Page 64 - Bio Engineering Approaches to Cancer Diagnosis and Treatment

62 CHAPTER 3 Immune assay assisted cancer diagnostic

diagnosis only four of these techniques due to three-dimensional imaging feature
which they have can help in detection of cancer cells. As it has been mentioned,
imaging is designed for various illnesses, and it's not designed for cancer cell detec-
tion alone. This technique doesn’t have ability to detect small tumor cells, so the
diagnosis of cancer requires designing and modifying these techniques or combining
them with new techniques for rapid, sensitivity and high selectivity detection [47,48].
As the specificity and accuracy of cancer investigation is critical, recent studies
focus more on the combined use of imaging and other immunodiagnostic assays for
maximum effectiveness.
Molecular imaging is a novel technique that has the potential to enhance the
diagnostic and therapeutic approaches for cancer treatment. Historically for solid
tumors, the methods were used regular imaging modalities such as ultrasonography
(US), CT, MRI, and PET. These were not accurate in detecting the biochemical or
molecular stage of the neoplastic cell. Molecular Imaging also enhanced the induc-
ible “smart” molecular MRI probes because of their potential for imaging tumors
before and after surgical removal, without a renewal of the probe to evaluate the
accuracy of surgical resection. Moreover, these smart MR/optical imaging probes
can be used in screening programs for the detection of small tumors. New methods
have been investigated today and this includes the dual labeling of molecular MR
probes with fluorescent dyes. By the development of this technique detection of can-
cerous tissue from healthy tissue become more facile.
In general, the main aim of scientists is detecting malignancies at an earlier state.
In imaging methods, this aim has led to development in techniques such as US,
CT, and MRI, however they could not delineate the detection of solid tumors [49].
Molecular imaging techniques vastly improve cancer diagnosis through display-
ing entirely new possibilities for early detection and effective treatment of cancer;
two factors that are crucial to successfully fighting the disease. Molecular imaging
is commonly defined as a noninvasive method of imaging cellular and subcellular
occurrences. The operation of molecular imaging is based on the distinctive molecu-
lar characteristics of malignant cells. Molecular imaging probes detect and highlight
these specific characteristics which can be exhibited in, or on any side of each malig-
nant cells, or in the rounding of extracellular matrix and cells in the vicinity, such
as T cells, dendritic cells, fibroblasts, macrophages, or endothelial cell. Therefore,
molecular imaging of these malignant cells enhances the cancer diagnosis and stag-
ing, and makes it easier for tumor detection. Traditional imaging technique such as
US, CT, and MRI do not have this ability, however today, detection is continuously
developed through the use of molecular imaging.
With all of these new techniques, tumor detection is still based on anatomical
characteristics. Recent studies have shown that molecular imaging can detect carci-
nogenesis at a much earlier time as it can detect alterations on the cellular level, and
they are targeted as soon as they occur. For example, signaling changes in malignant
cells’ glucose metabolism occur early in carcinogenesis and it is detectable by molec-
ular imaging. PET imaging with F-FDG is another technique for detection of these
changes, however compared to molecular imaging, it has a limited ability to detect