ABSTRACT
Over the past decade, advances in medical imaging have revolutionized the eld of cancer diagnosis and treatment. The use of computed tomography (CT), magnetic resonance imaging (MRI), and ultrasound has become standard practice for visualizing anatomical structures within the body. Newer developments including positron emission tomography (PET) and single photon emission computed tomography (SPECT) are capable of identifying the functional and molecular aspects of disease and when combined with anatomic imaging can provide improved detection and localization of even small neoplastic lesions [6]. While these systems have shown remarkable capabilities in preclinical and clinical use [24,39,49,52,69], they have limited spatial resolution (typically ranging from 100 μm to 5 mm) and thus cannot visualize alterations in tumor morphology, function, and architecture at the cellular level. To overcome this limitation, current diagnostic approaches still rely heavily on optical microscopy of stained cytology or histology specimens obtained from ne needle aspiration or open biopsies. Specimen collection by these methods is often invasive, painful, expensive, and samples only a small fraction of the suspicious tissue site, contributing to the limited sensitivity of such techniques [10,35,65].
