Higher body weight and distant metastasis are associated with higher radiation exposure to the household environment from patients with thyroid cancer after radioactive iodine therapy.

There were insufficient data regarding radiation exposure to the household environment from patients with thyroid cancer who received radioactive iodine (RAI) therapy in Asia; we therefore performed the present study at the Chang Gung Memorial Hospital in Keelung, Taiwan.Patients with papillary or follicular thyroid cancer who received 3.7 GBq (100 mCi) RAI were enrolled in this prospective hospital-based study. The enrolled patients were asked to place a thermoluminescent dosimeter in the living room, bedroom, and bathroom of their houses for 4 weeks to measure radiation exposure to the household environment.A total of 43 patients (18 men and 25 women; mean age 51 ±â€Š13 years) who received 3.7 GBq (100 mCi) RAI completed the study. The mean value of total radiation exposure over 4 weeks from the patients to the bedroom, bathroom, and living room (eliminating the background radiation factor) was 0.446 ±â€Š0.304 (0.088-1.382) mSv. We divided the patients into 2 groups: those with more than and less than the mean value of total radiation exposure to the bedroom, bathroom, and living room. Factors associated with the higher amount of radiation exposure from the patients to the household environment were patient body weight (P = .025, univariate analysis; P = .037, multivariate analysis, odds ratio [95% confidence interval] 1.067 [1.004-1.134]) and distant metastases based on I post-therapy scanning (P = .041, univariate analysis; P = .058, multivariate analysis, odds ratio [95% confidence interval] 6.453 [0.938-44.369]); age, sex, body mass index, renal function, serum stimulated thyroglobulin level, and recombinant human thyroid-stimulating hormone use were not associated with the amount of radiation exposure from the patients to the household environment.Higher body weight and distant metastases may be the best predictors for higher radiation exposure to the household environment from patients with thyroid cancer after RAI therapy.

Efficacy of vancomycin-releasing biodegradable poly(lactide-co-glycolide) antibiotics beads for treatment of experimental bone infection due to Staphylococcus aureus.

BACKGROUND: Clinical experience and animal studies have suggested that positron emission tomography (PET) using fluorine-18-labeled fluorodeoxyglucose ((18)F-FDG) may be promising for imaging of bone infections. In this study, we aimed to establish the accuracy of (18)F-FDG PET scanning for monitoring the response to poly(lactide-co-glycolide) (PLGA) vancomycin beads for treatment of bone infection. METHODS: PLGA was mixed with vancomycin and hot-compress molded to form antibiotic beads. In vitro, elution assays and bacterial inhibition tests were employed to characterize the released antibiotics. In vivo, cylindrical cavities were made in six adult male New Zealand white rabbits, and Staphylococcus aureus or saline was injected into the cavity to create a bone infection. After 2 weeks, the infection was confirmed by bacterial cultures, and the defect was filled with PLGA vancomycin beads. The treatment response was monitored by (18)F-FDG PET. RESULTS: The biodegradable beads released high concentrations of vancomycin (well above the breakpoint sensitivity concentration) for treatment of bone infection. In bacterial inhibition tests, the diameter of the sample inhibition zone ranged from 6.5 to 10 mm, which was equivalent to 12.5-100 % relative activity. (18)F-FDG PET results showed that uncomplicated bone healing was associated with a temporary increase in (18)F-FDG uptake at 2 weeks, with return to near baseline at 6 weeks. In the infected animals, localized infection resulted in intense continuous uptake of (18)F-FDG, which was higher than that in uncomplicated healing bones. Bone infection was confirmed with positive bacterial cultures. In vancomycin-treated animals, data showed rapidly decreasing amounts of (18)F-FDG uptake after treatment. CONCLUSIONS: In vitro and in vivo analyses showed that the use of biodegradable PLGA vancomycin beads successfully eradicated S. aureus infection in damaged bone.