Cone beam CT plays an essential role in image-guided radiation therapy (IGRT), a state-of-the-art cancer treatment. IGRT uses repeated scans during a course of radiation therapy to precisely target tumors and minimize radiation damage in surrounding tissue. Though IGRT has improved outcomes, the large cumulative radiation dose from the repeated scans has raised concerns among physicians and patients.
Reducing the total number of X-ray projections and the mAs level per projection (by tuning down the X-ray generator pulse rate, pulse duration and/or current) during a CT scan can help minimize patient’s exposure to radiation, but the change results in noisy, mathematically incomplete data that takes hours to process using the current iterative reconstruction approaches. Because CBCT is mainly used for treatment setup while patients are in the treatment position, fast reconstruction is a requirement, explains lead author Xun Jia, a UCSD postdoctoral fellow.
Based on recent advances in the field of compressed sensing, Jia and his colleagues developed an innovative CT reconstruction algorithm for graphic processing unit (GPU) platforms. The GPU processes data in parallel –-- increasing computational efficiency and making it possible to reconstruct a cone beam CT scan in about two minutes. (Modern GPU cards were originally designed to power 3D computer graphics, especially for video games.)
With only 20 to 40 total number of X-ray projections and 0.1 mAs per projection, the team achieved images clear enough for image-guided radiation therapy. The reconstruction time ranged from 77 to 130 seconds on an NVIDIA Tesla C1060 GPU card, depending on the number of projections –-- an estimated 100 times faster than similar iterative reconstruction approaches, says Jia.
Compared to the currently widely used scanning protocol of about 360 projections with 0.4 mAs per projection, Jia says the new processing method resulted in 36 to 72 times less radiation exposure for patients.
“With our technique, we can reconstruct cone beam CT images with only a few projections -- 40 in most cases -- and lower mAs levels,” he says. “This considerably lowered the radiation dose.”
The reconstruction algorithm is part of the UCSD group’s effort to develop a series of GPU-based low dose technologies for CT scans.
“In my mind, the most interesting and compelling possibilities of this technique are beyond cancer radiotherapy,” says Steve Jiang, senior author of the study and a UCSD associate professor of radiation oncology.
“CT dose has become a major concern of medical community. For each year’s use of today’s scanning technology, the resulting cancers could cause about 14,500 deaths.
“Our work, when extended from cancer radiotherapy to general diagnostic imaging, may provide a unique solution to solve this problem by reducing the CT dose per scan by a factor of 10 or more,” says Jiang.
"This work is partially funded by the University of California Laboratory Fees Research Program. We also used GPU cards provided by NVIDIA for this project."The presentation "GPU-Based Fast Cone Beam CT Reconstruction From Undersampled and Noisy Projection Data Via Total Variation" by X Jia et al. will be at 4:00 p.m. on Wednesday, July 21 in room 201B of the Philadelphia Convention Center.
ABSTRACT: http://www.aapm.org/meetings/amos2/pdf/49-13505-3328-390.pdfMORE MEETING INFORMATION
The presentations at the AAPM meeting will cover topics ranging from new ways of imaging the human body to the latest clinical developments on treating cancer with high energy X-rays and electrons from accelerators, brachytherapy with radioactive sources, and protons. Many of the talks and posters are focused on patient safety -- tailoring therapy to the specific needs of people undergoing treatment, such as shaping emissions to conform to tumors, or finding ways to image children safely at lower radiation exposures while maintaining good image quality.RELATED LINKS
Advanced registration form online: http://www.aapm.org/meetings/2010AM/VirtualPressRoom/documents/pressregform.pdf
Press registration on-site will take place at the AAPM Registration Desk, 200 Level Bridge just outside Hall A-B in the Pennsylvania Convention Center.
Questions about the meeting or requests for interviews, images, or background information should be directed to Jason Bardi (firstname.lastname@example.org, 858-775-4080).ABOUT MEDICAL PHYSICISTS
Jason Socrates Bardi | Newswise Science News
Black hole spin cranks-up radio volume
15.01.2018 | National Institutes of Natural Sciences
The universe up close
15.01.2018 | Georg-August-Universität Göttingen
What enables electrons to be transferred swiftly, for example during photosynthesis? An interdisciplinary team of researchers has worked out the details of how...
For the first time, scientists have precisely measured the effective electrical charge of a single molecule in solution. This fundamental insight of an SNSF Professor could also pave the way for future medical diagnostics.
Electrical charge is one of the key properties that allows molecules to interact. Life itself depends on this phenomenon: many biological processes involve...
At the JEC World Composite Show in Paris in March 2018, the Fraunhofer Institute for Laser Technology ILT will be focusing on the latest trends and innovations in laser machining of composites. Among other things, researchers at the booth shared with the Aachen Center for Integrative Lightweight Production (AZL) will demonstrate how lasers can be used for joining, structuring, cutting and drilling composite materials.
No other industry has attracted as much public attention to composite materials as the automotive industry, which along with the aerospace industry is a driver...
Scientists at Tokyo Institute of Technology (Tokyo Tech) and Tohoku University have developed high-quality GFO epitaxial films and systematically investigated their ferroelectric and ferromagnetic properties. They also demonstrated the room-temperature magnetocapacitance effects of these GFO thin films.
Multiferroic materials show magnetically driven ferroelectricity. They are attracting increasing attention because of their fascinating properties such as...
The oceans are the largest global heat reservoir. As a result of man-made global warming, the temperature in the global climate system increases; around 90% of...
08.01.2018 | Event News
11.12.2017 | Event News
08.12.2017 | Event News
16.01.2018 | Materials Sciences
16.01.2018 | Materials Sciences
16.01.2018 | Power and Electrical Engineering