Siemens SOMATOM Definition AS 20-Slice CT

Siemens Definition AS 20 CT Highlights & Benefits

The Siemens SOMATOM Definition AS 20 combines routine diagnostic CT performance with Siemens technologies designed to improve patient access, dose management, and workflow consistency. This Siemens 20-slice CT scanner is well suited for facilities that need broad general imaging capabilities without requiring the acquisition performance of a higher-slice system.

Key Benefits

• • 20-slice CT acquisition with a UFC detector: Supports routine head, chest, abdominal, pelvic, spine, and musculoskeletal CT with thin-section and broader-coverage acquisition options.
  • 0.5-second rotation with a faster option: Supports routine diagnostic imaging, with 0.33-second rotation available on applicable configurations for more time-sensitive exams.
  • Wide patient access: A 78 cm (30.7 in) gantry is standard, while the Definition AS Open configuration increases the opening to 80 cm (31.5 in). Applicable table options support patients up to 676 lb (307 kg).
  • STRATON X-ray tube: Rapid cooling supports repeated scanning with less dependence on lengthy tube-cooling intervals.
  • CARE dose management: Automated exposure technologies help tailor X-ray output to the patient and exam.
  • FAST CARE workflow: Automated planning and setup tools reduce repetitive steps and help standardize exams.
  • Advanced clinical options: Compatible systems can support CT angiography, Dual Energy, perfusion imaging, and CT-guided procedures.

Definition AS 20 Acquisition & Imaging Performance

20-Slice Acquisition with a UFC Detector

The Definition AS 20 uses Siemens’ Ultra Fast Ceramic (UFC) detector with 20 × 0.6 mm acquisition for thinner sections and 16 × 1.2 mm acquisition for broader coverage. Axial and spiral modes support routine imaging of the head, chest, abdomen, pelvis, spine, joints, and extremities.

Thin-section reconstruction, multiplanar reconstruction, and compatible 3D visualization can provide additional views of complex anatomy from the acquired CT dataset without requiring another scan.

Motion-Reducing 0.5-Second Rotation with a Faster Option

Standard gantry rotation is 0.5 seconds, with 0.33-second rotation available on applicable configurations. Faster rotation helps reduce motion during chest, abdominal, emergency, and other time-sensitive exams.

The AS 20 is best suited for routine diagnostic CT. Facilities requiring greater acquisition coverage or more demanding advanced imaging should also compare the higher-slice Definition AS configurations.

Thin-Slice Reconstruction for Detailed Anatomy

The AS 20 can reconstruct thin image sections for closer evaluation of smaller structures and complex anatomy.

Siemens syngo, the scanner’s image-processing and workflow environment, supports multiplanar reconstruction (MPR), which creates coronal, sagittal, and other views from the same acquired CT dataset. Compatible 3D visualization tools extend that information for fracture assessment, spine imaging, vascular review, and procedural or surgical planning without requiring another acquisition.

Definition AS 20 Image Quality & Dose Management

The Definition AS 20 combines Siemens’ high-performance X-ray tube with image-processing and automated dose-management technologies. These systems work together to maintain usable image quality across different patient sizes while limiting radiation that does not contribute to the clinical examination.

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 dependence on lengthy tube-cooling periods.

Image Quality & Dose Technologies

• • Adaptive Signal Boost: Reduces noise and streak artifacts in low-signal areas, helping maintain image quality in larger patients and challenging anatomy.
  • CARE Dose4D & CARE kV: Adjust X-ray output and tube voltage according to the patient and exam, with low-voltage settings available for compatible pediatric and other protocols.
  • Adaptive Dose Shield & X-CARE: Help limit unnecessary exposure outside the reconstructed spiral range and toward selected radiation-sensitive organs.
  • SAFIRE: Optional iterative reconstruction that reduces image noise and can support appropriately selected lower-dose protocols. Availability depends on the installed software generation.

Definition AS 20 Patient Access & Workflow

78 cm Gantry with an 80 cm Definition AS Open Option

The standard Definition AS 20 provides a 78 cm (30.7 in) gantry, while the Definition AS Open configuration increases the opening to 80 cm (31.5 in) for additional clearance during larger-patient imaging, specialized positioning, interventional procedures, and applicable radiation therapy planning.

Applicable table configurations can support patients up to 676 lb (307 kg), and gantry tilt up to ±30° is available on compatible systems.

Patient Table Options up to 676 lb

Patient-table specifications vary by Definition AS generation and configuration. Applicable high-capacity configurations can support patients weighing up to 676 lb (307 kg), while available table designs provide different travel ranges and positioning capabilities.

Facilities planning bariatric imaging, trauma CT, radiation therapy planning, or specialized procedures should verify the installed table, scan range, and positioning accessories when evaluating a pre-owned system.

FAST CARE Tools for Simplified Exam Setup

FAST CARE combines Siemens workflow tools such as FAST Adjust, FAST Planning, and FAST Spine to reduce repetitive setup and help standardize CT exams.

• • FAST Adjust: Helps technologists modify acquisition parameters
  • FAST Planning: Assists with selecting scan and reconstruction ranges
  • FAST Spine: Automates portions of spine reconstruction.

Clinical Environments & Applications

The Siemens SOMATOM Definition AS 20 is best suited for routine diagnostic CT, with patient-access options and configurable software extending its use into selected specialty applications.

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

Clinical Specialties & Applications

• • Neurology & Emergency Imaging: Head CT for trauma, intracranial hemorrhage, and other neurologic conditions, plus selected acute chest, abdominal, pelvic, and fracture assessment.
  • Orthopedics, Podiatry & Spine: Fractures, joints, complex bone anatomy, foot-and-ankle CT, and cervical, thoracic, and lumbar spine imaging, including chiropractic-related referrals.
  • Chest, Abdominal & Pelvic Imaging: Pulmonary nodules and lung disease, abdominal and pelvic CT, kidney stone evaluation, and urinary tract imaging.
  • Oncology & Radiation Oncology: Cancer staging, treatment monitoring, follow-up imaging, and CT simulation on appropriately configured systems.
  • Pediatric Imaging: Head, chest, abdominal, and musculoskeletal CT using appropriate pediatric acquisition and dose protocols.
  • Vascular & Interventional Imaging: Selected CT angiography and CT-guided procedures when the required software and accessories are installed.
  • Veterinary Medicine: Head, spine, chest, abdominal, pelvic, and musculoskeletal CT using appropriate veterinary protocols and positioning.

Advanced Imaging Options

Compatible Definition AS 20 systems can extend beyond routine CT with optional vascular, dynamic, and interventional applications. Installed capabilities vary by system.

• CARE Bolus & vascular software: Help coordinate CT acquisition with contrast enhancement for selected CT angiography, with compatible syngo applications providing vessel analysis and 3D visualization.
• Dual Energy: Uses two X-ray energy levels to support material differentiation, with compatible applications for tasks such as gout evaluation and metal-artifact reduction.
• Adaptive 4D Spiral & perfusion imaging: Support dynamic acquisition and selected tissue-perfusion applications when the required software is installed.
• Intervention Pro, i-Fluoro & HandCARE: Support selected biopsies, needle placement, rapid procedural image updates, and radiation-management functions during compatible CT-guided procedures.

These are configuration-dependent capabilities rather than standard features on every Definition AS 20.

Available Definition AS 20 Configurations & Installed Options

Pre-owned SOMATOM Definition AS 20 systems can vary by gantry design, detector generation, patient table, software version, and installed clinical applications.

Key configuration differences may include:

• Gantry & patient table: Standard Definition AS or 80 cm Definition AS Open configuration, standard or high-capacity table, and applicable specialized positioning options
• Acquisition & detector configuration: UFC detector generation, optional 0.33-second rotation, and compatible detector upgrades
• Image quality & dose software: SAFIRE, CARE Dose4D, CARE kV, X-CARE, and FAST CARE applications
• Advanced clinical applications: CARE Bolus, vascular software, Dual Energy, Adaptive 4D Spiral, perfusion, and CT-guided intervention applications
• Workflow & specialty configuration: syngo workstation and software packages, DICOM connectivity, and applicable radiation therapy or specialized accessories

MXR Imaging can compare available systems against the facility’s planned exams, patient needs, and required clinical capabilities.

Definition AS 20 Availability & Project Planning

The Siemens SOMATOM Definition AS 20 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 CT and MRI systems 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. Higher slice counts provide greater acquisition capability, while the best fit depends on the facility’s exam mix, patient volume, and advanced imaging requirements.

• SOMATOM Definition AS 20: Best suited for routine diagnostic CT, including head, body, spine, musculoskeletal, pediatric, and general outpatient imaging.
• SOMATOM Definition AS 40: Provides greater acquisition capability than the AS 20, creating a middle ground for facilities that need more performance without moving directly to a 64-slice system.
• SOMATOM Definition AS 64: Better suited for higher-volume facilities and more demanding vascular, trauma, neurologic, and advanced body imaging workflows.
• SOMATOM Definition AS+ 128: Provides the highest acquisition capability in the family for facilities performing more demanding cardiovascular, vascular, perfusion, and advanced imaging applications.

Slice count is only one part of the buying decision. Detector generation, X-ray tube condition, software, patient table, and installed clinical applications should also be compared when evaluating pre-owned Definition AS systems.