Senior Design P09052Molecular Imaging System Upgrade
Ben McGee
Brandon Luquette
Aaron Phipps
Patricia Heneka
Dien Nguyen
Project Description
• To develop a research prototype of a clinical system capable of performing depth-resolved optical molecular imaging of a stationary human hand – Integration of Qioptiq Linos’s Optigrid with existing
Carestream molecular imaging platform.– Prototype must be functional and flexible enough
for Carestream to investigate for commercialization
Proposed Modifications
Existing Platform Prototype System
Optigrid Functionality• Motors provide 120o phase shifts and focus– Grid moves on the x-axis 11.11 um to complete a
phase change– Improves Clarity– Grid moves 2 mm on the z-axis to focus image– 30 line pair/mm on a 10x10 mm square– Lines spatially modulate the illumination
A portion of the OptiGrid at 200x
y
xz
Design Objective• Projection of the Optigrid at an angle while maintaining focus
Mechanical Design Solution
Implemented Mechanical Design
System Analysis and Calibration
• Characterization– Capable of projecting grid at spatial frequencies
ranging from 0.8 – 1.4 line pair/mm• Calibration– Developed a system specific procedure to provide
repeatable phase movements• Processing– Depth discrimination proof of concept using depth
of modulation analysis
System Characterization.8 line pair/mm
1.4 line pair/mm
• Projected at a 30o angle Steepest angle capable
of the system The system was set to a
zoom of 40 pixels/mm•Magnified using Computar C mount lens
Different Lenses provide different spatial frequency ranges
• Captured with a blue excitation filter and a green emission filter
Calibration
• Coarse Calibration– Capture images in
a general range of 30, 55 and 90 V
– Calculate phase at each point
– Determine approximate voltages for 120o phase shifts.
Demodulation
• Images are combined to eliminate the projected frequency using
• Incorrectly phase shifted images have residual lines
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Processing
• Phase shifted images were captured of the phantom block– Fluorescent sheets
were inserted between polycarbonate sheets
• The block was imaged at two spatial frequencies
Depth Discrimination
0 50 100 150 200 250 3006200
6400
6600
6800
7000
7200
7400
7600
7800
8000
8200
Depth Discrimination
• Squared error away from the mean at each point is used to evaluate the depth at each point.
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Recommendations
• Projection Angle– A shorter rail will result in a steeper projection angle which
would reduce distortion• Automation– The calibration process is very time consuming and prone to
human error. – Timing is very critical to achieving repeatable phase shifts in
the Optigrid.• Calibration Procedure Modifications– Warm up routine– Increase the number of phase shifts
Thanks!
• Dr. Gilbert Feke • Linda Antos • Dr. Daniel Phillips • Dr. Maria Helguera • Carestream Health• Qioptiq Linos Imaging Solutions
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