The association of bone, fingernail and blood manganese with cognitive and olfactory function in Chinese workers

Occupational manganese (Mn) exposure has been associated with cognitive and olfactory dysfunction; however, few studies have incorporated cumulative biomarkers of Mn exposure such as bone Mn (BnMn). Our goal was to assess the cross-sectional association between BnMn, blood Mn (BMn), and fingernail Mn (FMn) with cognitive and olfactory function among Mn-exposed workers. A transportable in vivo neutron activation analysis (IVNAA) system was designed and utilized to assess BnMn among 60 Chinese workers. BMn and FMn were measured using inductively coupled plasma mass spectrometry. Cognitive and olfactory function was assessed using Animal and Fruit Naming tests, World Health Organization/University of California-Los Angeles Auditory Verbal Learning Test (AVLT) and the University of Pennsylvania Smell Identification Test (UPSIT). Additional data were obtained via questionnaire. Regression models adjusted for age, education, factory of employment, and smoking status (UPSIT only), were used to assess the relationship between Mn biomarkers and test scores. In adjusted models, increasing BnMn was significantly associated with decreased performance on average AVLT scores [β (95% confidence interval (CI)) = -0.65 (-1.21, -0.09)] and Animal Naming scores [β (95% CI) = -1.54 (-3.00, -0.07)]. Increasing FMn was significantly associated with reduced performance measured by the average AVLT [β (95% CI) = -0.35 (-0.70, -0.006)] and the difference in AVLT scores [β (95% CI) = -0.40 (-0.77, -0.03)]. BMn was not significantly associated with any test scores; no significant associations were observed with Fruit Naming or UPSIT tests. BnMn and FMn, but not BMn, are associated with cognitive function in Mn-exposed workers. None of th

Preliminary Clinical Evaluation of Intrafraction Prostate Displacements for Two Immobilization Systems

Immobilization systems and their corresponding set-up errors influence the clinical target volume to the planning target volume (CTV-PTV) margins, which is critical for hypofractionated prostate stereotactic body radiotherapy (SBRT). This preliminary study evaluates intrafraction prostate displacement for two immobilization systems (A and B). Six consecutive patients having localized prostate cancer and implanted prostate marker seeds were studied. Planar X-ray images were acquired pre- and post-treatment to find the intrafraction prostate displacement. The average absolute displacements (lateral, longitudinal, vertical) were 0.9 +/- 0.4 mm, 1.7 +/- 0.1 mm, 1.3 +/- 0.3 mm (system A), and 0.5 +/- 0.2 ram, 0.6 +/- 0.1 mm, 0.8 +/- 0.3 mm (system B), with average three-dimensional displacements of 2.6 +/- 0.2 mm (system A) and 1.3 +/- 0.2 mm (system B). The computed CTV-PTV margins (lateral, longitudinal, vertical) were 2.5 mm, 2.5 mm, 3.6 mm and 1.4 mm, 1.6 mm, 2.4 mm for systems A and B, respectively. This suggests that the immobilization system influences intrafraction prostate displacement and, therefore, the margins applied. However, the margins found for both systems are comparable to the margins used for hypofractionated prostate SBRT.Open access journalThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]

Variations of MRI-assessed peristaltic motions during radiation therapy.

PURPOSE:Understanding complex abdominal organ motion is essential for motion management in radiation therapy (RT) of abdominal tumors. This study investigates abdominal motion induced by respiration and peristalsis, during various time durations relevant to RT, using various CT and MRI techniques acquired under free breathing (FB) and breath hold (BH). METHODS:A series of CT and MRI images acquired with various techniques under free breathing and/or breath hold from 37 randomly-selected pancreatic or liver cancer patients were analyzed to assess the motion in various time frames. These data include FB 4DCT from 15 patients (for motion in time duration of 5 sec), FB 2D cine-MRI from 4 patients (time duration of 1.7 min, 1 second acquisition time per slice), FB cine-MRI acquired using MR-Linac from 6 patients in various fractions (acquisition time is less than 0.6 seconds per slice), FB 4DMRI from 2 patients (time duration of 2 min), respiration-gated T2 with gating at the end expiration (time duration of 3-5 min), and BH T1 with multiphase dynamic contrast in acquisition times of 17 seconds for each of five phases (pre-contrast, arterial, venous, portal venous and delayed post-contrast) from 10 patients. Motions of various organs including gallbladder (GB) and liver were measured based on these MRI data. The GB motion includes both respiration and peristalsis, while liver motion is primarily respiration. By subtracting liver motion (respiration) from GB motion (respiration and peristalsis), the peristaltic motion, along with small residual motion, was obtained. RESULTS:From cine-MRI, the residual motion beyond the respiratory motion was found to be up to 0.6 cm in superior-inferior (SI) and 0.55 cm in anterior-posterior (AP) directions. From 2D cine-MRI acquired by the MR-Linac, different peristaltic motions were found from different fractions for each patient. The peristaltic motion was found to vary between 0.3-1 cm. From BH T1 phase images, the average motions that were primarily due to peristalsis movements were found to be 1.2 cm in SI, 0.7 cm in AP, and 0.9 cm in left-right (LR) directions. The average motions assessed from 4DCT were 1.0 cm in SI and 0.3 cm in AP directions, which were generally smaller than the motions assessed from cine-MRI, i.e., 1.8 cm in SI and 0.6 cm in AP directions, for the same patients. However, average motions from 4DMRI, which are coming from respiratory were measured to be 1.5, 0.5, and 0.4 cm in SI, AP, and LR directions, respectively. CONCLUSION:The abdominal motion due to peristalsis can be similar in magnitude to respiratory motion as assessed. These motions can be irregular and persistent throughout the imaging and RT delivery procedures, and should be considered together with respiratory motion during RT for abdominal tumors

Development of a Cumulative Exposure Index (CEI) for Manganese and Comparison with Bone Manganese and Other Biomarkers of Manganese Exposure

Manganese (Mn) exposure can result in parkinsonism. However, understanding of manganese neurotoxicity has been limited by the lack of a cumulative Mn biomarker. Therefore, the current goal was to develop Mn cumulative exposure indices (MnCEI), an established method to estimate cumulative exposure, and determine associations of MnCEI with blood Mn (BMn), fingernail Mn (FMn), and bone Mn (BnMn). We completed a cross-sectional study of 60 male Chinese workers. Self-reported occupational history was used to create two MnCEIs reflecting the previous 16 years (MnCEI16) and total work history (MnCEITOT). An in vivo neutron activation analysis system was used to quantify BnMn. BMn and FMn were measured using ICP-MS. Mean (standard deviation) MnCEITOT and MnCEI16 were 37.5 (22.0) and 25.0 (11.3), respectively. Median (interquartile range) BMn, FMn, and BnMn were 14.1 (4.0) μg/L, 13.5 (58.5) μg/g, and 2.6 (7.2) μg/g dry bone, respectively. MnCEI16 was significantly correlated with FMn (Spearman’s ρ = 0.44; p = 0.02), BnMn (ρ = 0.44; p < 0.01), and MnCEITOT (ρ = 0.44; p < 0.01). In adjusted regression models, MnCEI16 was significantly associated with BnMn (β = 0.03; 95% confidence interval = 0.001, 0.05); no other biomarkers were associated with MnCEI. This suggests BnMn may be a useful biomarker of the previous 16 years of Mn exposure, but larger studies are recommended