Biomedical subjects

J A Patton

Publications and source records attributed to J A Patton.

60 records · Page 4Linked to original sources

PubMed1976

Differentiation between malignant and benign solitary thyroid nodules by fluorescent scanning.

A quantitative fluorescent technique has been developed for making in vivo iodine content determinations of the total thyroid gland or of selected parts. In solitary thyroid nodules "cold" to radionuclide studies, the ratio of iodine content in the nodule to that in a corresponding area of the contralateral lobe has proven to be a good indicator of malignancy. In a preliminary study of 42 surgical patients, an iodine content ratio (ICR) below 0.60 (chosen a posteriori) proved to be an excellent indication of malignancy with a sensitivity of 100%, a specificity (predictive value) of 79%, and an overall accuracy of 90%. Further definitive studies are needed to verify these preliminary observations.

Diagnosis, Differential↗

PubMed1975

Carcinoma of the thyroid with description of a new scanning technic.

A statistical analysis of 193 patients with thyroid carcinoma encountered at Vanderbilt University Hospital from 1925 to 1974 is reported, from which the following conclusions are drawn: (1) Papillary thyroid carcinoma is an extremely favorable lesion that when grossly limited to one thyroid lobe can usually be managed successfully by ipsolateral total lobectomy. (2) Cervical lymph node enlargement in patients with papillary carcinoma requires lymph node dissection. When feasible, the spinal accessory nerve should be preserved. (3) Failure to cure papillary and follicular thyroid carcinoma is influenced by advanced age, inadequate local extirpation, and unresectability of the carcinoma. (4) Prophylactic lymph node dissection is rarely indicated in the treatment of follicular carcinoma. A new isotope scanning procedure, developed at Vanderbilt University Hospital, promises to be helpful in preoperatively differentiating benign from malignant solitary thyroid nodules.

Adenocarcinoma↗

PubMedDate not supplied

Fluorine 18-labeled fluorodeoxyglucose myocardial single-photon emission computed tomography: an alternative for determining myocardial viability.

The identification of hibernating myocardium in patients with poor ventricular function has become increasingly important as investigators demonstrate an improvement in ventricular performance in patients with injured but viable myocardium who undergo surgical revascularization. Modifications of 201Tl redistribution protocols and rest/stress 99mTc-labeled hexakis-2-methoxy-2-methyl propylisonitrile perfusion studies continue to underestimate myocardial viability compared with resting 18F-labeled fluorodeoxyglucose (18FDG) positron emission tomography. The combined data from multiple investigators suggest that 18FDG single-photon emission computed tomography used in combination with cardiac perfusion agents, either sequentially or with simultaneous dual-isotope acquisition, may provide an acceptable alternative to positron emission tomographic imaging for the detection of hibernating myocardium.

Coronary Disease↗

PubMedDate not supplied

Radionuclide measurement of differential glomerular filtration rate.

The authors sought to determine whether radionuclides could provide a reasonable estimate of differential renal function in five normal dogs and six dogs with unilateral segmental renal infarction. Glomerular filtration rate (GFR) of each kidney was measured by the standard technique using constant infusions of 99mTc-DTPA, iothalamate, and creatinine following ureteral catheterization. These results were correlated with total GFR estimated by bolus injection of 99mTc-DTPA and analysis of the plasma 99mTc-DTPA disappearance curve obtained by blood sampling. Differential GFR was then calculated by multiplying the total GFR from double exponential analysis of this curve (DTPA2) by each of three measures of differential function. These include the percent differential uptake of 99mTc-DTPA and 99mTc-DMSA in the posterior projection as well as the geometric mean of 99mTc-DMSA uptake. There were good correlations between differential GFR calculated from iothalamate clearances obtained at ureteral catheterization and all noninvasive methods involving radionuclides and DTPA2 (r = 0.85 - 0.99). Single exponential analysis of the 99mTc-DTPA plasma disappearance curve was less satisfactory. The authors suggest that measurement of total and differential GFR calculated from plasma clearance of 99mTc-DTPA and external counting may be a useful method with potential clinical applications.

Animals↗

PubMedDate not supplied

Radionuclide measurement of differential glomerular filtration rate in urinary tract obstruction.

In a previous study using dogs whose renal function was rendered asymmetric by unilateral infarction, the efficacy of technetium-99m (99mTc) DTPA and DMSA in measuring differential glomerular filtration rate (GFR) was demonstrated. The present study was undertaken to determine whether the same techniques were applicable to unilateral ureteral obstruction. Five normal dogs and nine dogs with partial unilateral ureteral obstruction had determination of glomerular filtration rate by standard techniques using constant infusions of iothalamate and creatinine after ureteral catheterization. These results were compared with total GFR as measured by single injection of 99mTc DTPA and analysis of the plasma disappearance curve. Calculated differential GFR was obtained by multiplying total GFR from double exponential analysis of this curve (DTPA2) by each of three measures of differential function. These included the percent differential uptake of 99mTc DTPA and 99mTC DMSA in the posterior projection as well as the geometric mean of 99mTc DMSA uptake. There were good correlations between differential GFR determined by iothalamate clearances at ureteral catheterization and all noninvasive methods involving radionuclides and DTPA2 ( r = 0.93-0.99). Single exponential analysis of the 99mTc DTPA plasma disappearance curve was less satisfactory than double exponential analysis. These results and those reported previously support the use of radionuclides in the determination of differential GFR in a variety of clinical situations.

Animals↗

PubMedDate not supplied

Introduction to nuclear physics.

Photons for counting or imaging applications in nuclear medicine result from several processes. Gamma rays are produced from excited state transitions after beta decay and electron capture. Annihilation photons result from positron decay. The de-excitation of the atom after electron capture results in the production of characteristic x rays or Auger electrons. Metastable state transitions result in gamma ray emission or internal conversion electrons. All radiopharmaceuticals used in diagnostic nuclear medicine applications are tagged with radionuclides that emit photons as a result of one of these processes.

Curriculum↗