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Biomedical subjects

D D Patton

Publications and source records attributed to D D Patton.

At least 19 recordsLinked to original sources
PubMed1992

Skin damage associated with the Norplant contraceptive.

Three cases of localized skin reaction in the first month after implantation of the Norplant contraceptive resulted in a partial implant expulsion and removal in one patient, and implant removal in another. Clinical evidence of infection was absent in all patients. While lidocaine with epinephrine was used in all three patients, the cause for these skin reactions remains unclear. Physicians should be alerted to the possibility of significant skin reactions associated with this procedure.

Adult↗
PubMed1990

A full-field modular gamma camera.

A modular gamma ray camera is described that gives useful image information over its entire crystal face. The lack of dead area on the periphery of the camera is made possible by a unique application of digital electronics and optimal position estimation using maximum likelihood (ML) estimates. The ML estimates are calculated directly from photomultiplier tube responses and stored in a lookup table, so the restriction of calculating the position estimates in separate circuitry is removed. Each module is designed to be optically and electronically independent, so that many modules can be combined in a large system. Results from a prototypical module, which has an active crystal area of 10 cm X 10 cm, are presented.

Equipment Design↗
PubMed1989

A utility-based model for comparing the cost-effectiveness of diagnostic studies.

The effective cost of a diagnostic test is the money spent per unit of diagnostic performance. The latter can be measured as diagnostic utility (DU), the probability-weighted sum of the utilities of the four test outcomes TP, TN, FP, and FN: DU = U(TP)P(TP) + U(TN)P(TN) + U(FP)P(FP) + U(FN)P(FN). DU (which also is called expected utility) incorporates the clinical decision analytic variables sensitivity (Se), specificity (Sp), equivocal fraction (EF), disease probability (P(D)), and outcome utility (U). DU is not an inherent property of a diagnostic test but of test-observer interactions in a clinical setting. The model sets the effective cost (EC) of a diagnostic test = actual direct cost (ADC)/DU. When DU = 1 (perfect test) EC = ADC and the patient benefits from the test dollar for dollar. When DU less than 1, EC exceeds ADC. If DU approaches O, EC becomes infinite; the test has no effectiveness at any cost. DU depends strongly on P(D) if Se and Sp differ significantly; then EC also depends on P(D), and the effective cost of a test performed in the wrong P(D) setting may be several times its actual direct cost. This model of comparing effective costs compares actual direct cost with clinical measures of test performance and utility values that allow expression of patient/doctor fears and preferences. It offers a more clinically realistic setting than models based on costs alone.

Cost-Benefit Analysis↗
PubMed1979

Cobalt-57 bleomycin for imaging head and neck tumors.

Cobalt-57 bleomycin imaging was performed in 11 patients with a history of head and neck cancer. Clinical and scan findings concurred on the presence and extent of tumor in 9 patients (82%); tumor was present in 7 and absent in 2 of the 9. In 2 patients (18%) the scan demonstrated tumor in the neck but failed to show metastatic sites. Cobalt-57 bleomycin images were of good technical quality, with remarkably low background activity at 24 hours after administration. Cobalt-57 bleomycin imaging appears to be a promising technique for evaluating patients with head and neck tumors.

Adult↗
PubMed1979

Radioiodine in the treatment of medullary carcinoma of the thyroid.

Medullary carcinoma (MC) of the thyroid, in contrast to papillary-follicular carcinoma, fails to concentrate iodine and thus has not been treated with radioactive iodine. We have successfully treated a 16-yr-old Mexican-American girl with residual MC after maximal thyroidectomy (Tx), utilizing radioiodine (131I) to deliver radiation to residual follicular cells in the tumor bed. Immediately after Tx, plasma thyrocalcitonin levels before and during calcium infusion were all elevated (640--1200 pg/ml). 131I (150 mCi) was administered 12 days after Tx after four daily im injections of bovine TSH. Three months after 131I therapy, thyrocalcitonin levels before and during calcium infusion were all normal (less than 50 pg/ml). Ten months after 131I therapy, thyrocalcitonin levels before and after iv pentagastrin were all normal (less than 60 pg/ml). These results suggest that parafollicular cells are radiosensitive, and that therapeutic levels of radiation can be delivered to these cells after Tx if iodine trapping by the remaining follicular cells is enhanced by high levels of circulating TSH. 131I may be the therapy of choice for MC after Tx, if disease has not spread beyond the area proximate to the thyroid gland.

Adolescent↗
PubMed1978

Introduction to clinical decision making.

In the last few years there has been a remarkable increase in the amount of clinical data in the average hospital chart, and more and more problem-solving algorithms have been developed. We need better "thinking tools" to help us handle the flow of information. The term "clinical decision making" is used to describe a systematic way to handle data and algorithms to decide on a best course of action. This introductory article discusses some of the problems in establishing a decision criterion, both for a population and for an individual patient. Comparing the probabilities and utilities of various diagnostic outcomes (true positive, false positive, etc.) leads to a diagnostic strategy. The article also discusses conditional probability. Bayes' theorem, and likelihood ratios.

Bayes Theorem↗
PubMed1977

Radionuclide bone scanning in diseases of the spine.

Radionuclide bone scans provide a sensitive, no-risk diagnostic technique for the detection and evaluation of a wide variety of diseases of the spine. Scans and radiographs provide complementary diagnostic information, and should both be considered in the medical imaging portion of the diagnostic plan.

Arthritis↗
PubMed1977

Detection of bronchopleural-subarachnoid fistula by radionuclide myelography: case report.

Radionuclide myeloscintigraphy has previously been used to demonstrate subarachnoid fistulae. In the present case a patient with bronchogenic carcinoma developed spontaneous pneumocephalus postoperatively. Chest radiographs showed an air-fluid level in the postoperative area. Various diagnostic tests were used, but only a radionuclide myeloscintigram showed the presence of a bronchopleural-subarachnoid fistula.

Adult↗
PubMed1976

Liver-lung scan in the diagnosis of right subphrenic abscess.

To assess the value of liver-lung scanning in the diagnosis of right subphrenic abscess, 148 scans were reviewed against corresponding charts. Of 91 scans with adequate clinical data, overall scanning error was 19.3% with 14 false positive and 3 false negative scans. Among 49 scans (of the initial group of 91 studies) with presence or absence of actual pathology proved by surgery and/or autopsy, there were 3 true positive, 12 false positive, 29 true negative, and 3 false negative scans. Analysis of data indicated (1) lower accuracy of scan interpretations than generally reported, (2) low specificity for positive scans and high specificity for negative scans, (3) correlations of false interpretations with atypical degrees of liver-lung separation and with scanning defects in liver and lung, and (4) failure of rereading significantly to improve accuracy of interpretation.

Angiography↗
PubMed1976

Bone scans of the facial bones: normal anatomy.

Some features of facial anatomy have been identified on 99mTc polyphosphate bone scans by a comparison of scans, radiographs, and photographs. 99mTc polyphosphate bone scans are used clinically to show bone injury and increased osteoblastic activity; the primary use is to identify malignancy and other diseases involving bone. A knowledge of normal anatomy is of the utmost importance in the accurate interpretation of bone scans of the face.

Facial Bones↗
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↗