Hadamard Transform Imaging

Paul Holcomb

Tasha Nalywajko

Melissa Walden

Problem Definition

• Current 3D imaging systems for brain surgery are too slow and possess too low of a resolution to be effective in an operating room setting

Why is this important?

• 71% mortality rate for diagnosed brain tumors

• Correlation between complete resectioning of tumors and improved prognosis

• Complete resectioning requires knowing the location of the tumor, especially tumor margins

• Imaging in a clinical setting should be fast• Operating room billed by the quarter- or

half hour

Cost/Benefit Analysis

• Treatment costs:– OR cost: $10K - $15K

per surgery (depending on length)

– ICU: $1963/24 hrs– Floor: $779/24 hrs– Chemotherapy– Radiation therapy

Cost Reduction:

• Shorter surgeries• Less time in hospital (ICU or

floor)• Less post-surgical treatment

required

Design Criteria

• Must produce an image in real time

• Must accurately reproduce area of interest in the brain

• Must distinguish healthy versus tumor tissue

• Must be small enough to be usable in an operating room setting

• Must interface with operating microscope

Design Objective

Construct imaging system using digital micro-mirror device and Hadamard transform for use with operating microscope in a clinical setting

System Design

Hadamard Transform

• Decreased imaging time

• Increased SNR Hadamard Matrix Definition

Inverse Hadamard Transform

Digital Micro-mirror Device

• Allows use of Hadamard Transform

Fourier vs. Hadamard Imaging

Wuttig and Riesenburg, “Sensitive Hadamard Transform Imaging Spectrometer”

SNR Increase with Hadamard: √n

SNR Increase with S-Matrix: (√n)/2

System Diagram

Collect and collimate

reflected light

Illuminate sample with white light

System Diagram

Decrease image size to fit within 512 x 512 matrix

Magnification:~0.4

System Diagram

Apply Hadamard matrix using

DMD

1

1-1

-1

1

1

-1

-1

Compress image to 160um line

Disperse light spectrally using

spectrograph and collect image

using CCD camera

Apply inverse Hadamard

transform using computer

X

YSpectrum

System Diagram

System Output

Design Timeline

February: Align and test Stage 1; align DMD; align and test

Stage 2

March: Insert, align, and test spectrograph; test system

using reflectance standard to determine SNR; test

system using normal and tumor tissue samples

April: Continue testing and analysis; compile and present

findings at Senior Design Day