Diffusion-weighted whole-body imaging with background body signal suppression (DWIBS): features and potential applications in oncology

Diffusion-weighted magnetic resonance imaging (DWI) provides functional information and can be used for the detection and characterization of pathologic processes, including malignant tumors. The recently introduced concept of “diffusion-weighted whole-body imaging with background body signal suppression” (DWIBS) now allows acquisition of volumetric diffusion-weighted images of the entire body. This new concept has unique features different from conventional DWI and may play an important role in whole-body oncological imaging. This review describes and illustrates the basics of DWI, the features of DWIBS, and its potential applications in oncology

PRESSURE BROADENING AND SATURATION LINESHAPES OF CO AT PRESSURES BETWEEN 10−210^{-2} PA AND 10210^{2} PA

Author Institution: Institut f\""{u}r Angewandte Physik, der Universit\""{a}t BonnSaturated absorption lineshapes of rovibrational transitions in the CO fundamental band were measured at pressures between $10^{-2}$ Pa and $10^{2}$ Pa in pure CO, CO-He, and CO-Ar mixtures at a spectral resolution of better than $\delta\nu/\nu =10^{-9}$. Data was recorded using a new high resolution saturation spectrometer based on a CO fundamental band laser, frequency stabilized to narrow saturation dips in OCS by the use of tunable microwave sidebands. The laser has up to 40 mW of output power on the $v=1\to0$ band, a linewidth of less than 10 kHz, a long term frequency stability of better than $\Delta \nu/\nu=10^{-11}$, and is linearly tunable with full frequency control within the gain profile of each laser line. Absorption cells with lengths between 0.04 m and 24 m and beam diameters between 1 mm and 30 mm were used. The saturation signals mainly consist of narrow dips with a homogenous width that nonlinearly depends on pressure due to contributions of elastic as well as inelastic collisions and a broader, also pressure dependent background due to velocity changing collisions (VCC). A complex model is fitted to the data in order to separate different contribution to the lineshapes. Inelastic collisions as well as the VCC background can provide information about the intermolecular potentials and the well unterstood CO can serve as a model system for this approach