Radiation doses in diagnostic imaging for suspected physical abuse.

OBJECTIVE: To measure the actual radiation dose delivered by imaging techniques commonly used in the radiography of suspected physical abuse and to make this information available to health professionals and families. METHODS: Data were collected retrospectively on children under 3 years referred for skeletal surveys for suspected physical abuse, non-contrast CT head scan or radionuclide imaging of the bones in Starship Children's Hospital, Auckland, New Zealand from January to December 2015. Patient size-specific conversion coefficients were derived from International Commission on Radiologic Protection tissue weighting factors and used to calculate effective dose. RESULTS: Seventy-one patients underwent an initial skeletal survey, receiving a mean effective dose of 0.20 mSv (95% CI 0.18 to 0.22). Sixteen patients had a follow-up survey with a mean effective dose of 0.10 mSv (95% CI 0.08 to 0.11). Eighty patients underwent CT head which delivered a mean effective dose of 2.49 mSv (95% CI 2.37 to 2.60). Thirty-nine patients underwent radionuclide bone imaging which delivered a mean effective dose of 2.27 mSv (95% CI 2.11 to 2.43). CONCLUSIONS: In a paediatric centre, skeletal surveys deliver a relatively low effective radiation dose, equivalent to approximately 1 month of background radiation. Non-contrast CT head scan and radionuclide bone imaging deliver similar doses, equivalent to approximately 1 year of background radiation. This information should be considered when gaining informed consent and incorporated in patient education handouts.

Development of a transmucosal technique for erythromycin delivery to treat gastroparesis.

Gastroparesis is a serious condition that limits meal or medication emptying from the stomach, resulting in a variety of symptoms, altered nutrition, and inconsistent medication delivery. Our aim was to develop a transmucosal system to deliver erythromycin (EM), a gastric prokinetic agent, to bypass intestinal absorption. Humans and Sprague-Dawley rats were given EM by injection, gavage, or transmucosal gel with or without permeation enhancers. Pharmacokinetics were compared between subjects and across different delivery modalities. Drug concentrations in blood were measured using a bioassay. Design of Experiment techniques were used to optimize transmucosal antibiotic delivery in the Sprague-Dawley Model. Finally, we examined the scale-up of transmucosal delivery to human patients. Transmucosal delivery of EM increased with addition of ursodeoxycholate. While EM release from gels with ursodeoxycholate was significant, it was less than by injection. Scale-up to a human model indicated that delivery of EM using this transmucosal delivery system is insufficient for clinical need. The transport of EM seems limited by its solubility in water and thickness of the epithelial cell layers. Providing successful transmucosal delivery of EM and similar molecules to humans will require more aggressive techniques to disrupt the cellular layer, or pro-drug strategies to increase lipid solubility.