Critical reviews in biomedical engineering
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Image-guided ablation of tumors is assuming an increasingly important role in many oncology services as a minimally invasive alternative to conventional surgical interventions for patients who are not good candidates for surgery. Laser-induced thermal therapy (LITT) is a percutaneous tumor-ablation technique that utilizes high-power lasers placed interstitially in the tumor to deliver therapy. Multiple laser fibers can be placed into the treatment volume and, unlike other interstitial heating techniques, can be fired simultaneously to rapidly treat large volumes of tissue. ⋯ Additionally, because this approach to thermal therapy is easily made magnetic resonance (MR) compatible, the incorporation of magnetic resonance imaging (MRI) for treatment planning, targeting, monitoring, and verification has helped to expand the number of applications in which LITT can be applied safely and effectively. We provide an overview of the clinically used technology and algorithms that provide the foundations for current state-of-the-art MR-guided LITT (MRgLITT), including procedures in the brain, liver, bone, and prostate as examples. In addition to advances in imaging and delivery, such as the incorporation of nanotechnology, next-generation MRgLITT systems are anticipated to incorporate an increasing presence of in silico-based modeling of MRgLITT procedures to provide human-assisted computational tools for planning, MR model-assisted temperature monitoring, thermal-dose assessment, and optimal control.
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Crit Rev Biomed Eng · Jan 2009
ReviewAdvances in multimodality imaging through a hybrid PET/MRI system.
The development of integrated imaging systems for magnetic resonance imaging (MRI) and positron emission tomography (PET) is currently being explored in a number of laboratories and industrial settings. PET/MRI scanners for both preclinical and human research applications are being developed. PET/MRI overcomes many limitations of PET/computed tomography (CT), such as limited tissue contrast and high radiation doses delivered to the patient or the animal being studied. ⋯ In this review, we discuss motivations, challenges, and potential research applications of developing PET/MRI technology. A brief overview of both MRI and PET is presented and preclinical and clinical applications of PET/MRI are identified. Finally, issues and concerns about image quality, clinical practice, and economic feasibility are discussed.
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Force platforms and video tracking systems have been used to characterize subject movements and resultant forces to identify common characteristics of individuals who have experienced recurring falls. Short-term training using force platforms with feedback has been effective in reducing sway. Because of the expense and size requirements of these systems, researchers have pursued alternate means of quantifying postural motion. ⋯ This review article summarizes the main aspects of many of these designs and shows the high correlation of results obtained relative to video tracking methods. Most notably, measurements of the lower leg have reached correlation coefficients as high as 0.98 when using high-pass filters to eliminate signal drift. Many complications have been overcome, such that accelerometers and gyroscopes are considered acceptable for use in human motion measurement devices.