PhD Position - Visualization for Digital Radiation Therapy

Job description

Research group

The 'DR THERAPAT' project comprises multiple and diverse scientific and technical challenges. Therefore, the project will be developed by a multidisciplinary team from leading academic and research institutions worldwide. The PhD student will be embedded in this team formed by Philips Research (Hamburg) and Healthcare (The Netherlands), Stichting Antoni van Leeuwenhoek Ziekenhuis (The Netherlands), Katholieke Universiteit Leuven (Belgium), Aarhus Universitet (Denmark), The Institute of Communication and Computer Systems (Greece) and Eindhoven University of Technology (TU/e - The Netherlands) where the PhD student will be located.

The PhD student will also be embedded in the Multivalued Image Analysis & Visualization group (bmia.bmt.tue.nl/research/MVIAV/) led by dr. Anna Vilanova.  This group is part of the recently TU/e established Imaging Science and Technology Eindhoven (IST/e, cf. www.iste.nl) High Potential Research Program which has the ambition to become a leading research institute on the crossroads of image acquisition, mathematical modeling, algorithmic, visualization and biomedical applications on the basis of advanced imaging techniques. This ambitious goal is feasible through synergy of perfectly complementary research groups within TU/e and their collaborative partners, such as Philips Healthcare, and regional and academic medical centers.

Project description

This PhD position is part of the FP7 EU-STREP project 'DR THERAPAT'- Digital Radiation Therapy Patient'. This project is based on the past decade advances in radiation therapy technology, offering exceptional flexibility in dose delivery. Image guidance during treatment ensures a reliable targeting of the dose to the tumor. This has created the possibility to irradiate the tumor with a high dose with minimal exposure of surrounding tissue. Thus an improvement in tumor control is no longer invariably associated with an increase in radiation-induced toxicity. Now, the capacity exists to create treatment plans that are tailored to the specific characteristics of the patient. However, an individualized representational model that informs on radiation therapy planning and outcome prediction is still lacking. There are several modeling approaches available that have the potential to fill this gap, among them empirical, but established radiobiological models and more sophisticated multi-scale models.

DR THERAPAT aim is to create the Digital Radiation Therapy Patient, integrating the available knowledge on tumor imaging, image analysis and interpretation, radiobiological models and radiation therapy planning into a reusable, multi-scale digital representation.

The PhD appointed to this position will work in the visualization of the multimodal and multi-value data that plays a role throughout the complete model-based radiotherapy planning pipeline. Prior to the radiotherapy modeling, different imaging modalities will be combined by means of image registration, relevant anatomical structures will be segmented, multiple parameters will be quantified and different tissues will be classified. The resulting multitude of information is the input for the patient-specific radiotherapy modeling. We aim at methods for the visualization and exploration of all relevant information in the radiotherapy planning pipeline; we especially focus on methods that incorporate the uncertainty that is introduced in each step in the pipeline.

The goal is to achieve an easy-to-use and easy-to-understand visualization and exploration of the multimodal, multi-value data involved in cancer radiotherapy planning - including the uncertainty in these data - in each step of the radiotherapy planning pipeline and in the final planning outcome.

Tasks 

Study of data visualization and exploration methods currently used in radiotherapy

Study and modeling using probability theory of the uncertainty (e.g. noise) in the image data acquired with the multimodal imaging modalities involved in radiotherapy planning.

Study and modeling of the propagation and accumulation of uncertainty in the multimodal image registration, segmentation & quantification steps.

Analysis and implementation of methodology for the comprehensive visualization and interactive exploration of the multimodal, multi-value information and its uncertainty: data mining, visual analysis and real-time user interaction will be combined to optimally facilitate the visual representation and exploration of this multidimensional information and its uncertainty.

Analysis, development and implementation of methods for the visualization of the effect of uncertainty in the tissue modeling and therapy planning results.

Evaluation of the effectiveness of the developed visualization and exploration methods.

 

Requirements

Requirements

We are looking for a candidate who meets the following requirements: 

You are a talented and enthusiastic researcher.

You have experience with or a strong background in visualization, computer graphics, mathematics, and image processing. Preferably you finished a master in Computer Science, (Applied) Mathematics, (Applied) Physics or Electrical Engineering.

You have excellent programming skills and experience.

You have good communicative skills, and the attitude to partake successfully in the work of a multidisciplinary      research team.

You are creative, ambitious, hard working and persistent.

You have good command of the English language (knowledge of Dutch is not required).

 

Conditions of employment

Appointment and Salary

We offer:

A challenging job at a dynamic and ambitious University and in an enthusiastic team

An appointment for four years

Gross monthly salaries are in accordance with the Collective Labor Agreement of the Dutch Universities (CAO NU), increasing from € 2042 per month initially, to € 2612 in the fourth year.

An attractive package of fringe benefits, including excellent work facilities, end of the year allowance and sport facilities.

TU/e offers opportunities for personal development by developing your social and communication skills. We do this by offering every PhD student a series of courses that are part of the PROOF program as an excellent addition to your scientific education.

Additional information

Information and application

More information on the vacancy and project can be obtained from Dr. Anna Vilanova (a.vilanova@tue.nl) or Prof. Marcel Breeuwer (M.Breeuwer@tue.nl)

For terms of employment please take a look at our website www.tue.nl or contact HR Services

Postdoc Opening in Radiation Biology with Auger Electron Emitters

A two years Postdoc position in the area of Experimental Radiation Biology will be available starting 1 January 2012 or soon thereafter. This new position is part of a larger project at the Hevesy Lab at Risø, DTU (Technical University of Denmark) focused on development of radionuclide cancer therapy based on Auger Electron emitters.

Job description
DTU wishes to setup a new method for experimental verification of the (often unknown) relative biological effectiveness of Auger emitters when decaying inside the cell nucleus of proliferating cancer cells. We have built a new lab for this specific purpose, focusing on cellular scale microinjections of radioactivity in individual cancer cells in culture.

For this, DTU needs a devoted experimental scientist. The work area is interdisciplinary, and we are very open to the educational, scientific or occupational background of the applicants. This new field straddles nuclear and atomic physics, radiochemistry, cell biology and radiation biology. Candidates with hands on experience from microinjections, cancer cell cultures, evaluation of radiation damage at DNA level or similar are highly encouraged to apply.

The Postdoc will work in close collaboration with our professor Mikael Jensen and the Hevesy Lab. group. The group has already experience with several of the involved methods, but the successful combination of quantitative microinjections of radioactivity with microscopic DNA damage readout is a totally new tool. If successful, the experimental method will have great impact on the future of internal dosimetry in general, and much further experimental work is expected.

Qualifications
A candidate must have a relevant PhD degree or equivalent and preferably some years of experience in experimental research. Emphasis will be placed on the candidate’s research potential and commitment concerning the actual project.

You will become part of a young and devoted group (22 people at present) of radiation researchers in the Hevesy Lab. They develop and supply cutting edge radiopharmaceuticals for both biomedical research and for routine use in diagnosis and therapy.

Salary and terms of employment
The appointment will be based on the collective agreement with the Confederation of Professional Associations. The period of employment is two years. The place of work will be Risø DTU in Roskilde.

Applications
DTU must have your online application in English by 1 November 2011. Please open the “apply online” and fill in the application form and attach your application, CV, diploma and a list of publications. Applications should be submitted in English.

Applications and enclosures received after the deadline will not be considered.

All interested candidates irrespective of age, gender, disability, race, religion or ethnic background are encouraged to apply.

Further information
Further information can be obtained from Prof. Mikael Jensen, +45 2625 5890, kmje@risoe.dtu.dk.

Apply online for this job

Low Dose CT

Computed Tomography technology has revolutionized medicine in the last decade as it can provide cross-sectional snapshots deep inside someone's body with unprecedented clarity. These images help doctors diagnose unseen illnesses and injuries, and they guide treatment for millions of people per year around the world. Yet for years, its imaging power has been constrained by the need to limit the radiation dose delivered to patients. In order to lessen concerns over radiation and open the door into new areas, even lower dose techniques have been developed.

High Definition & Low Dose Computed Tomography
The development of the world’s first high-definition CT scanner is one of the technological innovations in imaging that will revolutionize the way doctors view CT image clarity and capability for their patients. Building upon the natural properties of a garnet gemstone, scientists at GE have created the first new CT scintillator material in 20 years — making the world’s first HDCT scanner — the Discovery™ CT750 HD — possible. This CT scanner marks the next generation of CT imaging that delivers better image clarity at faster detector speeds than ever before and with the ASiR™* dose reduction technology to significantly reduce X-ray dose. Moreover, Gemstone™ Spectral Imaging is a revolutionary advanced imaging application that is exclusive to the Discovery CT750 HD. With this technology, clinicians and doctors are able to confidently diagnose disease delivering world-class patient care. (*Adaptive Statistical Iterative Reconstruction).

Click here to know the scientists behind.
Click here to know the details of  Discovery CT750 HD.

Healthy dose of freedom with ASiR™: High Image Quality and Low Dose

Today, thanks to innovation ASiR technology from GE, clinicians have the freedom to lower patient dose dramatically without compromising image quality. ASiR technology is especially beneficial in higher risk populations, such as children and young women, in whom the greater sensitivity of growing tissues makes strict dose limitation a real necessity. Based on wide experience in patients scanned with ASiR, GE customers can attest to consistently high image quality with low dose levels throughout the entire CT product range.

View video: Dose less is more
Low Dose CT: Learn more
Low Dose CT: healthymagination Factsheet
View video: ASiR- Ease of Use 
Discovery CT750HD: Clinical Cases
LightSpeed™ VCT XTe: New clinical dimensions 
BrightSpeed™ Elite with ASiR: Small Giant

Integrating Dose Reduction techniques across Clinical Education Curriculum

GE Healthcare’s CT Clinical Education team is integrating Dose reduction techniques across its range of different customer training offerings. This starts right from the initial on-site applications visit through to the various customer support re-visits. During these sessions the CT Clinical Education Specialist will work with the customer to optimise their protocols using the latest ASiR technology where appropriate to achieve the highest level of Image Quality possible at the lowest achievable dose. Dose Reduction is fast becoming one of the key modules within the Classroom based and Doctor-to-Doctor offerings targeting the educational needs of both the Radiographers and Radiologists/Cardiologists.

Click here to know about training education.

LINEAR ACCELERATOR (LINAC)

A linear particle accelerator (also called a linac) is an electrical device for the acceleration of subatomic particles. This sort of particle accelerator has many applications, from the generation of X-Rays in a hospital environment, to an injector into a higher energy synchrotron at a dedicated experimental particle physics laboratory. The design of a linac depends on the type of particle that is being accelerated: electron, proton or ion. They range in size from a cathode ray tube to the 2-mile long Stanford Linear Accelerator Center in California.



CONSTRUCTION & OPERATION

A linear particle accelerator consists of the following elements:

1.)The particle source. The design of the source depends on the particle that is being accelerated. Electrons are generated by a cold cathode, a hot cathode, a photocathode, or RF ion sources. Protons are generated in an ion source, which can have many different designs. If heavier particles are to be accelerated, (e.g. uranium ions), a specialized ion source is needed.

2.)A high voltage source for the initial injection of particles.

3.)A hollow pipe vacuum chamber. The length will vary with the application. If the device is used for the production of X-rays for inspection or therapy the pipe may be only 0.5 to 1.5 meters long. If the device is to be an injector for a synchrotron it may be about ten meters long. If the device is used as the primary accelerator for nuclear particle investigations, it may be several thousand meters long.

4.)Within the chamber, electrically isolated cylindrical electrodes whose length varies with the distance along the pipe. The length of each electrode is determined by the frequency and power of the driving power source and the nature of the particle to be accelerated, with shorter segments near the source and longer segments near the target. The mass of the particle has a large effect on the length of the cylindrical electrodes; for example an electron is considerably lighter than a proton and so will generally require a much larger section of cylindrical electrodes as it accelerates very quickly - think about a concrete ball and a tennis ball; it is easier to accelerate the tennis ball from rest (this comes about because of the kinetic energy 1/2 mv2 being equal to the energy gained by the electron as it is accelerated through the potential difference, usually in the region of 5KV.)

5.)One or more sources of radio frequency energy, used to energize the cylindrical electrodes. A very high power accelerator will use one source for each electrode. The sources must operate at precise power, frequency and phase appropriate to the particle type to be accelerated to obtain maximum device power.

6.)An appropriate target. If electrons are accelerated to produce X-rays then a water cooled tungsten target is used. Various target materials are used when protons or other nuclei are accelerated, depending upon the specific investigation. For particle-to-particle collision investigations the beam may be directed to a pair of storage rings, with the particles kept within the ring by magnetic fields. The beams may then be extracted from the storage rings to create head on particle collisions.

As the particle bunch passes through the tube it is unaffected (the tube acts as a Faraday cage), while the frequency of the driving signal and the spacing of the gaps between electrodes are designed so that the maximum voltage differential appears as the particle crosses the gap. This accelerates the particle, imparting energy to it in the form of increased velocity. At speeds near the speed of light, the incremental velocity increase will be small, with the energy appearing as an increase in the mass of the particles. In portions of the accelerator where this occurs, the tubular electrode lengths will be almost constant.

i.)Additional magnetic or electrostatic lens elements may be included to ensure that the beam remains in the center of the pipe and its electrodes.
ii.)Very long accelerators may maintain a precise alignment of their components through the use of servo systems guided by a laser beam.



TYPES OF ACCELERATOR

The acceleration of the particles can be made with three general methods:

1.)Electrostatically: The particles are accelerated by the electric field between two different fixed potentials. Examples include the Van de Graaf, Pelletron and Tandem accelerators.

2.)Induction: A pulsed voltage is applied around magnetic cores. The electric field produced by this voltage is used to accelerate the particles.

3.)Radio Frequency (RF): The electric field component of radio waves accelerates particles inside a partially closed conducting cavity acting as a RF cavity resonator. Examples include the travelling wave, Alvarez, and Wideroe cavity type accelerators.


ADVANTAGES

Linacs of appropriate design are capable of accelerating heavy ions to energies exceeding those available in ring-type accelerators, which are limited by the strength of the magnetic fields required to maintain the ions on a curved path. High power linacs are also being developed for production of electrons at relativistic speeds, required since fast electrons traveling in an arc will lose energy through synchrotron radiation; this limits the maximum power that can be imparted to electrons in a synchrotron of given size.

Linacs are also capable of prodigious output, producing a nearly continuous stream of particles, whereas a synchrotron will only periodically raise the particles to sufficient energy to merit a "shot" at the target. (The burst can be held or stored in the ring at energy to give the experimental electronics time to work, but the average output current is still limited.) The high density of the output makes the linac particularly attractive for use in loading storage ring facilities with particles in preparation for particle to particle collisions. The high mass output also makes the device practical for the production of antimatter particles, which are generally difficult to obtain, being only a small fraction of a target's collision products. These may then be stored and further used to study matter-antimatter annihilation.

As there are no primary bending magnets, this cost of an accelerator is reduced.

Medical grade linacs accelerate electrons using tuned-cavity waveguide in which the RF power creates a standing wave. Some linacs have short, vertically mounted waveguides, while higher energy machines tend to have a horizontal, longer waveguide and a bending magnet to turn the beam vertically towards the patient. Medical linacs utilise monoenergetic electron beams between 4 and 25 MeV, giving an x-ray output with a spectrum of energies up to and including the electron energy when the electrons are directed at a high-density (such as tungsten) target. The electrons or x-rays can be used to treat both benign and malignant disease. The reliability, flexibility and accuracy of the radiation beam produced has largely supplanted cobalt therapy as a treatment tool. In addition, the device can simply be powered off when not in use; there is no source requiring heavy shielding.

DISADVANTAGES

1.)The device length limits the locations where one may be placed.

2.)A great number of driver devices and their associated power supplies are required, increasing the construction and maintenance expense of this portion.

3.)If the walls of the accelerating cavities are made of normally conducting material and the accelerating fields are large, the wall resistivity converts electric energy into heat quickly. On the other hand superconductors have various limits and are too expensive for very large accelerators. Therefore, high energy accelerators such as SLAC, still the longest in the world, (in its various generations) are run in short pulses, limiting the average current output and forcing the experimental detectors to handle data coming in short bursts.

GAMMA KNIFE

Gamma Knife is a neurosurgical device used to treat brain tumors with radiation therapy. The device was invented by Lars Leksell, a Swedish neurosurgeon, in 1967 at the Karolinska Institute in Sweden.

The Leksell Gamma Knife device contains 201 cobalt-60 sources of approximately 30 curies (1.1 TBq) each, placed in a circular array in a heavily shielded assembly. The device aims gamma radiation through a target point in the patient's brain. The patient wears a specialized helmet that is surgically fixed to their skull so that the brain tumor remains stationary at target point of the gamma rays. A killing dose of radiation is thereby sent through the tumor in one treatment session, while all surrounding brain tissues receive less than a killing dose.

FEATURES OF GAMMA KNIFE

Radiosurgery uses high doses of radiation to kill cancer cells and shrink tumors, delivered with surgical precision to avoid damaging healthy brain tissue. The key to the success of Gamma Knife surgery is its ability to accurately focus many beams of high-intensity gamma radiation to converge on one or more tumors. Each individual beam is relatively low energy, so the radiation has virtually no effect on healthy brain tissue.

APPLICATIONS

Gamma Knife surgery has proved effective for thousands of patients with benign or malignant brain tumors, vascular malformations such as an arteriovenous malformation (AVM), pain or other functional problems. The procedure is less invasive than alternative surgeries such as micro-decompression. For treatment of trigeminal neuralgia the procedure may be used repeatedly on patients.

RISKS

The risks of Gamma Knife radiosurgery treatment include but are not limited to radiation necrosis, secondary malignancy caused by the radiation (ie: formation of new tumor), hemorrhage, infection from the placement of the stereotactic headframe, paralysis and death.

ACTINOTHERAPY

1.)Actinotherapy: Use of radiation such as UV and x-rays to treat conditions such as skin disorders.

2.)It is also the treatment of disease (especially cancer) by exposure to radiation from a radioactive substance.