MicroView 2.5.0 alpha8 is now available from our website for win64 platforms; additional platforms to follow (once we undo the damage that upgrading to Mountain Lion has caused us on our Mac development machine). This release has a number of major changes, including the replacement of the Tkinter-based user interface with a newer, more modern wxWidgets interface. While in the long run this will make plugin development easier, and code management simpler, the porting process is not yet complete - many users will want to stay put with the 2.2 version of MicroView for now. See http://www.parallax-innovations.com/microview for all download links to this pre-release version.
Today we turn our attention to the GE Locus Ultra platform in our continuing set of posts on GPU reconstruction: Integrating a faster GPU reconstruction engine into the GE Locus Ultra requires more careful consideration than some other CT scanners because of the system's complexity and the need for end-to-end integration. Without this, the scanner cannot maintain it's incredible scan workflow. Keeping this in mind, we've sought out a solution that improves not only the raw reconstruction speed, but the data access rate to the operator console too. We've blended the original 32-bit-only console software with a 64-bit host computer that runs GPU reconstructions as well as a 64-bit MicroView for visualization purposes. The workflow is almost indistinguishable from the original, but is faster in almost all aspects, since data is no longer situated on a remote computer, but rather at the operator's console computer. See the video below for an introduction to the work we're doing in this area.
Another GPU reconstruction progress update day: See below two line profiles drawn through an aluminum stack phantom, imaged on a CT-120 microCT scanner. A typical "cupping" artifact, caused by beam hardening, is clearly visible in the left-hand, uncorrected image. The right image demonstrates the advantage of the basic beam hardening correction algorithm integrated into our GPU reconstruction engine.
Click on the image to see a larger version.
Our efforts to integrate our GPU reconstruction engine into different CT scanner platforms continue: see below a video showing the installation process for the Parallax Innovations GPU engine on an eXplore CT-120 console computer. The total install time is about 2 minutes, not including the download of the software. We recommend upgrading to NVidia driver version 295.49, since this driver provides the aforementioned Fermi architecture support such as on the GTX 680 and 690 GPU adapters.
And here's a video comparing CPU vs. GPU CT engines on the same machine:
As before, if you're interested in helping to test this release, don't hesitate to contact us.
A couple weeks ago, I introduced the Rapid Fluoroscopy application and hinted that it could be used for more than the typical fluoroscopy applications. In this post, I'm going to elaborate on that.
Parallax Innovations has been working with Dr. Eugene Wong and Ph.D. candidate Michael Jensen at the University of Western Ontario, who have customized their eXplore CT120 to allow it to be used for image-guided radiation delivery. In particular, they have added a motorized, computer controlled collimator (shown below) to the system that allows them to narrow the x-ray beam for targeting a specific region of the specimen. The image to the right is of a 4x4 cm radiochromic film showing how they can achieve an elliptical radiation pattern.
The problem that we helped them solve was how to define a series of exposures at prescribed angles as part of a micro CT protocol. They needed the ability to fire any number of exposures with any allowable x-ray settings from any gantry position. And in addition, they needed to be able to control the size of the collimator aperture at any given gantry position. Except for the control of custom collimator, the requirements seemed to me to be close to the functionality already provided by the Rapid Fluoroscopy application. Parallax Innovations assisted by implementing a new custom protocol to the application – the treatment protocol.
Treatment protocols allow the operator to specify any number of gantry angles and for each angle, specify a number of other properties. As you can see in the property editor pictured below, one can prescribe the x-ray settings (voltage/current/duration), a table offset from the landmark position, the focal spot size, and how many exposures to fire. There are also settings for the maximum allowable anode heat before the exposures at this particular position can begin (anode heat threshold), the amount of time between exposures (decay time), and an option to wait for a given amount of time before beginning the exposures at this particular position (pause).
Note: the 140 kV voltage setting is not available with standard x-ray generators. 120 kV is normally the maximum.
For the custom collimator, Michael had already written an application to control it. I asked him to add a remote procedure call (RPC) interface that would allow the fluoroscopy software to make RPC calls passing the collimator motor positions defined in the treatment protocol.
A custom protocol using Rapid Fluoroscopy was implemented and integrated with collimator control in a timely and efficient manner. It provided a flexible and simple solution which accelerated the readiness of such a platform for targetted radiation delivery. Now, when the Rapid Fluoroscopy software is switched on, it is possible to build and run radiation treatment protocols. Such a combination can also be used for cardiac imaging, with the collimator shielding the rest of the animal from unnecessary radiation exposures, which could potentially improve image quality by reducing scattered radiation. For more information about Dr. Wong's research, visit the University of Western Ontario website.
Special thanks to Michael Jensen for all the testing he has done with the treatment protocols.
We've posted a YouTube video that some of our readers might find interesting: it's a video showing a side-by-side comparison of CPU vs. GPU for CT conebeam reconstruction - the GPU engine here, is the one that Parallax Innovations has developed. We compare it against a conventional CPU-based multiprocessor CT FDK reconstruction engine found in GE Locus products.
The astute reader will realize that perhaps what is really news here is that this reconstruction engine can now be integrated into existing scanning workflow on the Locus and Locus SP platforms. Drop us a note if you are interested in beta testing this software on 32-bit or 64-bit Windows platforms.
Parallax Innovations is pleased to introduce our latest software product - Rapid Fluoroscopy for the CT-120. It is an inexpensive way to expand the capabilities of your scanner by opening up a suite of fluoroscopy applications such as:
Building on the CT-120's strength as a cardiac imaging system, the fluoroscopy acquisitions can be cardiac or respiratory gated, or a combination of both.
Fluoroscopic acquisitions are protocol driven, allowing you control over the x-ray settings:
40 - 125 kV
16 - 80 mA
6.3 - 200 ms
Full range of gating options:
For applications that require repeated imaging and may require imaging at multiple bed positions, the protocol definition allows you to specify an anode heat threshold and a table offset. The anode heat threshold defines the maximum heat level that is allowed before the acquisition will continue. If the current heat level is above this, the acquisition system will wait until it drops below the threshold (Note: heat level is continuously monitored and displayed - even during x-ray exposure). The table offset is a distance (mm) from the landmark position. Before the acquisition, the specimen cradle will be moved to this position. Both of these features streamline work flow and assist automation.
If you look at the data/protocol overview window to the left, you will notice that there are two categories of protocols: fluoroscopy and treatment. In an upcoming blog post, I'll describe how one of our customers is using Rapid Fluoroscopy to study radiation therapy.
For more information, please contact us.
Rumour has it that Nvidia is set to release their Kepler-based GTX 680 on March 22. With a reported 1536 CUDA cores, and retailing around $560 USD, this card may quickly become the low-cost GPU of choice - certainly at Parallax Innovations HQ. We've been happy with the cost-effectiveness and performance of the GTX 580 GPU, which we use with our GPU CT conebeam reconstruction software, but at a comparatively small 512 cores we see a hardware upgrade in our not-so-distant future. More details to be found here.
The MicroView website on sourceforge.net got an overhaul today; we're using sphinx now to produce the main website and MicroView online help. If you have a moment, let us know what you think!
Over the past few years, the future of MicroView on the Mac platform was a bit grim: the only available binary was 32-bit, PPC-only, and relied on the Carbon compatibility layer. Performance was lacklustre compared to Windows and Linux releases. With the release of OS X Lion, the original distribution of MicroView on Apple hardware reportedly doesn't run at all. Jumping forward to today, however, the story is somewhat different - we've successfully ported the majority of the open-source components of MicroView to a 64-bit Intel Mac platform running OS X Lion 10.7.3. There's plenty more to do to stabilize the platform, but the majority of the technical hurdles have been crossed. See attached: a picture is worth a 1000 words.