US3796879A - Automated multiple sample processing for well type radioactivity counters - Google Patents

Automated multiple sample processing for well type radioactivity counters Download PDF

Info

Publication number
US3796879A
US3796879A US00237662A US3796879DA US3796879A US 3796879 A US3796879 A US 3796879A US 00237662 A US00237662 A US 00237662A US 3796879D A US3796879D A US 3796879DA US 3796879 A US3796879 A US 3796879A
Authority
US
United States
Prior art keywords
sample
samples
replicate
radioactive
detection
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US00237662A
Other languages
English (en)
Inventor
R Obrycki
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
TM ANALYTIC Inc AN IL CORP
GD Searle LLC
Original Assignee
GD Searle LLC
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by GD Searle LLC filed Critical GD Searle LLC
Application granted granted Critical
Publication of US3796879A publication Critical patent/US3796879A/en
Assigned to TM ANALYTIC, INC. AN IL CORP reassignment TM ANALYTIC, INC. AN IL CORP ASSIGNMENT OF ASSIGNORS INTEREST. Assignors: TRACOR ANALYTIC, INC., A TX CORP
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01T—MEASUREMENT OF NUCLEAR OR X-RADIATION
    • G01T7/00—Details of radiation-measuring instruments
    • G01T7/08—Means for conveying samples received
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01T—MEASUREMENT OF NUCLEAR OR X-RADIATION
    • G01T1/00—Measuring X-radiation, gamma radiation, corpuscular radiation, or cosmic radiation
    • G01T1/16—Measuring radiation intensity
    • G01T1/20—Measuring radiation intensity with scintillation detectors

Definitions

  • the radioactivity in the samples is automatically compared with the radioactivity level of a refer- 56]
  • the invention is particularly applicable to radioactivity measurement where a great multiplicity of samples are processed and compared against reference samples.
  • tests are based on a binding reaction between a ligand and a compatible binding agent in which one member is accompanied by tracer molecules labeled with a radioisotope, usually radioiodine 1-125.
  • the test is used to detect substances which are in such low concentrations or small amounts that they can be quantified best through the use of radiotracers.
  • Principal uses of such tests include quantification of hormones, enzymes, drugs, proteins, viruses, microbial toxins, and food additives. Knowledge of the quantity present or the absence of these substances in the tissues, fluids, and excretions of biological subjects is quite useful in diagnosing and treating certain illnesses.
  • radioimmunoassay a principal technique in such tests, is one of the most promising methods of detecting the presence of various cancers in their early stages in a living subject.
  • a related object is to increase the speed with which a given number of samples may be processed. This speed is realized from the concurrent counting of replicate samples and from the elimination of the need for mathematical calculations by the laboratory personnel.
  • a further object is to increase the reliability of the measurement of radioactivity in liquified samples by eliminating manual arithemtic calculations and the resultant errors that follow therefrom. Reliability may also be increased by designing the components of the radioactivity measuring device for use with a particular radioisotope.
  • a further object is to increase the simplicity of the performance of radioactivity analysis of a multiplicity of sample specimens. This may be achieved, particularly in the field of radioimmunoassay, by designing the radioactivity measuring device to analyze and extract information from reference samples, and to analyze subsequent samples and compare them with the reference samples first analyzed.
  • this invention is a method of determining quantitatively the presence of a substance exist: ing at least partially in a radioactive form in each set of a series of sets of replicate samples utilizing a scintillation counter having a comparison means and an output means comprising concurrently analyzing each sample in a set of replicate samples in said scintillation counter to determine the radioactivity level in each sample, generating electrical signals representative of the radioactivity level in each sample concurrently measured, combining the electrical signals for the radioactivity levels of all the replicate samples in each set, comparing said combined electrical signals with an electrical signal representing the radioactivity level of a reference set of samples utilizing said comparison means, and indicating the results of the comparison on said output means.
  • the samples in the sample set which are concurrently analyzed need not be replicate samples.
  • the samples are grouped in a sample set merely to increase the speed of processing.
  • the radioactivity level of each sample in the set is concurrently measured and a representative electrical signal is generated for each of these samples.
  • Each of these electrical signals is compared separately with an electrical signal representing the radioactivity level of a reference sample. The results of each of these comparisons are separately indicated.
  • this invention is, in a scintillation counter having a rate monitor for measuring the level of radioactivity, an output means, and a counting well, the improvement comprising a plurality of separate scintillation crystal assemblies, each constructed to accomodate concurrently a proximately positioned sample in a set of samples, a plurality of photodetectors, one each being in optical communication with only one of the plurality of scintillation cryatal assemblies, signal combining means connected to the rate monitor for combining the signals of the plurality of photodetectors, reference memory means for storing a signal indicative of level of radioactivity of a reference, and comparison means for receiving signals from the rate monitor and the reference memory means for determining the ratio between the level of radioactivity of samples in the counting well and the level of radioactivity of the reference, and for transmitting the ratio so derived to the output means.
  • the invention further includes a signal combining means connected to the count tabulating means or rate monitor.
  • the signal combining means combines the signals of the plurality of photodetectors.
  • the reference memory means stores a signal representing the elapsed counting time for the reference samples for a number of radioactive events.
  • the count tabulating means is constructed to receive signals from the reference memory means for measuring the ratio between the radioactivity rate for the reference samples and the radioactivity rate of each set of replicate samples.
  • a residual memory means for storing a signal representing residual radioactivity is also included in the device ln this arrangement a residual subtracting means connected between the photodetectors and the count tabulating means reduces the tabulated radioactive event count according to the level of residual radioactivity.
  • FIG. 1 is a block diagram of a well type scintillation counter constructed according to this invention.
  • FIG. 2 is a sectional view of the counting well of the scintillation counter of FIG. 1.
  • FIG. 3 is a typical standard curve for radioimmunoassay.
  • a scintillation counter having an output means in the form of a readout device 9, and a counting well defined by the enclosing walls 23.
  • a plurality of separate scintillation crystal assemblies 2 optically shielded from each other by the counting walls 23 and the partition means 28.
  • a photodetector 3 is positioned directly under each scintillation crystal assembly 2.
  • Windows 27 are interposed between each crystal 2 and photodetector 3, while the remaining surface area of each of the crystals 2 is surrounded by a metallic moisture shield 24.
  • One of each of a plurality of replicate samples 1 is positioned proximate to a scintillation crystal assembly 2 respectively associated therewith.
  • a residual subtracting means 6 is interposed between the output of each of the pulse height analyzers 5 and a summing device 7 to reduce the rate of electrical pulse passage through the pulse height analyzers 5 by an amount equal to the rate of residual radioactivity.
  • subtracting means 6 may be a typical conventional device such as an up-down counter which will pass pulses to signal combining means 7 only when positive counts exceed negative counts.
  • the negative, residual counts are initially set into subtracting means 6 by residual memory means 34.
  • the residual radioactivity is equal to the sum of the instrument background and residual or non-specific binding radioactivity, in the case of radioimmunoassay samples and standards.
  • the count rate passed to a counter from each photodetector 3 then reflects the count rate passed by the associated pulse height analyzer 5 less the residual radioactivity rate.
  • the pulse amplitude windows in the pulse height analyzers 5 will be set to cover identical ranges as long as the same radioisotope of interest is utilized in all of the sample vials l.
  • the scintillation detector is run in the reference measuring mode under the influence of the reference controller 13. Operation in the reference mode is for the purpose of obtaining and storing reference figures from reference samples. Information subsequently obtained from unknown samples in the sample mode is then compared with the corresponding reference figures obtained from the reference samples in the analysis of unknown samples.
  • the reference mode may be manually altered so that the reference figures may reflect the ratios of: number of bound sites to maximum binding; number of free sites to maxi mum free sites; number of free sites to total free sites; or number of bound sites; to total binding sites. Usually the ratio of bound sites to maximum binding is the most useful figure.
  • the reference controller 13 provides an actuating signal to the time counter which, when a reset signal is present at the AND gate 20, resets and starts the time counter 15.
  • a clock 14 generates clock pulses which are recorded in the time counter 15.
  • the time counter 15 thereby serves as a timing means for determining and generating an electrical signal representing elapsed counting time.
  • Time counter 15 passes this signal to the buffer counter 16 when the master counter 22 is full.
  • Master counter 22 serves as a count tabulating means, and when it is full, an appropriate signal is generated on electrical lead 29 which removes one of the inputs to AND gate 18, thereby preventing further storage of clock pulses in the time counter 15.
  • the same signal actuates buffer counter 16 through AND gate 17 to accept and store an electrical signal from time counter 15 by way of line 35.
  • the buffer counter 16 serves as a reference memory means for storing a signal representing elapsed counting time for a reference sample, or set of samples, for the predetermined number of events which were required to fill the master counter 22.
  • the predetermined number of events required to fill the master counter 22 may be less than the number of electrical pulses passed from the signal combining means 7 if an accuracy divider 10 is interposed between the signal combining means 7 and the master counter 22.
  • the accuracy divider passes one pulse to the master counter 22 for each time that a whole positive number of pulses are received from the signal combining means 7.
  • the accuracy divider 10 thereby effectively divides the composite electrical signal from the signal combining means 7 by a whole positive integer.
  • the denominator set dial 11 may be used to manually change the denominator setting in accuracy divider 10 if desired.
  • the sample controller 12 After the reference mode of operation, the sample controller 12 is not actuated until the samples 1 have been lowered into the counting well and are positioned for counting therein. Thereafter the scintillation counter ceases to operate in the reference mode, and instead is automatically switched to operate in the sample mode under the influence of sample controller 12.
  • the sample controller 12 initiates a signal through the OR gate 19 which, when combined with the reset signal from circuit 30, resets and starts the time counter 15 again.
  • the clock 14 passes pulses to the time counter 15 which begins recording the time elapsed.
  • a comparison command is sent to the buffer counter 16 from sample controller 12 on line 36 so that as soon as the contents of the time counter 15 equals the contents of the buffer counter 16, which were stored from counting the reference sample set, then a signal is generated on lead 31 from the buffer counter 16.
  • This signal is passed as an input to AND gate 21 along with an input from the sample controller 12.
  • AND gate 21 when actuated, generates a shut-off signal to the master counter 22 so that the count then present in the master counter 22 records the number of radioactive events.
  • readout device 9 Once the shut-off signal has been received by master counter 22 from AND gate 21 in the sample mode of operation, and the count from master counter 22 and the time from buffer counter 16 have been registered in readout device 9, readout device 9 generates a reset signal on circuit 30 which resets the time-counter as well as the counting means 8a, 8b, and 8c, and the master counter 22. Another start up signal is not generated by the sample controller 12 until the samples 1 have been removed from the scintillation counting well and subsequent samples placed in the counting well. At this point in time, as at the beginning of the reference mode, buffer counter 16 contains the time elapsed for counting during the reference mode and the master counter 22 and the time counter 15 are reset to zero.
  • master counter 22 may also be treated as containing the reference sample count, since reference sample measurement terminated at overflow at which time there was also a zero reading in master counter 22.
  • the counting cycle is then repeated indefinitely in the sample mode until no more samples are available or until a signal switching to the reference mode of operation is received. Such a signal may be eigher automatic or manual.
  • the residual memory means 34 is cleared and is reset by the new references.
  • the number in the master counter 22 is not only a raw count of pulses for the same length of time that elapsed during the counting of the reference sample set, but is also a ratio of the quantity of the radioisotope of interest in a subsequent sample set to the quantity of the same radioisotope present in the samples in the reference sample set.
  • the electrical signal from the signal combining means 7 is thereby compared with an electrical signal representing the radioactivity level of a reference set of samples utilizing a master counter 22 which serves as a comparison means.
  • the result of each comparison is in the form of a ratio which is indicated at the output means 9.
  • This ratio may be used to determine the quantity of a substance of interest which exists either in a radioactive form, or, by applying well known principles of isotope dilution analysis, the quantity of both radioactive and non-radioactive forms.
  • the ratio registered in readout device 9 represents the percentage fraction of tracer bound antibodies in a radioimmunoassay to determine the concentrations of ligand.
  • the curve of FIG. 3 is only an exemplary curve, as the standard curves in radioimmunoassay must be recalculated for each new batch of samples or for a new scintillation device if the same set of samples is to be used in more than one scintillation detector.
  • radioimmunoassay samples and standards have particular application to radioimmunoassay samples and standards.
  • the reaction that takes place is usually between a ligand, typically an antigen, and an antibody or other binding agent, with the antigen typically being the substance of interest.
  • the antigen molecules will combine with the antibodies until the antibody binding sites are saturated. The excess antigen present will remain free in solution in an uncombined state.
  • the substance being investigated, the antigen exists in both radioactive and non-radioactive forms in all of the reference samples and the unknown samples.
  • the radioactive form of the antigen is created by reacting a stock preparation of antigen with iodine, preferably 1-1 25.
  • Iodine reacts very readily with most antigens in a manner which does not later interfere with the antigen-antibody reaction. Therefore, at least some of the antigens are combined with radioactive iodine, to form a tracer labeled antigen.
  • the antibodies react equally with the tracer labeled antigens and the cold, or non-radioactive antigens, which compete for antibody binding sites, so that the amount of radioactivity in the combined substances is indicative of the total quantity of antigen present.
  • the number of radioactive tracer antigen molecules competing successfully, thus becoming bound will, of course, depend upon the extent to which they have been diluted by non-radioactive antigen molecules. The higher the concentration of antigen in the test samples, the smaller the fraction of radioactive antigen tracer molecules bound by antibody.
  • a reference sample is prepared which is best described as a maximum binding reference, wherein a maximum of the radioactive form of the antigen is bound by reason of the presence of only a minimum of the non-radioactive form of the antigen.
  • the maximum binding reference sample, or maximum binding reference sample set in the case of replicate samples, serves as the principal reference in radioimmunoassay.
  • the level of radioactivity in each sample in the sample set is concurrently measured in the scintillation counter.
  • Separate electrical signals are generated representing the level of radioactivity in each replicate sample in the common set.
  • a uniform adjustment of each of the electrical signals is made to nullify the influence of residual radiation on the electrical signals.
  • the electrical signals are thereafter combined, usually by addition, to produce a composite electrical signal representing the level of radioactivity in the set of replicate samples.
  • the signals representing each replicate sample may be combined by summation together to form an electrical signal reflecting the total radioactive events occurring in the entire set of replicate samples, followed by division of the total radioactive events by the number of replicate samples measured in the set to obtain an average level of radioactivity.
  • a composite signal is produced and is compared against an electrical signal representing a composite radioactivity level of a reference standard sample set. The results of this comparison are indicated at some output ing the counting.
  • Each set of subsequent unknown replicate samples may be analyzed by counting the same number of radioactive events while recording the time elapsed during the counting process.
  • a ratio of radioactivity may be obtained by dividing the time elapsed during counting of the reference samples by the time elapsed during counting of each of the sets of unknown samples. This resultant ratio is a ratio of the quantity of the tracer labeled substance present in each set of unknown samples to the quantity of the tracer labeled substance present in the reference.
  • all of the measured times elapsed are increased by a uniform increment to negate the effects of radioactive events attributable to residual radiation.
  • the scintillation counter must be provided with a plurality of comparison means and output means.
  • the level of radioactivity of each of the diverse samples in the sample set is concurrently compared with the level of radioactivity in a maximum binding reference sample saturated to the maximum extent with the tracer labeled substance to obtain ratios for each of the unknown samples in the sample set. Each of these ratios is separately indicated in one of the plurality of output means.
  • a method of automatically comparing the amount of a substance existing at least partially in a radioactive form in each set of a series of sets of replicate samples with the amount of said same substance present in reference samples using a scintillation counter comprising the following steps:
  • time rate of detection of radioactive events in said reference samples is determined by counting the number of electrical signals associated with radioactive events in said reference samples for a measuring interval of time
  • time rate of detection of radioactive events in each replicate sample set is determined by counting the number of combined electrical signals associated with radioactive events in each of said replicate sample sets for the same measuring interval of time
  • output signals are representations of the ratios of the number of combined electrical signals associated with each replicate sample set to the counted number of electrical signals associated with said reference samples.
  • the time rate of detection of radioactive events in said reference samples is determined by measuring the time elapsed during counting a predetermined number of electrical signals associated with radioactive events in said reference samples, and further comprising counting the same predetermined number of electrical signals associated with each of said replicate sample sets while measuring the time elapsed during counting of the samples in each replicate sample set, and wherein said output signals are representations of the ratios of time elapsed during counting of said reference samples to time elapsed during counting of each of said replicate sample sets, thereby indicating the ratios of the quantities of the aforesaid substance present in each of said replicate sample sets to the quantity of the aforesaid substance present in said reference samples.
  • the improvement comprising, for each replicate sample set, concurrently analyzing all of the samples of a replicate sample set, combining electrical signals indicative of the results of analysis of all of the samples of a replicate sample set, and generating output signals for each replicate sample set which indicate separately the results of comparison of each replicate sample set with the reference samples.
  • the method of claim 8 further comprising analyzing said reference sample by measuring the time elapsed during counting a predetermined number of electrical signals associated with radioactive events in said reference sample, analyzing each of said sample specimens in said set of sample specimens by counting the same predetermined number of electrical signals associated with radioactive events in said sample specimens in said sample specimen sets, and wherein said output signals are representations of the ratios of time elapsed during analysis of said reference sample to time elapsed during analysis of each of said sample specimens in each of said sets of sample specimens, thereby indicating the ratios of the quantities of the aforesaid substance present in each of said sample specimens to the quantity of the aforesaid substance present in said reference sample.
  • a scintillation counter having a counting well for accommodating samples positioned therein, the improvement comprising a plurality of separate scintillation crystal assemblies in said counting well, each constructed to concurrently accommodate a single one of a set of samples in proximate location thereto, a plurality of photodetectors for generating electrical signals each being in optical communication with a different one of said scintillation crystal assemblies, and each scintillation crystal assembly being in optical communication with only one photodetector, count tabulating means for receiving and counting signals from said photodetectors, timing means for recording elapsed sample counting time, said count tabulating means and said timing means being operative together to produce a signal indicative of time rate of detection of radioactive events from said scintillation crystal assemblies, reference memory means for storing a signal indicative of time rate of detection of radioactive events in reference samples, and output means for receiving signals from said count tabulating means and said reference memory means to represent comparisons of the time rate of detection of radioactive events occurring in subsequent samples with the
  • the scintillation counter of claim 10 further comprising a signal combining means connected to all of said photodetectors and to said count tabulating means.
  • the scintillation counter of claim 10 further comprising a residual memory means for storing a signal representing residual radioactivity, and a residual subtracting means connected between said photodetectors and said count tabulating means for reducing the tabulated radioactive event count according to the level of residual radioactivity.
  • a scintillation counter for analyzing specimen samples having a means for determining time rate of detection of radioactive events, an output means, and a counting well, the improvement comprising a plurality of separate scintillation crystal assemblies in said counting well, each constructed to accommodate concurrently a proximately positioned sample in a set of samples, a plurality of photodetectors for providing signals to said means for determining time rate of detection of radioactive events, each photodetector being in optical communication with only one of said plurality of scintillation crystal assemblies, and each scintillation crystal assembly being in optical communication with only one photodetector, reference memory means, a reference controller for actuating said reference memory means to store a signal from said means for determining time rate of detection of radioactive events in reference samples, and a sample controller for actuating said reference memory means and said means for determining time rate of detection of radioactive events to provide signals to said output means to indicate the ratio of the time rate of detection of radioactive events in specimen samples to the time rate

Landscapes

  • Physics & Mathematics (AREA)
  • Health & Medical Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • General Physics & Mathematics (AREA)
  • High Energy & Nuclear Physics (AREA)
  • Molecular Biology (AREA)
  • Spectroscopy & Molecular Physics (AREA)
  • Measurement Of Radiation (AREA)
US00237662A 1972-03-24 1972-03-24 Automated multiple sample processing for well type radioactivity counters Expired - Lifetime US3796879A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US23766272A 1972-03-24 1972-03-24

Publications (1)

Publication Number Publication Date
US3796879A true US3796879A (en) 1974-03-12

Family

ID=22894649

Family Applications (1)

Application Number Title Priority Date Filing Date
US00237662A Expired - Lifetime US3796879A (en) 1972-03-24 1972-03-24 Automated multiple sample processing for well type radioactivity counters

Country Status (10)

Country Link
US (1) US3796879A (US20050192411A1-20050901-C00001.png)
JP (1) JPS4915485A (US20050192411A1-20050901-C00001.png)
CA (1) CA965193A (US20050192411A1-20050901-C00001.png)
CH (1) CH578184A5 (US20050192411A1-20050901-C00001.png)
DE (1) DE2311779A1 (US20050192411A1-20050901-C00001.png)
FR (1) FR2177871B1 (US20050192411A1-20050901-C00001.png)
GB (1) GB1431445A (US20050192411A1-20050901-C00001.png)
IT (1) IT982911B (US20050192411A1-20050901-C00001.png)
NL (1) NL7304196A (US20050192411A1-20050901-C00001.png)
ZA (1) ZA732057B (US20050192411A1-20050901-C00001.png)

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3944832A (en) * 1974-02-28 1976-03-16 Yehoshua Kalish Scintillation spectrometer
US4005292A (en) * 1974-01-24 1977-01-25 G. D. Searle & Co. Mass counting of radioactivity samples
US4131798A (en) * 1977-04-05 1978-12-26 Abbott Laboratories Array gamma counter
US4297574A (en) * 1979-02-26 1981-10-27 Card Jeffrey W Radon detection
US5144136A (en) * 1989-09-07 1992-09-01 RSM Analytiche Instrumente GmbH Device for simultaneously measuring particle or quantum beams from many samples at once
US5198670A (en) * 1989-09-29 1993-03-30 Packard Instrument Company Scintillation counting system for in-situ measurement of radioactive samples in a multiple-well plate
WO2002060565A1 (en) * 2001-01-29 2002-08-08 Metara, Inc. Automated in-process isotope and mass spectrometry
FR2858413A1 (fr) * 2003-07-30 2005-02-04 Ungda Methode analytique d'identification de l'origine naturelle ou fossile de l'acide tartrique par determination du carbone 14-comptage en scintillation liquide
US11029418B2 (en) 2017-09-06 2021-06-08 The United States Of America, As Represented By The Secretary, Department Of Health And Human Services Micro-dose calibrator

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CA1220168A (en) * 1983-09-09 1987-04-07 Henry J. Rahn Magnetic separator for solid phase immunoassays
FR2555760B1 (fr) * 1983-11-28 1988-01-15 Commissariat Energie Atomique Procede et appareil de mesure de l'activite d'au moins un produit radioactif

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4005292A (en) * 1974-01-24 1977-01-25 G. D. Searle & Co. Mass counting of radioactivity samples
US3944832A (en) * 1974-02-28 1976-03-16 Yehoshua Kalish Scintillation spectrometer
US4131798A (en) * 1977-04-05 1978-12-26 Abbott Laboratories Array gamma counter
US4297574A (en) * 1979-02-26 1981-10-27 Card Jeffrey W Radon detection
US5144136A (en) * 1989-09-07 1992-09-01 RSM Analytiche Instrumente GmbH Device for simultaneously measuring particle or quantum beams from many samples at once
US5198670A (en) * 1989-09-29 1993-03-30 Packard Instrument Company Scintillation counting system for in-situ measurement of radioactive samples in a multiple-well plate
WO2002060565A1 (en) * 2001-01-29 2002-08-08 Metara, Inc. Automated in-process isotope and mass spectrometry
FR2858413A1 (fr) * 2003-07-30 2005-02-04 Ungda Methode analytique d'identification de l'origine naturelle ou fossile de l'acide tartrique par determination du carbone 14-comptage en scintillation liquide
US11029418B2 (en) 2017-09-06 2021-06-08 The United States Of America, As Represented By The Secretary, Department Of Health And Human Services Micro-dose calibrator
US11614548B2 (en) 2017-09-06 2023-03-28 The United States Of America, As Represented By The Secretary, Department Of Health And Human Services Radioactive source calibration

Also Published As

Publication number Publication date
CA965193A (en) 1975-03-25
DE2311779A1 (de) 1973-09-27
ZA732057B (en) 1974-05-29
CH578184A5 (US20050192411A1-20050901-C00001.png) 1976-07-30
FR2177871A1 (US20050192411A1-20050901-C00001.png) 1973-11-09
IT982911B (it) 1974-10-21
NL7304196A (US20050192411A1-20050901-C00001.png) 1973-09-26
FR2177871B1 (US20050192411A1-20050901-C00001.png) 1974-05-17
GB1431445A (en) 1976-04-07
AU5368173A (en) 1974-09-26
JPS4915485A (US20050192411A1-20050901-C00001.png) 1974-02-09

Similar Documents

Publication Publication Date Title
US4483816A (en) Apparatus and method for quantitative assay of generic transuranic wastes from nuclear reactors
US4229654A (en) Determining fissile content of nuclear fuel elements
US3796879A (en) Automated multiple sample processing for well type radioactivity counters
US4005292A (en) Mass counting of radioactivity samples
JP2517102B2 (ja) 免疫測定装置の発光光量検出方法
US3717753A (en) Liquid scintillation spectrometer with automatic setting of channel limits
US4348588A (en) Method for compensating measuring values when measuring the radiation from a number of radioactive samples in an automatic radiation detecting instrument
US4555629A (en) Method and apparatus for determination of sample homogeneity in scintillation counting
US3511989A (en) Device for x-ray radiometric determination of elements in test specimens
US5550382A (en) Process and apparatus for compacting informations to be stored and processing said compacted informations
US3974088A (en) Mock iodine-125 radiation source
Mehany et al. Immunoradiometric assay for the in-vitro determination of thyroid stimulating hormone in human serum and plasma using solid phase anti-TSH cellulose particles
US3691386A (en) Data processing system employing quench simulation for enabling accurate computation of sample activity levels in liquid scintillation spectrometry
JPS60111981A (ja) ストロンチウムの定量測定方法
JPS6362694B2 (US20050192411A1-20050901-C00001.png)
SU1040389A1 (ru) Способ определени химического состава вещества
Parsons Jr et al. Use of a solid-state multihead gamma counter in a second-generation system for solid-phase immunoassay.
RU2029316C1 (ru) Спектрометр-дозиметр
Grass Activation analysis with a high-resolution high rate gamma-spectroscopy system
SU1183875A1 (ru) Устройство дл определени радиационных характеристик хлопкового волокна
RU2189612C1 (ru) Способ контроля обогащения газообразного гексафторида урана ураном-235
US3665192A (en) Labeling of molecules using the perturbed angular correlation of gamma radiation
Olson et al. On-line quantitative gamma spectrometry with computerized data reduction
Antico et al. Assay of prick test inoculum volume. I. Use and reliability of a gamma camera-based method
Rhodes et al. NBS SP456 (1976) QUALITY ASSURANCE FOR MEASUREMENTS IN NUCLEAR MEDICINE

Legal Events

Date Code Title Description
AS Assignment

Owner name: TM ANALYTIC, INC. AN IL CORP

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNOR:TRACOR ANALYTIC, INC., A TX CORP;REEL/FRAME:004220/0818

Effective date: 19830701