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G F Gates

Publications and source records attributed to G F Gates.

At least 19 recordsLinked to original sources
PubMed1999

Consensus report on quality control of quantitative measurements of renal function obtained from the renogram: International Consensus Committee from the Scientific Committee of Radionuclides in Nephrourology.

Among all the physiological indices that can be quantified using renography, measurement of renal function is the most basic. These measurements are used to make critical clinical management decisions and, as such, their reliability needs to be quality assured. This article seeks to address each aspect of the renography procedure, with particular emphasis on the effect on measurement of relative renal function. Estimation of individual kidney function is mentioned, but only briefly. A consensus approach was adopted, overseen, and directed by a chairman appointed by the Scientific Committee of the International Radionuclides in Nephro-Urology Group. The chairman selected the panel of experts from eight different countries based on their practical experience in the field. Where evidence exists to support the various recommendations it is given. Otherwise, the stated guidance represents the considered opinion of a body of experts, based on long experience and unpublished data. Some necessary compromises were made to account for the fact that renography is seldom performed solely with the purpose of measuring relative renal function. The technicalities of renography have always been a source of debate in nuclear medicine, which is reflected by the fact that a consensus could simply not be reached on a small number of issues. The structure of the report ensures that these are clearly indicated. This should serve to highlight gaps in our current knowledge, thus helping to direct future research. It is envisaged that the recommendations will be revised on a 2-year cycle to ensure that they remain up to date. An "open" process will be used to encourage participation and ownership. It is hoped that promotion of these guidelines, suitably complemented by audit processes, will raise standards in the practice of gamma camera renography.

Adult↗
PubMed1999

Bone SPECT of the back after lumbar surgery.

PURPOSE: It may be difficult to evaluate back pain in patients who have undergone spinal surgery, because symptoms may be secondary to all the possible abnormalities in patients who have not had surgery plus postoperative complications, including infection, unstable fusion sites, or transfer of biomechanical stresses to other regions. MATERIALS AND METHODS: Sixty-three patients with back pain and a history of lumbar spinal surgery had bone SPECT examinations. Twenty-eight patients had laminectomies, 10 had laminectomies with fusion, 10 had laminectomies with fusion and metallic stabilization devices (3 of which were removed), 7 had fusion without laminectomy, 7 had discectomies, and 1 had a fusion with metallic stabilization but no laminectomy. Eighty-seven percent of the fusions were posterior. The results of SPECT scanning were correlated with surgery, clinical information, and diagnostic radiologic studies. RESULTS: Patients with fusions tended to be scanned further out from the time of surgery than were patients with laminectomy alone or especially discectomy. Bone SPECT excluded bony abnormalities in the operative site in 7 of 63 patients. One hundred thirty-two lesions were uncovered, with facet abnormalities (n = 51) the most common followed by disc space-centered conditions (n = 29), pseudarthrosis (n = 20), sacroiliac joint (n = 18), vertebral body lesions (n = 9), and miscellaneous sites (n = 5). Sixty percent of the abnormalities located in the facets, disc spaces, and vertebral bodies were located in the operative field, whereas 29% were above and 11% were below it. CONCLUSION: Bone SPECT was useful in evaluating these patients to exclude bony lesions or to identify pseudarthrosis, abnormal facets, disc space-centered lesions, and sacroilitis.

Adult↗
PubMed1998

SPECT bone scanning of the spine.

Radionuclide bone scanning is a well accepted method for uncovering a variety of bony lesions including abnormalities of vertebral bodies that may be causing spinal pain. Single photon emission computed tomography (SPECT) is especially useful in such an evaluation because it allows for precise localization of a lesion to the vertebral body, disc space, or vertebral arch. This anatomic distinction is necessary in order to accurately diagnose the underlying condition detected by the bone scan. Most bony abnormalities result in focal areas of abnormal tracer activity but do not affect all components of a vertebra with equal frequency nor have a random pattern of involvement. Vertebral diseases tend to conform to predictable patterns that can be more readily identified by SPECT than planar imaging. Metastatic tumors commonly involve the posterior portion of the vertebral body, often in combination with a pedicle. Extensive abnormalities involving the vertebral body and vertebral arch, but sparing the pedicles, are usually benign as are lesions isolated to articular facets and lamina or disc space. Postoperative patients have additional potential problems including pseudarthrosis and complications following use of internal fixation devices including pedicle screws. Nuclear medicine physicians must speak the language of their referring physicians who are anatomically oriented and used to the exquisite morphologic detail of computed tomography (CT) and magnetic resonance imaging (MRI). SPECT allows for greater anatomic information compared with planar imaging as well as straightforward comparison with other tomographic-based studies such as CT and MRI.

Humans↗
PubMed1996

Oblique angle bone SPECT imaging of the lumbar spine, pelvis, and hips. An anatomic study.

Bone SPECT offers advantages over planar imaging in detecting skeletal lesions because of increased contrast enhancement and tomographic effect with the latter, allowing for precise anatomic localization of an uncovered abnormality. However, tomographic sections of curved structures or regions obliquely oriented to the reconstruction plane may have inherent limitations as far as case of image interpretation, which can be overcome by oblique reorientation of the SPECT views. A method for oblique angle presentation of the lumbar spine, pelvis, and hips has been developed with results correlated with radiographic tomograms of a phantom to order to ensure correct anatomic orientation. These oblique SPECT images allow for easier differentiation between facet and pars interarticularis abnormalities, as well as improved imaging of hips and sacrum.

Contrast Media↗
PubMed1996

Bone SPECT imaging of the painful back.

Bone SPECT imaging offers advantages over planar techniques based on improved contrast enhancement plus tomographic effect, with the latter allowing for precise anatomic localization of an abnormality. This is important when evaluating patients with back pain because placement of a lesion in the vertebral body, component of the vertebral arch, or disc space region significantly affects diagnostic possibilities and, in some circumstances, can effectively exclude malignancy in favor of benign disease. Such an approach to SPECT interpretation requires high-quality images capable of precise anatomic placement of a lesion and a systematic method of analysis based on recognition of normal anatomic relationships plus knowledge of the common presentations of bony abnormalities shown on SPECT scanning.

Back Pain↗
PubMed1995

SPECT reveals causes of painful lumbar spine.

SPECT greatly enhances the utility of radionuclide bone scanning and is superior to planar techniques in many instances. Its unique ability to localize sites of increased metabolic activity to specific anatomic sites is a significant advance in clinical science, with meaningful applications to daily patient care.

Adolescent↗
PubMed1991

A dose-attenuation shield for use in glomerular filtration rate computations. A method for combined renal scintiangiography and functional quantification.

Renal perfusion and function can be determined by renography using Tc-99m DTPA. However, the high dose of tracer necessary for scintiangiography may result in inaccurate syringe-count determinations when measured by the gamma camera necessary for calculating the glomerular filtration rate by a camera technique. This report describes a syringe shield, constructed at minimal cost, which allows for suitable count attenuation and use of high doses of tracer for assessment of both renal perfusion and function.

Adult↗
PubMed1988

Normal anatomy of the lumbosacral spine and pelvis. A correlation of SPECT and radiographic techniques.

SPECT of the lumbosacral spine and pelvis is an advancement over planar imaging, which allows for improved lesion detection and more precise anatomic localization of an abnormality. Recognition of skeletal anatomy shown by SPECT is paramount for diagnostic accuracy as well as for meaningful consultations with referring physicians and diagnostic radiologists. This is a correlative study of normal anatomy of the lumbosacral spine and pelvis demonstrated by SPECT and radiography in order to assure that morphologic detail resulting from SPECT is recognized and matched with radiographic landmarks in the same area.

Humans↗
PubMed1988

SPECT imaging of the lumbosacral spine and pelvis.

This is a prospective comparison of SPECT versus planar imaging of the lumbosacral spine and pelvis, performed in order to assess which technique was more useful in clinical practice. One hundred adults were studied with both techniques, and abnormalities uncovered by either imaging method were graded 1-4 based on the lesion's relative uptake intensity. SPECT imaging significantly improved lesion detection, especially in conditions resulting in only low grade tracer uptake on planar studies. Precision in anatomic localization furthermore improved the quality and usefulness of diagnostic information resulting from SPECT imaging compared to planar examinations. SPECT is recommended for routine imaging of the lumbosacral spine and pelvis in symptomatic patients, especially when planar examinations are normal or equivocal.

Adolescent↗
PubMed1987

Diagnosis of malignant pericardial effusion during dynamic hepatic scintigraphy.

Three clinically unsuspected malignant pericardial effusions were discovered during routine dynamic hepatic scintigraphy. The only common clinical feature shared by the patients was dyspnea. Static scintigrams alone would not have detected these effusions, which points out again the importance of including dynamic scintigraphy in routine radionuclide evaluations of the liver.

Aged↗
PubMed1986

Bone marrow island vs focal infection. An indium-111 leukocyte imaging dilemma.

An island of bone marrow surrounded by the glue used in securing a hip prosthesis accumulated In-111 leukocytes in a patient being imaged for hip pain. This was shown to be normal marrow uptake of labeled cells and not an abscess by performing bone marrow imaging. The appearance of the leukocyte and bone marrow scans of the area were identical.

Abscess↗
PubMed1986

Splenic "disappearance" during gated exercise nuclear angiocardiography.

Decreasing splenic activity occurred during the maximum exercise phase of gated stress testing in 24 patients who underwent 26 such studies. This event was related to increasing exercise, and correlated with the relative increase in heart rate, pulse-pressure product, and cardiac output, but not ejection fraction. A multiple linear regression analysis showed that the combination of increases in pulse-pressure product and cardiac output had the best correlation with decreasing splenic activity at the conclusion of exercise. Redistribution of cardiac output toward muscle and away from splanchnic viscera is a consequence of exercise, and is graphically demonstrated by decreasing splenic visualization, which in some patients was so marked as to result in disappearance of the organ from the video monitor.

Adolescent↗
PubMed1985

Creatinine clearance estimation from serum creatinine values: an analysis of three mathematical models of glomerular function.

The logarithmic relationship of serum creatinine and creatinine clearance was analyzed in 100 adult patient studies using a geometric regression technique. Each sex was independently analyzed, and the subsequently derived regression formulae were age corrected resulting in mathematical models useful in estimating creatinine clearance from serum creatinine concentrations. These formulae were tested prospectively in another group of 100 patient studies in which creatinine clearance had been determined, and the results compared to values derived by use of two other published formulae. This newer method resulted in a closer distribution of data around a line of identity compared to other formulae and allowed for a good "bedside" estimation of creatinine clearance from serum creatinine concentration.

Adolescent↗
PubMed1984

Computation of glomerular filtration rate with Tc-99m DTPA: an in-house computer program.

The glomerular filtration rate (GFR) can be computed from the scintigraphic determination of Tc-99m DTPA (diethylenetriaminepentaacetic acid) uptake within the kidneys. The required computations are straightforward and can easily be included in the software of various computers, including a hospital's existing data-processing system. This report presents a complete operational program based on extensive experience with this method. The program is easy to use, allows for adjustments to be made for unusual clinical conditions, and produces a permanent record that can be issued as part of the final report.

Computers↗
PubMed1983

Transient reduction in renal function following arteriography: a radionuclide study.

The effects of iodinated contrast agents upon renal function were determined in 11 patients undergoing arteriography. Serial radionuclide renograms were performed to calculate the glomerular filtration rate, effective renal plasma flow and filtration fraction before and after arteriography. The effective renal plasma flow was the parameter most adversely affected. The magnitude of renal dysfunction depended upon the amount of contrast medium administered, as well as probably pre-existing renal disease and site of injection.

Adult↗
PubMed1983

Split renal function testing using Tc-99m DTPA. A rapid technique for determining differential glomerular filtration.

The fractional renal uptake of intravenously administered Tc-99m DTPA, within 2 to 3 minutes following radiotracer arrival in the kidneys, is proportional to the glomerular filtration rate (GFR). Thus it is possible to determine total, as well as individual kidney, GFR by a radionuclide technique which needs only six minutes of patient time and requires neither blood nor urine samples. The radionuclide computed GFR correlates extremely well with 24-hour creatinine clearance determinations, and is highly reproducible. This method has been used in nearly 500 split renal function determinations and has provided valuable, accurate information.

Adolescent↗