use of soil column, especially the transformation of CO2 between water and gas phases at wetting front was studied. The soil column in the test was 1 m long and the concentration of CO2 solution was 748 mg/L. Through analysis, it was shown that CO2 migration in water phase was governed by advection, dispersion, reaction and mass transfer between water and gas phases, that in gas phase by advection, dispersion, mass transfer between two phases. Sampling method under dynamic condition of two phase flow in soil column was approached and mass transfer coefficient from water phase to gas phase was determined as 0.00061. This showed that there was certain mass transformation of CO2 from water phase to gas phase and yet it was not so significant. This study can provide the quantitative scientific bases for safety assessment of geological disposal of low and intermediate level radioactive waste and environmental impact assessment of solid waste disposal by landfilling.

Air Pollutants↗
PubMedDate not supplied

Depleted uranium: an overview of its properties and health effects.

There has been much debate about the use of depleted uranium in the Gulf War and its health effects on United States and European war veterans. However, studies on the impact of this radioactive substance on the residents of the surrounding Gulf region are far from adequate. Depleted uranium introduces large quantities of radioactive material that is hazardous to biological organisms, continues to decay for millennia and is able to travel tens of kilometres in air. If depleted uranium were used in the Gulf War, its impact on the health of people in the area would have been considerable. This review of depleted uranium--its origin, properties, uses and effects on the human environment and health--aims to trigger further research on this subject.

Alpha Particles↗
PubMed1992

[Scintigraphic use of 87Y during 90Y therapy of bone metastases].

Carrier-free 87Y is produced by cyclotron irradiation of Rb. It decays with a half-life of 80.3 h, transforming via 87mSr to stable 87Sr with the emission of gamma lines of 0.48 and 0.39 MeV. Experience in 6 patients shows good scan quality and correspondence between 99mTc-DPD and 87Y images useful in 90Y-citrate therapy for bone metastases. 87Y offers new possibilities of studying biological kinetics in 90Y therapy. To avoid contamination this should only be used in departments with possibilities of radioactive waste storage and controlled disposal.

Aged↗
PubMedDate not supplied

[Radioprotection and environmental pollution by the use of the radionuclides 89Sr, 186Re, and 153Sm for pain palliation in metastatic bone diseases. Related calculations].

Due to the fact that the existing commercial analgesic drugs are not able to reduce effectively the pain caused by the metastatic bone disease, the use of radiopharmaceuticals with avidity to selectively localize in the metastatic skeletal sites, such as strondium-89 chloride (89Sr-Cl2), rhenium-186-hydroxy ethylene diphosphonate (186Re-HEDP), and samarium-153-ethylene diamine tetramethylene (153Sm-EDTMP), is widely accepted. However this medical application may be dangerous for the occupied personnel and more for general public, if radioactive waste is not properly disposed. In the following article we try to estimate the degree and the significance of that risk. For that reason we discuss the physical properties of these radionuclides and their distribution in the body of the patient. We conclude that 89Sr is not harmful for the physician, the attending personnel or those who live with the patient, because it radiates beta-radiation, while its gamma-radiation is negligeable. The radionuclides 186Re and 153Sm besides beta-radiation, also emit a perceptible amount of gamma-radiation. It has been shown that the exposure to gamma-radiation from these radionuclides of the physician, the attending personnel or those who live with the patient is very low as compared to the internationally accepted radioprotection limits. However the environmental contamination per treatment by either of these three radionuclides is not negligeable in comparison to the national and international accepted limits. Patients that are not in good clinical condition may pose an additional contamination danger to those attending them. For limiting radiocontamination, the annual number of treatments by the above three previous radionuclides, should be considered according to the ALARA principle in relation with the correct handling of these patients, and also considering the fundamentals of radioprotection.

Algorithms↗
PubMed1990

[Therapeutic consequences of contamination injuries by highly radioactive substances].

A case of plutonium injury of the left hand is used to explain the correct management. In addition to radical surgical excision under repeated monitoring of radioactivity, it is obligatory to commence parenteral chelation therapy with DTPA. Close cooperation with radiological technologists is necessary. Discharges and used bandages have to be analysed for their radioactive content before elimination as radioactive waste. Isolation of the patient is not required. The relevant government department has to be contacted. A health center for radiation victims with special measuring equipment is desirable.

Accidents, Occupational↗
PubMed1989

[Methodology of cultivating human tissue in diffusion chambers].

The proliferative activity of human pulmonary carcinoma cells has been examined by autoradiography in 48 cultures in diffuse chambers, incubated with 3H thymidine under various conditions. 3H thymidine has been injected intraperitoneally to one group of animals, in another group the diffuse chambers have been removed from the animals and incubated in culture medium with 3H thymidine in the same concentration. The proliferation intensity of the cell cultures from the same patients has been virtually the same in both modes of incubation. This permits simplifying the autoradiography technique for such experiments, thus helping to avoid the difficulties connected with radioactive waste utilization.

Adenocarcinoma↗