Optimal equations for describing the relationship between prostate volume, number of sources, and total activity in permanent prostate brachytherapy

OBJECTIVES: To determine whether there is an optimal type of mathematical equation for predicting seed and activity requirements for permanent prostate brachytherapy. METHODS: Four institutions with extensive brachytherapy experience each submitted details of more than 40 implants. The data was used to generate power and linear equations to reflect the relationship between preimplant volume and the number of seeds implanted, and preimplant volume and the total implant activity. We compared the R and standard error of the generated equations to determine which type of equation better fit the data. RESULTS: For the limited range of prostate volumes commonly implanted (20-60 mL), power and linear equations predict seed and activity requirements comparably well. CONCLUSIONS: Linear and power equations are equally suitable for generating institution-specific nomograms

Inter-institutional variation of implant activity for permanent prostate brachytherapy

PURPOSE: Despite the existence of guidelines for permanent prostate brachytherapy, it is unclear whether there is interinstitutional consensus concerning the parameters of an ideal implant. METHODS AND MATERIAL: Three institutions with extensive prostate brachytherapy expertise submitted information regarding their implant philosophy and dosimetric constraints, as well as data on up to 50 radioiodine implants. Regression analyses were performed to reflect each institution\u27s utilization of seeds and implanted activity. RESULTS: Despite almost identical implant philosophy, target volume, and dosimetric constraints, there were statistically significant interinstitutional differences in the number of seeds and total implant activity across the range of prostate volumes. For larger volumes, the variation in implanted activity was 25%; for smaller glands, it exceeded 40%. CONCLUSIONS: There remain wide variations in implanted activity between institutions espousing seemingly identical implant strategies, prescription, and dosimetry constraints. Brachytherapists should therefore be wary of using nomograms generated at other institutions

Growth in HIV-infected children on long-term antiretroviral therapy

OBEJECTIVES : To describe growth in HIV‐infected children on long‐term antiretroviral therapy (ART) and to assess social, clinical, immunological and virological factors associated with suboptimal growth. METHODS : This observational cohort study included all HIV‐infected children at an urban ART site in South Africa who were younger than 5 years at ART initiation and with more than 5 years of follow‐up. Growth was assessed using weight‐for‐age Z‐scores (WAZ), height‐for‐age Z‐scores (HAZ) and body mass index (BMI)‐forage Z‐scores (BAZ). Children were stratified according to pre‐treatment anthropometry and age. Univariate and mixed linear analysis was used to determine associations between independent variables and weight and height outcomes. RESULTS : Majority of the 159 children presented with advanced clinical disease (90%) and immunosuppression (89%). Pre‐treatment underweight, stunting and wasting occurred commonly (WAZ<‐2= 50%, HAZ<‐2= 73%, BAZ<‐2= 19%). Weight and BMI improvement occurred during the initial 12 months, while height improved during the entire 5‐year period. Height at study exit was significantly worse for children with growth impairment at ART initiation (p<0.001), whilst infants (<1 year) demonstrated superior improvement in terms of BMI (p=0.04). Tuberculosis was an independent risk factor for suboptimal weight (p=0.01) and height (p=0.02) improvement. Weight gain was additionally hindered by lack of electricity (p=0.04). Immune reconstitution and virological suppression were not associated with being underweight or stunted at study end point. CONCLUSIONS : Malnutrition was a major clinical concern for this cohort of HIV‐infected children. Early ART initiation, tuberculosis co‐infection management and nutritional interventions are crucial to ensure optimal growth in HIV‐infected children.http://onlinelibrary.wiley.com/journal/10.1111/(ISSN)1365-31562017-05-31hb2016Paediatrics and Child Healt