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At least 19 recordsLinked to original sources
PubMed1975

Mechanical deficiencies in scintillation counters, scanners, and gamma cameras.

After an accident involving a scintillation counter, the machanical integrity of scintillation counters and their stands, rectilinear scanners, and gamma cameras was examined. An alarming proportion of these divices were found to be poorly designed with consequent danger to patients and staff. This class of equipment should be covered by standards incorporated in a comprehensive hospital technical memorandum.

Accident Prevention↗
PubMed1982

Chemiluminescence response in normal human phagocytes. I. Automated measurements using a standard liquid scintillation counter.

We present a fast, simple and highly accurate method for measuring Phagocyte Chemiluminescence by using a standard liquid scintillation counter with a simple modification. The method allows the measurement of multiple samples automatically, with standardized mixing and measurement times, at a constant temperature. This is achieved with a minimum of technician time as opposed to the single measurement facility of many of the available manual luminescence photometers. The modifications can be made to any standard liquid scintillation counter, are simple and inexpensive, can allow the handling of large numbers of samples in a short time and improve standardization.

Computers↗
PubMed1981

Novel determination of protein, fat, and lactose of milk by liquid scintillation counter.

A method for routine determination of protein, fat, and lactose contents of milk is based on the ability of a scintillation counter to measure coloration or opalescence through attenuation of photons emitted from sealed miniature carbon-14 and hydrogen-3 radioactive standards. A series of simplified and accurate analytical procedures enable full advantage to be taken of the automatic facilities on the modern liquid scintillation counter. The methods provide several advantages over existing procedures. Accuracy of quantification was high as assessed by comparing the results with those derived by recommended Kjeldahl, Gerber, and colorimetric procedures for protein, fat, and lactose determinations, respectively.

Animals↗
PubMed1984

[Effect of chemical quenching on background counting rate in tritium channel of a large volume liquid scintillation counter].

Background counting rate in tritium channel of a large volume liquid scintillation counter increased with water content ranged 0 to 50% of liquid scintillator. This phenomenon can be explained as follows: The height of scintillation pulses of Compton electrons induced by background gamma radiation is lowered by chemical quenching and shifts to tritium channel. The background counting rate in tritium channel showed a linear relationship with external standard channel ratio of background samples. This relationship is applicable to determine the correct background counting rate for quenching samples and to achieve higher precision of tritium measurement.

Background Radiation↗
PubMed2003

Counting efficiency of a double-well single-plastic scintillation counter to commercially available radionuclides (Tl-201, Tc-99m, I-123, Ga-67, In-111 and I-131).

UNLABELLED: A new type of well-scintillation counter with a double-well and single-plastic scintillator (DW-counter) was developed to simplify time consuming and cumbersome dilution procedures inherent to in-vivo sample measurement. It has the potential to measure many radionuclides which emit a gamma ray or positron. We tested the counting efficiency (CE) of the DW-counter (DCM-200, Aloka Co., Tokyo, Japan) with respect to 6 radionuclides. MATERIALS AND METHODS: The outline of DW-counter is altered to a single unit as compared to the prototype, while its basic mechanical constitution was not changed. Six commercially available radionuclides (Tl-201, Tc-99m, I-123, Ga-67, In-111, I-131) were used in this study. For each radionuclide, we prepared two standard solutions containing high (>100 MBq/ml) and relatively low radioactivity (10-20 MBq/ml). The radioactivity (Bq) of the radionuclide in each sample at time = 0 was measured with a dose calibrator. Afterwards, it was determined from a decay-time with correction by the physical half-life of each radionuclide. Count rate (cps) of each standard sample was measured in each well ten times per sample. The counting efficiency (CE) of the counter for each radionuclide was determined by measured count rate (cps)/standard radioactivity (Bq) x 100 (%). The conversion constant (CC) which predicts standard radioactivity (Bq) from measured count rate (cps) was obtained as a reciprocal value of the CE. RESULTS: The CE (mean +/- SD) in well-A to Tl-201, Tc-99m, I-123, Ga-67, In-111 and I-131 was 5.90 +/- 0.285%, 8.56 +/- 0.0981%, 8.33 +/- 0.344%, 7.77 +/- 0.15%, 16.4 +/- 0.495% and 10.2 +/- 0.139%, respectively. They were significantly different. The coefficient of variation of the measured count rates was less than 1% in radioactive range higher than 10(3) Bq in well-A and 106 Bq in well-B. The difference in the CE between well-A and -B ranged from 7.614 x 10(2) (I-131) to 9.395 x 10(2) (Tl). The CC ranged from 6.14 (In) to 17.15 (Tl) in well-A and from 5.05057 x 10(3) (In) to 15.83773 x 10(3) (Tl) in well-B. The CE was not significantly affected by a sample volume from 1 to 4 ml in well-A, but showed a slight difference in well-B, which seemed due to a collimation. CONCLUSION: The measurement error of the DW-counter was less than 1% and the measured count rate (cps) was exactly converted to the standard radioactivity (Bq) by determined CC. The counter is considered useful in the easy evaluation of in-vivo tracer kinetics by avoiding time consuming and cumbersome dilution techniques.

Citrates↗
PubMed1978

Determination of 222Rn by liquid scintillation counter combined with p-xylene extraction technique.

222Rn Determination method by liquid scintillation counter after extracting 222Rn with p-xylene was studied. It was confirmed that extraction of 222Rn with p-xylene proceeds quantitatively. Several experimental conditions for the counting such as scintillator content in p-xylene, the quencher effect, the zero level extrapolation method and 3-channel counting method were examined. The recommended procedures were successfully applied to measure 222Rn content in one of the natural water. It was noticed that we should pay attention to 220Rn (Tn) which is simultaneously extracted with 222Rn in case of p-xylene extraction.

Radon↗
PubMed1983

The colorimetric estimation of protein by the Lowry technique using a liquid scintillation counter.

A comparison has been made of the use of the spectrophotometer and liquid scintillation counter for the colorimetric quantification of protein. The attenuation of photon detection from sealed miniature 14C radioactive standards enabled protein quantification over a concentration range far in excess of that achievable by the use of a spectrophotometer. Accuracy of quantification was high over the entire range of protein concentration. The ability of the technique to provide quick and accurate protein estimations is discussed.

Colorimetry↗
PubMed1967

A computer programme for the calculation of radioactivity data from liquid-scintillation counters fitted with external standards.

1. A method for transferring data from liquid-scintillation counters to automatic punched-card read-out is described. 2. A method of calibration of an external standard is presented that supplies sufficient information for the correction of quenched data by computer. 3. A computer programme in FORTRAN IV is described that calculates the data from one isotope, or two isotopes counted simultaneously, and that incorporates features for examining the reproducibility of the input data. 4. With the methods described, quench correction of samples containing either (3)H or (14)C was accurate until samples were quenched 70%. When the two isotopes were both present in one sample and counted simultaneously, the correction was accurate until the samples were quenched 60%. When quenching was greater than either 70 or 60% respectively, its correction was still possible but with slightly diminished accuracy and with greater variability.

Carbon Isotopes↗
PubMed1991

Quantification of 32P-labeled samples in gel fragments using the flat-bed liquid scintillation counter.

Quantification of 32P in bands after gel electrophoresis was performed using the flat-bed scintillation counter (Betaplate). The most convenient system involved placing fragments of dried gel between two glass fiber sheets, each previously sealed in a thin plastic bag with liquid scintillant. Good pulse-height spectra and counting efficiencies were obtained with low cross talk and background. The method has been used to quantify mRNA in RNA antisense-protection assays that were linear over a wide range (1-20000 cpm). Cross talk and background could be reduced further by an alternative technique utilizing plastic trays with shallow wells in which a solid scintillant had been melted. Fragments were immersed in the molten scintillant (90 degrees C), which was allowed to solidify, by cooling, before counting.

Animals↗
PubMed2001

Determination of glomerular filtration rate by means of newly developed plastic scintillation counter both with and without dilution procedures.

UNLABELLED: The double-well single-plastic scintillation counter (DW counter) has been developed to reduce the need for technical expertise in a plasma sample method after a single injection of radioactive marker. The DW counter serves the 2 functions of a standard well counter in well A and a dose calibrator in well B. The aim of this study was to assess the clinical feasibility of the counter for the estimation of glomerular filtration rate (GFR) with (99m)Tc-diethylenetriaminepentaacetic acid (DTPA). METHODS: The study was performed on 25 patients with varying degrees of renal dysfunction. The GFR was estimated by a single-sample method after a single injection of (99m)Tc-DTPA. Total injected dose and plasma radioactivity were calculated following 2 methods: standard dilution with a single well (dilution method) and no dilution with 2 wells (direct method). RESULTS: The GFR directly estimated by the DW counter correlated excellently with the GFR estimated by the dilution method (r = 0.998; root mean square error = 2.01 mL/min/1.73 m(2)). The 95% of differences (-0.3124 to 0.0423 percentage injected dose [%ID]/L/1.73 m(2)) in plasma concentration between the 2 comparative methods was <2 SDs. The direct method tended to give slightly higher readings of plasma concentration than did the dilution method (95% confidence interval = -0.0364 to -0.0904 %ID/L/1.73 m(2)). CONCLUSION: The DW counter can circumvent laborious dilution techniques and expertise required for quantifying the GFR in a single-sample method after a single injection of (99m)Tc-DTPA in clinical practice. It is proposed as an alternative to the standard dilution method.

Adolescent↗
PubMed1985

A new design for a liquid scintillation counter for micro samples using a flat-bed geometry.

A new design for a liquid scintillation counter based on a flat-bed geometry is described. Micro-samples are dried or filtered onto transfer membranes or glass fibre filters in a 6 X 16 matrix, compatible with 96-well micro-titration plate filtration assays of labelled cells. A prototype counter without lead shielding had low background countrates (2-3 cpm for 3H) giving a figure of merit of 1325 (and 1292 for 14C). Only 5-15 ml of scintillant/96 samples are required and thus the volume of radioactive waste is low.

DNA↗
PubMed1983

Vial effect and background subtraction method in low-level tritium measurement by liquid scintillation counter.

Counting efficiencies of individual Teflon vials used in low-level tritium measurement by a liquid scintillation counter were investigated. The efficiency observed was fairly varied among vials in spite of being prepared in the same way. And the plots of the efficiency vs the external standard ratio give a straight line. More detailed investigation showed that this vial quenching and chemical quenching are simultaneously corrected by an external standard ratio. On the basis of the above results an appropriate background subtraction method is proposed.

Environmental Pollutants↗
PubMed1990

[Solid scintillator "Ready Cap" for measurement with a liquid scintillation counter--spectra and counting efficiencies for 15 different radionuclides].

"Ready Cap", a small plastic container coated with solid scintillator has recently been introduced (Beckman Instruments, Inc.). Pulse height spectra and counting efficiencies obtained with a liquid scintillator and Ready Cap using a liquid scintillator counter were compared for 15 different radionuclides. For radionuclides emitting low-energy beta-rays or characteristic X-rays, the spectra for Ready Cap shifted toward the higher energy side compared with the spectra for the liquid scintillator. This tendency was reversed for the nuclides emitting higher-energy beta-radiations (36Cl and 32P). Generally, counting efficiencies both in Ready Cap and in liquid scintillator increased with increase in the energy of beta- or X-rays. For some nuclides, Ready Cap gave higher counting efficiencies and for others it gave lower values than in the liquid scintillator. However, the differences were not large within each nuclide. The use of Ready Cap is recommended for measurements of radionuclides when liquid scintillation cocktails have no means of waste disposal under the present Japanese radioisotope regulation.

Evaluation Studies as Topic↗