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harmonize diagnosis and reporting in an innovative
optically-based breast cancer detection system.
2 DIAGNOSTIC METHODS
Currently, breast cancer detection encompasses three
stages. First, a physical examination or screening
mammography identifies an abnormality in the
breast tissue. Second, additional imaging modalities
may be used to help deciding if the third step, a
biopsy, is required (Nass et al., 2001).
Today, mammography is the most popular
diagnostic tool, however it has two main drawbacks:
(i) it is radiating, which can induce long term
negative effects on young women; (ii) it is
inefficient on dense breasts, which is typically the
case for young women.
Although most studies demonstrate a substantial
reduction in death rates from breast cancer among
women screened by mammography, women over
age 50 benefit the most. In fact, below age 50, the
value of mammography screening is less clear
(Eliceiri and Cheresh, 1998) because the greater
density of breast tissue in younger, premenopausal
women makes mammography results more difficult
to interpret, reaching the 50% of false negative or
positive reports.
Further investigation methods are breast
ultrasound, MRI and PET.
According to the National Cancer Institute,
however, about half of cancers detected by
mammography appear as a cluster of
microcalcifications and ultrasound does not
consistently detect it, nor detects very small tumors
(Angiogenesis Foundation, 2001).
Theoretically speaking, Breast MRI (Magnetic
Resonance Imaging) is a powerful imaging modality
in anatomical and physiological detection But the
drawback is that it is uncommon to use Breast MRI
in screening or follow-up because of the timing, cost
and sophisticated environment. Moreover, MRI
cannot detect microcalcifications (National Cancer
Institute, 2011).
Positron Emission Tomography (PET), that
requires radioactive substance injection into the
body, is an expensive and very invasive alternative.
Consequently, optical technology appears to
offer the best perspectives as far as scanning of
young women is concerned. Optical breast
examination (Dynamic Optical Breast Imaging,
DOBI) (Zhang et al.) is an innovative, non-invasive
methodology based upon the use of a red
monochromatic light beam. The DOBI method is a
functional examination of the breast that aims to
identify neoangiogenetic areas related to the onset of
cancer.
The system based on DOBI – ComfortScan - is
digital, operator-independent and easy-to-integrate
with any other diagnostic systems; it allows quick,
painless examinations and makes available new
functional physiological data.
3 DOBI
DOBI is based upon the tissue deoxyemoglobin light
absorption principle. Dynamic volumetric changes
in blood and deoxyhemoglobin absorption changes
are commonly found in malignant tumors and result
in a unique angiogenic “signature.” The DOBI
method allows to measure these changes by applying
mild uniform pressure to the breast. The change in
pressure traps blood in the tortuous angiogenic
structures that form around the tumor. This trapped
blood becomes deoxygenated up to four times faster
than normal tissue. ComfortScan, the DOBI-based
system, displays the effects of the changes in volume
and/or the changes in deoxyhemoglobin over time.
These changes appear as areas of low light level in
the ComfortScan images because of greater light
absorption. Normal or benign tissue, which has
normal vascular structures and a slower metabolic
rate, does not absorb as much light. Consequently, it
has a higher light level than malignant tumors.
3.1 ComfortScan Operation Principles
ComfortScan (Figure 1) is a system based on DOBI
and designed to detect dynamic (physiologic)
changes, increased blood volume levels and depleted
oxygen levels (deoxygenated haemoglobin), that
characterize malignancies. It consists of the
following primary components:
Figure 1: The ComfortScan System.
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