Respiratory motion has significant effects on abdominal and lung tumor position, and incorporation of this uncertainty
increases volumes for focal cancer treatments. Respiratory correlated CT, obtained by oversampling images throughout
the respiratory cycle based on an external surrogate, is increasingly being used for radiation therapy planning.
Respiratory correlated CT is dependant on a fixed relationship between the external surrogate and the tumor, which may
change based on weight loss, breathing pattern changes or non-respiratory motion. Moreover, the process decouples
localization of the tumor (which is the goal of tumor directed therapy) with respiratory motion management. Recently,
implantable passive transponders (Calypso Medical Technologies) have been developed which can be tracked via an
external electromagnetic array in real-time and without ionizing radiation. We aimed to integrate wireless
electromagnetic tracking with multislice CT, and create volumetric datasets that are correlated to tumor position, as
opposed to an external surrogate. We call this process 'tumor correlated CT' (TCCT). Use of these images for
treatment planning will allow localization of the tumor to predict the position of other organs during treatment delivery.
We show the preliminary work in the integration of electromagnetic tracking and CT imaging.
It is well established that respiratory motion has significant effects on lung tumor position, and incorporation of this
uncertainty increases the normal lung tissue irradiated. Respiratory correlated CT, which provides three
dimensional image sets for different phases of the breathing cycle, is increasingly being used for radiation therapy
planning. Cone beam CT is being used to obtain cross sectional imaging at the time of therapy for accurate patient
set-up. However, it is not possible to obtain cross sectional respiratory correlated imaging throughout the course of
radiation, leaving residual uncertainties. Recently, implantable passive transponders (Calypso Medical
Technologies) have been developed which are currently FDA-cleared for prostate use only and can be tracked via an
external electromagnetic array in real-time, without the use of ionizing radiation. A visualization system needs to be
developed to quickly and efficiently utilize both the dynamic real-time point measurements with the previously
acquired volumetric data. We have created such a visualization system by incorporating the respiratory correlated
imaging and the individual transponder locations into the Image Guided Surgery Toolkit (IGSTK.org). The tool
already allows quick, qualitative verification of the differences between the measured transponder position and the
imaged position at planning and will support quantitative measurements displaying uncertainty in positioning.
Here, we present real-space studies of Brownian hard sphere transport though externally defined potential energy
landscapes. Specifically, we examine how colloidal particles are re-routed as moderately dense suspensions pass
through optical lattices, concentrating our attention upon the degree of sorting that occurs in multi-species flows.
While methodologies reported elsewhere for microfluidic sorting of colloidal or biological matter employ active
intervention to identify and selectively re-route particles one-by-one, the sorting described here is passive, with
intrinsically parallel processing. In fact, the densities of co-flowing species examined here are sufficient to allow for
significant many-body effects, which generally reduce the efficiencies of re-routing and sorting. We have studied
four classes of transport phenomena, involving colloidal traffic within, respectively, a static lattice with a DC fluid
flow, a continuously translating lattice with a DC fluid flow, a flashing lattice with AC fluid flow, and a flashing
lattice with combined AC and DC fluid flow. We find that continuous lattice translation helps to reduce nearest
neighbor particle distances, providing promise for efficiency improvements in future high throughput applications.
The growth of research into microfluidics, especially towards micro-Total Analysis Systems (μTAS), is leading to a demand for highly efficient and accurate methods for analyte delivery, sorting, mixing and analysis. Optical techniques, due to their non-invasive, non-contact properties are ideally suited to integration in to microfluidic systems. One of the key abilities in a μTAS device is the ability to sort microscopic matter. When done optically this typically involves fluorescence detection, management of the information detected and subsequent action such as the actuation of an electric field or electro-mechanical valve. We present here a method whereby the detection of a micro-particle's properties is done passively, with simultaneous separation of those particles. To do this particle streams are injected into a three-dimensional crystal-like lattice of optical intensity maxima. A particle's response to the three-dimensional optical potential landscape formed by the lattice depends on its polarisability. This leads to a sensitivity to size, refractive index and shape. More strongly interacting particles are deflected away from the main flow whilst those that interact weakly are washed straight through the lattice without little or no net deflection. We present analysis of both injection and subsequent re-routing/sorting of particle streams, using body-centred tetragonal and three-dimensional "log-pile" optical lattices to separate both inert colloid and blood cells by refractive index or size. Sorting with an efficiency as high as 96% has been achieved with particle deflections in excess of 45 degrees.