Siemens SOMATOM Definition AS 40-Slice CT

Definition AS 40 CT Highlights & Benefits

The Siemens SOMATOM Definition AS 40 adds faster acquisition and greater slice sampling than the AS 20 without requiring a 64-slice platform. It is well suited for routine diagnostic CT plus selected cardiac, vascular, neurologic, and interventional studies.

Key Benefits

• • 40-slice z-Sharp acquisition: Combines Siemens’ z-Sharp technology with the Ultra Fast Ceramic detector to support 40 slices per rotation and fine anatomical detail.
  • 0.33-second rotation: Faster acquisition helps reduce motion during trauma, vascular, body, and selected cardiac exams.
  • 78 cm gantry & high-capacity table: Provides additional patient access, with compatible table configurations supporting up to 660 lb (300 kg).
  • STRATON X-ray tube: Rapid cooling supports repeated scanning with less dependence on long cooling intervals.
  • CARE dose management: Automated exposure technologies adapt X-ray output to the patient and exam while maintaining diagnostic image quality.
  • FAST CARE workflow: Automated planning and setup tools reduce repetitive steps and help standardize exams.
  • Advanced clinical options: Compatible systems can support cardiac CT, CT angiography, perfusion imaging, Dual Energy, and CT-guided procedures.

40-Slice Acquisition & Fine-Detail Imaging

z-Sharp Technology for 40-Slice Acquisition

Optional z-UHR is Siemens’ ultra-high-resolution acquisition mode. Its 16 × 0.3 mm acquisition provides additional detail for temporal bones, inner-ear anatomy, small joints, complex fractures, and foot-and-ankle CT where visualization of small structures can affect diagnosis or treatment planning. Availability depends on the individual system.

0.33-Second Rotation for Faster Exams

The SOMATOM Definition AS 40 supports rotation times down to 0.33 seconds, with 0.5- and 1-second settings also available. Faster rotation shortens acquisition and helps reduce motion during chest, abdominal, trauma, vascular, and other time-sensitive studies.

This speed also supports selected cardiac imaging when the required cardiac package is installed. Facilities with heavier cardiac workloads should compare the greater acquisition capabilities of the Definition AS 64 and AS+ 128.

z-UHR for Small Anatomy & Fine Bone Detail

Optional z-UHR is Siemens’ ultra-high-resolution acquisition mode. Its 16 × 0.3 mm acquisition provides additional detail for temporal bones, inner-ear anatomy, small joints, complex fractures, and foot-and-ankle CT.

The benefit is clearer visualization when very small anatomical structures can affect diagnosis or treatment planning. Availability depends on the individual system.

Definition AS 40 Image Quality & X-Ray Performance

The Siemens Definition AS 40 combines a high-performance X-ray tube with Siemens image-processing technologies that help maintain diagnostic image quality across different patients and exams.

STRATON X-Ray Tube for Sustained Scanning

STRATON’s approximately 7.3 MHU/min cooling rate helps dissipate heat quickly during repeated scanning, supporting busy schedules with less need for lengthy cooling periods.

Supporting Image Quality Technologies

• • Neuro BestContrast: Improves gray-and-white-matter differentiation during noncontrast head CT while limiting additional noise, supporting neurologic evaluation such as suspected stroke and intracranial hemorrhage.
  • Adaptive Signal Boost: Reduces noise and streak artifacts during low-signal imaging, helping maintain image quality in larger patients or dense anatomy.

Definition AS 40 Dose Management & Image Reconstruction

The Siemens Definition AS 40 uses Siemens CARE technologies to tailor radiation exposure to the patient and exam. Available reconstruction technologies then help control image noise, allowing facilities to balance radiation management with the image quality needed for diagnosis.

Definition AS 40 Dose Management & Image Reconstruction

Siemens CARE and reconstruction technologies help adapt radiation output to the patient while controlling image noise and preserving diagnostic detail.

• • CARE Dose4D, CARE kV & CARE Child: Adjust tube current and voltage according to the patient and exam, with pediatric-focused protocols and low-voltage scanning available through CARE Child on compatible systems.
  • Adaptive Dose Shield & X-CARE: Limit unnecessary exposure at the ends of spiral scans and reduce direct exposure toward radiation-sensitive areas such as the breasts, thyroid, and eye lenses while preserving image quality.
  • IRIS & SAFIRE: Iterative reconstruction technologies that reduce image noise and can support appropriately selected lower-dose protocols. The installed option depends on the system’s software generation.

78 cm Patient Access & Workflow

Wide Gantry & High-Capacity Table Options

The Siemens SOMATOM Definition AS 40 has a 78 cm (30.7 in) gantry opening for larger patients, trauma positioning, life-support equipment, and CT-guided procedures. The multipurpose table supports up to 500 lb (227 kg), while an available high-capacity tabletop increases capacity to 660 lb (300 kg).

FAST CARE for More Consistent Exam Setup

FAST CARE reduces repetitive setup through tools such as FAST Planning, FAST Adjust, FAST Scan Assistant, FAST Spine, and FAST Cardio Wizard. WorkStream4D automates predefined image reconstructions while the next patient is being prepared, helping standardize exams and reduce post-processing work.

WorkStream4D for Automated Reconstruction

WorkStream4D automates image reconstruction using predefined protocols that can generate axial, sagittal, coronal, and oblique image series without recreating each view manually.

Reconstruction jobs can process while the next patient is being prepared, helping higher-volume departments reduce post-processing work and move images to clinical review more efficiently.

Clinical Environments & Applications

The Siemens SOMATOM Definition AS 40 is well suited for routine CT plus selected specialty exams, with 40-slice acquisition, 0.33-second rotation, fine-detail imaging, and configurable software supporting a broad clinical range.

Common clinical environments include hospitals, outpatient imaging centers, emergency and trauma departments, orthopedic and spine imaging centers, interventional facilities, radiation oncology settings, and veterinary specialty hospitals.

Clinical Specialties & Applications

• • Neurology & Stroke Care: Head CT, intracranial hemorrhage assessment, neurovascular imaging, and selected perfusion studies, with Neuro BestContrast available for improved tissue differentiation.
  • Cardiology: Selected coronary visualization, acute chest-pain assessment, and functional cardiac imaging with HeartView CT and compatible cardiac software.
  • Vascular Medicine: CT angiography of intracranial, pulmonary, mesenteric, renal, and peripheral vessels.
  • Orthopedics & Podiatry: Fractures, joints, complex bone anatomy, and foot-and-ankle imaging, with optional z-UHR for additional fine-detail evaluation.
  • Spine Care: Cervical, thoracic, and lumbar CT for fractures, degenerative conditions, and surgical planning, including chiropractic-related imaging referrals.
  • Oncology: Cancer staging, tumor assessment, treatment monitoring, and follow-up imaging.
  • Radiation Oncology: CT simulation and treatment-planning imaging with the appropriate table, positioning accessories, and facility workflow.
  • Pulmonology: Chest CT for pulmonary nodules, lung disease, and selected pulmonary vascular exams.
  • Gastroenterology & Urology: Abdominal and pelvic CT, kidney stone evaluation, urinary tract imaging, and contrast-enhanced body studies.
  • Emergency & Trauma Medicine: Rapid head and body imaging, polytrauma assessment, and exams involving patients with life-support equipment.
  • Pediatric Imaging: Head, chest, abdominal, pelvic, and musculoskeletal CT using CARE Child and pediatric-specific protocols.
  • Bariatric Imaging: CT for larger patients using the 78 cm gantry, high-capacity table option, and Adaptive Signal Boost.
  • Interventional Radiology: CT-guided biopsies, needle placement, and other minimally invasive procedures with compatible guidance software.
  • Veterinary Medicine: Head, spine, chest, abdominal, pelvic, and musculoskeletal CT using appropriate veterinary protocols and positioning.

Advanced Imaging Options

The AS 40 can extend beyond routine CT when the required hardware and software are installed. These options make it useful for mixed routine and specialty workloads, while the Definition AS 64 and AS+ 128 remain better suited to more demanding advanced CT programs.

Compatible Definition AS 40 systems can extend beyond routine diagnostic CT with optional cardiac, vascular, dynamic, and interventional applications. Installed capabilities vary by individual system.

• HeartView CT: Supports selected cardiac imaging with approximately 165 ms temporal resolution when paired with 0.33-second rotation, helping reduce heart-motion artifacts.
• CARE Bolus: Monitors contrast enhancement and helps trigger scanning at the intended phase for CT angiography.
• Adaptive 4D Spiral: Supports dynamic and perfusion imaging by repeatedly moving the table through the selected anatomy, with documented AS 40 configurations providing up to approximately 8 cm of dynamic coverage.
• Dual Energy: Uses two X-ray energy levels to support material differentiation, with compatible applications for tasks such as gout assessment, contrast analysis, and metal-artifact reduction.
• CT-Guided Interventions: Compatible interventional software can support biopsies, needle placement, 3D planning, rapid image updates, and in-room procedure controls.

Facilities planning heavier cardiac, vascular, or other advanced CT workloads should also compare the greater acquisition capabilities of the Definition AS 64 and AS+ 128.

Specialized Imaging & CT-Guided Procedures

Dual Energy for Material Differentiation

Compatible systems may support Siemens Dual Energy imaging, which acquires information at two X-ray energy levels. Materials that appear similar on conventional CT can respond differently at each energy, providing additional information for characterization.

Available applications may support gout assessment, contrast analysis, material differentiation, and reduction of metal-related artifacts. Hardware and software requirements vary by system.

3D-Guided CT Interventions

Compatible Definition AS 40 systems can support biopsies, needle placement, and other minimally invasive procedures using Siemens interventional software.

Available tools can provide 3D planning, rapid image updates, and in-room controls so physicians can monitor instrument position while remaining near the patient. The 78 cm gantry also provides useful procedural clearance.

Available Definition AS 40 Configurations & Installed Options

Pre-owned Siemens SOMATOM Definition AS 40 systems can vary by production year, detector generation, patient table, software version, reconstruction package, and installed clinical applications.

Key configuration differences may include:

• Acquisition & detector technology: z-Sharp 40-slice acquisition, optional z-UHR fine-detail imaging, UFC detector technology, or a compatible Stellar detector upgrade
• Image reconstruction & processing: IRIS or SAFIRE reconstruction, Neuro BestContrast, Adaptive Signal Boost, and related image-quality software
• Patient table: Standard or high-capacity table configurations
• Advanced clinical applications: HeartView CT, FAST Cardio Wizard, CARE Bolus, Adaptive 4D Spiral, perfusion, Dual Energy, and CT-guided intervention software
• Workflow & system configuration: FAST CARE tools, WorkStream4D, syngo workstation and post-processing packages, and air- or water-cooled system setup

MXR Imaging can help compare available systems based on the facility’s planned exam mix, patient needs, and required clinical capabilities.

Definition AS 40 Availability & Project Planning

The Siemens SOMATOM Definition AS 40 is available as a pre-owned CT scanner, subject to availability. Pricing varies by system age, tube condition, detector generation, patient table, installed software and clinical applications, accessories, reconditioning, and project scope.

MXR Imaging can help evaluate available systems against the facility’s clinical needs, patient volume, existing space, and project requirements to identify an appropriate configuration. Eligible systems may also be available through the Platinum Certified program.

For facilities that need additional installation support, turnkey imaging project management is also available for room planning, rigging, installation, and project coordination.

Choosing a SOMATOM Definition AS Slice Configuration

The SOMATOM Definition AS family includes 20-, 40-, 64-, and 128-slice configurations. The best fit depends on exam mix, patient volume, and required acquisition performance.

• SOMATOM Definition AS 20: Best suited for routine head, body, spine, musculoskeletal, pediatric, and general diagnostic CT.
• SOMATOM Definition AS 40: Adds z-Sharp 40-slice acquisition and 0.33-second rotation for routine imaging plus selected cardiac, vascular, perfusion, and interventional studies.
• SOMATOM Definition AS 64: Provides greater detector coverage and stronger cardiac performance for higher-volume cardiac, vascular, trauma, neurologic, and body imaging.
• SOMATOM Definition AS+ 128: Provides the greatest detector coverage in the family for demanding cardiovascular, vascular, perfusion, and advanced CT workflows.

Slice count is only one consideration. Detector generation, X-ray tube condition, patient table, software, and installed clinical applications should also be compared.