International Conference on Medical Physics August 03-05, 2015 Birmingham, UK

Biography:

Dr. Barber completed his PhD in Physics in 2000 at the University of California Santa Cruz and postdoctoral studies at the University of California San Francisco School of Medicine in 2006. He is currently Vice President of Medical Imaging at DxRay Inc., and Development Engineer at Interon AS. He has published more than 34 papers in reputed journals including 5 invited paper and has been developing novel high flux photon counting x-ray imaging arrays for applications in radiology.

Abstract:

Energy integrating x-ray detectors are used in virtually all clinical x-ray systems including digital radiography (DR), digital mammography (DM), and computed tomography (CT). This is because of the high output count rate (OCR) required and detectors such as the energy dispersive photon counting x-ray detectors described in this presentation have been previously unobtainable. Photon counting detectors have the potential to significantly expand the diagnostic benefit of current clinical x-ray imaging applications provided they can achieve the required OCR while maintaining good energy resolution. Higher OCR is now obtainable due to the development of direct conversion semiconductor sensors connected to high throughput application specific integrated circuits (ASICs) which readout the fast signals from the sensors. In considering the development of photon counting detectors for clinical radiology sufficient performance in terms of the OCR and dynamic ranges, as well as the spatial and energy resolutions required for the specific application must be achieved. The sensors and ASICs used, as well as the methods for interconnecting the sensor pixels to the ASIC inputs, need to be designed with the ranges and resolutions required by the application kept in mind. Also modules need to be used which can be tiled with small dead space and preserved pixel pitch to achieve the required field of view (FOV). Sensor, ASIC, and interconnect design for application in clinical radiology will be discussed and clinical and preclinical results using CdTe, Si, and CdZnTe arrays for DR, DM, and CT respectively will be shown.

Biography:

The developed automated assessment methodology of LCD detectability performance in CT has the potential to effectively evaluate the effects of protocol parameters on image quality of different CT scanners and systems. The new phantom needs further improvement and the software should be also improved to increase the sensitivity and accuracy of their performance. Wider range of different kVp, mAs, slice thicknesses and other protocol parameters and different CT scanners should be also examined in future studies to ensure that the results conform to theory in a wider range of variables. \\r\\nCT IQFinv values were obtained objectively by the software and subjectively from radiographers’ assessment. The results from radiographers and software showed that the new methodology of CT image quality assessment was sensitive to changing kVp, mAs and slice thicknesses. \\r\\nConclusion: The developed automated assessment methodology of LCD detectability performance in CT has the potential to effectively evaluate the effects of protocol parameters on image quality of different CT scanners and systems. The new phantom needs further improvement and the software should be also improved to increase the sensitivity and accuracy of their performance. Wider range of different kVp, mAs, slice thicknesses and other protocol parameters and different CT scanners should be also examined in future studies to ensure that the results conform to theory in a wider range of variables. \\r\\n

Abstract:

Rationale: The essential principle of maintaining lower radiation dose and optimum image quality is to understand the effects of exposure factors on image quality. The evaluation method of low contrast detail (LCD) detectability performance—particularly the automated approach—is a good choice for deep understanding the influences of exposure parameters on image quality. However, this method requires a certain specification of an LCD phantom and dedicated software that are not commercially available. The study aimed to develop a new methodology of evaluation and optimisation of computed tomography (CT) image quality based on LCD detectability performance.\\r\\nMethodology: A new phantom was designed to obtain CT images of LCD. The specifications of the phantom design were optimised to satisfy the requirement of the new evaluation methodology of LCD detectability performance and based on evaluation of the limitations of available phantoms and the standard recommendations of phantom manufacturing. The phantom was manufactured with the cooperation of Artinis Medical Systems (Zetten, The Netherlands). A dedicated software was developed with the cooperation of Artinis Medical Systems to objectively evaluate the obtained CT images of the new phantom. The LCD detectability performance of CT images were measured by calculating the CT inverse image quality figure (CT IQFinv). The new methodology was validated by determining the influences of exposure factors of kVp and mAs, slice thicknesses and objects location within the phantom on the image quality in terms of CT IQFinv measurements. The validation was based on software and radiographers’ scoring results. \\r\\nResults: A new method of calculating the IQFinv values for CT images, CT IQFinv, was developed based on the method of calculating the IQFinv in digital radiography (Equation 1). A further requirement was the linear interpolation of the Hounsfield Units of the phantom’s objects to account for both positive and negative contrast values. \\r\\n

Biography:

Sarah S. Knox, received her PhD and MS degrees from Stockholm University (S.U.), Sweden; and began her career as a Principal Investigator at the Karolinska Institute in Stockholm.\r\nAfter spending many years at the National Institutes of Health, Dr. Knox came to WVU where her research interests have focused on a systems biology approach to carcinogenesis, integrating gene x environment interactions and biophysical signaling. She has published widely, reviews for a broad range of medical and scientific journals, and been the recipient of multiple honors and awards.

Abstract:

The strong focus on genetics in carcinogenesis research has somewhat obscured the important role of the microenvironment in regulating gene expression and controlling mutations. The membranes of all cells and mitochondria contain multiple ion channels that create a voltage gradient across the cell membrane, and combined with gap junctional currents create endogenous bioelectrical fields. These fields have long range effects on physiological functioning. Extensive research into multiple aspects of this bioelectric signaling system indicates that they play an important role in development, cell cycle progression, differentiation, migration and apoptosis; and interact with epigenetic mechanisms to influence gene expression. Depolarization (a prerequisite for the epithelial mesenchymal transition initiating tumor formation) has also been experimentally demonstrated to initiate mutagenic cell behavior in the absence of any primary tumor or genetic mutation. The current ‘targeted’ treatment modalities aim to bioengineer specific parts of signaling systems (e.g. kinases), but even in the most successful cases, inevitably perturb other, unintended components, having unintended consequences. Preliminary work on limb regeneration in frogs (the Levin lab) has demonstrated that an appropriate bioelectric signal can activate an entire subroutine to initiate limb regeneration, without micromanaging individual components. Implications for cancer therapeutics will be discussed.