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Mammography Unit Evaluation and DICOM Header Checklist

Mammography Unit Evaluation and DICOM Header Checklist. Mei Ge 21/Dec/2010. Unit Evaluation Spreadsheet Template. DICOM Header Checklist Spreadsheet Template. Unit Evaluation Example. Need to call service person immediately?. DICOM Header Checklist Example.

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Mammography Unit Evaluation and DICOM Header Checklist

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  1. Mammography Unit Evaluation and DICOM Header Checklist Mei Ge 21/Dec/2010

  2. Unit Evaluation Spreadsheet Template

  3. DICOM Header Checklist Spreadsheet Template

  4. Unit Evaluation Example Need to call service person immediately?

  5. DICOM Header Checklist Example

  6. Mammographic Unit Assembly Evaluation Gord: MammoEquipment2.ppt

  7. Mammographic Unit Assembly Evaluation Gord: MammoEquipment2.ppt

  8. What is DICOM? • DICOM stands for “Digital Imaging and COmmunications in Medicine”. • For related information: http://medical.nema.org • For most recently DICOM standard: ftp://medical.nema.org/medical/dicom/2009/ • DICOM Standard mainly specifies: • How to construct a modality-specific image by “Information Object Definitions”. • How the medical devices communicate with each other in a network environment.

  9. ftp://medical.nema.org/medical/dicom/2009/

  10. What is IHE? • IHE stands for “Integrating the Healthcare Enterprise”. • http://www.ihe.net/ • “IHE is an initiative by healthcare professionals and industry to improve the way computer systems in healthcare share information. IHE promotes the coordinated use of established standards such as DICOM and HL7 to address specific clinical need in support of optimal patient care.”

  11. DICOM Data Dictionary • A DICOM image contains two parts: header and pixel data. • The DICOM standard segments the real information entity (e.g., CT Image, Digital Mammo X-Ray Image, Structured Report, etc.)into attributes. • Those property-related attributes are grouped into modules semantically. • Each attribute translates to an element in the DICOM Data Dictionary. • There more than 2000 items in the standard DICOM Data Dictionary. • Each element is numbered as a hexadecimal tag such as (0018,11A0) to be orderable and computer friendly. • A DICOM file consists of a structured set of data elements which are all from the Data Dictionary.

  12. Data Elements and DICOM Objects Encoding • The DICOM standard is like a language which has grammar other than its dictionary. • Data elements encoding is the grammar how to make a sentence with an element. • DICOM objects encoding is nothing more than putting the elements together in ascending order of tags. DICOM Standard: PS3.5-2009 12/25

  13. Digital Mammography X-Ray Image IOD Module Table M = Mandatory U = User Optional C = Conditional

  14. Patient Module Attributes (Partial)

  15. DX Image Module Attributes (partial)

  16. DX Positioning Module Attributes (Partial)

  17. DX Positioning Module Attributes (Cont)

  18. Data Element Type • A data element may or may not be required in a DICOM dataset depending on the Attribute’s Data Element Type. • Type 1 = Required data elements • Type 1C = Conditional data elements • Type 2 = Required data elements, however, the value can be empty • Type 2C = Conditional data elements • Type 3 = Optional data elements

  19. Patient Identification Tags • Everything is required in OBSP except Patient Age. • Acquisition Date/ Acquisition Time/ Institution Name are system provided. Current systems cannot handle different time zone on network. • If no “Acquisition Date”, “Acquisition Time” doesn’t make sense. • Patient Name/ Patient ID are Type 2 elements in DICOM standard. Confused? • Make sure to type in patient birth date during testing in order to check if it’s correct.

  20. Quality Control Tags • Can we change those tags to required in OBSP? • (0800, 0070) Manufacturer • (0008, 1090) Model Name • (0018, 700A) Detector ID • Can we add the tag as required for CAD reason? • (0028, 1040) Pixel Intensity Relationship • For tag (0018, 1000) Device Serial Number, in a CR system, it’s the CR reader’s serial number. • The Standard defines it as: ”Manufacturer’s serial number of the equipment that produced the composite instance. Note: This identifier corresponds to the device that actually created the images, such as a CR plate reader or a CT console, and may not be sufficient to identify all of the equipment in the image chain, such as the generator or gantry or plate.” • Is the value for (0018, 1008) Gantry ID system provided?

  21. Image Display Tags • No tags here are required for OBSP. However, we do have other DICOM required image-related tags in an image. • OBSP required tags>= DICOM required tags? • (0008, 2112) Source Image Sequence is an optional list of ReferencedSOP Class UID(0018,1150) / ReferencedSOP Instance UID(0008,1155) pairs that identifies the source images used to create the derived images. • (0018, 1114) Estimated Radiographic Magnification Factor is defined as: • Ratio of Distance Source to Detector (SID) over Distance Source to Patient (SOD). • This can be a derived value of SID/SOD if tag (0018, 1110) Distance Source to Detector and tag (0018, 1111) Distance

  22. Geometry of Mammography Unit Anode Focal Spot Filtration Beam Limitation (cone or collimator) SOD SID Compression Plate Chest Wall Breast Grid Table Detector Gord: MammoEquipment2.ppt 22/25

  23. Technical Factors Tags • (0018,1152) Exposure = (0018,1150) Exposure Time + (0018,1151) X-Ray Tube • Can we change these to required in OBSP? • (0018,11A0) Body Part Thickness • (0018,11A2) Compression Force • For (0018,1510) Positioner Primary Angle, do we need to test CC-View and MLO-View ? • CC-View: 0º • LMLO-View: -45º • RMLO-View: 45º • (0040,0316) Organ Dose: Average organ dose value measured in dGy during the acquisition of the image. • 1Gray = 10dGy = 100mGy • (0040,8302) Entrance Dose in mGy: Average entrance dose value measured in mGy at the surface of the patient during the performed procedure step.

  24. Patient Orientation • The Patient Orientation (0020,0020) relative to the image plane shall be specified by two values that designate the anatomical direction of the positive row axis (left to right) and the positive column axis (top to bottom). • The first entry is the direction of the rows, given by the direction of the last pixel in the first row from the first pixel in that row. The second entry is the direction of the columns, given by the direction of the last pixel in the first column from the first pixel in that column. • If Anatomical Orientation Type (0010,2210) is absent or has a value of BIPED, anatomical direction shall be designated by abbreviations using the capital letters: • A (anterior) • P (posterior) • R (right) • L (left) • H (head) • F (foot) • For (0020,0020) Patient Orientation, do we need to test CC-View and MLO-View for both left and right breast? • LCC-View: A/R • RCC-View: P/L • LMLO-View: A/FR • RMLO-View: P/FL

  25. Patient Orientation DICOM Standard: PS3.17-2009

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