Protocols for assessing the risks of discarded electronic products (e-waste) vary across jurisdictions, complicating the tasks of manufacturers and regulators. We compared the Federal Toxicity Characteristic Leaching Procedure (TCLP), California's Waste Extraction Test (WET), and the Total Threshold Limit Concentration (TTLC) on 34 phones to evaluate the consistency of hazardous waste classification. Our sample exceeded TCLP criteria only for lead (average ) 87.4 mg L -1 ; range ) 38.2-147.0 mg L -1 ; regulatory limit ) 5.0 mg L -1 ), but failed TTLC for five metals: copper (average 203 g kg -1 ; range ) 186-224 g kg -1 ; limit ) 2.50 g kg -1 ), nickel (9.25 g kg -1 ; range ) 6.34-11.20 g kg -1 ; limit ) 2.00 g kg -1 ), lead (10.14 g kg -1 ; range ) 8.22-11.60 g kg -1 ; limit ) 1.00 g kg -1 ), antimony (1.02 g kg -1 ; range ) 0.86-1.29 g kg -1 ; limit ) 0.50 g kg -1 ), and zinc (11.01 g kg -1 ; range ) 8.82-12.80 g kg -1 ; limit ) 5.00 g kg -1 ). Thresholds were not exceeded for WET. We detected several organic compounds, but at concentrations below standards. Brominated flame retardants were absent. These results improve existing environmental databases for e-waste and highlight the need to review regulatory testing for hazardous waste.
This study demonstrates 3D printed bolus in postmastectomy radiation therapy improves fit of the bolus and reduces patient setup time marginally compared with standard vinyl gel sheet bolus. The time savings on patient setup must be weighed against the considerable time needed for the 3D printing process.
The purpose of this work is to develop a prototype system for continuous, three-dimensional (3D) monitoring of patient cranial motion during stereotactic radiosurgery. Using novel capacitive detector plates, the goal was to provide detection of cranial position inside a thermoplastic immobilizing mask, without relying on skin monitoring or use of ionizing radiation. A novel capacitive detector array was used to detect cranial translations with sub-millimeter accuracy. The array was comprised of four conductive plates arranged around the cranium. One superior plate was positioned at the cranial vertex, two lateral plates were positioned in sagittal planes at the lateral aspects of the cranium and one plate was located in a coronal plane anterior to the face. The system was calibrated by parameterizing a capacitive signal for each dimension as a function of spatial translation. The detector array performance was evaluated with the help of a volunteer in the absence of radiation. Separately, possible effects of electromagnetic interference and irradiation in the linac suite were assessed. Detector plates mounted at 1 cm original distance to the thermoplastic mask can detect sub-millimeter lateral and superior cranial motion. Detection of sub-millimeter anterior motion is possible when the plate is mounted closer to the patient (5-10 mm). No signal interference was observed when the capacitive array was irradiated. Our prototype detector array provides continuous, 3D translation detection with sub-millimeter precision. The signal provides sufficient signal to noise ratio and is stable in linac room environment and in direct radiation beam. The detector plate is sensitive to the position of the cranium inside a mask and offers the advantage of being insensitive to the mask itself. Future work will involve modifying the array to detect patient rotation.
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