Source type estimation using noble gas samples.

A Bayesian source-term algorithm recently published by Eslinger et al. (2019) extended previous models by including the ability to discriminate between classes of releases such as nuclear explosions, nuclear power plants, or medical isotope production facilities when multiple isotopes are measured. Using 20 release cases from a synthetic data set previously published by Haas et al. (2017), algorithm performance was demonstrated on the transport scale (400-1000 km) associated with the radionuclide samplers in the International Monitoring System. Inclusion of multiple isotopes improves release location and release time estimates over analyses using only a single isotope. The ability to discriminate between classes of releases does not depend on the accuracy of the location or time of release estimates. For some combinations of isotopes, the ability to confidently discriminate between classes of releases requires only a few samples.

Waiting for a liver--hidden costs of the organ shortage.

Discussion about the economics of end-stage liver disease has typically focused on the high cost of liver transplantation, but the management of complications in patients waiting for an organ can also be very expensive. Our research considered the hypothesis that an increase in the number of organ grafts would decrease health care costs in patients with liver disease by eliminating the cost of waiting for an organ. We examined treatment costs for a consecutive series of liver transplant candidates listed at our institution between November 1, 1996 and December 31, 1997. Costs were estimated for inpatient stays, outpatient visits, and posttransplant medications for 2 1/2 years from the date of listing. Of the 58 study patients, 26 (45%) received transplants, 7 of whom died within 2 1/2 years. A total of 11 patients (19%) died while waiting for an organ, and another 21 patients (36%) were still waiting after 2 1/2 years. Pretransplantation costs accounted for 41% of the total cost. Transplanting all 58 candidates without delay through a hypothetical increase in the supply of organs to meet demand would have more than doubled the number of transplantations while increasing costs in this cohort by only 37% (from 123,000 dollars to 169,000 dollars per patient). In conclusion, although an adequate supply of donor organs would not decrease total health care spending for patients with end-stage liver disease, so much money is currently spent on medical management during the waiting period that the savings achieved by transplanting all candidates without delay would offset a large portion of the cost of the additional transplants.