Siemens focuses on
lowering radiation dose


For more than a decade, Siemens has been leading the way in reducing radiation dose in diagnostic and interventional radiology and is the first medical device manufacturer to release a comprehensive ‘Guide to Low Dose’ aimed at physicians and medical technical staff.

The company held a media roundtable event at Arab Health in Dubai in January to discuss the issue, which if left unchecked could result in an increase in the incidence of cancers on the back of a significant rise in the use of diagnostic radiology, particularly Computed Radiography (CT).

The mechanisms by which radiation damages the human body are twofold: (1) radiation directly destroys the DNA of the cells by ionizing atoms in its molecular structure or, (2) radiation creates free radicals which are atoms, molecules, or ions with unpaired electrons. These unpaired electrons are usually highly reactive, so radicals are likely to take part in chemical reactions that eventually change or harm the DNA of the cells.

Siemens notes in their guide that “the human body can repair damaged cells to a certain extent, but if exposed to a high amount of radiation beyond a given threshold in a short period of time, ‘deterministic’ damage will occur. This term implies that the radiation poisoning definitely occurs and that the damage is dependent on the amount of radiation received. Deterministic radiation damage includes changes of the blood count, hair loss, tissue necrosis or cataract.”

However, Siemens stresses that the exposure levels of typical medical CT scans are far below the threshold for deterministic radiation damage.

History of dose reduction

As early as 1994, scientists and engineers from Siemens were looking at dose reduction in computed tomography. They developed CARE Dose4D, the first fully automatic radiation exposure control technique This was followed by ECGsynchronised dose modulation (ECG pulsing) and the Adaptive Dose Shield. ECG pulsing automatically reduces the dose during cardiac CT examinations, while the Adaptive Dose Shield is the first dynamic collimator capable of eliminating unnecessary radiation that cannot be used for image reconstruction.

Waclaw Lukowicz CEO Siemens Healthcare Middle East and Africa Cluster, pointed out that in the most relevant imaging procedures, such as computed tomography, angiography and molecular imaging, Siemens has pioneered the development of dose reduction technologies and incorporated them into these systems.

Because it usually takes an increased dose to enhance the image quality, the aim is to strike an ideal balance between the required image quality and the radiation dose using all available technology. For examinations and minimally invasive treatment that involve the use of ionising radiation with X-ray fluoroscopy radio diagnostics, the “ALARA” (As Low As Reasonably Achievable) principle – agreed at the International Commission on Radiological Protection (ICRP) – is applied. ALARA represents the international benchmark for limiting radiation dose.

CARE applications

Siemens has 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.

For interventional imaging in radiology and cardiology, Siemens’ CARE applications 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.

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 paediatric patient examinations.

“The use of myocardial perfusion PETCT, delivered by the Biograph mCT is a major technical advance in cardiac care in the UAE,” explained Thomas F Heston, MD, medical director of the cardiac PETCT programme at Tawam Molecular Imaging Centre in Al Ain. Dr Heston is a Fellow of the American Society of Nuclear Cardiology. “The new technology is safer than older techniques in terms of radiation exposure, but delivers higher quality images.”

All mobile X-ray devices of the Aracadis family from Siemens are equipped with the latest dose reduction functions as standard. They include EASY (Enhanced Acquisition System), which can be used to analyse 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 paediatric surgery, where dose levels are most critical, the Arcadis Avantic features a detachable grid. Siemens mammography platform Mammomat has dose reduction features as does the multifunctional urology workstation UROSKOP.  

ate of upload: 25th Apr 2011


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