Reducing the dose in radiology: Siemens issues dose guide and explains low-dose technologies in detail
Chicago, USA, 2010-Nov-29
Siemens Healthcare has already contributed to reducing the radiation dose in diagnostic and interventional radiology with many technical innovations. Now Siemens is the first manufacturer to issue a "Guide to Low Dose". Aimed at physicians and medical technical staff, this guide describes the basics of radiation used for medical purposes. It gives a detailed explanation of the functions currently available to reduce the dose in radiological imaging from Siemens. Users learn about how these features can help them to protect patients and clinical staff by minimizing the dose during examinations. Siemens is also stepping up its communication activities around the issue of low dose: by offering numerous new seminars, training courses and presentations over the next two years, Siemens will be working harder than ever before to support clinical staff and management in implementing dose monitoring and reduction measures.
"In the most relevant imaging procedures, such as computed tomography, angiography and molecular imaging, Siemens has pioneered the development of dose reduction technologies for many years," says Dr. Bernd Montag, CEO Imaging & Therapy Systems Division, Siemens Healthcare. "Now we're planning to launch a comprehensive education program which will support clinical staff in protecting themselves and patients better against avoidable radiation exposure. In this context, we'll be offering new training seminars and we will provide a Guide to Low Dose, among other initiatives."
For radiological and nuclear medicine examinations that involve the use of ionizing radiation with X-ray fluoroscopy or radiodiagnostics, the medical profession generally applies the "ALARA" principle - As Low As Reasonably Achievable. The aim here is to strike an ideal balance between the required image quality and the radiation dose. It usually takes an increased dose to enhance the image quality. For its radiological devices that work with X-rays or radioactive tracers, Siemens has therefore developed an entire range of technologies - Combined Applications to Reduce Exposure (CARE) - that enable the dose to be reduced significantly without compromising the image quality. These technologies include, for example, IRIS (Iterative Reconstruction in Image Space), a new method for the reconstruction of computed tomography (CT) images, and High Definition PET, a high-resolution Positron Emission Tomography technology for molecular imaging.
Alongside dose reduction, dose control is an important measure for avoiding unnecessary radiation. In future radiological devices from Siemens therefore will issue a warning message to the user if a certain dose threshold is exceeded in critical applications. Reports are generated for examinations; these contain the patient data, the relevant protocol and the dose values. Clinics can then analyze this information according to specific criteria, such as the doses administered, and optimize their protocols and processes accordingly.
Examples of dose reduction innovations from Siemens
Right from the start, Siemens was one of the pioneers of dose reduction in computed tomography. As early as 1994, scientists and engineers from Siemens had developed CARE Dose4D, the first fully automatic radiation exposure control technique.Â This was followed by ECG-synchronized dose modulation (ECG pulsing) and the Adaptive Dose Shield. ECG pulsing automatically reduces the dose during cardiograms, while the Adaptive Dose Shield is the first collimator capable of eliminating unnecessary radiation that cannot be used for image reconstruction.Â In 2008, Siemens expanded its portfolio in the premium segment with the SOMATOM Definition Flash, a dual-source CT scanner that produces an image of the entire heart in less than a quarter of a second. The radiation dose that occurs during scanning is less than one millisievert (mSv) - a value that corresponds to just under half the annual natural background radiation in Germany.
The latest innovation is FAST CARE, a hardware and software platform for CT scanners. The FAST CARE applications offer new functions and protocols for dose reduction. They also simplify time-consuming, complex procedures such as patient scanning or preparation for image reconstruction.
Siemens recently launched SIERRA (Siemens Radiation Reduction Alliance), and established an expert panel to advance the cause of dose reduction in computed tomography. The new Low Dose Expert Panel comprises sixteen specialists in the fields of radiology, cardiology and physics, who are internationally recognized for their publications on the subject of dose in CT.Â The panel is working on generating proposals for how manufacturers can improve their technology and how users can help to bring about further dose reduction.
The molecular imaging technologies SPECT (Single Photon Emission Computed Tomography), SPECT/CT and PET/CT from Siemens are designed to reduce the radiation dose for all exams, simplifying the scanning process considerably and yielding high image quality at the lowest possible dose level, even for obese and pediatric patient examinations.
Technologies such as IRIS (Iterative Reconstruction in Image Space), TrueV and Ultra-High-Definition PET (ultraHDâ?¢PET) improve the image quality and can provide for additional dose savings. The Biograph mCT system includes ultraHDâ?¢PET technology– a high-resolution PET (Positron Emission Tomography) technique. It ensures increased image sharpness and precision and allows physicians to pinpoint small lesions with a smaller quantity of tracer than commonly administered.
The Symbia T series can also perform diagnostic spiral CT, which enables low dose, ultra-fast cardiac studies including calcium scoring, a unique feature compared to other general purpose SPECT/CT systems on the market.
For interventional imaging in radiology and cardiology, Siemens has developed a range of CARE applications that are supplied as standard with every angiography system of the Artis zee family. The new CARE applications reduce radiation not only for patients but also for clinical staff, as well as simplifying the post-examination documentation of the dose values. Thanks to special applications such as radiation-free collimation and patient positioning or pulsed fluoroscopy, both the patient and the examiner are exposed to as much as 75 percent less radiation. For 3D imaging with syngo DynaCT, there are new, particularly low-dose image acquisition protocols that enable 3D imaging for neurology from as low as 0.3 mSv, reducing the dose by up to 72 percent compared to conventional 3D protocols. CAREguard is an innovation for dose monitoring in interventional imaging. This application enables skin dose values to be predefined. Once these values have been reached, the control console issues both an acoustic and a visual warning signal to the examiner. This enables the continuous control and monitoring of the applied skin dose. At the end of the examination, a structured dose report documents all patient dose values, making it easier for hospitals to manage their dose reporting. All new and existing customers of Artis zee systems will receive the new CARE applications free of charge. This underlines Siemens' commitment to dose reduction and the optimization of treatment results in hospitals.
All mobile X-ray devices of the ARCADIS family from Siemens are equipped with the latest dose reduction functions as standard. They include EASY (Enhanced Acquisition System), which can be used to analyze the images during acquisition to optimize dose, brightness and contrast. Even objects outside the focus are displayed with high precision. Additional copper filters, radiation-free collimation and multilevel dose control also help to ensure that the minimum necessary dose is applied. For pediatric surgery, where dose levels are most critical, the ARCADIS Avantic features a detachable grid. The devices of the ARCADIS family can also be equipped with a highly sensitive DAP (Dose Area Product) measurement chamber. Physicians using a surgical navigation system can reduce the dose even further. NaviLink is an open interface from Siemens that enables the acquired patient dataset to be sent automatically from the mobile C-arm to the navigation system.Â The physician can then navigate within the patient's anatomy without the need for any further radiographs during the operation.Â NaviLink is optionally available for the ARCADIS Varic and for 3D imaging with the Orbic.
The mammography platform Mammomat Inspiration features a wide range of functions and technical details to minimize the radiation dose. These include, for example, a special X-ray tube with a tungsten anode and new AEC algorithms that optimize the dose individually according to breast size and tissue type.
The multifunctional urology workstation UROSKOP Omnia is also equipped with CARE programs. Pulsed fluoroscopy and radiation-free collimation and patient positioning enable the radiation dose to be reduced. In addition, the physician can adjust the dose required for acquisition and fluoroscopy to exactly the right level by selecting an organ program specially tailored to the examination being conducted.