Page 12 - Cellular Imaging in Regenerative Medicine, Cancer and Osteoarthritis

Chapter 1
Introduction
Non-invasive imaging of cells in vivo plays a major role during diagnosis and therapy of various diseases. So, to understand the composition of a tissue or organ, or to visualize processes within a certain body area disease-related and labelled cells can be visualized. Such labels must first reach the cell, efficiently incorporate in the cell or attach to the cell and give a detectable signal (1) and next to that they should not affect the functionality of the cell (2). Cell labelling can be performed in a non-targeted manner; the label can be taken up in a cell, e.g. through endocytosis. Also targeted cell labelling is being applied; the label specifically binds a target, e.g. receptor or enzyme, on or in the cell. After labelling of the cells, they can be visualized using an imaging device. Depending on the imaging device the molecular, (patho)physiological and/ or anatomical changes of the cells/tissue/organ can be imaged using different methods:
• In case of the use of (super) paramagnetic labels magnetic resonance imaging (MRI) can be applied
• When the labels are radioactive, single photon emission computed tomography (SPECT) and positron emission tomography (PET) might be used
• With fluorescent/bioluminescent labels optical imaging (OI) is the technique of choice
• Bubbles filled with gas are used in ultrasound (US) imaging.
Within the focus of this thesis we will explain MRI, SPECT, CT and US technologies in more detail below. For detailed descriptions of these and other technologies the reader is referred to review papers (3, 4) and books (5-7) on this topic.
In this thesis we describe cellular imaging in regenerative medicine where damaged or aged tissue needs to be substituted with healthy cells to regain a proper function of the tissue. We also address cancer cell imaging, it is of importance to detect tumour cells to establish the location and spread of the tumour to decide on/or to investigate options for therapy, and to detect any changes in tumour growth. Finally, we also focused on imaging of specifically
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