Showing posts with label imaging equipment. Show all posts
Showing posts with label imaging equipment. Show all posts
Hospital Engineering
Cardio MRI Developments
Spiral Scanner
A New Medical Imaging Technology: Terahertz Radiation
Terahertz technologies harness sub-millimeter-wave radiation at frequencies from 0.1 to 10 terahertz, known as t-rays, corresponding to the spectrum between the infrared and microwave bands. Many scientists regard t-rays as the last great frontier of the electromagnetic spectrum, but finding “killer” applications outside the traditional niches of radio astronomy, Earth and planetary remote sensing, and molecular spectroscopy—particularly in biomedical imaging — has been relatively slow.
Residing at the lower end of the electromagnetic spectrum, t-rays behave like radio waves. When excited, they propagate and focus via traditional quasi-optical techniques, but utilize lenses typically made of low-loss plastics or crystals rather than the glasses prevalent at optical wavelengths.
Radiologists find this area of study fascinating, because t-rays are non-ionizing, which suggests no harm is done to tissue or DNA. They also offer the possibility of performing spectroscopic measurements over a very wide frequency range, and can even capture very broad signatures from liquids and solids. In some non-biomedical applications, t-rays have already yielded impressive gains, such as: airport security, protecting valuable art, detecting surface cracks in space flights, improving telecommunications and more.
Terahertz t-rays have traditionally been used to detect lightweight molecules and atoms. Until now, nearly a dozen spaceflight instruments have measured these signatures, which are critical tracers for such processes as ozone depletion, global warming, and pollution monitoring, as well as in furthering research in basic astrophysics, planetary composition, and cosmology.
Terahertz radiation has key strengths, but also limitations. Most notably, t-rays cannot penetrate water or metal. Some terahertz frequencies can penetrate fatty tissue a few millimeters thick, leading some researchers to speculate about their use in detecting epithelial cancer.
Terahertz-radiation imaging is just one of several methods under investigation for use in detecting early cancer of the GI tract. However, these findings open up exciting new medical applications for Terahertz technology. With further development the goal of the professional imaging community is for the technology to be used during endoscopic and surgical procedures to enable complete removal of diseased tissues. Further work is required to fully understand the contrast between diseased and healthy tissue.
MedWOW, the multilingual, global medical equipment eCommerce marketplace, features a huge variety of new and used imaging equipment. MedWOW’s comprehensive catalogue facilities easy buying and selling of every category of medical equipment: both complete systems and hospital parts.
MedWOW provides a number of methods to guarantee that you get the very best imaging equipment at the best price, with all the features you need. MedWOW attracts international sellers of imaging, so you have a wider range of competitive offers. You can also take advantage of the Market Value Calculator tool, which gives you high, low and average prices for all types of new and used imaging equipment.
Incorporating MRI Parallel Imaging Technologies
Advantages of MRI Parallel Imaging MRI parallel imaging technology uses complex software algorithms to reconstruct the signals from multiple channels in a way that can reduce imaging times or increase image resolution, without the corresponding increase in imaging times associated with standard MRI scanner imaging. Although parallel imaging techniques have only recently been introduced into MRI scanners in hospitals and clinics, they have already achieved wide clinical acceptance in many imaging applications. Their considerable advantages in terms of better spatial and temporal resolution and enhanced image quality, have updated the position of MRI in a wide range of abnormality and disease imaging.
Multi-channel technology and parallel imaging allows for significant improvements in most clinical MRI scanner examinations. There is no significant degradation in performance, compared to non-parallel imaging. Faster scanning could increase the patient throughout, as well as dramatically improve patient comfort during scans.
This technology could potentially contribute to the use of MRI scanning as an alternative to CT scanning and play a significant role in radiation protection strategies, particularly in young patients.
MRI scanning offers superb soft tissue contrast. However, high- resolution scans are often excluded, due to long scan times. Parallel imaging offers much shorter acquisition times, while retaining the high resolution necessary for early lesion and/or tumor detection
Phased Array Coil System
MRI parallel imaging takes advantage of the numerous elements of phased array coil system. Each element of the coil system is associated with a dedicated radio frequency channel (a special single-channel radio receiver) whose output is processed and combined with the outputs of the other channels (signals acquired by the other coil elements). This technology improves the signal–to-noise ratio (the signal quality) as compared to a standard MRI scanner coil system; while covering the same explored body volume.
Multi-Channel Radio Frequency and Parallel Imaging
Multi-channel radio frequency and parallel imaging technologies are hardware and software implementations, respectively aimed at improving the coverage signal resolution and speed of MRI scanner examinations. With multi-channel technology, the MRI scanner signal used to form an image is collected by a collection of separate coil elements. Each element relays signal information along a separate channel to an image reconstruction computer. Such arrays of coil elements can improve imaging coverage and the ratio of signal-to-noise in the image. The number of elements in the array of detectors is an important factor in characterizing a parallel imaging system.
Multi-channel coil and receiving systems and parallel imaging technologies were first implemented in brain examinations. Recent developments in both hardware and software have allowed for broader clinical applications of these technologies, such as in cardiac, lung, abdomen, and limb studies. For example, parallel imaging, in partnership with multi-channel radiofrequency systems allows for better visualization of small lesions and blood vessels that may allow for an earlier diagnosis of cancer and cardiovascular disease. Greater imaging coverage is possible with multi-channel radiofrequency system technology facilitating oncology screening and peripheral angiography. Finally, scan times are considerably reduced using parallel imaging, allowing for tolerable breath holds when scanning patients. The most current MRI scanners at 1.5T and 3T all feature multi-channel radiofrequency system technology and parallel imaging.
Locating Parallel Imaging Upgrades on MedWOW
MedWOW, the global medical equipment marketplace, is a good place to look when you are ready to upgrade your imaging department by adding multi-channel technology and parallel imaging to your MRI system.
MedWOW features imaging inventories from dealers all over the world, so locating the specific MRI parts you need from a variety of makes, models and manufacturers in a safe and protected environment, is easy and secure. MedWOW is the leading medical equipment portal for all types of medical equipment trade, and with over 12,000 users visiting the site daily; locating your particular MRI parallel imaging upgrade is a relaxed experience.
What You Need to Know About Your CT Scanner Gantry
In this continuing informational CT scanner blog series, this time we are discussing the CT scanner gantry. The CT scanner gantry is the doughnut-shaped part of the CT scanner that houses the apparatus necessary to produce and detect x-rays in order to create a CT image. The x-ray tube and detectors are positioned exactly opposite each other and rotate around the CT scanner gantry aperture. Continuous rotation in one direction without cable wrap around is possible due to the use of low-voltage slip rings.By definition, a CT scanner gantry is a moveable frame that contains the x-ray tube, including: collimators and filters, detectors, data acquisition system, rotational components including slip ring systems, and all associated electronic accessories such as the CT scanner gantry angulation motors and positioning laser lights. The CT scanner gantry is the largest of all of the CT parts. The rotating frame, rotates at a speed of 100 – 200 RPM. A heavy x-ray tube is mounted on it, as well as a banana-shaped detector arch and other associated CT scanner gantry parts. Electric power, preconditioning lines and signal lines are provided by slipping rings. In the newer models, the signals are transmitted by a wireless system. The inclusion of slip ring technology into a CT system scanners allows for continuous scanning without cables getting in the way. A CT scanner gantry can be angled up to 30 degrees in both directions (forwards and backwards). CT scanner gantry angulation allows the operator to line up the part of the patient’s body which needs to be evaluated with the scanning plane, for precise imaging.
In the newer systems, the CT scanner gantry is continuously rotated to acquire important and comprehensive data, as the patient table is smoothly moved through the CT scanner gantry. The resulting route of the tube and detectors, in relation to the patient, forms a helical or spiral path. This powerful concept, called either helical CT or spiral CT, facilitates quick scans of entire regions of interest, in some cases within a few seconds. So significant were improvements in body CT quality and throughput that helical scanning became the standard of care for body CT scanners. This is very important for patients who suffer from claustrophobia.
Hospitals or imaging departments of healthcare facilities understand the importance of maintaining an up-to-date CT scanner gantry, as the technological advances allow great patient comfort, as well as much better imaging for diagnosis and treatment.
MedWOW has an enormous parts department, with a major focus on CT scanner gantries and other imaging equipment. If you need a replacement CT scanner gantry for your CT equipment, if it isn’t found on the MedWOW portal, the MedWOW parts finder team will conduct a thorough international search and find it for you.
There are currently nearly 2,000 CT scanner gantries parts available through the MedWOW marketplace, representing Esaote, GE Healthcare, Ige, Philips, Picker, Shimadzu, Siemens, Toshiba and other manufacturers. MedWOW’s search engines allow you to filter for make, model, price, condition, location and other variables.
Fixed C-Arms and Their Uses
Throughout the world, many progressive hospitals have begun using fixed C-arms in operating room environments, as opposed to the more popular mobile C-arms. This movement has surfaced as a result of the physician movement towards collaborative surgeries, in which many medical specialists work together to perform complex procedures. The installation of a fixed C-arm system in the operating room allows for the ideal imaging environment for this approach. C-Arms have been used with growing frequency in the medical field since it was released as a technology in the 1950s.Fixed C-Arms are employed for many different reasons. Some of the more common circumstances that might require the use of a C-Arm are: barium studies, fertility studies, therapeutic studies, cardiac studies, endoscopy studies, and angiography studies.
Single-plane systems consist of a single C-arm, while biplane systems comprise two C-arms mounted at a 90-degree angle in relation to each other. Fixed C-arm systems are used to guide surgeons performing interventional procedures. Modern flat-panel detector systems provide surgeons with superior image quality when performing complex, time-sensitive procedures.
Mobile C-arms are smaller than fixed C-arms, so that they can easily be transported to a variety of settings, as needed. As technology evolves, mobile C-arms increasingly are becoming more and more powerful.
While all of this is extremely helpful to for the medical professionals using the medical equipment, it is important to understand the importance of the C-arm to patients, themselves. C-arms are extremely precise in their readings and help to reduce the amount of discomfort that the patient feels. Using C-arms during various surgical or non-surgical procedures helps to minimize the need for more invasive procedures.
From a financial perspective, the use of C-arms leads to more cost-effective outpatient care in hospitals, as compared with more costly and time-consuming in-patient stays.
The versatility of C-arms is also something that is of primary importance to medical professionals. C-arm machines can be used during spinal, orthopedic and general surgeries; as well as for urological, vascular, neurovascular and cardiac applications. This versatility is just one of the many reasons that fixed C-arms are becoming more characteristically used in the majority of hospitals around the world.
Physicians unquestionably welcome the precise and instantaneous information that C-arm medical equipment is able to report, while x-ray lab technicians can take advantage of the simplicity of the C-arm system and the complex information that it reports so much better than previous technologies.
MedWOW is the multilingual, global medical equipment portal: specializing in providing a safe and secure environment for key players in the industry to conduct trade, as well as offering a large variety of related support services.
MedWOW currently features hundreds of complete C-arm systems, as well as thousands of C-arm parts in inventories throughout the world. It is also possible to post a buying request on MedWOW to search for a specific new or used C-arm system.
Tomosynthesis Imaging in Mammography Applications
Digital, cutting-edge imaging technologies, such as 3-dimensional tomosynthesis, have already found to be significant in earlier identification and diagnosis of breast cancer. Unlike current mammography systems, which generate a two-dimensional (2-D) image, breast tomosynthesis produces a three-dimensional image. Additionally, it is anticipated that tomosynthesis will enhance new applications, in combination with ultrasound. Using current mammography technologies, usually two x-rays of each breast are taken from different angles: from top-to-bottom and from side-to-side. The breast is pulled away from the body, compressed, and held between two glass plates to make sure that the entire breast can be carefully observed. Standard mammography records the images on film, and digital mammography records the images on computer, which can then be read and interpreted by a radiologist. Breast cancer, which is denser than most healthy nearby breast tissue, appears as uneven white areas which are referred to as shadows. Mammography is an excellent technology, but also has the following considerable limitations, which tomosynthesis technologies overcome:
- Some women cannot tolerate the breast compression component and find it so uncomfortable that they avoid annual or indicated testing.
- This necessary compression also causes overlapping of the breast tissue. Breast cancer can be hidden in the overlapping tissue and not show up on the mammogram.
- Mammograms take only one picture, across the entire breast, in the two directions as described above. In this limited way, it is possible to miss cancerous areas or lesions that are too small to detect.
Digital tomosynthesis was developed to overcome these limitations. Tomosynthesis takes multiple x-ray pictures of each breast from many angles and the breast is positioned the same way it is in a conventional mammogram, but much less pressure is necessary. Tomosynthesis requires just enough pressure to keep the breast in a stable position during the procedure. The x-ray tube moves in an arc around the breast while 11 images are taken during a 7-second examination. Then the information is sent to a computer, where it is assembled to produce clear, highly focused 3-dimensional images throughout the breast. In this way, none of the tissue is missed as using tomosynthesis, there is no folding or “hiding” of potentially cancerous tissue.
Early results with digital tomosynthesis are promising and it is believed that this new imaging technique will make breast cancers easier to see in dense breast tissue and will make mammography screenings more comfortable.
In addition to mammography, tomosynthesis also gives better results than standard planar X-ray in the following applications:- Brachytherapy
- Dental imaging
- Chest imaging
- Orthopedics
- Nephrology
Factors to Consider When Buying a CT Scanner
Technical specifications of available CT scanners are often quite extensive. Although it is helpful to review these for each CT scanner component, this may not reflect the relative clinical performance of the systems. It is also important to recognize that the performance in practice depends on the trade-off between image quality and radiation dose. The time taken to complete a scan is a key factor in scanner performance and may limit the type of procedure that can be performed. In most cases, the limitation is set by the need to control artifacts due to involuntary patient motion, such as restlessness, or breathing and peristalsis.
CT Scanner design factors which affect the total scan time are the gantry rotation time and detector array design along the z-axis (scan axis).
The maximum scan length is governed by the z-axis detector array design, and the X-ray tube heat characteristics. With the large volumes of data generated with a 64 slice scanner, for example, the total scan length may also be limited by computer memory capacity.
The rotation time of the tube and the detectors around the patient has a direct effect on total scan time. Image quality will improve with faster rotation time, as there will be reduced misregistration of data arising from patient movement. This misregistration of data introduces artifacts into the image.
The length of the detector array determines the number of rotations needed to cover the total scan length, and thus the overall scan time. Multislice (MSCT) scanners cover a patient volume between 20 and 40 mm in length per rotation, and the latest diagnostic MSCT scanners can image patient volumes of up to 160 mm per rotation.
Complete coverage of an organ, such as the heart or the brain, offers advantages for both dynamic perfusion and cardiac studies. The z-axis detector array lengths of up to 80 mm on current scanners are adequate to cover these organs in only a few rotations. A coverage length of 160 mm usually allows complete organ coverage in a single rotation, so the function of the whole organ can be monitored over time.
Modern CT scanning techniques place a high heat load on the X-ray tube due to the need for high tube current values, in order to give enough photons in the image when scanning with fast rotations and fine slices. To scan a sufficiently long length, while avoiding overheating, X-ray tubes have generally been developed to have high anode heat capacities and high cooling rates. Some designs have low anode heat capacities, but very high cooling rates to compensate.
The principal parameters that describe image quality are: spatial resolution, contrast resolution, temporal resolution, and the prevalence of artifacts. The image quality actually achieved on any scanner depends not only on scanner design features, but also on scan parameters selected and patient-related factors, and will always be a compromise between image quality and radiation dose.
Modern MSCT scanners should be capable of achieving isotropic resolution: a z-axis resolution equal to, or approaching, the scan plane resolution, as this is essential for good quality multiplanar and 3D reconstructions.
Contrast resolution is the ability to resolve an object from its surroundings. The ability to detect an object will depend on its contrast, the image noise and the size.
Dose efficiency of the scanner is a significant factor in the examinations, as it will determine the dose required for a given level of contrast resolution.
In CT, temporal resolution is usually considered in the context of cardiac scanning. The aim is to minimize image artifacts due to the motion of the heart.
Generator power is an important factor in low-contrast examinations. Low noise images require high tube current values, particularly when coupled with fast rotation speeds and narrow slice acquisitions. Fast rotation speeds improve the temporal resolution and reduce movement artifacts.
Artifacts are defined as structures in the image that are not present in the object. An imaging system will invariably produce some level of artifact, but it becomes an issue if it obscures an abnormality, resulting in a false negative diagnosis, or mimics an abnormality, giving a false positive result.
Artifacts can be due to patient factors, scanner design factors or the reconstruction process, which by necessity involves some approximations.
Doses from CT examinations are generally significantly higher than those for conventional X-ray, although a CT scan provides more diagnostic information. The CT doses may be typically factors of 10s higher for standard head and abdomen examinations, and factors of 100s for chest examinations.
Understanding Diffusion MRI
Diffusion MRI is a well-known and widely accepted magnetic resonance imaging (MRI) methodology which generates in vivo images of biological tissues weighted with the local microstructural characteristics of water diffusion, providing an effective way of visualizing functional connectivities in the nervous system. This relatively new and powerful imaging technology gives us further tools to study variations and development of normal brain anatomy, and diagnose disruption to the white matter in neurological disease or psychiatric disorder. Diffusion MRI helps us to better understand the structural organization of the brain through an identification of the neural connectivity patterns with the help of Diffusion Tensor Imaging and High Angular Resolution Diffusion Imaging. Diffusion-weighted magnetic resonance (MR) imaging, boosted by established successes in clinical neurodiagnostics and powerful new applications for studying the anatomy of the brain in vivo, has been an important area of research in the past decade. Current clinical applications are based on many different types of contrast, such as contrast in relaxation times for T1- or T2-weighted MR imaging, in time of flight for MR angiography, in blood oxygen level dependency for functional MR imaging, and in diffusion for apparent diffusion coefficient (ADC) imaging. Even more highly developed technologies than these are in use today for the study of brain connectivity and neural fiber tract anatomy.
Over the years, increasingly complex data acquisition schemes have been developed, while the theoretical foundations of diffusion MRI have come to be better understood. For the radiologist who wants to use these techniques in clinical practice and research, it is important to understand a few key principles of diffusion MRI, as follows:
A recent advance in MRI known as Diffusion MRI looks at the random motion of water particles in the body. This is particularly interesting when taking images of the brain, because water tends to move more along the directions of the connections inside the brain. These connections in the brain, known as "white matter", are crucial to keeping the brain working correctly. They are the pathways that carry information from one part of the brain to another, and if they are damaged, the brain cannot perform even the most simple tasks. Diffusion MRI is unique in its ability to study these pathways, based on how water flows along them.
There are many diseases that affect the white matter in the brain, and it can be very hard to understand exactly how the disease attacks the white matter, to predict how the disease will develop in a particular person, and to decide what the right treatment is for that person. Fortunately, because diffusion MRI is sensitive to changes in white matter, it is an excellent way of finding out about these diseases. For example, if the disease is breaking down the pathways, water stops moving along them, or leaks out of them, and diffusion MRI pinpoints this for diagnostic purposes.
The Wonders of Digital Radiography
Digital radiography is one of the most important technological advancements in medical imaging over the last ten years. Using the radiographic films of the past in x-ray imaging is likely to become outmoded within a few years. Similar to the replacement of standard film cameras with digital cameras, digital radiography images can be immediately obtained, revised, if necessary and then sent to a network of computers.The benefits of digital radiography are vast. To begin with, radiological facilities or departments can become filmless and the technician or physician can view the requested image on a desktop or a personal computer and often report a diagnosis within just a few minutes after the examination was performed. The images are no longer stored in a single location, but can be seen at the same time by physicians who are miles away from each other.
Another major advantage of digital radiography is that radiographic images can be viewed immediately, rather than having to wait for film to be developed. Many physicians and dentist feel that this benefit, alone, is enough to cause a medical facility to switch to using only digital radiography equipment.
Just as important and beneficial, is the ability to enhance images using digital radiography. Digital radiography lets the technician make the image lighter or darker, increase contrast, increase images, and make other changes to the original image to assist in easier diagnosis of any irregularities.
In addition, the patient can be given the x-ray images on a CD to take to another physician or hospital, thanks to digital radiography. Radiographic images can be stored for years and easily retrieved when needed, and from multiple locations. Digital radiography has been very helpful as huge patient files that are difficult to keep track of are no longer necessary.
It is also no longer necessary to weight the risks of x-rays, as it exposes the patient to radiation. Digital radiography has reduced the amount of radiation the patient is exposed to by 70-80%, which is particularly important when multiple images are necessary in dental or medical applications.
A Look at Digital Mammography Systems
Designed to produce radiographic images of the breast, mammography x-ray systems are primarily used for breast cancer screening, staging and grading, and pinpointing specific diagnoses in patients displaying symptoms. Most mammographs show magnified views of the breast, as well as spot images. Special stereotactic attachments facilitate performing stereotactic biopsy procedures. Digital mammography images can be achieved either by a full-field digital detector, or by using CR cassettes and a CR reader. Also, a small-sized digital detector can be integrated into an analogue mammography for image spotting and for of guiding stereotactic biopsies.The major components of a mammography system are:
- The pedestal support for the tube, the breast platform and the cassette holder or detector
- The X-ray tube assembly, including the collimator and the filters to reduce low energy radiation
- The breast-holding platform and compression paddle
- The detector or cassette holder
- More efficient storage of and access to images
- Fewer retakes
- Better visualization of dense breasts
- Availability of image post-processing and image manipulation
Clinical studies have been reported and generally suggest that digital mammography provides either equal or better imaging performance than film or screen imaging. Digital mammography systems usually have a deeper dynamic range. It is important to note that pixel size is not a good indicator of spatial resolution, as the noise and blurring effects in the detector system can have a significant effect on resolution. In addition, different types of detector technologies have different noise and blurring characteristic.
The user interface should enable full visualization of image data. Standard imaging processing typically includes:
- Magnification, zoom and roam functionalities
- Window and leveling (contrast and brightness)
- Image flip and rotation
- Edge enhancement and noise reduction
- Black/white inversion
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