Alarm criteria in radiation portal monitoring.

Gamma detectors at border crossings are intended to detect illicit nuclear material. These detectors collect counts that are used to determine whether to trigger an alarm. Several candidate alarm rules are evaluated, with attention to background suppression caused by the vehicle. Because the count criterion leads to many nuisance alarms and because background suppression by the vehicle is smaller for ratios of counts, analysis of a ratio criterion is included. Detection probability results that consider the effects of 5 factors are given for 2 signal-injection studies, 1 for counts, and 1 for count ratios.     

Choice and criteria for selection of sampling strategies in environmental radioactivity monitoring.

Environmental radioactivity monitoring requires a sampling strategy to be defined, adopted and delivered using sound scientific principles. Statistical sampling delivers a set of sampling units from the population that is representative of all sampling units that could be taken. Such a representative set can then be used to draw inference(s) and conclusion(s) about the population based upon a statistical model. The environmental knowledge of the context in which the sampling is to be carried out plays a vital role in determining the appropriate statistical sampling strategy.     

Isostructural fluorescent and radioactive probes for monitoring neural stem and progenitor cell transplants

A construct for tagging neurospheres and monitoring cell transplantations was developed using a new technology for producing luminescent and radiolabeled probes that have identical structures. The HIV1-Tat basic domain derivatives NAcGRKKRRQRRR(SAACQ)G (SAACQ-1) and [NAcGRKKRRQRRR(Re(CO)3SAACQ)G]+ (ReSAACQ-1) were prepared in excellent yields using the single amino acid chelate-quinoline (SAACQ) ligand and its Re(I) complex and conventional automated peptide synthesis methods. The distribution of the luminescent Re probe, using epifluorescence microscopy, showed that it localized primarily in the cell nucleus with a significant degree of association on the nuclear envelope. A smaller amount was found to be dispersed in the cytoplasm. The 99m Tc analogue was then prepared in 43+/-7% (n=12) yield and very high effective specific activity. Following incubation, average uptake of the probe in neurospheres ranged between 10 and 20 Bq/cell. As determined by colorimetric assays, viability for cells labeled with high effective specific activity 99m TcSAACQ-1 was 97+/-4% at 2 h postlabeling and 85+/-25% at 24 h postlabeling for incubation activities ranging from 245 to 8900 Bq/cell. DNA analysis showed that at these levels, there was no significant difference between the extent of DNA damage in the treated cells versus control cells. A series of preliminary SPECT/CT studies of transplants in mice were performed, which showed that the strategy is convenient and feasible and that it is possible to routinely assess procedures noninvasively and determine the number of cells transplanted.     

Safety and feasibility of percutaneous vertebroplasty with radioactive (153)Sm PMMA in an animal model

Purpose

We investigated the safety and feasibility of the combination of samarium-153-ethylenediamine tetramethylene phosphonate (¹⁵³Sm-EDTMP)-incorporated bone cement (BC) with percutaneous vertebroplasty (PVP) in dogs.

Methods and materials

¹⁵³Sm-EDTMP-incorporated BC was prepared by combining solid ¹⁵³Sm-EDTMP and polymethylmethacrylate (PMMA) immediately before PVP. It was then injected into the vertebrae of four healthy mongrel dogs (two males and two females) by PVP under CT guidance. Each dog was subjected to five PVP sessions at a ¹⁵³Sm-EDTMP dose of 30-70 mCi. The suppressive effect of local injection of ¹⁵³Sm-EDTMP on the hematopoietic system was evaluated through counting of peripheral blood cells. Distribution of ¹⁵³Sm-EDTMP-incorporated BC and the status of tissues adjacent to injected vertebrae were evaluated with SPECT, CT and MRI. Histopathology was carried out to assess the influence of PVP on the vertebra and adjacent tissues at the microscopic level.

Results

PVP was done successfully, and all dogs exhibited normal behavior and stable physical signs after procedures. ¹⁵³Sm-EDTMP-incorporated BC was concentrated mainly in target vertebrae, and the peripheral blood cells remained within normal range. The spinal cord and tissues around BC did not exhibit signs of injury even when the dosage of ¹⁵³Sm-EDTMP increased from 30 mCi to 70 mCi.

Conclusion

A dose lower than 70 mCi of ¹⁵³Sm is safe when it was injected into vertebrae. ¹⁵³Sm-EDTMP-incorporated BC did not influence the effect of PVP. This means might strengthen anti-tumor activity locally for vertebra with osseous metastasis without damaging adjacent tissues.     

Analysis of outdoor radon progeny concentration measured at the Spanish radioactive aerosol automatic monitoring network

An analysis of 10-year radon progeny data, provided by the Spanish automatic radiological surveillance network, in relation to meteorology is presented. Results show great spatial variability depending mainly on the station location and thus, the surrounding radon exhalation rate. Hourly averages show the typical diurnal cycle with an early morning maximum and a minimum at noon, except for one mountain station, which shows an inverse behaviour. Monthly averaged values show lower concentrations during months with higher atmospheric instability.     

Continuous monitoring of change in hemodilution during water immersion in humans: effect of water temperature

BACKGROUND: The present study was designed to examine whether water temperature during head-out immersion (HOI) modifies hemodilution dynamics. METHODS: We made continuous measurements of blood density (rho(b)) during HOI at 3 different water temperatures; the lower critical (32 degrees C), neutral (34.5 degrees C), and upper critical (36 degrees C) temperatures in 6 healthy male volunteers. Blood was withdrawn continuously from the antecubital vein for measurement of rho(b) during 60 min of water immersion with a 10-min control period before the immersion. The density was measured with the mechanical oscillator technique. Hematocrit (Hct), plasma density (rho(p)), and osmolality were measured at 5-min intervals. Erythrocyte density (rho(e)) was calculated from rho(b), rho(p) and Hct. Cardiac output and BP were measured to calculate total peripheral resistance. RESULTS: Hct, rho(b), and rho(p) decreased rapidly in the first 20-25 min of immersion and were maintained at a reduced level during immersion. Plasma volume calculated from rho(p) and Hct increased with the rho(b) reduction. These immersion-induced changes were independent of these water temperatures. Plasma osmolality and rho(e) remained constant throughout the experimental period in the three temperature conditions, indicating that the increase in plasma volume and hence hemodilution was induced by an isotonic fluid shift from extravascular space. The total peripheral resistance increased inversely in proportion to the water temperature during HOI. CONCLUSION: In the present condition, water temperature did not modify the net transcapillary fluid transfer during HOI in the presence of the temperature dependent increase in vascular tone.     

Draining of radioactive waste water from departments working with radioactive material after introduction of the law for radiation protection (author's transl)

In order to establish the drainage of radioactive waste water 1976 in the Federal Republic of Germany a new law for radiation protection was introduced. In this paper a concept is introduced how to determine specifications for constructing a decay plant using the given data of a department for nuclear medicine. The given boundary conditions were to secure a low concentration of radioactive material in order to establish the drainage of extreme low activities without diluting it.     

Radionuclide monitoring in environmental water body using an in situ gamma probe

An HPGe gamma probe designed to monitor radioactive nuclides in environmental water in situ is described. The probe is equipped with a 15% HPGe detector and an associated spectrum analyzer. Laboratory tests were performed to evaluate its operating depth, detecting sensitivity, detecting volume and the detection limits of radionuclides. A field operation was conducted to measure in situ radionuclide concentrations in a nuclear reactor pool, and the feasibility as well as the disadvantages of this rapid survey are discussed.     

核医学放射性废水槽式衰变池容积的评价与设计

目的:提供评价与设计核医学槽式衰变池容积的计算方法,为医疗机构、环境影响评价机构和管理部门等提供技术参考。方法:通过构建数学模型并推导计算式,建立槽式衰变池容积与废水放射性水平之间的关系。结果:不同医疗机构的核医学科患者诊疗量、核素使用量以及废水产生量等存在差异,槽式衰变池的评价与设计的结果也不相同,但结果均应符合GB...     

Safety and efficacy of radioactive seed localization with I-125 prior to lumpectomy and/or excisional biopsy

Purpose

To evaluate the safety and efficacy of pre-operative I-125 radioactive seed localization (RSL) as an alternative to wire localization (WL).

Methods

A waiver was granted by the institutional review board for this HIPAA compliant study. Review of 356 consecutive single site nonpalpable mammographic and ultrasound guided I-125 RSLs done between November 2011 and April 2012 was conducted. Preoperative mammograms and specimen radiographs were reviewed for seed-target distance, lesion location, and target/seed removal. During a brief surgical training period, 35 of 356 women had both RSL and wire localization (WL) of the same lesion. Chi-square and single sample t-tests were used to compare margin status and duration of procedures.

Results

Of the 356 RSLs, 303 (85.1%) were performed ≥1 day before surgery. Mammographic guidance was used in 330 (93%) and ultrasound in 26 (7%). Mean seed to target distance was 1 mm (range 0–20 mm); all targeted lesions were retrieved. In 31 women in whom mammographic guidance was used for both RSL and WL, median procedure time was not significantly different (RSL 9.0 min; WL 7.0 min; p = 0.91), and median seed migration distance was <1 mm (range 0–15 mm). No difference was detected between margin status with RSL alone versus WL (p = 0.40 and p = 0.65 for positive and <1 mm margins, respectively). Two adverse events occurred requiring an additional wire/surgery.

Conclusion

RSL ≥ 1 day before surgery is a safe effective procedure for pre-operative localization, with few adverse events and surgical outcomes comparable to those achieved with wire localization.     

Ultra-thin radioactive sources

A method is described for the preparation of ultra-thin radioactive sources by the adsorption of insoluble compounds of radionuclides on to suitable substrates.     

The radioactive patient

Patients containing diagnostic or therapeutic amounts of radionuclides present exposure problems for medical and technical personnel. It is essential that personnel be aware of the magnitude of exposure expected and the methods available for its reduction. The design of a nuclear medicine facility should consider patients as sources of exposure. The size of imaging areas may be increased to reduce exposure to attending personnel. Patients containing radioactivity should be segregated from other patients and their families. Hospitalized patients given therapeutic amounts of radionuclides represent sources of exposure and contamination to personnel providing care. The use of disposable materials and the monitoring of these materials for contamination will reduce contamination of the hospital environment. Adequate instruction of personnel is essential to programs using therapeutic amounts of radionuclides so that patients are not made to feel isolated because of the form of treatment they are receiving.