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At least 487 records · Page 27Linked to original sources
PubMed1999

A non-invasive immobilization system and related quality assurance for dynamic intensity modulated radiation therapy of intracranial and head and neck disease.

PURPOSE: To develop and implement a non-invasive immobilization system guided by a dedicated quality assurance (QA) program for dynamic intensity-modulated radiotherapy (IMRT) of intracranial and head and neck disease, with IMRT delivered using the NOMOS Corporation's Peacock System and MIMiC collimator. METHODS AND MATERIALS: Thermoplastic face masks are combined with cradle-shaped polyurethane foaming agents and a dedicated quality assurance program to create a customized headholder system (CHS). Plastic shrinkage was studied to understand its effect on immobilization. Fiducial points for computerized tomography (CT) are obtained by placing multiple dabs of barium paste on mask surfaces at intersections of laser projections used for patient positioning. Fiducial lines are drawn on the cradle along laser projections aligned with nasal surfaces. Lateral CT topograms are annotated with a crosshair indicating the origin of the treatment planning and delivery coordinate system, and with lines delineating the projections of superior-inferior field borders of the linear accelerator's secondary collimators, or with those of the fully open MIMiC. Port films exposed with and without the MIMIC are compared to annotated topograms to measure positional variance (PV) in superior-inferior (SI), right-left (RL), and anterior posterior (AP) directions. MIMiC vane patterns superposed on port films are applied to verify planned patterns. A 12-patient study of PV was performed by analyzing positions of 10 anatomic points on repeat CT topograms, plotting histograms of PV, and determining average PV. RESULTS AND DISCUSSION: A 1.5+/-0.3 mm SD shrinkage per 70 cm of thermoplastic was observed over 24 h. Average PV of 1.0+/-0.8, 1.2+/-1.1, and 1.3+/-0.8 mm were measured in SI, AP, and RL directions, respectively. Lateral port films exposed with and without the MIMiC showed PV of 0.2+/-1.3 and 0.8+/-2.2 mm in AP and SI directions. Vane patterns superimposed on port films consistently verified the planned patterns. CONCLUSION: The CHS provided adequately reproducible immobilization for dynamic IMRT, and may be applicable to decrease PV for other cranial and head and neck external beam radiation therapy.

Brain Neoplasms↗
PubMed1988

[Endemic situation of leprosy in the municipality of Rondonopolis-Mato Grosso].

Here we show a report about the incidence of leprosy in Rondonópolis, State of Mato Grosso in Brazil. We direct attention to the fact that the contemporary index of prevalence in Brazil doesn't correspond to our reality when one makes a program of dynamic research of new cases and clearances to the population, medical staff and co-workers, through lectures and programs on radio and television, besides articles in local papers.

Brazil↗
PubMed1983

Contraceptive use by adolescent females in relation to knowledge, and to time and method of contraceptive counseling.

Contraceptive behavior of adolescent females was examined in relation to their level of knowledge, and time and method of contraceptive counseling. Subjects were 122 subscribers to a prepaid health plan, 13-18 years of age, unmarried, sexually active, and not desiring pregnancy. Contraceptive counseling was offered to 62 adolescents following receipt of a negative pregnancy test and to 60 adolescents following a routine medical visit. The 80 adolescents who chose to participate in the study were randomly assigned to a conventional or developmental method of counseling. The effectiveness of their contraceptive practice was measured 1 year later. Two hypotheses were not upheld: Sexually active adolescents were not more likely to accept contraceptive counseling at the time of a negative pregnancy test than at a time of a routine medical visit, and did not subsequently become more effective users of contraceptives. Two hypotheses were upheld: Effective and ineffective users of contraception did not differ in level of knowledge, and adolescents counseled by a developmental method practiced contraception more effectively than those counseled by a conventional method. Findings are discussed in terms of the theory of adolescent development and the proposition that a pregnancy scare motivates teenagers to control fertility.

Adolescent↗
PubMedDate not supplied

The impact of service delivery frequency on family planning program output and efficiency.

Operations research is the study of factors that can be controlled by program administrators. Among such factors is the frequency of performing program activities. The present experiment, conducted in Lima, Peru during 1985-86, tested the impact of holding family planning post sessions once per month, twice per month, and weekly. Frequency was shown to have a major impact on program outputs, costs, and cost-effectiveness. Depending on the indicator, sessions held twice per month produced between 1.5 and 2.1 times the output of those conducted once per month. Weekly sessions produced between 1.3 and 1.6 times the output of those held twice per month. At an output level of nearly 11,200 visits per year, twice-per-month sessions were estimated to be 7-38 percent more cost-effective, depending on the indicator, than once-per-month sessions, and 6-28 percent more cost-effective than weekly sessions.

Community Health Services↗
PubMed1991

Localization of small renal tumor by dynamic computerized tomography.

Herein we report on 4 cases of renal tumor whose diameter was less than 3 cm. A mass lesion was suggested by renal echography in mass screening program. Renal dynamic computerized tomography (CT) with bolus injection can delineate a mass lesion clearer than ordinary plain and enhanced CT, and renal angiography. In renal dynamic CT, tumor lesion is well depicted because of the difference between the time density curve in the tumor lesion and that in the surrounding renal parenchyma. Renal dynamic CT is considered to be an especially versatile modality to diagnose small tumors which are hardly delineated by ordinary enhanced CT.

Aged↗
PubMed2001

Teaching dairy herd health dynamics using a web-based program.

INTRODUCTION: This course teaches veterinary students basic principles of epidemiology. Dynamic relationships of dairy herd performance parameters are demonstrated. METHODOLOGY: Courseware combines lectures (both in-class and Web-based) and problem-based exercises using two computer simulation models. The format of this eight-week, one-credit course is a lecture followed by exercises in a computer laboratory working with simulation models. Currently, Cornell University and nine test sites use the courseware. CURRENT STATUS: The course has been taught for two years, with students and experts providing evaluations and critical feedback for courseware modification.

Animals↗
PubMed1994

Recent evidence on trends and differentials in Bangladesh fertility: an update.

A comparison of contraceptive and fertility data for 1985-91 with data for 1983 shows that fertility has continued to decline in Bangladesh, in all segments of society. The magnitude of decline varied according to educational level, region and urban-rural locality. The percentage decline in total marital fertility rate was somewhat higher among urban than rural residents; educated women showed greater declines than uneducated, increasing the overall educational differences in total fertility by 1991. Factors contributing to the recent decline in fertility are discussed.

Adolescent↗
PubMed1991

The establishment of a centralised referral service leads to earlier abortion.

In 1988 a centralised referral service for termination of pregnancy was established in Edinburgh. This has led to a significant reduction in the time women who have requested termination wait to see a gynaecologist (mean 4.7 days) and in the time it takes before suction termination of pregnancy is undertaken (total wait 10.2 days). In 1988 only 40% of induced abortions in Edinburgh were carried out at 9 weeks gestation or before while in 1989 that figure had risen to 60%. In 1989 less than 10% of pregnancies were terminated at or after 12 weeks gestation, compared with 21% in 1988. Reasons for delays in obtaining an abortion are multifactorial but rapid referral once a woman has made the decision to seek help will be essential if she is to avail herself of the advantages of medical termination--only available until eight weeks of pregnancy.

Abortion, Legal↗
PubMed1989

Mortality pattern in the Emergency Paediatric Unit of Ahmadu Bello University Teaching Hospital, Zaria, Nigeria.

Three hundred and seven (307) deaths were recorded out of 3,155 admissions into the Emergency Paediatric Unit of Ahmadu Bello University Teaching Hospital Zaria between January 1st and December 31st 1986, giving a percentage mortality of 9.9 percent. 67 percent of the patients who died were aged between one month and twenty four months, and the overall male: female ratio of deaths was 1:1.04. Measles with complications was the commonest cause of death (24.1 percent) closely followed by protein energy malnutrition (23 percent) and respiratory tract infection (18 percent). Over half of the patients (57.6 percent) died less than 24 hours after admission. As most deaths resulted from preventable conditions, the implications of this finding, and suggestions on how to improve the situation are discussed.

Cause of Death↗
PubMed2000

The importance of root gravitropism for inter-root competition and phosphorus acquisition efficiency: results from a geometric simulation model.

We have observed that low soil phosphorus availability alters the gravitropic response of basal roots in common bean (Phaseolus vulgaris L.), resulting in a shallower root system. In this study we use a geometric model to test the hypotheses that a shallower root system is a positive adaptive response to low soil P availability by (1) concentrating root foraging in surface soil horizons, which generally have the highest P availability, and (2) reducing spatial competition for P among roots of the same plant. The growth of nine root systems contrasting in gravitropic response over 320 h was simulated in SimRoot, a dynamic three-dimensional geometric model of root growth and architecture. Phosphorus acquisition and inter-root competition were estimated with Depzone, a program that dynamically models nutrient diffusion to roots. Shallower root systems had greater P acquisition per unit carbon cost than deeper root systems, especially in older root systems. This was due to greater inter-root competition in deeper root systems, as measured by the volume of overlapping P depletion zones. Inter-root competition for P was a significant fraction of total soil P depletion, and increased with increasing values of the P diffusion coefficient (De), with root age, and with increasing root gravitropism. In heterogenous soil having greater P availability in surface horizons, shallower root systems had greater P acquisition than deeper root systems, because of less inter-root competition as well as increased root foraging in the topsoil. Root P acquisition predicted by SimRoot was validated against values for bean P uptake in the field, with an r2 between observed and predicted values of 0.75. Our results support the hypothesis that altered gravitropic sensitivity in P-stressed roots, resulting in a shallower root system, is a positive adaptive response to low P availability by reducing inter-root competition within the same plant and by concentrating root activity in soil domains with the greatest P availability.

Computer Simulation↗
PubMedDate not supplied

Program evaluation. Part 2: A responsive model proposal.

While program evaluation is necessary for understanding and improving educational programs in nursing, it is frequently surrounded by a climate of unease and perplexity. The first article (September/October 1990) in this two-part series reviewed models of program evaluation. This second article examines the state-of-the-art of program evaluation in nursing education and proposes implementation of a responsive model of evaluation in schools of nursing. The series aims to foster more dynamic, efficient program analysis, thereby enhancing the effectiveness of nursing education programs.

Education, Nursing↗