DICOM Conformance Statement for Scanner Interface. Release 4.7.1

Transcription

1 DICOM Conformance Statement for Scanner Interface Release Document: Pd088CONFSTAT edition 3 11 August Elekta. All rights reserved.

2 Issued by: P. O. BOX 7593 SE STOCKHOLM SWEDEN Tel: Fax: Scanner Interface Release Elekta Instrument AB. All rights reserved. Page 2

3 Contents 1 Introduction Scope and field of application Reference documents Terminology Important notes 6 2 Implementation Model... 8 Applications data flow diagram Functional definitions of Application Entities Sequencing of Real World Activities 10 3 AE specifications Storage Server AE Specification Image Converter AE Networking Specification Image Converter AE Media Storage Specifications Echo Utility AE Specifications 21 4 Communication profiles Supported Communication Stacks TCP/IP Stack Physical Media Support 23 5 Extensions, Specialization, Privatization Configuration AE Title/Presentation Address Mapping Configurable Parameters 25 7 Support of Extended Character Sets A. Image Objects Attributes Stored in the Local ENS Database Scanner Interface Release Elekta Instrument AB. All rights reserved. Page 3

4 List of tables Table 1: SOP Classes supported by the Storage Server Table 2: Presentation context table: C-STORE service...13 Table 3: Presentation context table: C-ECHO service...14 Table 4: SOP Classes supported by the Image Converter Table 5: Presentation context table: C-FIND service...16 Table 6: Patient Level Attributes used as Keys in C-FIND queries...16 Table 7: Study Level Attributes used as Keys in C-FIND queries...17 Table 8 Series Level Attributes used as Keys in C-FIND queries...17 Table 9: Image Level Attributes used as Keys in C-FIND queries...17 Table 10 Status handled in C-FIND response...18 Table 11: Presentation context table: C-MOVE service user...18 Table 12 Attributes used in C-MOVE requests...19 Table 13 Status handled in C-MOVE response...19 Table 14 Media Storage specification...20 Table 15 Media Storage: Objects and Transfer...21 Table 16: Presentation context table: C-ECHO service user...22 Table 17 Attributes used by Elekta applications...28 Scanner Interface Release Elekta Instrument AB. All rights reserved. Page 4

5 1 Introduction 1.1 Scope and field of application The scope of this DICOM conformance statement is to facilitate data exchange with equipment of Elekta Neuro Sciences. This document specifies the conformance to the DICOM standard (formally called the NEMA PS3.X-1993 standards). It contains a short description of the applications involved and provides technical information about the data exchange capabilities of the equipment. The main elements describing these capabilities are the supported DICOM service object pairs (SOP) classes, Roles and Transfer Syntaxes. 1.2 Reference documents Digital Imaging and Communications in Medicine (DICOM). Version 3.0. National Electrical Manufacturer s Association. Rosslyn, VA, United States of America Scanner Interface Release Elekta Instrument AB. All rights reserved. Page 5

6 1.3 Terminology Term AE AET AP Elekta workstation ENS FSR PDU SCP SCU SOP UID Explanation Application Entity Application Entity Title Application Profile The workstation that supports Storage Server and Image Converter AEs Elekta Neuro Sciences File Set Reader Protocol data unit Service Class Provider Service Class User Service Object Pair Unique Identifier 1.4 Important notes This Conformance Statement by itself does not guarantee successful interoperability of Elekta equipment with non-elekta equipment. The user (or user's agent) should be aware of the following issues: Scope The goal of DICOM is to facilitate inter-connectivity rather than interoperability. Interoperability refers to the ability of application functions, distributed over two or more systems, to work successfully together. The integration of medical devices into a networked environment may require application functions that are not specified within the scope of DICOM. Consequently, using only the information provided by this Conformance Statement does not guarantee interoperability of Elekta equipment with non-elekta equipment. It is the user's responsibility to analyze thoroughly the application requirements and to specify a solution that integrates Elekta equipment with non- Elekta equipment. Scanner Interface Release Elekta Instrument AB. All rights reserved. Page 6

7 Validation Elekta equipment has been carefully tested to assure that the actual implementation of the DICOM interface corresponds with this Conformance Statement. Where Elekta equipment is linked to non- Elekta equipment, the first step is to compare the relevant Conformance Statements. If the Conformance Statements indicate that successful information exchange should be possible, additional validation tests will be necessary to ensure the functionality, performance, accuracy and stability of image and image related data. It is the responsibility of the user (or user's agent) to specify the appropriate test suite and to carry out the additional validation tests. New versions of the DICOM Standard The DICOM standard will evolve in future to meet the user's growing requirements and to incorporate new features and technologies. Elekta plans to adapt its equipment to future versions of the DICOM standard. In order to do so, Elekta reserves the right to make changes to its products or to discontinue its delivery. The user should ensure that any non-elekta provider linking to Elekta equipment also adapts to future versions of the DICOM Standard. If not, the incorporation of DICOM enhancements into Elekta equipment may lead to loss of connectivity (in case of networking) and incompatibility (in case of media). Scanner Interface Release Elekta Instrument AB. All rights reserved. Page 7

8 2 Implementation Model The scanner interface consists of three different Application Entities: Storage Server, Image Converter and Echo Utility 2.1 Applications data flow diagram Local Remote Storage Server DICOM AE C-STORE request Verify request Query/ Retrieve Request Image Converter DICOM AE Query/ Retrieve Respons Display Directory of MO-disk Copy to local Storage FSR (M-READ) DICOM 1,2 GB MO-disk Verify respons Echo utility DICOM AE Verify request Verify respons DICOM Standard Interface Scanner Interface Release Elekta Instrument AB. All rights reserved. Page 8

9 2.2 Functional definitions of Application Entities Storage Server The Elekta Storage Server waits for another application to connect at the TCP/IP port number specified when the application is installed. When another application makes a DICOM association request, the Storage Server acts as a SCP for the storage service class: It stores some attributes of the received image in the local database of the Elekta workstation. The only purpose of the Storage Server is to provide source DICOM images to the Elekta Image Converter. The Storage Server also acts as a SCP for the verification service class: It responds to C- ECHO requests from other applications. Image Converter The Elekta Image Converter interacts with the DICOM standard in three ways: as a SCU of the Query/Retrieve (C-FIND and C-MOVE) service class, as a partially conformant FSR to read files from some DICOM conformant media, and to extract from DICOM objects (image files) useful information for other Elekta applications. As a SCU of Query/Retrieve service class, the Image Converter tries to initiate association with selected applications on other DICOM nodes. When the other application accept the association, the Image Converter first sends "Find" requests to get lists of patients, studies, series and images stored on the other node. The Image Converter then sends move requests for images selected from the above lists in order to retrieve the selected images from the Elekta Workstation. The normal result of these "move" requests is a "Storage" request emitted by the other node and handled by the Elekta Storage Server. As a partially conformant FSR, the Image Converter is able to perform the M-READ Media Storage Operation: it recognizes the DICOMDIR structure and the DICOM files stored on some media (optical disks). The Image Converter does not perform the M-INQUIRE Media Storage Operation. Echo Utility The Echo Utility is available to Elekta Service engineers for test and validation purposes. It sends a verify request to a specified DICOM node. It therefore acts as a SCU for the verification service class. Scanner Interface Release Elekta Instrument AB. All rights reserved. Page 9

10 2.3 Sequencing of Real World Activities Not applicable Scanner Interface Release Elekta Instrument AB. All rights reserved. Page 10

11 3 AE specifications 3.1 Storage Server AE Specification The Storage Server Application Entity provides Standard Conformance the following DICOM V3.0 SOP classes as a SCP: SOP Class Name UID CT Image Storage STORE MR Image Storage - STORE XA Image Storage - STORE PET Image Storage STORE SC Image Storage - STORE Verification Table 1: SOP Classes supported by the Storage Server. Association Establishment Policies General The Elekta Storage Server accepts association in response to C-STORE requests from other Applications Entities. It will only accept C-STORE requests for CT, MR, XA, PET and SC SOP classes and in this case will act as storage service class provider. It also accepts association in response to C-ECHO requests and act as verification service class provider. The Storage Server is a UNIX daemon, waits for C-STORE or C-ECHO requests, and performs the necessary operations upon it receiving such requests. Upon receiving a Query/Retrieve MOVE request from the Image Converter, the Storage Server provides the C-STORE service. Number of Associations The number of simultaneous associations that will be accepted by the Elekta Storage Server is limited to 1. Asynchronous Nature The Elekta Storage Server does not perform asynchronous operations window negotiation. Scanner Interface Release Elekta Instrument AB. All rights reserved. Page 11

12 Implementation Identifying Information The Elekta Storage Server does not export any DICOM object. The only occasion where an Implementation Identifier may be used is during the establishment of the association with a DICOM peer. For this reason the implementation identifying information of the underlying Merge COM3 toolkit has been kept unchanged: IMPLEMENTATION_CLASS_UID = IMPLEMENTATION_VERSION= MergeCOM3_251 Association Initiation by Real World Activity The Elekta Storage Server never initiates an association. Association Acceptance Policy Remote System Requests Image Storage Associated Real World Activity A DICOM AE sends a storage request to the Elekta Storage Server. If the request is accepted the images are stored on the Elekta Storage Server. Scanner Interface Release Elekta Instrument AB. All rights reserved. Page 12

13 Presentation context table Presentation Context Table Abstract Syntax Transfer Syntax List Role Extended Negotiation Name UID Name UID CT Image Storage Implicit VR Little Endian SCP None Explicit VR Little Endian Explicit VR Big Endian MR Image Storage Implicit VR Little Endian SCP None Explicit VR Little Endian Explicit VR Big Endian PET Image Storage Implicit VR Little Endian SCP None Explicit VR Little Endian Explicit VR Big Endian X-Ray Angiografic Implicit VR Little Endian SCP None Image Storage Explicit VR Little Endian Explicit VR Big Endian Secondary Capture Implicit VR Little Endian SCP None Image Storage Explicit VR Little Endian Table 2: Presentation context table: C-STORE service Explicit VR Big Endian C-STORE SCP conformance The Elekta Storage Server is Conformance Level 0 Storage SCP. Only a subset of the attributes of the received images is stored (see Appendix A). All other attributes are discarded. On the Elekta workstation, the stored attributes may be accessed only through Elekta applications and only for display. The duration of storage of these attributes is at the user discretion. Scanner Interface Release Elekta Instrument AB. All rights reserved. Page 13

14 Presentation context acceptance criterion The Elekta Storage Server will accept any context listed in Table 2. There is no check for duplicate contexts. Transfer syntax selection policies The preference in acceptance of Transfer Syntaxes is: Explicit Big Endian above Explicit Little Endian above Implicit Little Endian. Remote system requests verification Associated real world activity A remote DICOM AE wish to verify the application level communication using the C-ECHO command. Presentation context table Presentation Context Table Abstract Syntax Transfer Syntax List Role Extended Name UID Name UID Negotiation Verification Implicit VR Little Endian SCP None Explicit VR Little Endian SCP None Explicit VR Big Endian SCP None Table 3: Presentation context table: C-ECHO service C-ECHO SCP conformance The Elekta Storage Server provides standard conformance to the C-ECHO service as a Service Class Provider. Presentation context acceptance criterion The only accepted presentation context is defined in Table 3. Transfer syntax selection policies The preference in acceptance of Transfer Syntaxes is: Explicit Big Endian above Explicit Little Endian above Implicit Little Endian Scanner Interface Release Elekta Instrument AB. All rights reserved. Page 14

15 3.2 Image Converter AE Networking Specification The Image Converter Application Entity provides Standard Conformance with the following DICOM V3.0 SOP classes as an SCU: SOP Class Name UID Patient Root Q/R Information Model FIND Patient Root Q/R Information Model MOVE Table 4: SOP Classes supported by the Image Converter. Association Establishment Policies General The Elekta Image Converter attempts to initiate associations and issues C-FIND and C-MOVE requests to other Applications Entities. Number of Associations The number of concurrent associations that will be initiated by the Elekta Image Converter is limited to 1. Asynchronous Nature The Elekta Image Converter does not perform asynchronous operations window negotiation Implementation Identifying Information The Elekta Image Converter does not export any DICOM object. The only occasion where an Implementation Identifier may be used is during the establishment of the association with a DICOM peer. For this reason the implementation identifying information of the underlying Merge COM3 toolkit has been kept unchanged: IMPLEMENTATION_CLASS_UID = IMPLEMENTATION_VERSION= MergeCOM3_251 Scanner Interface Release Elekta Instrument AB. All rights reserved. Page 15

16 Association Initiation by Real World Activity Query a Remote Database Associated Real World Activity A remote database is queried when the user selects a pre-registered peer DICOM AE in the user interface of the ENS product. This initiates the C-FIND service. Proposed Presentation Context Image Converter proposes the presentation context shown in the table below when performing C- FIND requests. Presentation Context Table Abstract Syntax Transfer Syntax List Role Extended Negotiation Name UID Name UID Patient Root Q/R Implicit VR Little Endian SCU None Information Model FIND Explicit VR Little Endian Explicit VR Big Endian Table 5: Presentation context table: C-FIND service C-FIND SCU conformance For each level of the Patient Root Information Model, the Image Converter generates queries containing the Required, Unique and Optional keys listed in the tables below. An 'Empty' value means that the SCP will perform a universal match on that key. Name TAG Type Programmed value Patient Name (0010, 0010) Required Programmed PN Patient ID (0010, 0020) Unique Empty Table 6: Patient Level Attributes used as Keys in C-FIND queries "Programmed PN" is built as '*XYZ*', where X, Y and Z are the three first letters of the patient name typed by the user. Scanner Interface Release Elekta Instrument AB. All rights reserved. Page 16

17 Name TAG Type Programmed value Patient Name (0010, 0010) Optional as returned from Patient level Patient ID (0010, 0020) Optional as returned from Patient level Study date (0008, 0020) Required Empty Study Time (0008, 0030) Required Empty Accession number (0008, 0050) Required Empty Study ID (0020, 0010) Required Empty Study Instance UID (0020, 000D) Unique Empty Table 7: Study Level Attributes used as Keys in C-FIND queries Name TAG Type Programmed value Patient ID (0010, 0020) Optional as returned from Patient level Study ID (0010, 0020) Optional Empty Study Instance UID (0020,000D) Optional as returned from Study level Modality (0008, 0060) Required Empty Series number (0020, 0011) Required Empty Series Instance UID (0020, 000E) Unique Empty Table 8 Series Level Attributes used as Keys in C-FIND queries Name TAG Type Programmed value Patient ID (0010, 0020) Optional as returned from Patient level Study Instance UID (0020,000D) Optional as returned from Study level Modality (0008, 0060) Optional Empty Series number (0020, 0011) Optional Empty Series Instance UID (0020, 000E) Optional as returned from Series level Image number (0020, 0013) Required Empty SOP instance UID (0008, 0018) Unique Empty Table 9: Image Level Attributes used as Keys in C-FIND queries Scanner Interface Release Elekta Instrument AB. All rights reserved. Page 17

18 The Image Converter recognizes and handles the following statuses in the C-FIND response: Status Hex Code C_FIND_SUCCESS 0000 C_FIND_PENDING C_FIND_PENDING_NO_OPTIONAL_KEY_SUPPORT C_FIND_FAILURE_REFUSED_NO_RESOURCES C_FIND_FAILURE_INVALID_DATASET C_FIND_FAILURE_UNABLE_TO_PROCESS FF00 FF01 A700 A900 C001 Table 10 Status handled in C-FIND response Retrieve Image(s) from a Remote Database Associated Real World Activity The C-MOVE operation is initiated after the user has selected images to retrieve and asked for their transfer. The "retrieve" operation is performed only at the image level, but a shortcut in the User Interface allows asking in one request for all images of the same series. Proposed Presentation Context Presentation Context Table Abstract Syntax Transfer Syntax List Role Extended Negotiation Name UID Name UID Patient Root Q/R Implicit VR Little Endian SCU None Information Model MOVE Explicit VR Little Endian Explicit VR Big Endian Table 11: Presentation context table: C-MOVE service user C-MOVE SCU Conformance The Image Converter provides standard conformance. The Image Converter issues the C-MOVE Scanner Interface Release Elekta Instrument AB. All rights reserved. Page 18

19 request at the image level and specifies the following attributes in this request: Name TAG Programmed value Patient ID (0010, 0020) as returned from Patient level C_FIND Study Instance UID (0020,000D) as returned from Study level C_FIND Series Instance UID (0020, 000E) as returned from Series level C_FIND SOP instance UID (0008, 0018) as returned from Image level C_FIND Move destination (0000, 0600) see 6.1 "AE Title/Presentation Address Mapping" Table 12 Attributes used in C-MOVE requests The Image Converter recognizes and handles the following status of the C-MOVE response: Status Hex Code C_MOVE_SUCCESS_NO_FAILURES 0000 C_MOVE_PENDING_MORE_SUB_OPERATIONS FF00 C_MOVE_FAILURE_REFUSED_CANT_CALCULATE C_MOVE_FAILURE_REFUSED_CANT_PERFORM C_MOVE_FAILURE_REFUSED_DEST_UNKNOWN C_MOVE_FAILURE_INVALID_DATASET C_MOVE_FAILURE_UNABLE_TO_PROCESS A701 A702 A801 A900 C001 C_STORE_FAILURE_CANNOT_UNDERSTAND C_STORE_FAILURE_REFUSED_NO_RESOURCES C000 A700 C_STORE_FAILURE_PROCESSING_FAILURE 0110 C_STORE_FAILED_OPERATION C002 Table 13 Status handled in C-MOVE response Association Acceptance Policy The Image Converter does not accept associations initiated by another DICOM AE. Scanner Interface Release Elekta Instrument AB. All rights reserved. Page 19

20 3.3 Image Converter AE Media Storage Specifications Specification The Image Converter can be used to read DICOMDIR directories with CT/MR/SC images on 130 mm 1.2GB magneto-optical disks with 512 byte records. The Image Converter is then partially conformant to the following application profiles: Supported AP Real world activity Role SC Option STD-CTMR-MOD12 Read DICOMDIR CT/MR/SC images FSR Interchange Table 14 Media Storage specification The application is only partially conformant as FSR because it supports the M-READ service but does not support the M-INQUIRE service. The following table defines which objects are read by the application and which transfer syntaxes are supported: Information Object Definition Service Object Pair Class UID Transfer Syntax UID FSR requirement Status Basic Directory Explicit VR Little Endian Uncompressed CT Image JPEG Lossless Process 14 (selection value 1) CT Image Explicit VR Little Endian Uncompressed MR Image JPEG Lossless Process 14 (selection value 1) MR Image Explicit VR Little Endian Uncompressed Mandatory Mandatory Mandatory Mandatory Mandatory Supported Supported Supported Supported Supported SC Image (gray scale) JPEG Lossless Process 14 (selection value 1) Mandatory Supported SC Image (gray scale) Explicit VR Little Endian Uncompressed Mandatory Supported SC Image (palette) JPEG Lossless Process 14 (selection value 1) Optional Not Supported Scanner Interface Release Elekta Instrument AB. All rights reserved. Page 20

21 SC Image (palette) Explicit VR Little Endian Uncompressed Optional Not Supported Detached Patient Management Explicit VR Little Endian Uncompressed Optional Not Supported Table 15 Media Storage: Objects and Transfer Note: The scanner interface do not use the application profile information in the 128 byte preamble of the DICOM file. DICOM files with modality tag (0008,0060) PT, XA and DS can therefore also be imported from magneto-optical disks. Augmented and Private Application Profile Not applicable Extensions, Specialization, Privatization of SOP Classes Not applicable Configuration The M-READ service does not need configuration. Character Sets No extended character sets are supported 3.4 Echo Utility AE Specifications The Echo Utility is available to Elekta Service engineers for test and validation purposes. It sends a verify request to a specified DICOM node. Association Establishment Policies General The Echo Utility attempts to initiate associations and issues C-ECHO request to other Applications Entities. Number of Associations The number of concurrent associations that will be initiated by the Echo Utility is limited to 1. Asynchronous Nature The Echo Utility does not perform asynchronous operations window negotiation Scanner Interface Release Elekta Instrument AB. All rights reserved. Page 21

22 Implementation Identifying Information The Implementation Identifying Information of the underlying Merge COM3 toolkit has been kept unchanged: IMPLEMENTATION_CLASS_UID = IMPLEMENTATION_VERSION = MergeCOM3_251 Association Initiation by Real World Activity Verify Application Level Communication Associated Real World Activity The Elekta Service engineer starts the Echo Utility from the terminal window. Proposed presentation contexts Presentation Context Table Abstract Syntax Transfer Syntax List Role Extended Negotiation Name UID Name UID Verification Implicit VR Little Endian SCU None Explicit VR Little Endian Explicit VR Big Endian Table 16: Presentation context table: C-ECHO service user C-ECHO SCU conformance The Echo Utility provides standard conformance. Scanner Interface Release Elekta Instrument AB. All rights reserved. Page 22

23 4 Communication profiles 4.1 Supported Communication Stacks The Elekta Storage Server and the Image Converter provide DICOM V3.0 TCP/IP Network Communication Support as defined in part 8 of the DICOM standard. 4.2 TCP/IP Stack Elekta Storage Server and Image Converter inherit their TCP/IP stack from the HP-UX (Unix) operating system upon which they execute. 4.3 Physical Media Support See paragraph 3.3 Image Converter AE Media Storage Specifications. Scanner Interface Release Elekta Instrument AB. All rights reserved. Page 23

24 5 Extensions, Specialization, Privatization Not applicable. Scanner Interface Release Elekta Instrument AB. All rights reserved. Page 24

25 6 Configuration Configuration is done by editing application configuration files and resource files. It is intended to be performed by Elekta service engineers only. 6.1 AE Title/Presentation Address Mapping Application Entity Title for the Image Converter is determined by a resource. The value of this resource is defined in the resource file and may be modified by Elekta service engineers during installation/upgrade of the system. The default value (as generated when the application is installed) is ELEKTA_QR. Application Entity Title for the Storage Server is determined by a resource. The value of this resource is defined in the resource file and may be modified by Elekta service engineers during installation/upgrade of the system. The default value (as generated when the application is installed) is ELEKTA_STORAGE. 6.2 Configurable Parameters In addition to the AETs defined in the previous paragraph, the following parameters defining the query/retrieve service provider may be set in the "Image Converter configuration file" by Elekta service engineers: IP address or network node name of the machine supporting the query/retrieve SCP AE title of the query/retrieve SCP port number at which the query/retrieve SCP is waiting for queries Elekta service engineers may also configure the maximum PDU size by editing the mergecom.pro file. Its default value is bytes. Scanner Interface Release Elekta Instrument AB. All rights reserved. Page 25

26 7 Support of Extended Character Sets Extended characters can be handled, but are not fully supported. Scanner Interface Release Elekta Instrument AB. All rights reserved. Page 26

27 A. Image Objects Attributes Stored in the Local ENS Database As explained in paragraph "C-STORE SCP conformance", only a subset of the attributes of the received images is stored and used by other Elekta applications. The tables below list these attributes together with their DICOM tags. Name TAG Usage/Comment Patient Name (0010, 0010) Identification Patient Orientation (0020, 0020) 3D reconstruction Modality (0008, 0060) Identification/Validation See Note 1 Image Orientation Patient (0020, 0037) 3D reconstruction Bits Allocated (0028, 0100) Pixel data interpretation and display Bits stored (0028, 0101) Pixel data interpretation and display Samples per pixel (0028, 0002) Pixel data interpretation and display Photometric Interpretation (0028, 0004) Pixel data interpretation High Bit (0028, 0102) Pixel data interpretation and display Pixel Representation (0028, 0103) Pixel data interpretation and display Columns (0028, 0011) Pixel data interpretation and display Rows (0028, 0010) Pixel data interpretation and display Pixel Data (7FE0, 0010) Pixel data interpretation and display Transfer Syntax UID (0002, 0010) Criteria to perform byte swapping Pixel spacing (0028, 0030) 3D reconstruction Series Number (0020, 0011) Separation of a stack in several series Image Number (0020, 0013) User information Slice Location (0020, 1041) Separation of a stack in several series Study Instance UID (0020, 000D) Separation of a stack in several series Image Position Patient (0020, 0032) 3D reconstruction Slice Thickness (0018, 0050) 3D reconstruction/validation. See Note 2 Echo Numbers (0018, 0086) Separation of a stack in several series Spacing between Slices (0018, 0088) 3D reconstruction/validation See Note 2 Scanner Interface Release Elekta Instrument AB. All rights reserved. Page 27

28 CT rescale slope (0028, 1053) Pixel data interpretation and display CT rescale intercept (0028, 1052) Pixel data interpretation and display Window Center (0028, 1050) Pixel data interpretation and display Window Width (0028, 1051) Pixel data interpretation and display Manufacturer (0008, 0070) User information Series Instance UID (0020, 000E) Separation of a stack in several series SOP Instance UID (0008, 0018) Discriminates between ACR-NEMA 2.0 and DICOM images. Series Type (0054,1000) For rejection of dynamic PET studies. Table 17 Attributes used by Elekta applications Note 1 The accepted values for "modality" are: CT, MR, XA. PT and DS. Note DS is a retired enumerated value for modality since the introduction of XA, but it can still be found in some image headers. Note 2 For a valid 3D reconstruction, it is required that "slice thickness" and "spacing between slices" do not differ more than a site-configured tolerance. Scanner Interface Release Elekta Instrument AB. All rights reserved. Page 28