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Biomedical subjects

K Halverson

Publications and source records attributed to K Halverson.

15 recordsLinked to original sources

Reducing technology costs and risks in a managed care environment.

In the managed care environment, technology life-cycle management is necessary to minimize costs and maximize the quality of patient care. A careful approach to equipment acquisition and management can help managed care providers reduce the cost of delivering services while ensuring the right technology is available when and where it is needed to best serve patients. Proper management of technology assets from planning and budgeting through acquisition, usage and disposal can help managed care facilities reduce cost and risk, increase control, and improve productivity.

Capital Expenditures↗

Brachytherapy or electron beam boost in conservation therapy of carcinoma of the breast: a nonrandomized comparison.

PURPOSE: The results of breast-conservation therapy using breast irradiation and a boost to the tumor excision site with either electron beam or interstitial 192Ir implant are reviewed. METHODS AND MATERIALS: A total of 701 patients with histologically confirmed Stage T1 and T2 carcinoma of the breast were treated with wide local tumor excision or quadrantectomy and breast irradiation. The breast was treated with tangential fields using 4 or 6 MV photons to deliver 48 to 50 Gy in 1.8 to 2 Gy daily dose, in five weekly fractions. In 80 patients the regional lymphatics were irradiated. In 342 patients with Stage T1 and 107 with Stage T2 tumors, boost to the primary tumor excision site was delivered with 9 MeV and, more frequently, with 12 MeV electrons. In 91 patients with Stage T1 and 38 patients with Stage T2 tumors an interstitial 192Ir implant was performed. Tumor control, disease-free survival, cosmesis, and morbidity of therapy are reviewed. Minimum follow-up is 4 years (median 5.6 years; maximum, 24 years). RESULTS: The overall local tumor recurrence rates were 5% in the T1 and 11% in the T2 tumor groups. There was no significant difference in the breast relapse rate in patients treated with either electron beam or interstitial 192Ir boost. Regional lymph node recurrences were 1% in patients with T1 and 5% with T2 tumors. Distant metastases were recorded in 5% of the T1 and 23% of the T2 groups. The 10-year actuarial disease-free survival rates were 87% for patients with T1 and 75% with T2 tumors. Disease-free survival was exactly the same in patients receiving either electron beam or interstitial 192Ir boost. Cosmesis was rated as excellent/good in 84% of patients with T1 tumors treated with electron beam and 81% of patients treated with interstitial implant, and 74 and 79% respectively, in patients with T2 tumors. CONCLUSIONS: Breast-conservation therapy is an effective treatment for patients with T1 and T2 carcinoma of the breast. There is no difference in local tumor control, disease-free survival, cosmesis, or morbidity in patients treated with either electron beam or interstitial 192Ir implant boost. Clinical trials in progress will further elucidate this controversial subject.

Brachytherapy↗

Effect of antibody specificity on results of selected digoxin immunoassays among various clinical groups.

We examined the specificity of three automated digoxin immunoassays (Abbott TDxFLx Digoxin II assay, Baxter-Dade Stratus II Digoxin assay, and Ciba Corning ACS Digoxin assay) applied without modification to (a) sera from 229 digoxin-free patients in 12 cohorts associated with nonspecific or endogenous digoxin-like immunoreactive factor (DLIF) interference, and (b) drug-free serum supplemented with the major metabolites and analogs of digoxin. We observed three patterns of apparent digoxin results among the DLIF samples: one common to kidney and liver failure patients, where TDx and Stratus assays showed significant positive results; one common to newborns and cord blood, where only the TDx assay had significant interference; and one from cardiac surgery patients, where the Stratus assay alone showed interference. Of the three assays, the ACS had the least interference from DLIF. The assays also behaved differently with respect to cross-reactivity with digoxin metabolites, digitoxin, and digitoxin metabolites. The ACS assay again had the least analog or metabolite cross-reactivity. The three methods agreed well on digoxin-positive specimens, with a mean bias of <0.15 microgram/L digoxin for each and discrepancies (defined as >3 SD between the assay pairs compared) of only 3-5%.

Antibody Specificity↗

The cumulative verification image analysis tool for offline evaluation of portal images.

PURPOSE: Daily portal images acquired using electronic portal imaging devices contain important information about the setup variation of the individual patient. The data can be used to evaluate the treatment and to derive correction for the individual patient. The large volume of images also require software tools for efficient analysis. This article describes the approach of cumulative verification image analysis (CVIA) specifically designed as an offline tool to extract quantitative information from daily portal images. METHODS AND MATERIALS: The user interface, image and graphics display, and algorithms of the CVIA tool have been implemented in ANSCI C using the X Window graphics standards. The tool consists of three major components: (a) definition of treatment geometry and anatomical information; (b) registration of portal images with a reference image to determine setup variation; and (c) quantitative analysis of all setup variation measurements. The CVIA tool is not automated. User interaction is required and preferred. Successful alignment of anatomies on portal images at present remains mostly dependent on clinical judgment. Predefined templates of block shapes and anatomies are used for image registration to enhance efficiency, taking advantage of the fact that much of the tool's operation is repeated in the analysis of daily portal images. RESULTS: The CVIA tool is portable and has been implemented on workstations with different operating systems. Analysis of 20 sequential daily portal images can be completed in less than 1 h. The temporal information is used to characterize setup variation in terms of its systematic, random and time-dependent components. The cumulative information is used to derive block overlap isofrequency distributions (BOIDs), which quantify the effective coverage of the prescribed treatment area throughout the course of treatment. Finally, a set of software utilities is available to facilitate feedback of the information for treatment plan recalculation and to test various decision strategies for treatment adjustment. CONCLUSIONS: The CVIA tool provides comprehensive analysis of daily images acquired with electronic portal imaging devices. Its offline approach allows characterization of the nature of setup variation for the individual patient that would have been difficult to deduce using only a few daily or weekly portal images. Distribution of the tool will help establish an important database of setup variation from many clinics. The information derived from CVIA can also serve as the foundation to integrate treatment verification, treatment planning, and treatment delivery.

Computer Peripherals↗

Controlling technology costs as integrated networks expand.

The expansion of integrated healthcare networks is changing the way radiology technology should be acquired and maintained. Some significant effects are that utilization will decline with managed care; the radiology department is now a cost center, not a source of revenue; and integrated networks find themselves with redundant technology and excess radiology equipment. While hospitals shoulder additional financial risk associated with managed care, responsibility for finding solutions to new problems falls to the radiology administrator. Administrators can take the following steps to effectively reduce expense and risk: Understand current usage. Eliminate redundancies. Prioritize modalities. Find new financing opportunities. Lease equipment. Purchase reconditioned equipment. Redeploy assets instead of buying new. Radiology administrators who view these problems as a challenging puzzle will naturally explore creative options. They will provide the greatest flexibility and best position for their department's contributions to the hospital's overall strategic goals.

Capital Expenditures↗

Measurement of activities of daily living in hospitalized elderly: a comparison of self-report and performance-based methods.

OBJECTIVE: To determine the accuracy of self-reports of physical functioning by hospitalized elderly. DESIGN: Comparison of two measures. PATIENTS AND SETTING: Two-hundred forty-seven medical inpatients (mean age 78.7 years) hospitalized at St. Marys Hospital Medical Center, Madison, WI. MAIN OUTCOME MEASURES: Measures of five activities of daily living by self-report and by performance. RESULTS: The rate of agreement between self-report and performance ADL measures was the lowest in the areas of bathing and dressing where the agreement was 63% and 64%, respectively. When patients reported needing no help in these two tasks, they were measured lower 32% of the time for dressing and 42% for bathing. When patients reported needing help in an activity the agreement rate between patient and occupational therapist varied widely, from only 42% for toileting to 78% for bathing. The two factors which were statistically associated with poor agreement between the two ADL measurements were cognitive impairment (P less than 0.001) and a decline from the pre-hospital level of ADL functioning which had occurred during hospitalization (P less than 0.001). CONCLUSIONS: These data suggest that there may be significant differences between patient assessments and performance-based measurements of ADL functioning in hospitalized elderly at time of discharge. These differences may have implications for the collection of functional measurements for discharge planning or for geriatric research in the hospital environment.

Activities of Daily Living↗

The Yankton Model Program.

Changes in medical education towards a student-centered, problem-based learning, with continuity care experience in ambulatory settings have been recommended. The University of South Dakota School of Medicine has developed such an educational model for third year medical students named the Yankton Model Program and is herein described.

Curriculum↗

Molecular determinants of amyloid deposition in Alzheimer's disease: conformational studies of synthetic beta-protein fragments.

The amyloid beta-protein (1-42) is a major constituent of the abnormal extracellular amyloid plaque that characterizes the brains of victims of Alzheimer's disease. Two peptides, with sequences derived from the previously unexplored C-terminal region of the beta-protein, beta 26-33 (H2N-SNKGAIIG-CO2H) and beta 34-42 (H2N-LMVGGVVIA-CO2H), were synthesized and purified, and their solubility and conformational properties were analyzed. Peptide beta 26-33 was found to be freely soluble in water; however, peptide beta 34-42 was virtually insoluble in aqueous media, including 6 M guanidinium thiocyanate. The peptides formed assemblies having distinct fibrillar morphologies and different dimensions as observed by electron microscopy of negatively stained samples. X-ray diffraction revealed that the peptide conformation in the fibrils was cross-beta. A correlation between solubility and beta-structure formation was inferred from FTIR studies: beta 26-33, when dissolved in water, existed as a random coil, whereas the water-insoluble peptide beta 34-42 possessed antiparallel beta-sheet structure in the solid state. Solubilization of beta 34-42 in organic media resulted in the disappearance of beta-structure. These data suggest that the sequence 34-42, by virtue of its ability to form unusually stable beta-structure, is a major contributor to the insolubility of the beta-protein and may nucleate the formation of the fibrils that constitute amyloid plaque.

Alzheimer Disease↗

The unilateral pediatric inguinal hernia: Should the contralateral side by explored?

Development of herniography as a diagnostic tool has reopened the question of whether the asymptomatic groin should be explored at the time of unilateral herniorrhaphy in infants. In an attempt to provide data toward the formulation of an answer, the authors review 32 yr of experience with 160 infant hernias. They represent a sequential, unselected series of pediatric patients whose hernias were repaired only if confirmed by examination, and whose postoperative fate has been assessed over extended periods of time. Ninety-six percent of the group were able to be evaulated over an average follow-up interval of 20 yr. It was discovered that of the total group of children with hernias, 29% developed a hernia on the opposite side at some time in their lives. The chance of contralateral occurrence was found not to vary with the child's age at time of first repair, but was found to depend on which side the original repair involved; if the first repair was on the left, the child's chance of contralateral involvement was 41%; if on the right, the risk was only 14%. Morbidity was insignificant with the notable exception of testicular atrophy, which occurred in 2% of the group. The authors conclude that despite the 29% overall risk of future contralateral development, bilateral exploration is not justified for two reasons: First, that a number of unnecessary procedures would be performed, two operations to prevent each subsequent right-sided hernia, and six operations to preclude each later left-sided occurrence; Second, that the risk of bilateral testicular trauma, though slight, is too great.

Atrophy↗