Presentation on theme: "Linda Nie, Assistant Professor School of Health Sciences Purdue University."— Presentation transcript:
Linda Nie, Assistant Professor School of Health Sciences Purdue University
Why portable x-ray fluorescence technology Approach Results and discussion More work in progress Acknowledgements
Portable Multi-metals Fast More sensitive in some cases Accessible, suitable for large population human studies
Soft tissue attenuation It is difficult to detect signals through tissue over 5 mm Soft tissue attenuation correction ◦ Spectrum to determine the soft tissue thickness Bone surface/volumn? (mfp in bone: 0.5 mm vs. 25 mm)
Overall: develop a portable XRF technology to quantify multiple metals in bone and skin Hardware design selection of tube target, filter combination, and geometry design; selection of parameters Methodology and algorithm development Consider in vivo situation Radiation risk assessment
Monte Carlo simulations (MCNP) X-ray tube voltage, current, filter combinations; x- ray tube target, geometry design etc. Calculate minimum detection limit (MDL)
Once the hardware design is determined …… Method #1: peak fitting and traditional cal.
BoneKXRFLXRF (0mm)ICPMS 720221.371.51E+01 689513.171.03E+01 690022.631.30E+011.16E+019.87E+001.13E+01 691818.781.16E+01 700216.569.93E+00 703120.331.10E+01 713120.591.41E+011.23E+011.81E+011.40E+01 714215.727.39E+009.73E+008.03E+005.74E+00 716218.308.45E+008.47E+008.45E+006.82E+00 71686.903.04E+002.28E+001.50E+002.88E+00 Overestimate background Solution: a. ‘real’ bone phantoms; b. adjustment using MC simulation results; Surface bone? Pb distribution in bone.
Skin dose of ~13 mSv and total body effective dose of 1.5 µ Sv compared with Exposure limit of 500 mSv per year to extremities for occupational workers (no limit set for general public) and a typical whole body effective dose of 100 µ Sv for chest x-ray
System optimization – customized device Standardize the calibration process (true bone equivalent phantoms, or MC simulations to adjust for differences) Validation of the technology with a large human population Apply the technology for metal epi and metal toxicology study Bone Sr measurement
Steven Sanchez, Graduate Student, School of Health Sciences, Purdue University Aaron Specht, Graduate Student, School of Health Sciences, Purdue University Dr. Lee Grodzins, ThermoFisher Niton Dr. Marc Weisskopf, HSPH