Catálogo de publicaciones - libros

The quest to improve the accuracy of radiotherapy delivery began right after the introduction of radiotherapy in the early 1900s. Some of the initial data for external beam radiation therapy of head and neck tumors was reported in the 1960s confirming the improved clinical efficacy with periodic portal films. This has led to bony landmark verification with periodic portal film verification.

Introduction: Local hyperthermia has been suggested for many purposes, e.g. tumor ablation, control of gene therapy, local drug delivery, heat-activated chemotherapy. Focused ultrasound (FUS) with a wavelength of about 1mm is capable of noninvasively depositing energy in a target area deep within the body. However, FUS energy absorption and heat conduction depend on tissue composition and physiological processes like perfusion. Hence continuous thermometry of the target area is necessary. MRI is an ideal tool for guiding FUS because of its unique temperature mapping capabilities, and its soft tissue contrast for target definition.

Research and translational pilot study of regernerative medicine for CVD on-going at the National Cardiovascular Center, Japan, will be reported at this meeting.

Radiation dosimetry is an important discipline in most areas of Radiation Medicine (radiotherapy, radiodiagnostics and nuclear medicine) and in Radiation Protection. In the extremes is, on the one hand, radiotherapy where modern dose escalation requires optimization of the dose delivered so that the highest levels can be achieved with minimum complications and morbidity, in consistency with what some call AHARA: as high as reasonably achievable. The other extreme is radiodiagnostics, where again there is a need for optimizing patient dose delivery to the lowest level which allows a clinically useful image: the old concept of ALARA. These optimization processes, intrinsic to the clinical procedure, form part of the quality management process which establishes standards of good practice and includes protecting patients by “doing the right thing”.

The search for materials that effectively bridge the electronics — biology interface is challenging but is being pursued with relentless vigour. Such materials must possess a unique combination of electrical, mechanical and bioactive/biocompatible properties. The discovery of organic conducting materials has fuelled the enthusiasm of those involved in this search. These materials including inherently conducting polymers and carbon nanotubes can be configured as electrode materials that enable us to transcend the chasm that is the bionic interface. Compositions with all of the prerequisite properties have been produced in recent years. A further exciting aspect of these materials is their dynamic properties. The fact mechanical, electrical and bio properties can be altered in response to small electrical stimuli — makes them highly effective bionic materials. They can be tuned to interact with selected biomolecules even to the extent that antibody-antigen binding events can be controlled or release of biologically active molecules such as nerve growth factors can be triggered. Mammalian cells can be cultured on these new material platforms with electrical stimulation used to promote proliferation. At the skeletal level wearable sensors can be used to monitor human movement and artificial muscles based on organic conductors used to control this movement. Nanostructuring of these organic conductors has been shown to increase their effectiveness as bionic materials. Delving into the nanodomain it has recently been discovered that a concomitant improvement in both mechanical and electrical properties can be achieved with significant ramifications for artificial muscle design. Our recent results on the design and synthesis of organic conductor materials as well as the fabrication of devices that enable effective communication with biomolecules, mammalian cells (including nerve cells) and with skeletal systems for monitoring and controlling movement will be presented here.

The lecture will cover recent technological developments relating to scanner mechanics, x-ray sources, and detector systems, but also to new designs such as C-arm-CT and micro-CT systems. The introduction of dual-source CT (DSCT) systems, which host two complete measurement systems and offer effective scan times of down to less than 100 ms, will be a particular focus. In the second part new applications such as cardiac CT, dual energy CT and navigated interventions will be discussed.

We introduce a differential equation system of order 3 describing the excitation of the muscle cell of heart. The model consider the driven oscillations of intracellular ionic-concentration in coupling with membrane potential under variation of a relaxation constant and the frequency of excitation. Solving varieties describing limited cycles, respectively driven oscillator are typically over an extensive range. That is not inconsistent with hitherto existing results of time series analysis (complexity analysis) on longtime-EKG-reception. Furthermore we discuss an possibly founded strange attractor of heart muscle cell excitation.

Conventional blood flow simulators needed to generate meshes, which had to have fine resolution at the segments where significant flow pattern changes occurred. So, to generate ideal meshes, excellent ability in mesh generation itself was essential, at the same time, detailed knowledge in flow analysis was important. These had been reasons why the flow simulation was not widely used in medical field. We developed a new blood flow simulator without mesh generation. Our system used voxel model as simulation. The voxel models were directly made from grey scale medical modalities such as CT-Angiography, MR-Imaging or 3D-Angiography. We applied our system to two models, one was the model of coil embolization for brain aneurysm, the other was protection for carotid artery stenting. In coil embolization model, flow pattern change in aneurysm sac were calculated giving various amount of coils. Increasing volume embolization ratio, flow velocity in the sac was decreased. If protrusion of coil crossing flow in the parent artery, flow in the sac possibly increase. In case of carotid artery stenting, protective balloon occlusion of distal internal carotid artery could not prevent migration of debris from the site of balloon angioplasty to external carotid artery. In coil embolization, our simulator successfully showed decrease of flow velocity in aneurysm sac depending on increasing amount of coil(s). The result was significant alert that the crossing protrusion of coils possibly increase flow in the aneurysm sac. At carotid artery stenting, debris to the ECA might cause brain ischemia because of possible ECA ICA anastomosis. Our simulator can work stably even extremely complex structure such as “coils in aneurysm” model without detailed knowledge on the computational fluid dynamics nor mesh generation. Moreover, voxel models were directly built from medical modalities without special knowledge. Here, our simulator can work well in practical medical field.

Molecular transport through the tunica media layer is influenced by the smooth muscle cells (SMCs). This study considers the media layer as a heterogeneous porous media composed of smooth muscle cells of elliptic and circular shapes distributed in ordered or disordered configurations. To study the role of SMCs on the transport of molecules in the media, we model the media layer as a two dimensional numerical simulation of interstitial flow through the media layer. The assumption of the elliptic shape resembles the spindled shape of SMCs. The molecular transport of ATP is considerably dependent of the shape of SMCs according to the results of our numerical model. More importantly, the ATP concentration was found to be extremely sensitive to the random configuration of SMCs, which is more close to the real arrangement of SMCs within the media layer

Both 2D and 3D mathematical models are constructed based on the co-ordinates measurement of a six time enlarged eye model. The graphical image is developed using Pro-E before exported into the COMSOL Multiphysics 3.2. The ocular surface temperature obtained for the 2D model is 33.64°C while the 3D model gives 34.48°C. The 3D model is further simulated for conditions under microwave radiation exposure (750MHz and 1.50GHz). A peak rise in temperature can be observed which agrees well with results from open literatures. These models can be improved by including more complex boundary conditions to simulate the eye to a higher degree of accuracy. The models studied here can be further applied for simulation of diseased eye by specifying proper boundary conditions with the types of diseases. Success of such simulations with appropriate neural network system will provide options for patients with third opinion regarding to the diagnosis of a particular ocular disease.