Human, molecular imaging

Winter PM, Caruthers SD, Yu X, Song SK, Chen J, Miller B, Bulte JW, Robertson JD, Gaffney PJ, Wickline SA, Lanza GM. Improved molecular imaging contrast agent for detection of human thrombus. Magn. Reson. Med. 2003 50 411-416. 

Fig. 3. Digitized matrices of mass-scattered electrons from single-average molecular images of human a-fetoprotein (A) and bovine a-fetoprotein (B) with respective contoured mass maps (C and D). Reproduced with permission from Luft and Lorsheider (1983). Copyright 1983 American Chemical Society.

Understanding Alterations During Human Brain Development with Molecular Imaging Role in Determining Serotonin and GABA Mechanisms in Autism... 

Because of the importance of animal work in drug development that later translates into clinical use in humans, much improved small animal PET scanners have been developed by manufacturers such as Siemens Medical Solutions, GE Healthcare, and Bioscan, and several scanners are now commercially available. The features of small animal PET scanners of the three manufacturers are given in Table 2.4. A small animal PET scanner is shown in Fig. 2.10. With the advent of molecular imaging, much progress can be achieved in PET imaging from the use of these improved scanners. 

Today, the world remains plagued by violence. Tens of thousands of young men and some women have died in the process of killing others, while their colleagues applaud their martyrdom. With weapons of mass destruction, even a few people can inflict enormous harm on millions of people. Today, terrorism is a major threat to humanity. With molecular imaging, the minds and behavior of terrorists can become a major focus of study and research. 

The longer half-lives of these reactor-produced tracers facilitated their availability and decreased their cost compared to cyclotron-produced radionuclides. Carbon-14 and tritium emitted oifly beta particles with a very short range in tissue, so they could not be used to examine regional biochemistry with radiation detectors pointed at the human body. Three decades were to elapse before physicians and scientists returned to the cyclotron as an important, indeed essential, tool in molecular imaging. 

Molecular imaging requires both the proper radioactive tracer and an instrument for imaging the tracer distribution witbin the living human body. Kuhl and Edwards (1963) were the first to describe tomography in nuclear medicine. Their invention preceded that of Houndsfield using x-ray transmission tomography (Figs. 6.2 and 6.3). 

In 1983,1 wrote, One of the most intriguing problems in biomedical research today is that of relating manifestations of neuropsychiatric disease to chemical processes in different parts of the brain. .. Much of what we know about the brain is based on the study of animals. The proper study of mankind is man. Animal models may not reflect normal or diseased human beings. With molecular imaging, we can address the questions what is happening in the chemistry of the human brain in relation to mental activity Why is it happening And how is it happening ... 

Molecular imaging of the chemical processes in the human brain can define the chemistry of excessively aggressive behavior and identify the brain chemistry related to the instincts of friendship, love, kindness, and charity. 

Organizing a system of disease classification based on molecular processes is the central problem. Hierarchies of holons can be built from molecular processes that are related to specific physiologic and pathophysiologic processes. On a foundation of genetics, molecular imaging can examine regional processes within the living human body in health and disease. 

The existence of free will has been debated for >2 millenia. Religions teach that human beings have free will and choose their actions from among various alternatives. They connect free will to moral responsibility. Free will necessitates that a person is responsible for his or her actions, but most people agree that biological processes beyond our control determine our actions. Molecular imaging can help correlate these biological factors with behavior. 

One of the most active areas of research in molecular imaging is the study of the effect of age. Suhara and colleagues used PET to study the age-related changes in human muscarinic acetylcholine receptors. In persons between the ages of 18 and 75, uptake of [ C]N-methyl piperidyl benzilate continuously increased in all brain areas with the exception of the cerebellum. The binding of the tracer to acetylcholine receptors in eight brain regions (pons, hippocampus, frontal cortex, striatum, temporal cortex, thalamus, occipital cortex, and parietal cortex) showed an age-related decrease of about 45%. 

Sharma V, Luker GD and Piwnica-Worms D. Molecular imaging of gene expression and protein function in vivo with PET and SPECT. JMagn Reson Imaging 2002 16 336-351. Shen DW, Fojo A, Chin JE, Roninson IB, Richer N, Pastan I et al. Human multidrug-resistant cell lines increased mdrl expression can precede gene amplification. Science 1986 232 643-645. 

Nuclear medicine - in particular, positron emission tomography (PET) - is one of the emerging, important fields of practical application of iodonium salts. PET is a powerful and rapidly developing area of molecular imaging that is used to study and visualize human physiology by the detection of positron-emitting radiopharmaceuticals [50-55], PET experiments provide direct information about metabolism, receptor/enzyme... 

---