US3810976A - Lung scanning 99m technetium macroaggregate and method of preparation - Google Patents

Lung scanning 99m technetium macroaggregate and method of preparation Download PDF

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Publication number
US3810976A
US3810976A US00039857A US3985770A US3810976A US 3810976 A US3810976 A US 3810976A US 00039857 A US00039857 A US 00039857A US 3985770 A US3985770 A US 3985770A US 3810976 A US3810976 A US 3810976A
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particles
lung
technetium
dialdehyde
gelatin
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US00039857A
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V Ficken
S Halpern
L Miller
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OKLAHOMA FOUNDATION INC US, University of
OKLAHOMA FOUNDATION Inc, University of
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OKLAHOMA FOUNDATION Inc, University of
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Priority to US00039857A priority Critical patent/US3810976A/en
Priority to CA111,475A priority patent/CA949882A/en
Priority to GB1196071*[A priority patent/GB1303761A/en
Priority to DE19712125012 priority patent/DE2125012A1/de
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    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
    • A61K51/00—Preparations containing radioactive substances for use in therapy or testing in vivo
    • A61K51/12—Preparations containing radioactive substances for use in therapy or testing in vivo characterised by a special physical form, e.g. emulsion, microcapsules, liposomes, characterized by a special physical form, e.g. emulsions, dispersions, microcapsules
    • A61K51/1217—Dispersions, suspensions, colloids, emulsions, e.g. perfluorinated emulsion, sols
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
    • A61K51/00—Preparations containing radioactive substances for use in therapy or testing in vivo
    • A61K51/02—Preparations containing radioactive substances for use in therapy or testing in vivo characterised by the carrier, i.e. characterised by the agent or material covalently linked or complexing the radioactive nucleus
    • A61K51/04—Organic compounds
    • A61K51/08—Peptides, e.g. proteins, carriers being peptides, polyamino acids, proteins
    • A61K51/081—Peptides, e.g. proteins, carriers being peptides, polyamino acids, proteins the protein being an albumin, e.g. human serum albumin [HSA], bovine serum albumin [BSA], ovalbumin
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
    • A61K2123/00—Preparations for testing in vivo

Definitions

  • Pulmonary emboli have been found in recent studies to be present in a high percentage of adult patients dying from all causes. Many emboli are never detected because they produce no symptoms and oftentimes resolve without creating ill effects. Yet pulmonary embolism may cause a variety of symptoms which are similar to other disorders or diseases.
  • the condition created by blood clots trapped in the pulmonary arteries and their branches may exist in a grave form without being diagnosed by physical examination. Emboli often originate in the large pelvic veins or veins of the lower extremities and are found in those areas as a result of poor blood circulation. This condition frequently occurs in patients who are confined to bed as a result of surgery, pregnancy or almost any physiological problem which results in poor blood flow.
  • the emboli migrate through the great vessels and lodge in the heart or lungs. Damage to the lung depends upon the size of the embolus, and its location within the pulmonary vasculature and the cardiovasculature.
  • the emboli may be of such size or so located as to be broken down rapidly into smaller embolic proteolytic enzymes. If these mechanisms are defeated the areas distal to the location of the emboli may be damaged due to inadequate blood supply.
  • pulmonary blood flow may be measured but unfortunately there is no single examination that is accurate, specific, safe and inexpensive enough such that it may be utilized as a screening test for every suspected case of pulmonary embolism.
  • the most common methods employed are chest roentgenogram, pulmonary angiography and scintillation scanning techniques.
  • Pulmonary angiography is a complicated and possibly hazardous procedure dure involving the rapid injection of a large amount of radio-opaque dye. Following the injection, as many as 20 serial X-rays may be taken to trace the flow of the dye through the lung vasculature. This technique, while it may precisely locate emboli, is not desirable for screening a large population of hospital patients.
  • Organ scanning with radioactive materials is a method of particular value in the detection of pulmonary embolism. Such a method is currently accomplished utilizing macroaggregated human serum albumin labeled with Iodine131. This material is a heat-treated albumin which exists as particles typically from 10 to microns in diameter. When injected intravenously, particles of this size will lodge in the capillaries of those portions of the lungs being perfused with blood. Once the particles locate in the lung via the pulmonary artery, a scintillation crystal detector is mechanically passed over the lung fields. The information monitored by the detector is converted into electrical impulses which are used to expose a photographic emulsion, thus producing a picture of the activity distribution.
  • Lung visualization by this rectilinear scanning technique is accurate, presents little danger to the patient and provides a method for screening large numbers of suspected cases of pulmonary embolism and other diseases causing decreased pulmonary perfusion.
  • preparations of aggregated albumin have been used in the evaluation of total and regional perfusion of the lungs including the diagnosis of such specific conditions as emboli formation, emphysema, lung tumors, pulmonary tuberculosis, and the like.
  • the particles of aggregated albumin are mechanically filtered by the lungs because of the particle size, thus permitting definitive lung scanning by typical scintillation detection equipment.
  • the aggregates concentrate in various parts of the lungs in direct proportion to the blood flow supplied by the pulmonary artery and the amount of radioactivity detected is directly proportional to the concentration of aggregates in various parts of the lungs.
  • Imaging the perfused lung areas by the scintillation scanning technique unfortunately has some disadvantages, the most serious of which are the time required to obtain a picture and the radiation exposure of the patient. Also, the patient must lie motionless for long periods of time. This disadvantage can be overcome with stationary imaging devices now available, such as scintillation cameras, an example of which is the Anger camera.
  • the crystal of the Auger cameras with appropriate collimation is large enough to view the entire lung field at the same time. Consequently the entire detection equipment may be moved easily to accommodate the patients most comfortable position.
  • a lung scanning agent for use in man are: (1) the material must be nonantigenic, (2) it must not be harmful to the pulmonary system, and (3) the amount of significant information obtained by injection of the material must be in realistic proportion to the radiation exposure suffered by the patient.
  • the ideal lung scanning agent for a scintillation camera should have a short physical half-life, be a mono energetic y-emitter, have a photon energy of to kev., be devoid of ,B-radiation, harmless, inexpensive and simple to prepare.
  • iodine-tagged radiopharmaceuticals do not take advantage of the imaging speed of the scintillation camera.
  • Tagged to a suitable pharmaceutical 99m technetium would fulfill the noted criteria. While technetium can be incorporated into macroaggregates of albumin the process is time consuming and ditficult and requires technical ability not generally available in a small isotope laboratory. Technetium because of its desirable physical characteristics delivers a very high count rate and greatly shortens the scanning time when performed by a stationary imaging device. Using a scintillation camera and a diverging collimator, anterior, posterior, right and left lateral, and right and left oblique human lung scintiphotos can be obtained in approximately minutes with a 3 me. dose of macroaggregated 99m technetium. This shortened scanning time enables studies to be performed on seriously ill or very dyspneic patients who cannot tolerate the longer procedure with Iodine-131 tagged radiopharmaceuticals.
  • suitable technetium 99m **-sulfur** colloid macroaggregates can be formed in the presence of gelatin, sodium thiosulfate, sodium perrhenate and an inorganic acid.
  • the particles formed must be large enough to lodge in the lungs and fragile enough so that they will migrate from the lungs after an appropriate period. At the same time they must be stable enough so that they do not break down and are not promptly released into the liver and spleen. Any particles which promptly pass into the liver will cause a shadow and distort the scintiphoto of the lung.
  • no more than 2% of the particles should pass into the liver although some experts in the field will accept up to A lung-liver ratio of particle distribution of :1, i.e.
  • the macroaggregate particles thus formed can be stabilized by the addition of small amounts of dialdehydes. It is believed that the gelatin molecules are gently cross-linked with the dialdehydes, thus hardening them and increasing the melting point without changing other chemical properties of the molecule.
  • compositions prepared in this manner may be stored at 3 C. for several months.
  • Macroaggregates of 99m technetium were prepared in three steps as hereinafter described. The procedure was carried out in 10 ml. bottles since these are suitable for centrifuging in a table-top centrifuge.
  • EXAMPLE 1 To 1 ml. of water containing 2.15 mg. of gelatin, 2.15 mg. of sodium thiosulfate and 1.07 mg. of sodium perrhenate, were added 4.5 ml. of 99m TcO solution of the desired activity and 2 ml. of 2 N I-ICl acid. The solution was heated for 10 minutes at 100 C. and the pH adjusted to 4 to 4.5 with 2 ml. of 2 N sodium hydroxide after which 0.6 m1. of 25% glutaraldehyde was added. The solution was heated while shaking for an additional 3 minutes at 100 C. The resultant suspension was centrifuged and the supernatant withdrawn. The remaining particles were washed with saline solution and again centrifuged. After the supernatant was removed, the particles were suspended in 6 ml. of saline solution.
  • the presence of gelatin, sodium thiosulfate, sodium perrhenate and acid is required for the formation of macroaggregates.
  • the number of particles formed is proportional to the amount of each component present.
  • the effective range of acid is inversely proportional to the period of heating.
  • the size and number of the particles can in part be controlled by the period of heating, the amount of gelatin, sodium thiosulfate, sodium perrhenate and acid.
  • Gelatin 0.9 to 6.9 mg; a thiosulfate of one of the metals of Group IA of the Periodic Table of the Elements, 2.15 to 8.6 mg; a perrhenate of one of the metals of Group IA of the Periodic Table of the Elements, 0.2 to 3 mg., all in 1 ml. of water, to which is added 4.5 ml. of 99m TcO solution of the desired activity and 2.0 cc. of 0.5 N to 5 N HCl. After heating the solution, the pH is adjusted to 4.0 4.5 and then 0.3 to 0.6 ml. of 25% glutaraldehyde is added before further heating and centrifuging.
  • the size of the macroaggregates could be controlled by time of heating. The longer the heating, the larger the individual aggregates become. For example, proper particles sizes, 5 to 30 microns in diameter, are formed at 17 minutes of heating. When heating is extended to 20 minutes, aggregates up to 100 microns are produced. These particles, however, are extremely fragile and break down into small particles (1 micron or less) upon shaking, washing and centrifugation. As noted, such particles would be unsuitable for lung scanning so that need for stabilization of the particles was apparent. The particle size must be large enough so that the particles are mechanically filtered by the lungs thus permitting definitive lung scanning by typical scintillation detection equipment and yet fragile enough so that they are gradually broken up and released.
  • the macroaggregates formed by the gelatin, sodium thiosulfate, sodium perrhenate and acid could be stabilized with a dialdehyde. It is believed that stabilization occurs because of a cross-linking between the gelatin molecules and the dialdehyde. Accordingly, when varying amounts of a dialdehyde such as pentanedial (glutaraldehyde) are added to the preformed particles and heated the particles become firm and of an appropriate size, 5 to microns in diameter, for lung scanning. It is believed that once the macroaggregates are formed the dialdehyde reacts with the amine groups of the gelatin-coated colloidal particles binding them together.
  • a dialdehyde such as pentanedial (glutaraldehyde)
  • a suitable composition for preparing a scanning agent containing approximately 1,000,000 particles per ml. is as follows: to 2.15 mg. of gelatin, 8.6 mg. of sodium thiosulfate, and 1.6 mg. of sodium perrhenate in 1 ml. of water is added 2 ml. of 0.5 N hydrochloric acid and 3.5 ml. of 99m TcO solution. After heating for 17 minutes at 100 C. the pH is adjusted to 4 with .4 M Na HPO Six-tenths of a ml. of 25% glutaraldehyde is added and the mixture is heated at 100 C.
  • a suitable dose for lung scanning is 2 ml. containing 2 to 3 me. of activity.
  • EXAMPLE 2 Bio half-life A study was conducted to determine if the injected particles would migrate from the lungs. Particles were prepared and labeled with 99m technetium in the manner described in Example 1 with the exception that the sus pension contained 8.6 mg. of sodium thiosulfate and 4.3 mg. of sodium perrhenate per ml. The 99m technetium was eluted from a generator with an 0.9% saline eluant and 0.6 ml. of glutaraldehyde was used. After the particles were prepared, each of 24, 150-250 gm. Sprage Dawly rats were injected intravenously with 3 to 4 mc. of the 99m technetium labeled particles.
  • EXAMPLE 3 Acute toxicity of the composition would be reflected by pulmonary distress or anaphylaxis. The acute effects from very large doses were studied in one 15 kg. mongrel dog by the following procedure.
  • the animal was anesthetized by intravenous injection of sodium pentathal at a dose of 15 mg./kg. of body weight.
  • a catheter was fluoroscopically placed in the right atrium via a right foreleg vessel and the catheter was attached to a manometer to measure the central venous pressure in centimeters of water.
  • Prior to injection of the particles the following parameters were measured: arterial blood gases, arterial blood pH, and central venous pressure.
  • An intravenous injection of 34 million particles was then achieved via the catheter and thereafter the above-described parameters were measured. Twenty minutes after the first injection an additional million particles were injected via the catheter obtaining the same data as previously noted. Forty-five minutes following the second injection an additional 104 million particles were injected and the same parameters observed. Lung scans of the injected activity were obtained to determine any perfusion defects created by the particle injections.
  • EXAMPLE 4 Visualization of pulmonary perfusion defects in dogs An 18 kg. mongrel dog was injected with 4 million particles labeled with 4.8 mc. of 99m technetium prepared in accordance with Example 1 and a lung scan performed. One week later an embolus measuring 6 mm. in width and 30 mm. in length was inserted via a cutdown of the right jugular vein. One hour later 2 million particles labeled with 99m technetium were injected and a lung scan was performed. Lung scans were repeated at 3, 9 and 16 days post injection of the embolus to observe the effectiveness of the agent to measure perfusion defects in the lung, to observe any toxic effects created by the particles in animals with comprised pulmonary perfusion, and to observe the appearance of any antigenic response to the particles.
  • Lactic dehydrogenase is an enzyme which catalyzes the reversible oxidation of lactic acid to pyruvic acid. This enzyme is found in high concentrations in the heart, liver and lung. Normal values for the LDH are those less than 270 units. Had either the LDH or SGOT values been elevated, it would have indicated that tissues in the heart, liver or lung were damaged following the injection of the particles. Such was not the case.
  • the blood count was obtained to measure the effect of the injected particles on the white cell count and the Hematacrit. If these parameters had varied following injection, it may have indicated that the particles had created some hematological problem. No significant change was observed.
  • Premjection 9 500 10. 2 31 Adequate- 22 7. 41 45 49 2. 23 Infilgrate interior segment 01 right lower 1; mgpmm. 7. 41 63 4s 2. 24 hours-.- 14 1 4 days 10,600 10.6 35 16 123 No change.
  • the chest roentgenogram was considered a valuable method of observing the lung field for changes created by the injected particles. Allroentgenograms on these 10 subjects indicated no change in the heart size, no distention of pulmonary vessels, no apparent increase in fibrous tissue, and no new infitrates indicating infarction
  • the glutamic oxaloacetic transaminase (SGOT) is an 75 or obstruction of pulmonary vasculature
  • the blood gases were obtained to measure the ability of the lung to exchange atmospheric gases with the blood. Had either the pCO increased or p decreased, it would have indicated that the injected particles had influenced this process. Only one individual demonstrated a decrease in p0 after injection. This was explained by the fact that a venous arterial mixture of blood was obtained due to a technical problem.
  • a typical scintiphoto obtained in the study demonstrated the anterior-posterior (AP) view of the lung field.
  • the activity was homogeneously distributed throughout the lung field with the exception of the decreased uptake in a wedge-shaped area of the left lower lobe. This area is normally of lower activity due to the displacement of lung tissue by heart.
  • This scintiphoto was taken with the subject in an upright position and took only 71 seconds to complete, thus reducing the time per view by a factor of 20 when compared to the rectilinear scans utilizing Iodine-131 macroaggregated albumin.
  • a second scintiphoto of the same subject 29.5 hours post inpection indicated a large quantity of the injected dose had migrated to the liver.
  • a radiopharmaceutical lung scanning preparation comprising macroaggregates of 99m technetium and sulfur stabilized in a suspension containing perrhenates gelatin and a dialdehyde of from two to eight carbon atoms, said macroaggregates having a particle size of at least microns and less than 100 microns.
  • dialdehyde is selected from the group consisting of ethanedial, pentanedial, hexanedial and octanedial.
  • dialdehyde is selected from the group consisting of ethanedial and pentanedial.
  • a radiopharmaceutical lung scanning preparation comprising macroaggregates formed from a composition comprising 0.9 to 6.9 milligrams of gelatin, 2.15 to 8.6 milligrams of sodium thiosulfate and 0.2 to 3.0 milligrams of sodium perrhenate, all in one milliliter of water and in the presence of an acid, said macroaggregates being labeled with 99m technetium and having a particle size larger than 5 microns and formed and stabilized in a suspension containing a dialdehyde of from two to eight carbon atoms.
  • the method of preparing a stable radiopharmaceutical lung scanning preparation comprising the steps of: adding to one milliliter of water, 4.5 ml. of 99m TcO solution of a predetermined activity, 0.9 to 6.9 milligrams of gelatin, 2.15 to 8.6 milligrams of a thiosulfate of a metal selected from a group consisting of the metals of Group IA of the Period Table of the Elements, and 0.2 to 3.0 milligrams of a perrhenate of a metal selected from the group consisting of the metals of Group IA of the Periodic Table of the Elements, in the presence of an acid;
  • dialdehyde is selected from the group consisting of ethanedial and pentanedial.

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US00039857A 1970-05-20 1970-05-20 Lung scanning 99m technetium macroaggregate and method of preparation Expired - Lifetime US3810976A (en)

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US00039857A US3810976A (en) 1970-05-20 1970-05-20 Lung scanning 99m technetium macroaggregate and method of preparation
CA111,475A CA949882A (en) 1970-05-20 1971-04-27 Lung scanning agent and method
GB1196071*[A GB1303761A (enrdf_load_stackoverflow) 1970-05-20 1971-04-28
DE19712125012 DE2125012A1 (de) 1970-05-20 1971-05-19 Lungenabtastmittel und -verfahren

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Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4048296A (en) * 1975-05-27 1977-09-13 Mallinckrodt, Inc. Radiopharmaceutical scanning agents
US4062933A (en) * 1975-05-27 1977-12-13 Mallinckrodt, Inc. Colloidal compositions with protective agents suitable for radioactive labeling
US4406876A (en) * 1980-10-14 1983-09-27 Research Foundation Of The State Univ. Of New York Sulfur free small-particle production of technetium sulfur colloid
WO2000057924A3 (en) * 1999-03-26 2001-03-22 London Health Sciences Ct Colloid for scintigraphy
US6706251B1 (en) 1999-03-26 2004-03-16 London Health Sciences Centre Colloid for scintigraphy
WO2004091581A1 (de) * 2003-04-16 2004-10-28 Boehringer Ingelheim International Gmbh Radioaktiv markierte mikropartikel, verfahren zu deren herstellung und deren verwendung
US20050181758A1 (en) * 2004-02-13 2005-08-18 Nokia Corporation Generating charging information in a communication system

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4048296A (en) * 1975-05-27 1977-09-13 Mallinckrodt, Inc. Radiopharmaceutical scanning agents
US4062933A (en) * 1975-05-27 1977-12-13 Mallinckrodt, Inc. Colloidal compositions with protective agents suitable for radioactive labeling
US4406876A (en) * 1980-10-14 1983-09-27 Research Foundation Of The State Univ. Of New York Sulfur free small-particle production of technetium sulfur colloid
WO2000057924A3 (en) * 1999-03-26 2001-03-22 London Health Sciences Ct Colloid for scintigraphy
US6706251B1 (en) 1999-03-26 2004-03-16 London Health Sciences Centre Colloid for scintigraphy
WO2004091581A1 (de) * 2003-04-16 2004-10-28 Boehringer Ingelheim International Gmbh Radioaktiv markierte mikropartikel, verfahren zu deren herstellung und deren verwendung
US20100272638A1 (en) * 2003-04-16 2010-10-28 Boehringer Ingelheim International Gmbh Radiolabelled microparticles, processes for the preparation thereof and the use thereof
EP2338479A1 (de) * 2003-04-16 2011-06-29 Boehringer Ingelheim Pharma GmbH & Co. KG Radioaktiv markierte Mikropartikel, Verfahren zu deren Herstellung und deren Verwendung
US20050181758A1 (en) * 2004-02-13 2005-08-18 Nokia Corporation Generating charging information in a communication system

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DE2125012A1 (de) 1971-12-02
CA949882A (en) 1974-06-25
GB1303761A (enrdf_load_stackoverflow) 1973-01-17

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