[Determinants of geographic variations in asthma medication in Quebec].

Background: The study of geographic variations in the use of medication can constitute an interesting and useful option in public health surveillance for the identification of population needs and for the fair partition of resources. Many studies report variations in the use of medication that are not always understood. Considering the importance of medication, particularly for chronic diseases like asthma, it is important to identify factors that can explain geographic differences in the utilization of medications in order to determine optimal prescription practices.

AAPM recommendations on dose prescription and reporting methods for permanent interstitial brachytherapy for prostate cancer: report of Task Group 137.

During the past decade, permanent radioactive source implantation of the prostate has become the standard of care for selected prostate cancer patients, and the techniques for implantation have evolved in many different forms. Although most implants use 125I or 103Pd sources, clinical use of 131Cs sources has also recently been introduced. These sources produce different dose distributions and irradiate the tumors at different dose rates.

Dosimetric characterization of round HDR 192Ir accuboost applicators for breast brachytherapy.

Purpose: The AccuBoost brachytherapy system applies HDR 192Ir beams peripherally to the breast using collimating applicators. The purpose of this study was to benchmark Monte Carlo simulations of the HDR 192Ir source, to dosimetrically characterize the round applicators using established Monte Carlo simulation and radiation measurement techniques and to gather data for clinical use.

Methods: Dosimetric measurements were performed in a polystyrene phantom, while simulations estimated dose in air, liquid water, polystyrene and ICRU 44 breast tissue.

Evaluation of high-energy brachytherapy source electronic disequilibrium and dose from emitted electrons.

Purpose: The region of electronic disequilibrium near photon-emitting brachytherapy sources of high-energy radionuclides (60Co, 137CS, 192Ir, and 169Yb) and contributions to total dose from emitted electrons were studied using the GEANT4 and PENELOPE Monte Carlo codes.

Methods: Hypothetical sources with active and capsule materials mimicking those of actual sources but with spherical shape were examined. Dose contributions due to source photons, x rays, and bremsstrahlung; source beta-, Auger electrons, and internal conversion electrons; and water collisional kerma were scored.

Application of holographic display in radiotherapy treatment planning II: a multi-institutional study.

We hypothesized that use of a true 3D display providing easy visualization of patient anatomy and dose distribution would lead to the production of better quality radiation therapy treatment plans. We report on a randomized prospective multi-institutional study to evaluate a novel 3D display for treatment planning.The Perspecta Spatial 3D System produces 360 degrees holograms by projecting crosssectional images on a diffuser screen rotating at 900 rpm.

The evolution of brachytherapy treatment planning.

Brachytherapy is a mature treatment modality that has benefited from technological advances. Treatment planning has advanced from simple lookup tables to complex, computer-based dose-calculation algorithms. The current approach is based on the AAPM TG-43 formalism with recent advances in acquiring single-source dose distributions.

An approach to using conventional brachytherapy software for clinical treatment planning of complex, Monte Carlo-based brachytherapy dose distributions.

Certain brachytherapy dose distributions, such as those for LDR prostate implants, are readily modeled by treatment planning systems (TPS) that use the superposition principle of individual seed dose distributions to calculate the total dose distribution. However, dose distributions for brachytherapy treatments using high-Z shields or having significant material heterogeneities are not currently well modeled using conventional TPS. The purpose of this study is to establish a new treatment planning technique (Tufts technique) that could be applied in some clinical situations where the conventional approach is not acceptable and dose distributions present cylindrical symmetry.

Effects of a diet higher in carbohydrate/lower in fat versus lower in carbohydrate/higher in monounsaturated fat on postmeal triglyceride concentrations and other cardiovascular risk factors in type 1 diabetes.

Objective: To compare the effects of a eucaloric diet higher in carbohydrate/lower in fat versus lower in carbohydrate/higher in monounsaturated fat on postmeal triglyceride (TG) concentrations and other cardiovascular disease risk factors in nonobese subjects with type 1 diabetes and in good glycemic control.

Research Design And Methods: In a parallel group design study, 30 subjects were randomly assigned and completed one of the two eucaloric diets. Assessments included: BMI, blood pressure, A1C, plasma lipids, and markers of oxidation, thrombosis, and inflammation.

Monte Carlo simulations and radiation dosimetry measurements of peripherally applied HDR 192Ir breast brachytherapy D-shaped applicators.

Conformal dose coverage for accelerated partial breast irradiation or radiotherapy boost can be obtained with AccuBoost D-shaped brachytherapy applicators using a flattened surface positioned near the patient. Three D-shaped applicators (D45/D53/D60) were dosimetrically characterized using Monte Carlo methods (MCNP5), air ionization chambers (Farmer and Markus), and radiochromic film (GafChromic EBT) in polystyrene and ICRU 44 breast tissue. HDR 192Ir source dwell times were either constant or optimized to improve skin dose uniformity.

[Public health surveillance and role of administrative data].

Background: Public health surveillance constitutes an important activity since it helps in identifying health needs through data collection, and contributes to decision making and actions by analyzing and interpreting data and communicating key results.

Methods: This paper presents a discussion on the concept of public health surveillance, its objectives and its historical evolution. It deals with the importance of surveillance systems while describing their components and challenges.

Monte Carlo radiation dose simulations and dosimetric comparison of the model 6711 and 9011 125I brachytherapy sources.

Smaller diameter brachytherapy seeds for permanent interstitial implantation allow for use of smaller diameter implant needles. The use of smaller diameter needles may provide a lower incidence of healthy-tissue complications. This study determines the brachytherapy dosimetry parameters for the smaller diameter source (model 9011) and comments on the dosimetric comparison between this new source and the conventional brachytherapy seed (model 6711).

Equivalent phantom sizes and shapes for brachytherapy dosimetric studies of 192Ir and 137Cs.

The impact of phantom size and shape in brachytherapy dosimetry was assessed using Monte Carlo methods in liquid water for 192Ir and 137Cs point sources. This is needed since differences in published dosimetry data, both measurements and simulations, employ a variety of phantom sizes and shapes which can cause dose differences exceeding 30% near the phantom periphery. Spheres of radius, Rsph, 10-40 cm were examined to determine the equivalent spherical phantom size to a variety of cylinder and cube sizes, Rcyl and Rcube, respectively.

Anniversary paper: past and current issues, and trends in brachytherapy physics.

Brachytherapy began at the turn of the 20th century, contemporary with external-beam radiotherapy. Physicists and physicians together developed the field. There has not been a period since the beginning that has not witnessed innovations and progress in brachytherapy.

Third-party brachytherapy source calibrations and physicist responsibilities: report of the AAPM Low Energy Brachytherapy Source Calibration Working Group.

The AAPM Low Energy Brachytherapy Source Calibration Working Group was formed to investigate and recommend quality control and quality assurance procedures for brachytherapy sources prior to clinical use. Compiling and clarifying recommendations established by previous AAPM Task Groups 40, 56, and 64 were among the working group's charges, which also included the role of third-party handlers to perform loading and assay of sources. This document presents the findings of the working group on the responsibilities of the institutional medical physicist and a clarification of the existing AAPM recommendations in the assay of brachytherapy sources.

Albumin-conjugated C34 peptide HIV-1 fusion inhibitor: equipotent to C34 and T-20 in vitro with sustained activity in SCID-hu Thy/Liv mice.

Entry inhibitors of human immunodeficiency virus, type 1 (HIV-1) have been the focus of much recent research. C34, a potent fusion inhibitor derived from the HR2 region of gp41, was engineered into a 1:1 human serum albumin conjugate through stable covalent attachment of a maleimido-C34 analog onto cysteine 34 of albumin. This bioconjugate, PC-1505, was designed to require less frequent dosing and less peptide than T-20 and was assessed for its antifusogenic activity both in vitro and in vivo in the SCID-hu Thy/Liv mouse model.

The impact of prescription depth, dose rate, plaque size, and source loading on the central axis using 103Pd, 125I, and 131Cs.

Purpose: Modern dosimetry data are not available for Collaborative Ocular Melanoma Study-based eye plaques. This report aims to provide these data for eye plaques ranging from 10 to 22 mm, and for three different low-energy, photon-emitting radionuclides.

Methods And Materials: Recent publications on brachytherapy dosimetry parameters for 103Pd, 125I, and 131Cs were evaluated for use as eye plaque reference data.

Recommendations for permanent prostate brachytherapy with (131)Cs: a consensus report from the Cesium Advisory Group.

Purpose: Published clinical information on the safety and efficacy of (131)Cs implants is limited. We provide consensus recommendations for (131)Cs prostate brachytherapy based on experience to date.

Methods And Materials: The Cesium Advisory Group (CAG) consists of experienced (131)Cs users.

COMS eye plaque brachytherapy dosimetry simulations for 103Pd, 125I, and 131Cs.

Monte Carlo (MC) simulations were performed to estimate brachytherapy dose distributions for Collaborative Ocular Melanoma Study (COMS) eye plaques. Brachytherapy seed models 200, 6711, and CS-1 Rev2 carrying 103Pd, 125I, and 131Cs radionuclides, respectively, were modeled and benchmarked against previously published values. Calculated dose rate constants MClambda were 0.

COMS eye plaque brachytherapy dosimetry simulations for P103d, I125, and C131s.

Monte Carlo (MC) simulations were performed to estimate brachytherapy dose distributions for Collaborative Ocular Melanoma Study (COMS) eye plaques. Brachytherapy seed models 200, 6711, and CS-1 Rev2 carrying P103d, I125, and C131s radionuclides, respectively, were modeled and benchmarked against previously published values. Calculated dose rate constants ΛMC were 0.

Sexual behaviour and condom use among university students in Madagascar.

Although the number of known HIV-infected students in Madagascar increased significantly between 1989 and 1995, very little is known about student behaviour with regard to AIDS. The study objectives were: to describe Malagasy students' sexual behaviour and condom use; to document students' perceptions about condoms; and to study the relationships between students' socio-demographic characteristics, their perceptions about condoms, and their condom use. The survey used a cross-sectional design and was conducted at the Antananarivo's university campus sites.

Cefprozil versus Cefuroxime Axetil in the Treatment of Acute Sinusitis.

The objective of this multicentre, randomised, open-label, general practice (GP) study was to evaluate the efficacy and tolerability of cefprozil (Cefzil(trade mark), Bristol-Myers Squibb) compared with that of cefuroxime axetil (Ceftin((R)), Glaxo Wellcome) in the treatment of adult subjects with acute sinusitis. Typical of the GP setting, diagnosis was made based solely on clinical signs and symptoms of acute disease. Sinus radiography was performed post-randomisation.

Supplement to the 2004 update of the AAPM Task Group No. 43 Report.

Since publication of the 2004 update to the American Association of Physicists in Medicine (AAPM) Task Group No. 43 Report (TG-43U1), several new low-energy photon-emitting brachytherapy sources have become available. Many of these sources have satisfied the AAPM prerequisites for routine clinical use as of January 10, 2005, and are posted on the Joint AAPM/RPC Brachytherapy Seed Registry.

Dietary transition stages based on eating patterns and diet quality among Haitians of Montreal, Canada.

Objectives: To identify dietary transition stages based on dietary patterns of adult Haitians having lived in Montreal for various lengths of time, and to assess associated dietary quality.

Subjects: One hundred and eighty-one Haitians aged 25-60 years were recruited by the modified random digit dialling method.

Design: Socio-economic, diet and lifestyle variables were documented by questionnaire.

Brachytherapy dosimetry parameters calculated for a 131Cs source.

A comprehensive analysis of the IsoRay Medical model CS-1 Rev2 131Cs brachytherapy source was performed. Dose distributions were simulated using Monte Carlo methods (MCNP5) in liquid water, Solid Water, and Virtual Water spherical phantoms. From these results, the in-water brachytherapy dosimetry parameters have been determined, and were compared with those of Murphy et al.