In vitro susceptibility of swine pathogens to feed additives and active ingredients with potential as antibiotic replacements.

Aims: The rise in antibiotic resistance requires the reduction of antibiotic use in all sectors. In animal production, many commercial alternatives to antibiotics have been developed for incorporation into feeds, but a lack of evidence on their antibacterial activity limits confidence in their application. We aim to compare the antibacterial activity of feed additives and active ingredients to better understand their usefulness.

Medical physics external beam plan review: What contributes to the variability?

Purpose: In this article we report on the results of a survey of physics plan review practices conducted by the Cancer Care Ontario Communities of Practice and the variations in practice between and within centers.

Methods: The medical physicists at each center worked together to complete the survey and submit a single response for that center. A 4-point Likert scale, used to report the variation in practice at each center, was quantified into two parameters: "Intra-center variation", the distribution of responses within the center, and "Variation between centers", the difference between the center's response and the provincial mean.

Size fractionation of bioaerosol emissions from green-waste composting.

Particle size is a significant factor in determining the dispersal and inhalation risk from bioaerosols. Green-waste composting is a significant source of bioaerosols (including pathogens), but little is known about the distribution of specific taxa across size fractions. To characterise size fractionated bioaerosol emissions from a compost facility, we used a Spectral Intensity Bioaerosol Sensor (SIBS) to quantify total bioaerosols and qPCR and metabarcoding to quantify microbial bioaerosols.

Introducing operator characteristic curves to define appropriate frequency of quality control tests: A case study involving whole breast radiotherapy image guidance.

Background And Purpose: Sampling theory and operator characteristic curves are methods that can determine an optimal schedule for quality control tests. We apply this method to positional data for whole breast radiotherapy since several surveys report inconsistent image guidance practice for this technique.

Materials And Methods: Positional errors were defined, for 55 consecutive breast cancer patients, by comparing the central lung distance measured on portal images with that obtained from the corresponding digitally reconstructed radiograph.

Poster - Thur Eve - 39: SBRT imaging analysis - patient results and QA of imaging systems.

Our centre began offering stereotactic body radiation therapy (SBRT) treatments for peripheral lung lesions in 2011. As a high-precision technique, SBRT requires precise positioning of the target, and precise quality assurance (QA) of the imaging systems; these may be dependent on local equipment and procedures. We aimed to maintain target position within 3 mm throughout each treatment, and imaging and mechanical systems to at least 2 mm accuracy.