ABSTRACT
Although detection of tumor cells in peripheral blood using imitiunocytochemistry and optical scanning is a promising method for screening and monitoring cancer, it poses a major technical challenge due to the extremely low tumor cell concentration in blood. The preferred detection method - digital microscopy - is far too slow for analysis of the large numbers of cells required for statistical validity. We describe here a novel prescan instrument that rapidly identifies a small number of candidates for subsequent examination by digital microscopy to determine if they are genuine tumor cells. The prescan is 500 times faster than digital microscopy and yet has a similar sensitivity. The high prescan speed is accomplished by trading resolution for field of view. The resolution of the prescan is determined by the laser spot size of about 10 microns. While this resolution is much coarser than the submicron resolution of microscopes, it is still sufficient for detecting fluorescent cells because it matches the size of a typical cell. The wide field of view and high scan rate are enabled by a novel application of fiber optics.
ABSTRACT
OBJECTIVE: To obtain estimates on (1) the percentage of children who were up-to-date on the recommended childhood vaccination series, (2) the percentage of children who were age-appropriately immunized, and (3) coverage levels by individual vaccines. DESIGN: Vaccination levels were estimated by conducting retrospective immunization coverage surveys of the school health records of children entering kindergarten or first grade in the 1990-1991 or 1991-1992 school year. A multistage cluster survey design was used. SETTING: Survey sites were selected from among the 60 largest urban areas in the United States. One small city and one rural area were selected for comparison. RESULTS: By their second birthday, 11% to 58% (median, 44%) of the children were fully vaccinated. Stricter measurement criteria lowered coverage levels further. Completed series levels at school entry were 71% to 96% (median, 87%). CONCLUSIONS: Vaccination levels at the second birthday were far below the goal for the year 2000. All health providers need to administer vaccines according to the recommended schedule.