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