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At least 1,333 records · Page 74Linked to original sources
PubMed2006

Results of a phase II trial of transrectal ultrasound-guided permanent radioactive implantation of the prostate for definitive management of localized adenocarcinoma of the prostate (radiation therapy oncology group 98-05).

PURPOSE: To evaluate the effectiveness of transrectal ultrasound-guided permanent radioactive (125)I implantation of the prostate for organ-confined adenocarcinoma of the prostate compared with historical data of prostatectomy and external beam radiotherapy within a cooperative group setting. METHODS AND MATERIALS: Patients accrued to this study had histologically confirmed, locally confined, adenocarcinoma of the prostate with clinical Stage T1b, T1c, or T2a, no nodal or metastatic disease, prostate-specific antigen level of < or =10 ng/mL, and Gleason score of < or =6. All patients underwent transrectal ultrasound-guided radioactive (125)I permanent seed implantation into the prostate. The prescribed dose was 145 Gy to the prostate planning target volume. RESULTS: A total of 27 institutions accrued a total of 101 patients to this protocol, with no institution accruing >8 patients. Six patients were ineligible, leaving 95 properly entered as eligible in the study. The median follow-up was 5.3 years (range, 0.4-6.5 years). At 5 years, 5 patients had local failure, 1 had evidence of distant failure, and 6 (6%) had biochemical failure. The overall survival rate at 5 years was 96.7%. At last follow-up, no patient had died of prostate cancer or related toxicities. Eight patients had a maximal acute toxicity level of 3, and no patient had Grade 4 or 5 acute toxicity. During follow-up, 2 patients had maximal Grade 3 toxicity, both related to bladder issues, and no patient experienced Grade 4 or 5 toxicity. CONCLUSION: The results of this clinical protocol (a multi-institutional trial of brachytherapy for localized adenocarcinoma of the prostate) have demonstrated that this type of trial can be successfully completed through the Radiation Therapy Oncology Group. Biochemical disease-free survival was comparable with other brachytherapy published series and with the results after surgery and external beam radiotherapy.

Adenocarcinoma↗
PubMed2005

Measurement of natural radioactivity in building materials in Qena city, Upper Egypt.

Building materials cause direct radiation exposure because of their radium, thorium and potassium content. In this paper, samples of commonly used building materials (bricks, cement, gypsum, ceramics, marble, limestone and granite) in Qena city, Upper Egypt have been collected randomly over the city. The samples were tested for their radioactivity contents by using gamma spectroscopic measurements. The results show that the highest mean value of (226)Ra activity is 205+/-83 Bqkg(-1) measured in marble. The corresponding value of (232)Th is 118+/-14 Bqkg(-1) measured in granite. For (40)K this value is (8.7+/-3.9)x10(2) Bqkg(-1) measured in marble. The average concentrations of the three radionuclides in the different building materials are 116+/-54, 64+/-34 and (4.8+/-2.2)x10(2) Bqkg(-1) for (226)Ra, (232)Th and (40)K, respectively. Radium equivalent activities and various hazard indices were also calculated to assess the radiation hazard. The maximum mean of radium equivalent activity Ra(eq) is 436+/-199 Bqkg(-1) calculated in marble. The highest radioactivity level and dose rate in air from these materials were calculated in marble.

Cities↗
PubMed2005

A non-radioactive method for measuring Cu uptake in HepG2 cells.

At present, all data on Cu uptake and metabolism have been derived from radioactive uptake experiments. These experiments are limited by the availability of the radioactive isotopes 64Cu or 67Cu, and their short half-life (12.5 and 62 h, respectively). In this paper, we investigate an alternative method to study the uptake of Cu with natural isotopes in HepG2 cells, a liver cell line used extensively to study Cu metabolism. In nature, Cu occurs as two stable isotopes, 63Cu and 65Cu (63Cu/65Cu = 2.23). This ratio can be measured accurately using inductively coupled plasma mass spectrometry (ICP-MS). In initial experiments, we attempted to measure the time course of Cu uptake using 65Cu. The change in the 63Cu/65Cu ratio, however, was too small to allow measurement of Cu uptake by the cells. To overcome this difficulty, the natural 63Cu/65Cu ratio in HepG2 cells was altered using long-term incubation with 63Cu. This had a significant effect on Cu concentration in HepG2 cells, changing it from 81.9 +/- 9.46 pmol microg DNA(-1) (week 1) to 155 +/- 8.63 pmol microg DNA(-1) (week 2) and stabilising at 171 +/- 4.82 pmol microg DNA(-1) (week 3). After three weeks of culture with 2 microM 63Cu the 63Cu/65Cu changed from 2.18 +/- 0.05 to 15.3 +/- 1.01. Cu uptake was then investigated as before using 65Cu. Uptake was linear over 60 min, temperature dependent and consistent with previous kinetics data. These observations suggest that stable isotope ICP-MS provides an alternative technique for the study of Cu uptake by HepG2 cells.

Animals↗
PubMed2005

Unexpectedly high radioactivity burdens in ice-rafted sediments from the Canadian Arctic Archipelago.

Unexpectedly high specific activities of (137)Cs (1800-2000 Bq kg(-1) dry weight) have been detected in fine-grained sediments entrained in multi-year sea ice floes grounded in Resolute Bay near the center of the Northwest Passage through the Canadian Arctic Archipelago. These results are remarkable because: (1) the specific activities are about two orders of magnitude higher than average specific activities detected in previous studies of sea ice rafted sediments from the Arctic Ocean, (2) two independent observations of these unexpectedly high specific activities were made several years apart, (3) the sampling site is on the opposite side of the Arctic basin from potential radioactive sources such as disposal and weapons testing sites of the former Soviet Union and nuclear fuel reprocessing sites in western Europe, and (4) the closest compositional match to known geologic source regions is Banks Island, on the western edge of the Arctic Archipelago, although a smaller number of grains from one of the two samples were mineralogically matched to sediments in the Laptev Sea. Consequently, the sediments are probably not from a single distinct source and were likely mixed during sea ice transport. Coupled with previous observations of higher radionuclide specific activities in some sea ice rafted sediments relative to bottom sediments, these new observations indicate that comparatively high as well as variable radioactive contaminant burdens in ice rafted sediments must be common and geographically independent of proximity to known contaminant sources. The mechanisms that would facilitate these unexpected high radionuclide burdens in sea ice are not known and require additional study, as well as investigations of the implications for the transport and fate of contaminants in Arctic sea ice.

Journal Article↗
PubMed1998

Prostate cancer treatment with radioactive seed implantation.

Prostate cancer is the second leading cause of cancer death after lung cancer. The use of radioactive seeds (i.e., brachytherapy) to provide radiation therapy is one of the three recommended treatment options for localized carcinoma of the prostate. This technique places the radioactive source in close proximity to the malignancy and provides a predictable dose of radiation to a confined area, thus sparing nearby healthy tissue. The technique is performed under transrectal ultrasonography. Nursing care for the patient undergoing this ambulatory surgery procedure focuses on detailed preoperative instructions and highly technical intraoperative care, followed by individualized postoperative care.

Brachytherapy↗
PubMed1991

Techniques for radioactive decontamination in nuclear medicine.

Working with unsealed radioactive sources in nuclear medicine carries the potential risk of contamination. Careful design of a department and its operational procedures will minimize but never completely eliminate the possibility of such incidents occurring. Contingency planning forms as important a part of handling such incidents as the procedures to reduce the hazard once an incident has occurred. It should include anticipating where such incidents are likely to occur, training and exercising staff in the appropriate procedures to deal with these incidents, providing a comprehensive decontamination kit, and implementing a routine contamination monitoring survey. Assessing the magnitude of the radiation hazard and the effect of decontamination efforts, containing the spread of contamination, minimizing the radiation dose to individuals, and continuing to decontaminate to the lowest level possible are principles to follow in managing any incident. Nuclear medicine staff should be familiar with techniques for decontaminating different anatomical sites on the body; for eliminating or reducing the uptake of radioactivity absorbed into the body; and for decontaminating dry and wet surfaces, equipment, clothing, and bedding. Radiopharmaceutical dispensing procedures, ventilation scanning, and decontaminating 131I treatment areas are identified as the most likely causes of body surface and internal contamination of nuclear medicine staff.

Decontamination↗
PubMed1986

Management of individuals accidentally exposed to radiation or radioactive materials.

Sources of ionizing radiation are being used with increasing frequency in a wide spectrum of applications in society. These uses are accompanied by the possible occurrence of accidents resulting in persons exposed to radiation and contaminated with radioactivity. These persons pose a risk to facilities and attending personnel upon their arrival at the hospital. This risk can be minimized without compromising the quality of patient care only if careful planning for such patients has been conducted by the hospital. Planning should include identification of a radiation emergency area within the hospital, delineation of a radiation emergency response team of individuals knowledgeable about radiation and radioactivity, and development of protocols for the medical care and decontamination of patients involved in radiation accidents. Various agencies, including the Joint Commission on Accreditation of Hospitals, have stressed the need for preparation and periodic testing of radiation emergency response plans for hospitals.

Accidents↗
PubMed2003

Incidence and mechanism of late stent malapposition after phosphorus-32 radioactive stent implantation.

Late stent malapposition is a potential complication of intracoronary brachytherapy. The aim of our study was to determine the incidence and mechanism of late stent malapposition after implantation of phosphorus-32 radioactive stents. We analyzed 159 patients for de novo lesions after the implantation of phosphorus-32 radioactive stents. There were 15 late stent malappositions. The incidence of malapposition was higher in patients who received Hot-Ends Isostents. External elastic membrane expansion greater than plaque increase in malapposed segments was observed. Late stent malapposition is caused by a localized increase in external elastic membrane that is greater than the increase in plaque area; this is believed to be a dose-dependent phenomenon because it was more common with Hot-Ends Isostents.

Brachytherapy↗
PubMed1976

Rate of transport of radioactive ovum models through the oviducts of individual rabbits.

The transport of radioactive ovum models of 100, 200, 400, 800, and 1,000 mu diameter through the oviducts was measured. Four surrogates of a given size were transferred into each oviduct 6 hours after injection of human chorionic gonadotropin (HCG). The surrogates were located in the oviducts 24, 48, 60, 66, and 72 hours after HCG injection with a collimated end-window Geiger-Mueller tube. Thus the time-course of the transport of each surrogate, from ampulla to uterus in the same animal, was plotted. The time-course of surrogate transport was directly related to surrogate size. Our data suggest that normal tubal patency and ovum transport function can be tested by introducing radioactive ovum surrogates of appropriate size into the oviducts and monitoring their time of arrival at the uterus.

Animals↗
PubMed1984

Radioactivity in blood and urine following intraperitoneal instillation of chromic phosphate in patients with and without ascites.

Systemic distribution of radioactive colloidal chromic phosphate P 32 after intraperitoneal instillation was studied in 10 patients with ovarian or endometrial malignancies. Seven patients without ascites received chromic phosphate P 32 for positive peritoneal washings, rupture of the capsule of the cyst during operation, or minimal Stage III disease. Three patients received chromic phosphate P 32 for recurrent ascites after multiple abdominal paracenteses. Blood and urine radioactivity measurements were performed at selected intervals. There was a clear statistically significant difference (p less than 0.01) between chromic phosphate P 32 activity levels in whole blood, red blood cells, and plasma in patients with and without ascites.

Adult↗
PubMed1999

A technique for suturing peripapillary radioactive plaques.

PURPOSE: To describe a technique for suturing radioactive plaques positioned posteriorly and adjacent to the optic nerve. METHODS: Posterior and juxtapapillary notched radioactive iodine-125 plaques were sutured using four 5/0 nylon sutures. Two sutures were placed in the sclera at the anterior border of the plaque position and passed through the eyelets at the anterior edge of the plaque. Two sutures were attached to the posterior eyelets and brought to either side of the optic nerve, under the rectus muscles, to be sutured to sclera anterior to the insertion of the recti muscles. The position of the plaques was documented intraoperatively using sterile B-scan ultrasonography. RESULTS: Plaques positioned and sutured using this technique were found by ultrasonography to be tight up against the sclera and optic nerve.

Brachytherapy↗
PubMed1975

Studies of regional coronary flow using radioactive microspheres.

Radioactive microspheres accurately measure total coronary blood flow (+/- 10%) if the heart contains at least 400 spheres. Precision of the microsphere method depends upon the number of spheres in the region of interest and the reference sample, not on the radioactivity. Reliable flow can be calculated from reference samples collected from any vessel (carotid or femoral artery or aorta) in the beating, working heart and during cardiopulmonary bypass if the sample contains a minimum of 400 spheres. Spheres of 9 mu are distributed in the heart like diffusible indicators, while spheres greater than 9 mu preferentially stream to the endocardium, causing subendocardial flow to be overestimated. This overestimate is lessened with 15 mu spheres and can be readily taken into account. The microsphere method provides information about flow (ml/100 gm tissue/min) and allows comparisons with other regions (endocardial/epicardial flow ratios) but does not provide information about the adequacy of regional flow or its distribution; this must be assessed by biochemical, histochemical, and functional analysis.

Coronary Circulation↗
PubMed1980

An investigation of the effect of radioactive labeling of DNA on excision repair in UV-irradiated human fibroblasts.

Previous studies on the kinetics of thymine dimer excision and unscheduled DNA synthesis in UV-irradiated human fibroblasts showed a significant discrepancy in these two parameters (Ehmann et al., 1978. Biophys. J. 22: 249). In the present study we have investigated the effect of the level of the radioactive isotope used for labeling cells on the kinetics of a parameter that directly measures thymine dimer excision. We find no significant differences in the kinetics of this parameter in cells lightly or heavily labeled with radioactive thymidine.

Carbon Radioisotopes↗
PubMed2003

Improved TRAP-silver staining versus conventional radioactive TRAP assays: quantification of telomerase activity during immortalization and in pathological human endometrium.

OBJECTIVES: To develop a sensitive telomeric repeat amplification protocol (TRAP)-silver staining assay for telomerase activity quantification. DESIGN AND METHODS: TRAP assays were performed by using a TRAPeze telomerase kit with or without [alpha-32P]-dCTP. Amplification products were electrophoresed in polyacrylamide gels and detected by autoradiography or a modified silver staining protocol. Telomerase activity was quantified from radioactive counts or optical density of telomerase products from test extracts and controls. RESULTS: TRAP-silver staining assay was at least as sensitive as radioactive TRAP assay and quantified telomerase activity within linearity from 10 to 3,000 cell equivalents. Both methods quantified a weak telomerase activity in normal endometrial glandular epithelial cells (GEC) and a strong increase in immortalized GEC. In human pathologic endometria (n=24), telomerase activity was correlated with lesion seriousness and distinguished simple hyperplasias from nonhyperplasic or cancerous lesions. CONCLUSIONS: TRAP-silver staining assay is suitable for cell and tissue telomerase activity routine quantification.

Adult↗
PubMed1988

Radioactive needle implants in the treatment of anorectal cancer.

Radioactive needle implants were used to treat 44 patients with inoperable anorectal cancer. An implant dose of 60 Gy or higher was administered to 27 patients at a mean dose rate of 0.493 Gy/h (SE +/- 0.167 Gy/h). In five patients this was preceded by external beam irradiation. A further 17 patients received an implant dose of less than 60 Gy; this followed external irradiation in 10 patients. A complete response was achieved in 52% (16 out of 31) of patients assessed. Three of these patients later relapsed locally. The median duration of response was 23 months. A partial response of median duration 3 months was achieved by a further 13 patients. Five year actuarial survival was 23.9%. Serious morbidity occurred in six patients; three developed strictures and three necrosis. Features of the tumour and the treatment technique contributing to successful management are discussed. It is suggested that radioactive needle implants have an important part to play in the management of low-lying inoperable anorectal cancers.

Adenocarcinoma↗
PubMed1989

The treatment of essential thrombocythaemia with radioactive phosphorus.

The major complications of essential thrombocythaemia include haemorrhage and thrombosis, events which are related to the level of the abnormal platelet count. We report here on the use of radioactive phosphorus (32P) in eight patients with essential thrombocythaemia. Two patients required multiple injections of 32P to control platelet count, and there was no reduction in the rate of fall of platelets with each injection. Three patients required chemotherapy for persistent thrombocythaemia despite multiple doses of 32P. No clinical or haematological characteristics could be identified for those patients whose disease was difficult to control. Radioactive phosphorus is a safe and effective method to control platelet counts in patients with essential thrombocythaemia.

Adult↗
PubMed1981

Application of simultaneous UV-radioactivity high-performance liquid chromatography to the study of intermediary metabolism. I. Purine nucleotides, nucleosides and bases.

Procedures are presented for the continuous-flow, simultaneous measurement of concentration and radioactivity of purine metabolites separated by high-performance liquid chromatography (HPLC). A microprocessor-controlled radioactivity flow detector connected in series to a UV-flow detector provides on-line quantitative monitoring of separated components in the post-column effluent stream. Through use of two HPLC separations--reversed-phase and anion-exchange--quantitation of all major purine nucleotides, nucleosides and bases is possible. The procedures provides a rapid, sensitive, and convenient means for the systematic study of purine metabolism.

Animals↗
PubMed1978

Separation of radioactive histamine and some of its metabolites by one-dimensional paper chromatography.

A simple one-dimensional paper chromatograph technique is described for the separation of radioactive histamine and some of its metabolites in blood and tissues. After removal of protein, the supernatant fluid (200 microliter) is subjected to two-stage one-dimensional paper chromatography. This enables large numbers of samples to be chromatographed simultaneously. Using this technique in conjunction with liquid scintillation counting, it was possible to monitor the small amounts (0.02 nCi) of radioactive histamine and its metabolites in serial blood samples.

Animals↗