Presentation is loading. Please wait.

Presentation is loading. Please wait.

Linda Nie, Assistant Professor School of Health Sciences Purdue University.

Similar presentations


Presentation on theme: "Linda Nie, Assistant Professor School of Health Sciences Purdue University."— Presentation transcript:

1 Linda Nie, Assistant Professor School of Health Sciences Purdue University

2  Why portable x-ray fluorescence technology  Approach  Results and discussion  More work in progress  Acknowledgements

3  Portable  Multi-metals  Fast  More sensitive in some cases Accessible, suitable for large population human studies

4  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)

5

6 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

7  Monte Carlo simulations (MCNP) X-ray tube voltage, current, filter combinations; x- ray tube target, geometry design etc.  Calculate minimum detection limit (MDL)

8 Once the hardware design is determined …… Method #1: peak fitting and traditional cal.

9  Method #2: background subtraction

10

11  MC simulation  Experiments

12  Phantom, goat bone, and cadaver bone experiments ◦ ICP-MS, KXRF  Human studies

13 Lucite Thickness (mm) Detection Limit (ppm) 02.3 14.1 2.047.1 3.0811.8 4.0818.6 4.9225.9

14 Phantom Concentration (ppm) Portable XRF (ppm)KXRF (ppm)ICPMS (ppm) 0mm Lucite1mm Lucite2.72mm Lucite 0 -1.05±1.730.72±2.300.62±7.26-.068±1.960.63±0.20 10 11.3±1.8312.8±3.079.81±7.098.97±1.8111.2±0.71 20 17.2±1.9017.3±3.1520.2±7.1619.6±1.9116.7±1.89 30 31.3±2.0929.3±3.3026.6±7.3430.6±1.8436.0±0.89 50 45.4±2.2445.0±3.4940.0±7.5951.8±1.7772.5±11.7 10099.9±2.7296.0±3.96100±8.16106±2.16127±16.0

15 Goat Bone #Portable XRF (ppm) KXRF (ppm) 0mm Lucite1mm Lucite2mm Lucite 119.7±1.9515.4±3.0522.2±5.3123.5±1.64 92.73±2.230.84±2.726.33±5.304.5±1.40 1229.9±2.0032.3±3.1730.5±5.3231.5±1.75 1313.6±1.7915.6±2.9119.1±5.0612.3±1.49

16

17 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.

18

19  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

20  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

21

22

23  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

24 Thank you! Questions??

25 Portable XRF Cadaver Measurement, Pb concentration ~20ppm

26

27 ThermoFisher Niton: XL3t- GOLDD

28 1. 100 lbs vs. 3 lbs 2. 30 mins vs. 2 min 3. Multi-metals


Download ppt "Linda Nie, Assistant Professor School of Health Sciences Purdue University."

Similar presentations


Ads by Google