A hands-on introduction to medical physics and radiation therapy for middle school students.

Lesson plans were developed to present concepts of medical physics and radiation therapy to a middle school audience. These workshop learning units relied on hands-on participation and collaboration within student groups to acquaint students with computed tomography simulation and treatment planning processes. These lesson plans were delivered at two different educational outreach programs targeted at student groups that have traditionally been underrepresented in science, technology, engineering, and mathematics (STEM) fields. The lesson plans are scheduled to be delivered at a third program in the future. The activities were used to introduce occupations in medical physics and radiation therapy as possible career opportunities for students, and to generate enthusiasm for continuing STEM education. Lesson plans are available upon request for educators interested in exploring medical physics educational outreach activities in their communities.

West Nile virus testing experience in 2007: evaluation of different criteria for triggering individual-donation nucleic acid testing.

BACKGROUND: In 2007, clients served by Blood Systems Laboratories used variable approaches for triggering West Nile virus (WNV) RNA individual-donation (ID) nucleic acid testing (NAT). These included two minipool (MP) NAT-reactive donations and a greater than 1:1000 rate in a 7-day interval (primary trigger), criteria based on one MP-NAT-reactive donation when there was WNV activity in overlapping and/or adjacent geographic areas (neighbor trigger), or zero MP-NAT-reactive donation (self-trigger). STUDY DESIGN AND METHODS: The Procleix WNV assay was used in either a 16-sample MP or an ID format. NAT-repeat reactivity or anti-immunoglobulin M (IgM) positivity defined true positives (TPs). TPs that were negative on 1:16 dilution testing were considered ID-NAT yield cases. RESULTS: WNV NAT performed on 1,217,929 donations identified 162 TPs; 87 were detected by MP (rate of 0.008%) and 75 by ID (rate of 0.10%; p < 0.0001). There were 34 ID-NAT yield cases, including 4 IgM/immunoglobulin G (IgG)-negative and 9 IgM-positive/IgG-negative donations. Rates of yield cases by primary, neighbor, and self-triggering were 0.077, 0.052, and 0.004% (p = 0.0003). None of 11 ID-NAT yield cases detected by the neighbor trigger would have been detected if the primary trigger had been used. CONCLUSIONS: Primary triggering criteria identified 21 viremic donations that would have been missed by MP testing; however, 11 other low-level viremic donations required more stringent criteria (e.g., neighbor trigger) for detection. It is reasonable to adopt more stringent ID-NAT triggers, including elimination of the rate criterion and triggering on one NAT-reactive donation for regions adjacent to centers which have already triggered.

Evaluation of a new Trypanosoma cruzi antibody assay for blood donor screening.

BACKGROUND: This multicenter prospective study was designed to evaluate the performance characteristics of a new commercially available enzyme-linked immunosorbent assay (ELISA) for the detection of antibodies to Trypanosoma cruzi in blood donors, the ORTHO T. cruzi ELISA Test System (Ortho-Clinical Diagnostics). STUDY DESIGN AND METHODS: Assay specificity was evaluated among 40,665 serum and ethylenediaminetetraacetate (EDTA) plasma specimens from volunteer blood donors and 481 T. cruzi antibody-negative specimens from a high-risk population. Sensitivity was evaluated among 106 T. cruzi-infected subjects identified by parasite detection, among 93 radioimmunoprecipitation assay (RIPA)-positive specimens from high-risk subjects, and 662 specimens presumed positive for the presence of T. cruzi antibodies by serologic methods. Also assessed were the equivalence of serum and plasma as specimen sources, performance equivalence of automated and semiautomated processing methods, nonspecific reactivity in specimens from other disease states or clinical conditions, and assay precision. RESULTS: Assay specificity was 99.998 percent in volunteer blood donors and 99.4 percent among high-risk subjects. Sensitivity was 100 percent among specimens positive by parasite detection, or by serologic methods, and 98.9 percent among RIPA-positive specimens from high-risk subjects. No differences were demonstrated between serum and plasma or between semiautomated and automated processing methods. Cross-reactivity was observed with known positive leishmaniasis specimens. Total inter- and intraassay variability was less than 10 percent with both the automated and the semiautomated methods. CONCLUSION: The ORTHO T. cruzi ELISA Test System is an effective, qualitative assay for screening blood donors for immunoglobulin G antibodies to T. cruzi. The assay was licensed for donor screening by the FDA in December 2006.

Clinical significance of nondiscriminated reactive results with the Chiron Procleix HIV-1 and HCV assay.

BACKGROUND: A NAT was developed (Procleix multiplex, Chiron Corporation) to simultaneously detect HIV-1 and HCV RNA with multiplex transcription-mediated amplification (mTMA) on pooled or single donations. HIV-1 and/or HCV RNA discriminatory probes confirm infection and discriminate the virus type. When a multiplex reactive sample does not react in discriminatory assays, the result is considered nondiscriminated reactive (NDR) and the donor status is uncertain. This study was designed to determine the clinical significance of NDR results. STUDY DESIGN AND METHODS: Three years of donor NAT and serology results were reviewed to determine HCV and HIV-1 infection rates as well as NDR events. Index NDR and seronegative donations were retested by mTMA and serology. Follow-up samples were tested by serology, mTMA, and PCR (selected samples). RESULTS: From April 1999 through April 2002, 5.1 million donations were screened with Procleix HIV-1 and HCV mTMA. The observed NDR rate declined from 0.014 percent (1 in 7242) to 0.0053 percent (1 in 18,795). None of the 462 donors with index NDR donations and additional NAT and serology data (from 724 donation and follow-up samples) were found infected. CONCLUSION: In most NDRs, the original mTMA reactivity is not reproducible and likely related to technical errors (mTMA cross-contamination). The retest and clinical follow-up data, combined with published evidence that the two discriminatory assays have the same sensitivity as multiplex HIV-1 and HCV, support the recommendation that donors with an NDR result for whom the multiplex reactivity cannot be reproduced should either not be notified or be deferred or should be counseled that they are not infected and expeditiously reinstated.