<P> Breast cancer has affected many women around the world throughout history. In order
to recognize and treat the early signs of breast cancer, obtaining high quality images is crucial. A
variety of imaging modalities are available for use in breast imaging, including conventional
mammography and newer optical imaging techniques. One such optical imaging system is the
ComfortScan™, which uses red light to image the breast and was the focus of this study. The
objectives include investigating whether performing a large scale clinical trial with the
ComfortScan TM would be warranted to further patient care and diagnostics for breast imaging,
and determining whether the ComfortScan ™ would achieve better correlation to biopsy than
mammography alone. An additional goal was to investigate whether the ComfortScan TM system
would be beneficial as a mainstream method for a radiologist to diagnose breast cancer risk. </p> <p> The preliminary study with 19 patients demonstrated that there was no difference in
diagnostic information between the near-infrared (NIR) image and mammography (p>O.OS).
Anecdotal evidence suggests cases where mammography disagreed with biopsy, whereas
ComfortScan TM agreed, though these were not statistically significant. Based on these
encouraging results, a large scale clinical trial was launched to investigate the potential of
widespread use of the ComfortScan ™. The large scale trial included 126 NIR images and
found difference in diagnostic information between NIR and mammography (p<O.OS).
Mammography agreed with biopsy in 18/33 and the ComfortScan™ system agreed with
biopsy in 25/33 cases. The sensitivity and specificity for the ComfortScan™ system was 83%
and 67%, respectively. The sensitivity and specificity of mammography was 94% and 13%,
respectively. This study included a variety of women with varying ages and BIRADS scores,
and demonstrated the effective clinical use of a portable, non-ionizing, inexpensive imaging modality, indicating that the ComfortScan ™ system could likely be successful as a mainstream
adjunct to mammography. </p> <p> The potential of using polyvinyl alcohol cryogel (PVA-C) as a breast tissue mimic was
investigated and PV A -C was then used to validate the mode of action of the ComfortScan TM
system. Two experimental methods reported the absorption coefficients and reduced scattering
coefficients of PV A-C. Using a double integrating sphere, the values were J.la = 0.012 ± 0.002
mm-1 and J.ls' = 1.5 ± 0.2 mm-1 and using steady-state spatially resolved diffuse reflectance, the
values were J.la = 0.017 ± 0.005 mm-1 and J.ls' = 1.3 ± 0.2 mm-1 at 640 nm. These values are
comparable to typical absorption coefficients for tissue reported by others. </p> <p> The mode of action suggested by DOBI (Dynamic Optical Breast Imaging) Medical
for the ComfortScan ™ system is that under compression a malignant tumour will highly
attenuate light, due to a partial collapse in the tumourous vasculature, resulting in an
increased deoxygenation of blood over time. Using a PV A-C breast mimicking phantom, it
was shown that by deoxygenating horse blood in a cavity, there was an increase in the
attenuation of 640 nm light as compared with the surrounding phantom material; which
suggests that the colour representative of malignancies on the ComfortScan ™ is caused by
deoxygenating blood. Further evidence suggests that the ComfortS can TM system is not
recognizing a total collapse of the vasculature and subsequent void of blood from the
tumour as the trigger for malignant detection. The mode of action suggested by DOBI
Medical is supported by our findings. </p> / Thesis / Doctor of Philosophy (PhD)
| Identifer | oai:union.ndltd.org:mcmaster.ca/oai:macsphere.mcmaster.ca:11375/19452 |
| Date | 12 1900 |
| Creators | Wilson, Kyle |
| Contributors | Moran, Gerald, Medical Physics |
| Source Sets | McMaster University |
| Language | English |
| Detected Language | English |
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