The dual photopeak-area method applied to scintillation camera measurements of effective depth and activity of in vivo 123I-distributions

1977 ◽  
Vol 2 (2) ◽  
Author(s):  
Sven-Erik Strand ◽  
BertilR.R. Persson
Keyword(s):  
Scintillation Camera ◽  
Area Method ◽  
Photopeak Area ◽  
Effective Depth

Hemophilic Bledding Evaluated by Blood Pool Scanning

1981 ◽  
Vol 45 (03) ◽  
pp. 208-210 ◽  
Author(s):  
D Green ◽  
S M Spies ◽  
N A Rana ◽  
J W Milgram ◽  
R Mintzer
Keyword(s):  
Blood Volume ◽  
Blood Pool ◽  
Invasive Technique ◽  
Scintillation Camera ◽  
Knee Prostheses ◽  
Hemophilic Patient ◽  
Chronic Arthropathy ◽  
Image Density ◽  
Regional Blood Volume

SummaryThe technique of blood pool scanning was used to examine 15 hemophilic subjects. Employing an in vivo method for erythrocyte labeling with Technetium-99 m, a dynamic perfusion sequence is obtained using a scintillation camera positioned over the area to be examined. This demonstrates the vascularity of the tissue. Subsequently, equilibrium blood pool images of the area are obtained and analyzed with a densitometer to assess relative regional blood volume. In patients who were not bleeding but had chronic arthropathy, vascularity was not increased, and the blood volume of comparable joints was similar. By contrast, marked increases in vascularity and image density were observed in studies of acutely bleeding joints. Chronic hemarthroses were associated with persistent, but less marked increases in joint perfusion. Transient increases in joint vascularity were demonstrated after insertion of knee prostheses. In a patient with a thigh hematoma, the dimensions of the hemorrhage were clearly delineated. Since only a tracer dose of nuclide is infused intravenously, there are no allergic reactions or other side effects of the procedure. Blood pool scanning is a safe, non-invasive technique that augments clinical and radiographic evaluations, and provides a new dimension in the assessment of the hemophilic patient.

In Vivo Thromboscintigraphy With Indium-111-Labeled Platelets In A Dog-Catheter Model

1981 ◽  
Author(s):  
D C Price ◽  
M J Lipton ◽  
J A Hartmeyer ◽  
R J Prager
Keyword(s):  
Carotid Artery ◽  
Computer Processing ◽  
Catheter Insertion ◽  
Scintillation Camera ◽  
Data Points ◽  
Indium 111 ◽  
Quantitative Uptake

Autologous platelets from mongrel dogs have been labeled with 200-400 μCi Indium-111 complexed to oxine using the technique of Thakur, McAfee and others. Intraarterial thrombogenesis was studied in vivo by advancing a polyethylene angiographic catheter from a femoral into a carotid artery, then serially imaging the catheter over periods of 0.5-3 hours by scintillation camera with interfaced computer. Quantitative uptake was derived from computer processing of the studies, and compared with in vitro In-111 counts and clot weight obtained at various times by catheter excision. Labeled platelets were injected prior to or at periods of 2 or 24 hours after catheter insertion in order to evaluate both forming and preformed thrombus. Platelet In-111 radioactivity was found to peak at 30-80 minutes in newly forming thrombus and to fall thereafter. In vitro In-111 activity correlated well with wet clot weight.In-111 (% inj. dose) = 0.00209 × (mgm clot) + 0.00091 (r = 0.882) (n = 24)In vivo correlation was also linear, but with a broader scatter of data points. At the peak, In-111 uptake was 0.06044). 019% of i.d. per cm of catheter by in vitro measurement, and clot weight was 27.9±5.6 mgm per cm. Preformed thrombus picked up substantially less of the label (2 hr: 0.017±0.011% i.d./cm; 24 hr: 0.00245).001% i.d./cm) (n=6) and was not imageable in vivo. The study documents the effectiveness of this new platelet radiolabel for quantitative in vivo scintigraphy of newly forming thrombus, which can be useful for comparison of different anti-thrombogenic regimens and different biomaterials. It also indicates, however, the problems that can be anticipated in attempting to image established thrombus in vivo.

scholarly journals Platelet turnover and kinetics in immune thrombocytopenic purpura: results with autologous 111In-labeled platelets and homologous 51Cr- labeled platelets differ

Blood ◽  
1986 ◽  
Vol 67 (1) ◽  
pp. 86-92 ◽  
Author(s):  
P Heyns A du ◽  
PN Badenhorst ◽  
MG Lotter ◽  
H Pieters ◽  
P Wessels ◽  
...  
Keyword(s):  
Immune Thrombocytopenic Purpura ◽  
Severe Disease ◽  
Reticuloendothelial System ◽  
Computer Assisted ◽  
Scintillation Camera ◽  
Antiplatelet Antibody ◽  
Thrombocytopenic Purpura ◽  
Computer Assisted Image ◽  
The Difference

Abstract Mean platelet survival and turnover were simultaneously determined with autologous 111In-labeled platelets (111In-AP) and homologous 51Cr- labeled platelets (51Cr-HP) in ten patients with chronic immune thrombocytopenic purpura (ITP). In vivo redistribution of the 111In-AP was quantitated with a scintillation camera and computer-assisted image analysis. The patients were divided into two groups: those with splenic platelet sequestration (spleen-liver 111In activity ratio greater than 1.4), and those with diffuse sequestration in the reticuloendothelial system. The latter patients had more severe ITP reflected by pronounced thrombocytopenia, decreased platelet turnover, and prominent early hepatic platelet sequestration. Mean platelet life span estimated with 51Cr-HP was consistently shorter than that of 111In-AP. Platelet turnover determined with 51Cr-HP was thus over-estimated. The difference in results with the two isotope labels was apparently due to greater in vivo elution of 51Cr. Although the limitations of the techniques should be taken into account, these findings indicate that platelet turnover is not always normal or increased in ITP, but is low in severe disease. We suggest that this may be ascribed to damage to megakaryocytes by antiplatelet antibody. The physical characteristics in 111In clearly make this radionuclide superior to 51Cr for the study of platelet kinetics in ITP.

Kinetics and in Vivo Redistribution of 111Indium-Labelled Human Platelets after Intravenous Protamine Sulphate

1980 ◽  
Vol 44 (02) ◽  
pp. 065-068 ◽  
Author(s):  
A duP Heyns ◽  
M G Lötter ◽  
P N Badenhorst ◽  
H Kotze ◽  
F C Killian ◽  
...  
Keyword(s):  
Imaging System ◽  
Human Platelets ◽  
Computer Assisted ◽  
Scintillation Camera ◽  
Protamine Sulphate ◽  
Normal Volunteers ◽  
Activated Platelets ◽  
Platelet Survival ◽  
Platelet Aggregates

SummaryThe pathogenesis of thrombocytopenia induced by intravenous protamine sulphate was studied in six patients who underwent cardiopulmonary bypass surgery, and in three normal volunteers. Autologous platelets were labelled with 111Indium-oxine. Platelet lifespan was determined. In vivo 111In-platelet localization, organ redistribution and sites of destruction were quantitated with a scintillation camera and a computer-assisted imaging system. Protamine induced a transient thrombocytopenia, maximal 5-10 min after injection, and 30-40 min in duration. The thrombocytopenia was accompanied by a transient accumulation of platelets in the liver. The splenic platelet pool remained unaltered and no platelets accumulated in the lungs. Platelet survival, measured in two volunteers, was slightly longer than normal and fitted a linear function best. There was a severe transient neutropenia during the period of thrombocytopenia. We conclude that protamineinduced thrombocytopenia is caused by hepatic accumulation of "activated" platelets or platelet aggregates, the process is reversible, and in the two normal volunteers studied, platelet survival was not affected.

In Vivo Inhibition of Acute Platelet-Dependent Thrombosis in a Baboon Model by BAY U3405, a Thromboxane A2-Receptor Antagonist

1993 ◽  
Vol 70 (04) ◽  
pp. 672-675 ◽  
Author(s):  
H F Kotzé ◽  
S Lamprecht ◽  
P N Badenhorst ◽  
V van Wyk ◽  
J P Roodt ◽  
...  
Keyword(s):  
Platelet Aggregation ◽  
Receptor Antagonist ◽  
Ex Vivo ◽  
Thrombus Formation ◽  
Thromboxane A2 ◽  
Arterial Blood Flow ◽  
Scintillation Camera ◽  
Graft Material ◽  
Txa2 Receptor

SummaryBay U3405 is a thromboxane A2 (TxA2)-receptor antagonist that inhibits the binding of TxA2 to its target cells. The aim of this study was to determine if Bay U3405 could be used to inhibit arterial thrombosis. A thrombogenic de vice, consisting of uncrimped Dacron vascular graft material (0.5 cm2) built into the wall of silicone rubber tubing with 4 mm inside diameter, was exposed to native flowing blood under arterial blood flow conditions (100-140 ml/min) by interposing the devices as extension segments into permanent femoral arteriovenous shunts implanted in baboons. Thrombus formation was quantified in vivo by measuring the deposition of 111In-labelled platelets onto the graft material with a scintillation camera. In six baboons, a bolus injection of Bay U3405, calculated to attain an initial plasma concentration of 300 ng/ml, reduced the maximum thrombus formation measured over a 2 h study period. Platelet deposition was reduced by 33 ± 14% (SD) at 2 h as compared to control studies done in the same baboons. The accumulation of additional platelets onto a thrombus that was allowed to form for 1 h, was reduced by 58 ± 28% at 2 h. Ex vivo platelet aggregation in response to ADP, activated partial thromboplastin time (APTT), prothrombin time (PT), and thrombin time (TT) were not affected by the treatment. Ex vivo platelet aggregation in response to collagen was markedly inhibited for 2 h after treatment. The results demonstrated that selective blocking of the TxA2-receptor on platelets reduced platelet-dependent thrombus formation and the accumulation of additional platelets in a freshly formed thrombus. This may provide a viable approach for preventing excessive thrombus formation in patients undergoing arterial reconstructive surgery.

scholarly journals Inhibition of platelet-dependent thrombus formation by human activated protein C in a primate model

Blood ◽  
1989 ◽  
Vol 73 (3) ◽  
pp. 639-642 ◽  
Author(s):  
A Gruber ◽  
JH Griffin ◽  
LA Harker ◽  
SR Hanson
Keyword(s):  
Protein C ◽  
Thrombus Formation ◽  
Activated Protein C ◽  
Graft Patency ◽  
Scintillation Camera ◽  
Primate Model ◽  
Baboon Model ◽  
Platelet Deposition ◽  
Antithrombotic Effects

The in vivo antithrombotic properties of human plasma activated protein C (APC), a natural anticoagulant enzyme, were investigated in a baboon model of thrombus formation on prosthetic vascular grafts. Infusion of 0.25 to 1.1 mg/kg/h purified, human, APC inhibited blood clotting, as measured by the activated partial thromboplastin time (APTT), and reduced vascular graft platelet deposition by 40% to 70%, as determined by the real-time scintillation camera imaging of 111In-labeled platelet deposition. APC infusion also preserved graft patency. Hemostatic plug formation remained normal, as measured by the template bleeding times. These results suggest that APC administration may produce immediate antithrombotic effects under arterial flow conditions.

The Influence of Cycle Length on the Radionuclide Left Ventricular Volume Curve Acquired with a Scintillation Camera and ECG-Triggered Data Processor

1983 ◽  
Vol 22 (03) ◽  
pp. 145-148
Author(s):  
A. L. van Gelder ◽  
Irene Dormehl
Keyword(s):  
Cycle Length ◽  
Left Ventricular ◽  
Left Ventricular Ejection ◽  
Scintillation Camera ◽  
Atrial Pacing ◽  
Ventricular Ejection Fraction ◽  
Volume Curve ◽  
Cycle Lengths ◽  
Data Processor

This study was designed to evaluate the effect of cycle length on the parameters of left ventricular function such as left ventricular ejection fraction (LVEF), ejection rates and ejection times. Radionuclide (in vivo 99mTc-labelled red blood cells) volume curves were obtained from ten chacma baboons. Transoesophageal atrial pacing of the baboon hearts was controlled by a microcomputer. A sequence of four beats was generated during arrhythmic pacing, consisting of two beats of equal cycle lengths, followed by a beat 15% shorter and a subsequent beat after a compensatory pause. Triggering impulses were sent to the data processor coincident with one of these beats until sufficient counts were obtained, before advancing to the next beat. Global LVEFs were found to be influenced by the preceding cycle length, increasing on a previous long cycle and decreasing on a previous short cycle and were even found to be influenced one normal beat on from the unrepresentative cycle. Similar trends were found for ejection times and rates. Discarding specific unrepresentative cycle lengths in order to correct for arrhythmia without attention to the previous cycle and even to the following cycle is therefore inappropriate.

Kinetics, Redistribution And Fate Of Indium-111-Labelled-Platelets In Patients With Aortic Aneurysms

1981 ◽  
Author(s):  
A duP Heyns ◽  
M G Lötter ◽  
P N Badenhorst ◽  
F de Kock ◽  
H Pieters ◽  
...  
Keyword(s):  
Imaging System ◽  
Reticuloendothelial System ◽  
Aortic Aneurysms ◽  
Whole Body ◽  
Computer Assisted ◽  
Scintillation Camera ◽  
Normal Limits ◽  
Geometrical Mean ◽  
Indium 111

Platelets of 7 patients with abdominal aortic aneurysms were labelled with In-lll-oxine prior to surgery. The platelets were reinjected with the patient positioned under a scintillation camera with a computer assisted imaging system. Images were acquisitioned daily, areas of interest selected with the computer, organ radioactivity- quantitated with a geometrical mean method and expressed as a percentage of whole body radioactivity. Platelet survival (PS) in the circulation was determined, and disappearance curves fitted to a gamma function “multiple hit” model.Mean PS was shorthened to 143,2 ± 47h (normal 232<17); the dissappearance curves were exponential in all but the two patients who had PS within normal limits. The surgically removed aneurysms were dissected and radioactivity of different layers measured. In-111-activity was confined to the superficial layers of the aneurysm.These techniques allow quantitative studies of the in vivo distribution of labelled platelets. Platelets are deposited in the aneurysms, this shortens PS, the disappearance curves become exponential, and the major sites of deposition of In-111-activity are in the liver and spleen. This indicates that although platelets are damaged and deposited in the aneurysm, the reticuloendothelial system remains a major site of platelet sequestration.

THE EFFECT OF INTRAVENOUS IMMUNOGLOBULIN ON PLATELET KINETICS IN CHRONIC IMMUNE THROMBOCYTOPAENIC PURPURA (ITP)

1987 ◽  
Author(s):  
P N Badenhorst ◽  
H F Kotze ◽  
A duP Heyns ◽  
M G Lotter ◽  
P Wessels ◽  
...  
Keyword(s):  
Intravenous Immunoglobulin ◽  
Kinetic Studies ◽  
Ivig Therapy ◽  
Reticuloendothelial System ◽  
Computer Assisted ◽  
Scintillation Camera ◽  
Significant Difference ◽  
Before And After ◽  
High Doses

Most patients with ITP respond to high doses of intravenous immunoglobulin (IVIg) with a transient increase in platelet count. The effect of IVIg on platelet kinetics was studied in 5 patients with chronic ITP. Autologous platelets were labelled with In-111 and mean platelet lifespan (MPLS) calculated; in vivo distribution and sites of platelet sequestration were determined with a scintillation camera and computer assisted image analysis. The studies were performed before and after treatment with 2 g/kg Sandoglobulin. Two groups of patients were identified: those with a splenic platelet sequestration pattern (spleen-liver In-111-activity ratio >1.4) and those with diffuse sequestration of platelets in the reticuloendothelial system (RES).There was a significant difference in mean platelet counts before and after treatment (p<0.05). Patients with a splenic sequestration pattern responded better to IVIg: the MPLS lengthened and the high spleen-liver ratio decreased. In the diffuse RES sequestration pattern group, IVIg had almost no effect on platelet kinetics. We conclude that platelet kinetic studies identify a subgroup of patients with ITP who will respond to IVIg therapy.

scholarly journals Estimation of absolute renal uptake with technetium-99m dimercaptosuccinic acid: direct comparison with the radioactivity of nephrectomy specimens

2008 ◽  
Vol 126 (3) ◽  
pp. 150-155 ◽  
Author(s):  
Mariana da Cunha Lopes de Lima ◽  
Celso Darío Ramos ◽  
Sérgio Quirino Brunetto ◽  
Marcelo Lopes de Lima ◽  
Ubirajara Ferreira ◽  
...  
Keyword(s):  
Reference Method ◽  
Reference Value ◽  
Dimercaptosuccinic Acid ◽  
Scintillation Camera ◽  
Renal Uptake ◽  
Technetium 99M ◽  
Dose Calibrator ◽  
Standard Design ◽  
Acid Chelate

CONTEXT AND OBJECTIVE: Studies using radionuclides are the most appropriate method for estimating renal function. Dimercaptosuccinic acid chelate labeled with technetium-99m (99mTc-DMSA) is the radiopharmaceutical of choice for high-resolution imaging of the renal cortex and estimation of the functional renal mass. The aim of this study was to evaluate a simplified method for determining the absolute renal uptake (ARU) of 99mTc-DMSA prior to nephrectomy, using the radioactivity counts of nephrectomy specimens as the gold standard. DESIGN AND SETTING: Prospective study at the Division of Nuclear Medicine, Department of Radiology, Universidade Estadual de Campinas. METHODS: Seventeen patients (12 females; range 22-82 years old; mean age 50.8 years old) underwent nephrectomy for various reasons. Renal scintigraphy was performed three to four hours after intravenous administration of a mean dose of 188.7 MBq (5.1 mCi) of 99mTc-DMSA, which was done six to 24 hours before surgery. The in vivo renal uptake of 99mTc-DMSA was determined using the radioactivity of the syringe before the injection (measured using a dose calibrator) and the images of the syringe and kidneys, obtained from a scintillation camera. After surgery, the reference value for renal uptake of 99mTc-DMSA was determined by measuring the radioactivity of the nephrectomy specimen using the same dose calibrator. RESULTS: The ARU measurements were very similar to those obtained using the reference method, as determined by linear regression (r-squared = 0.96). CONCLUSION: ARU estimation using the proposed method before nephrectomy seems to be accurate and feasible for routine use.

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