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Current head and neck cancer diagnosis and treatment planning suffers from poor spatial resolution of whole-body positron emission tomography (PET) scans. A dedicated two-panel positron emission tomography system is developed to improve head and neck cancer management. The two-panel design was selected considering human factors to assist with patient comfort by removing detectors closer to eyesight of the patient and assist with optimal workflow in the PET environment. The proposed system will be the first head and neck scanner to exhibit features as small as 1 mm with high photon sensitivity, enabled by the use of high energy and spatial resolution properties of cadmium zinc telluride (CZT) crystals. The panels will be used right after standard PET, using the same bed and FDG dose. A novel event recovery scheme based on the 3D position sensitive cross-strip crystals is developed to recover multiple interaction photon events, reject random events, and significantly increase the photon sensitivity of the system. A penalized maximum-likelihood method with an image-based resolution model incorporated into a regularization term was considered to improve limited angle artifacts in reconstructed images of two panels using the whole-body image as prior.

Sugars are common ingredients for many commercial cryopreserving agents used in the long term preservation of biological tissues and proteins. However, their mechanism in this role is not resolved yet. Some believe that sugars preferentially bind with a protein thereby replacing ice-forming water. Others argue that aqueous sugars are easily vitrified into non-crystalline solid at sufficiently high concentrations, which avoids the formation of ice crystals. In an attempt to test the former idea, we have undertaken studies of the diffusion of L-tryptophan and streptavidin-coated polystyrene spheres (340 tryptophan residues on each) using fluorescence correlation spectroscopy in an effort to determine whether the hydrodynamic radius is influenced by the addition of sugar. Some novelty of our approach lies in exploiting the native fluorescence of tryptophan by use of two-photon excitation. Photon correlation spectroscopy was also utilized to check the results of fluorescence correlation spectroscopy. However, the two techniques showed different results.

Sugars are common ingredients for many commercial cryopreserving agents used in the long term preservation of biological tissues and proteins. However, their mechanism in this role is not resolved yet. Some believe that sugars preferentially bind with a protein thereby replacing ice-forming water. Others argue that aqueous sugars are easily vitrified into non-crystalline solid at sufficiently high concentrations, which avoids the formation of ice crystals. In an attempt to test the former idea, we have undertaken studies of the diffusion of L-tryptophan and streptavidin-coated polystyrene spheres (340 tryptophan residues on each) using fluorescence correlation spectroscopy in an effort to determine whether the hydrodynamic radius is influenced by the addition of sugar. Some novelty of our approach lies in exploiting the native fluorescence of tryptophan by use of two-photon excitation. Photon correlation spectroscopy was also utilized to check the results of fluorescence correlation spectroscopy. However, the two techniques showed different results.