Siemens Solutions for Dose Management

Siemens Solutions for Dose Management in CT Recognize the available dedicated adult and pediatric protocols and how protocol parameters can be modified when necessary By the end of this course you will be able to: Review the importance of iso-centering the patient and the negative effects of not doing so Explain how CARE Dose4D™ works and recognize its importance in daily workflow Identify other robust dose features, such as X-CARE, Adaptive Dose Shield, and Iterative Reconstruction and appreciate their roles in a comprehensive dose optimization strategy Discuss special filters and detector materials inherent in your CT scanner Review the Flash technology on select Siemens Dual Source CT scanners and the benefits it offers regarding dose ALARA - As Low As Resaonably Achievable Siemens is committed to dose reduction according to the ALARA principle. In practice, this means that scan parameters for every protocol should take into account: General Patient size (e.g., pediatric vs. adult protocols) Opportunities to Significantly Reduce Dose (e.g., full dose exam vs. low dose follow -up scan) Clinical Reason for the Examination (e.g. abdominal scan to detect subtle liver lesions vs. r/o shunt malfunction) Practical Tips for Scanning Children: Prepare/immobilize patient to reduce repeats Scan only the area of interest Question need for follow up exams Warm surroundings and dimmed lighting are helpful to make children more cooperative Features mAs  automatically adapted to patient size Real-time dose adaptation in multiple planes  Benefits Ease of use in protocol selection Optimal diagnostic image quality in every sliceLowest possible dose levels Dedicated Pediatric Scan Protocols CARE Dose4D CARE kV Iterative Reconstruction Adaptive Dose Shield X-CARE Flash Spiral Detectors Filters Eff. mAs values modulated automatically in the patient's long axis (Z-axis) for body parts of varying thickness.   Siemens uses Topogram to calculate dose and plan scan ranges Patient centering is critical Isocenter Incorrect positioning can lead to under- or over-irradiation Patient Too High in Gantry: Patient image magnified Patient size over-estimated May result in more dose/over irradiation May affect image quality Patient Too Low in Gantry: Patient image minified Patient size under-estimated May result in less dose/under irradiation May affect image quality  Iso-center positioning of patient helps ensure correct representation of true patient size. What role does kV play in image quality? What role does kV play in dose? Is it necessary to change the kV? If you do – what do you do with the mAs? 80 kV 100 kV 120 kV 140 kV Comment 1.000 1.000 1.000 1.000 equal noise 1.267 1.134 1.055 1.000 soft tissue 1.446 1.223 1.091 1.000 bone 1.624 1.312 1.127 1.000 + contrast 1.980 1.490 1.200 1.000 CTA Adaptation of tube voltage To the individual patient To the system capabilities To the clinical task at hand  Based on: Reference kV Examination type/clinical task Assessment of patient size using topogram Benefits: Works in conjunction with CARE Dose4D Optimized image quality Optimized exposure Optimized signal to noise ratio No calculations needed to get the right mAs value  Image quality is based on: Quality Reference mAs (CARE Dose4D) Reference kV Position of Dose Optimization Slider Off On Semi Filtered Back Projection Currently used by most conventional CT scanners Various filters used to improve image quality Projections are gathered at angles around the object “Star pattern” of data results in blurred images Can impart different image impressions based on diagnostic purpose Smooth = soft tissue Sharp = high resolution Good image quality with short reconstruction times Filtered Back Projection Currently used by most conventional CT scanners Various filters used to improve image quality Projections are gathered at angles around the object “Star pattern” of data results in blurred images Can impart different image impressions based on diagnostic purpose Smooth = soft tissue Sharp = high resolution Good image quality with short reconstruction times Back Projection Filtered Back Projection Weighted Filtered Back Projection Theoretical Iterative Reconstruction Iterative Reconstruction in Image Space Statistical Iterative Reconstruction Sinogram Affirmed Image Reconstruction Iterative Reconstruction Iterative reconstruction methods decouple spatial resolution and image noise Correction loop introduced into reconstruction process Historically difficult to implement due to clinically unacceptable computational power/reconstruction times *In clinical practice, the use of SAFIRE/ADMIRE may reduce CT patient dose depending on the clinical task, patient size, anatomical location, and clinical practice. A consultation with a radiologist and a physicist should be made to determine the appropriate dose to obtain diagnostic image quality for the particular clinical task. Iterative Reconstruction Improves image quality without the need for more dose Can retrospectively improve suboptimal images Iterative Reconstruction Siemens default IR protocols Enabled by checking SAFIRE/ADMIRE box   You should now be able to: Recognize the available dedicated adult and pediatric protocols and how protocol parameters can be modified when necessary Review the importance of iso-centering the patient and the negative effects of not doing so Explain how CARE Dose4D™ works and recognize its importance in daily workflow Identify other robust dose features, such as X-CARE, Adaptive Dose Shield, and Iterative Reconstruction and appreciate their roles in a comprehensive dose optimization strategy Discuss special filters and detector materials inherent in your CT scanner Review the Flash technology on select Siemens Dual Source CT scanners and the benefits it offers regarding dose Defines the desired image quality - or noise value - for a protocol for an averaged sized patient Average sized patient = 70 - 80kg