Biomedical subjects

Vernon Smith

Publications and source records attributed to Vernon Smith.

4 recordsLinked to original sources

PubMed2003

Combinatorial auction design.

Combinatorial auctions allow for more expressive bidding in which participants can submit package bids with logical constraints that limit allowable outcomes. This type of auction can be useful when participants' values are complementary or when participants have production and financial constraints. However, combinatorial auctions are currently rare in practice. The main problems confronted in implementing these auctions are that they have computational uncertainty (i.e., there is no guarantee that the winning bids for such an auction can be found in a "reasonable" amount of time when the number of bidders and items becomes larger) and that the auction is cognitively complex and can lead participants to pursue perverse bidding strategies. This article describes a type of combinatorial auction that, during laboratory testing, eliminated these problems and produced extremely efficient outcomes.

Journal Article↗

PubMed2003

Comparison of intensity-modulated radiosurgery with gamma knife radiosurgery for challenging skull base lesions.

PURPOSE: To quantitatively compare intensity-modulated radiosurgery (IMRS) using 3-mm mini-multileaf collimation with gamma knife radiosurgery (GKRS) plans for irregularly shaped skull base lesions in direct proximity to organs at risk (OAR). METHODS AND MATERIALS: Ten challenging skull base lesions originally treated with GKRS were selected for comparison with IMRS using inverse treatment planning and 3-mm mini-multileaf collimation operating in step-and-shoot delivery mode. The lesions ranged in volume from 1.6 to 32.2 cm(3) and were treated with 9-20 GK isocenters (mean 13.2). The IMRS plans were designed with the intent to, at minimum, match the GKRS plans with regard to OAR sparing and target coverage. For each case, IMRS plans were generated using 9 coplanar, 11 equally spaced noncoplanar, and 11 OAR-avoidant noncoplanar beams; the best of these approaches with respect to target conformality, sparing of OAR, and maintaining coverage was selected for comparison with the original GKRS plan. RESULTS: Assuming no patient motion or setup error, IMRS provided comparable target coverage and sparing of OAR and an improved conformity index at the prescription isodose contour but sometimes less conformity at lower isodose contours compared with the actual GKRS plan. All IMRS plans produced less target dose heterogeneity and shorter estimated treatment times compared with the GKRS plans. CONCLUSION: Compared with GKRS for complex skull base lesions, IMRS plans using a 3-mm mini-multileaf collimator achieved comparable or sometimes improved target coverage, conformity, and critical structure sparing with shorter estimated treatment times.

Brain Neoplasms↗

PubMed2002

Phase II study of high central dose Gamma Knife radiosurgery and marimastat in patients with recurrent malignant glioma.

PURPOSE: To assess the outcome of high central dose Gamma Knife radiosurgery plus marimastat in patients with recurrent malignant glioma. METHODS AND MATERIALS: Twenty-six patients with recurrent malignant glioma were enrolled in a prospective Phase II study between November 1996 and January 1999. The radiosurgery dose was prescribed at the 25-30% isodose surface to increase the dose substantially within the tumor's presumably hypoxic core. Marimastat was administered after radiosurgery to restrict regional tumor progression. Survival was compared with that of historical patients treated at our institution with standard radiosurgery. RESULTS: The median times to progression after radiosurgery for Grade 3 and 4 patients was 31 and 15 weeks, respectively. The corresponding median survival time after radiosurgery was 68 and 38 weeks. The median survival time after radiosurgery in the historical patients was 59 and 44 weeks. CONCLUSION: The dual strategies of using high central dose radiosurgery to overcome tumor hypoxia together with marimastat to inhibit local tumor invasion may offer a small survival advantage for recurrent Grade 3 tumors; they do not offer an advantage for recurrent Grade 4 tumors.

Adult↗

PubMed2002

Improving childhood asthma outcomes in the United States: a blueprint for policy action.

BACKGROUND/OBJECTIVE: Asthma is increasingly being recognized as an important public health concern for children in the United States. Effective management of childhood asthma may require not only improving guideline-based therapeutic interventions, but also addressing social and physical environmental risk factors. The objective of this project was to create a blueprint for improvement of national policy in this area. DESIGN/METHODS: A nominal group process with nationally recognized experts and leaders (referred to as "the committee") in childhood asthma. RESULTS: The committee identified 11 policy recommendations (numbered in order below) in 2 broad categories: Improving Health Care Delivery and Financing, and Strengthening the Public Health Infrastructure. Recommendations regarding Improving Health Care Delivery and Financing include the development and implementation of quality-of-care standards in 1) primary care, 2) self-management education, and 3) case-management interventions, and the expansion of insurance coverage and benefit design by 4) extending continuous health insurance coverage for all children, 5) developing model insurance benefits packages for essential childhood asthma services, and 6) educating health care purchasers in how to use them. Recommendations for Strengthening the Public Health Infrastructure include public funding of asthma services that fall outside the insurance system through establishing 7) public health grants to foster asthma-friendly communities and 8) school-based asthma initiatives. 9) Launching a national asthma public education campaign, 10) developing a national asthma surveillance system, and 11) establishing a national agenda for asthma prevention research, with an emphasis on epidemiologic and behavioral sciences, are also recommended. CONCLUSIONS: Implementing these recommendations will require coordination of activities at the national, state, and local community level, and within and outside the health care delivery system. With a further commitment of national and local resources, implementation of these recommendations will likely lead to improved child and family asthma outcomes in the United States. childhood asthma, health care policy, health care services.

Advisory Committees↗