Daily organ tracking in intensity-modulated radiotherapy of prostate cancer using an electronic portal imaging device with a dose saving acquisition mode

BACKGROUND AND PURPOSE: Daily use of conventional electronic portal imaging devices (EPID) for organ tracking is limited due to the relatively high dose required for high quality image acquisition. We studied the use of a novel dose saving acquisition mode (RadMode) allowing to take images with one monitor unit per image in prostate cancer patients undergoing intensity-modulated radiotherapy (IMRT) and tracking of implanted fiducial gold markers. PATIENTS AND METHODS: Twenty five patients underwent implantation of three fiducial gold markers prior to the planning CT. Before each treatment of a course of 37 fractions, orthogonal localization images from the antero-posterior and from the lateral direction were acquired. Portal images of both the setup procedure and the five IMRT treatment beams were analyzed. RESULTS: On average, four localization images were needed for a correct patient setup, resulting in four monitor units extra dose per fraction. The mean extra dose delivered to the patient was thereby increased by 1.2%. The procedure was precise enough to reduce the mean displacements prior to treatment to < o =0.3 mm. CONCLUSIONS: The use of a new dose saving acquisition mode enables to perform daily EPID-based prostate tracking with a cumulative extra dose of below 1 Gy. This concept is efficiently used in IMRT-treated patients, where separation of setup beams from treatment beams is mandatory.

Introduction of a novel dose saving acquisition mode for the PortalVision aS500 EPID to facilitate on-line patient setup verification

In external beam radiotherapy, electronic portal imaging becomes more and more an indispensable tool for the verification of the patient setup. For the safe clinical introduction of high dose conformal radiotherapy like intensity modulated radiation therapy, on-line patient setup verification is a prerequisite to ensure that the planned dosimetric coverage of the tumor volume is actually realized in the patient. Since the direction of setup fields often deviates from the direction of the treatment beams, extra dose is delivered to the patient during the acquisition of these portal images which may reach clinical relevance. The aim of this work was to develop a new acquisition mode for the PortalVision aS500 electronic portal imaging device from Varian Medical Systems that allows one to take portal images with reduced dose while keeping good image quality. The new acquisition mode, called RadMode, selectively enables and disables beam pulses during image acquisition allowing one to stop wasting valuable dose during the initial acquisition of "reset frames." Images of excellent quality can be taken with 1 MU only. This low dose per image facilitates daily setup verification with considerably reduced extra dose.

Structured training in intraosseous infusion to improve potentially life saving skills in pediatric emergencies - Results of an open prospective national quality development project over 3 years

BACKGROUND: Children in emergencies need peripheral intravenous (IV) access in order to receive drugs or fluids. The success of IV access is associated with the age of patients and fails in up to 50% of children younger than 6 years. In such situations, it is essential that physicians and paramedics have a tool and easily learnable skills with a high chance of success. According to international guidelines intraosseous (IO) access would be the next step after failed IV access. Our hypothesis was that the success rate in IO puncturing can be improved by standardizing the training; so we developed an IO workshop. METHODS: Twenty-eight hospitals and ambulance services participated in an evaluation process over 3 years. IO workshops and the distribution of standardized IO sets were coordinated by the study group of the University Hospital of Berne. Any attempted or successful IO punctures were evaluated with a standardized interview. RESULTS: We investigated 35 applications in 30 patients (a total of 49 punctures) between November 2001 and December 2004. IO puncture was not successful in 5 patients. The success rate depended neither on the occupation nor the experience of users. Attendance at a standardized IO workshop increased the overall success rate from 77% to 100%, which was statistically not significant (P = 0.074). CONCLUSIONS: Standardized training in IO puncturing seems to improve success more than previous experience and occupation of providers. However, we could not show a significant increase in success rate after this training. Larger supranational studies are needed to show a significant impact of teaching on rarely used emergency skills.

Asynchronous ECG time sampling: Saving bits with Golomb-Rice encoding

We present a technique for online compression of ECG signals using the Golomb-Rice encoding algorithm. This is facilitated by a novel time encoding asynchronous analog-to-digital converter targeted for low-power, implantable, long-term bio-medical sensing applications. In contrast to capturing the actual signal (voltage) values the asynchronous time encoder captures and encodes the time information at which predefined changes occur in the signal thereby minimizing the sensor's energy use and the number of bits we store to represent the information by not capturing unnecessary samples. The time encoder transforms the ECG signal data to pure time information that has a geometric distribution such that the Golomb-Rice encoding algorithm can be used to further compress the data. An overall online compression rate of about 6 times is achievable without the usual computations associated with most compression methods.

Towards End-User Driven Power Saving Control in Android devices

Abstract. During the last decade mobile communications increasingly became part of people's daily routine. Such usage raises new challenges regarding devices' battery lifetime management when using most popular wireless access technologies, such as IEEE 802.11. This paper investigates the energy/delay trade-off of using an end-user driven power saving approach, when compared with the standard IEEE 802.11 power saving algorithms. The assessment was conducted in a real testbed using an Android mobile phone and high-precision energy measurement hardware. The results show clear energy benefits of employing user-driven power saving techniques, when compared with other standard approaches.

Saving the Australian War Effort in 1916? The Significance and Impact of Global Climatic Conditions and Pests on William Morris Hughes’ Negotiations with the British Government

Taking up the thesis of Dipesh Chakrabarty (2009) that human history (including cultural history) on the one hand and natural history on the other must be brought into conversation more than has been done so in the past, this presentation will focus more closely on the significance and the impact of global climatic conditions and pests on the negotiations that Australian Prime Minister William Morris Hughes carried on with the British government between March and November 1916. Whereas Australia had been able to sell most of its produce in 1914 and 1915 the situation looked more serious in 1916, not least due to the growing shortage in shipping. It was therefore imperative for the Australian government to find a way to solve this problem, not least because it wanted to keep up its own war effort at the pace it had been going so far. In this context intentions to make or press ahead with a contribution to a war perceived to be more total those of the past interacted with natural phenomena such as the declining harvest in many parts of the world in 1916 as a consequence of climatic conditions as well as pests in many parts of the world.

Saving soils at degradation frontlines: Sustainable land management in drylands

Healthy soils are fundamental to life. They grow the food we eat and the wood we use for shelter and fuel, purify the water we drink, and hold fast to the roots of the natural world we cherish. They are the ground beneath our feet and beneath our homes. But they are under threat, especially from human overuse and climate change. Nowhere is this more evident than in dryland areas, where soil degradation – or desertification – wears away at this essential resource, sometimes with sudden rapidity when a tipping point is crossed. Though it is a challenge, preserving and restoring healthy soils in drylands is possible, and it concerns all of us. Sustainable land management points the way.