Материал: part03

intended to be delivered in an indivisible manner. An RT Radiation is typically referred to in end-user terminology as a beam (in ex-​ ternal beam treatment) or a catheter (in brachytherapy).​

7.14.7 RT Radiation Record​

The RT Radiation Record records actual treatment parameters that have been applied during the delivery of an RT Radiation in the​ context of a specific fraction. Typically, those parameters are the same as those described within an RT Radiation, but may differ due​ to therapist decisions and/or circumstances of the delivery technology and/or for various other reasons.​

7.14.8 RT Treatment Phase​

An RT Course may be divided into multiple RT Treatment Phases. Each RT Treatment Phase represents a period of time during​ which a defined number of RT Treatment Fractions are delivered by RT Radiation Sets in order to reach a specific treatment goal​ (see Section 7.14.9 and Section 7.14.10).​

AnRTTreatmentPhasealsodefinesthechronologicalrelationshipbetweenRTRadiationSetsthatareconcurrentlyand/orsubsequently​ treated.​

7.14.9 RT Fractionation, RT Fractionation Scheme​

Fractionation describes the splitting of a course of therapeutic radiation delivery into multiple sessions. Each session may consist of​ the delivery of one or more RT Radiation Sets. The temporal pattern of session is called a fractionation scheme.​

Further descriptions and examples of this such schemes can seen in Section 7.14.10.​

7.14.10 RT Treatment Session, RT Treatment Fraction​

An RT Treatment Session is a collection of RT treatment events which are performed in a contiguous manner without any break in-​ between(otherthantimeneededforrequiredpreparations)duringasingleVisit.Itdenotesthetimeperiodbetweenthepatiententering​ the treatment room and leaving the treatment room. In a treatment session one or more RT Radiation Sets (RSet in Figure 7.14-2)​ may be treated. An RT Treatment Session may also include imaging. A group of radiation deliveries that are separated by an inten-​ tional delay to accommodate radiobiological recovery effects are considered separate Treatment Sessions.​

Each treatment of an RT Radiation Set is labeled as an RT Treatment Fraction (often abbreviated as Fx) with a fraction number​ starting with 1 at the first RT Treatment Session in which the RT Radiation Set is delivered, incremented by 1 at each subsequent​ treatment session.​

An RT Treatment Fraction is the delivery of a portion of the total dose (whose delivery is defined by an RT Radiation Set) which has​ been divided equally into smaller doses to be delivered over a period of time (e.g. daily for 4-6 weeks). In radiotherapy, this division​ of dose over a period of time is known as dose fractionation.​

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RT Course

Treatment Phase

Phase 1: Normal

Treatment Phase Interval

Treatment Phase

Phase 2: Boost

Treatment Session

Treatment Fraction

RSet = RT Radiation Set

Figure 7.14-2. RT Treatment Phase, RT Treatment Session, RT Treatment Fraction​

Partial treatments annotate RT Treatment Fractions, that are not completely performed for any reason (e.g. patient sickness, delivery​ device breakdown). The remainder of the RT Treatment Session is usually delivered at a later time.This remaining portion has the​ same fraction number as the one of the Partial Treatment Session. Further treatments will start a new RT Treatment Fraction with an​ incremented fraction number.​

In Figure 7.14-3, the shaded areas of each Radiation Set represent the portion where dose is actually delivered. Partially shaded​ Radiation Sets therefore represents a partial treatment.​

RT Course

Treatment Phase

Phase 1: Normal

Treatment Session

Treatment Fraction

RSet = RT Radiation Set

Figure 7.14-3. Partial RT Treatment Fraction and Resumption​

7.14.11 Dosimetric Objective​

The Dosimetric Objective Macro specifies an intended goal to be used in the definition of the dosimetric plan for plan optimization​ etc. Dosimetric Objectives may define limits which affect the dose, such as dose volume constraints, minimum or maximum dose,​ treatment time or MU limits, and radiobiologic effects.​

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8 Encoding of Coded Entry Data​

The primary method of incorporating coded entry data in DICOM IODs is the Code Sequence Attribute. Code Sequence Attributes​ areencodedasaSequenceofItemsusingaMacrothatisdescribedinthissection.TheseAttributestypicallyincludethestring"Code​ Sequence" in the Attribute Name. Their purpose is to encode terms by using codes from coding schemes.​

Note​

In this Standard, Code Sequence Attributes are defined for a variety of concepts, for example: Primary Anatomic Structure​ Sequence (0008,2228) and other Attributes to describe anatomy; and Intervention Drug Code Sequence (0018,0029), to​ document administration of drugs that have special significance in Imaging Procedures.​

Each Item of a Code Sequence Attribute contains the triplet of Coding Scheme Designator (0008,0102), the Code Value (0008,0100)​ (or Long Code Value (0008,0119) or URN Code Value (0008,0120)), and Code Meaning (0008,0104). Other optional and conditional​ Attributes may also be present.​

For anyparticular Code Sequence Attributes, the range ofcodesthatmay be used for that Attribute(the Value Set) maybe suggested​ or constrained by specification of a Context Group. The Module or Template in which the Attribute is used will specify whether or not​ the context group is baseline or defined. A Baseline Context Group lists codes for terms that are suggested and may be used, but​ are not required to be used. A Defined Context Group lists codes for terms that shall be used if the term is used.​

Context Groups are defined in a Mapping Resource, such as the DICOM Content Mapping Resource (DCMR) specified in PS3.16.​ Context Groups consist of lists of contextually related coded concepts, including Code Value (0008,0100) (or Long Code Value​ (0008,0119) or URN Code Value (0008,0120)) and Coding Scheme Designator (0008,0102). Each concept is unique within the​ Context Group and identified by its Code Value (0008,0100) (or Long Code Value (0008,0119) or URN Code Value (0008,0120)) and​ Coding Scheme Designator (0008,0102). The Context Group specification identifies whether it is extensible, i.e., whether it may be​ modified in an Application to use additional terms (see PS3.16). Whether a Context Group is used as a Baseline or Defined Context​ Group is defined not in the mapping resource, but rather in the Template or Module in which the Code Sequence Attribute is used.​

Context Groups are identified by labels referred to as Context Identifiers (CID). Formally, the Context Identifier specifies the context​ of use, not the specific list of coded values selected for that context of use in the Context Group. The set of values specified in the​ Standard for a particular context may change over time, and set of values used by an Application Entity for a particular context may​ include a local or private extension beyond the Standard value set.​

Note​

1.​A specific set of coded values used by an Application Entity is therefore identified by the Mapping Resource Identifier,​ plus the Context Identifier, plus the Context Group Version, plus the identifiers for any private extension.​

2.​TheusebyanApplicationEntityofcodedtermsnotintheStandardspecifiedContextGroupdoesnotrequiretheexplicit​ identification of a private extension. The Application Entity is then the implicit source of the extension.​

3.​For the purpose of harmonization with HL7 vocabulary concepts, Context Groups are equivalent to HL7 Value Sets.​

8.1 Code Value​

Code Value (0008,0100) is an identifier that is unambiguous within the Coding Scheme denoted by Coding Scheme Designator​ (0008,0102) and Coding Scheme Version (0008,0103).​

The Long Code Value (0008,0119) or URN Code Value (0008,0120) is only used for codes that exceed the 16 character size limit of​ Code Value (0008,0100). If the code value length exceeds 16, the Code Value (0008,0100) shall not be present. If the code value​ length is 16 characters or less, the Code Value (0008,0100) shall contain the code and neither Long Code Value (0008,0119) nor​ URN Code Value (0008,0120) shall be present. The URN Code Value (0008,0120) shall be used for codes that are represented using​ URN or URL notation. The Long Code Value (0008,0119) shall be used for codes that are represented using other notations and that​ exceed 16 characters in length.​

Note​

The Code Value is typically not a natural language string, e.g., "76752008".​

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8.2 Coding Scheme Designator and Coding Scheme Version​

The Attribute Coding Scheme Designator (0008,0102) identifies the coding scheme in which the code for a term is defined. Standard​ coding scheme designators used in DICOM information interchange are listed in PS3.16. Other coding scheme designators, for both​ private and public coding schemes, may be used, in accordance with PS3.16. Further identification of the coding scheme designators​ used in a SOP Instance may be provided in the Coding Scheme Identification Sequence (0008,0110) (see Section C.12.1).​

Note​

1.​Typical coding schemes used in DICOM include "DCM" for DICOM defined codes, "SCT" for SNOMED CT, and "LN"​ for LOINC. See Annex 8 “Coding Schemes” in PS3.16.​

2.​Coding scheme designators beginning with "99" and the coding scheme designator "L" are defined in HL7 V2 to be​ private or local coding schemes.​

3.​Most IODs that define the use of coded terms provide for the use of private codes and coding schemes through replace-​ ment of Baseline Context Groups or extension of Defined Context Groups. Systems supporting such private code use​ must provide a mechanism for the configuration of sets of Coding Scheme Designator (0008,0102), Code Value​ (0008,0100) (or Long Code Value (0008,0119) or URN Code Value (0008,0120)), and Code Meaning (0008,0104) to​ support interoperation of the private codes with other systems.​

4.​It is highly recommended that local or non-standard coding schemes be identified in the Coding Scheme Identification​ Sequence (0008,0110). Documents or machine readable representations of the coding scheme (e.g., CSV or OWL​ files) can be linked to via a Coding Scheme URL (0008,010E). For appropriate values, see Table 8-1 “Coding Schemes”​ in PS3.16.​

5.​URN and URL codes usually lack a Coding Scheme Designator (0008,0102).​

The Attribute Coding Scheme Version (0008,0103) may be used to identify the version of a coding scheme if necessary to resolve​ ambiguity in Code Value (0008,0100), Long Code Value (0008,0119) or URN Code Value (0008,0120). Coding Scheme Version​ (0008,0103) is not required for backward-compatible revisions of a coding scheme, as the Coding Scheme Designator (0008,0102)​ identifies the coding scheme as a whole as currently published by the responsible organization.​

Note​

1.​See PS3.16 for a discussion of SNOMED Coding Scheme Designators 99SDM, SNM3, SRT and SCT.​

2.​ICD-10, for example, is not a backward-compatible revision of ICD-9, and hence it has a different Coding Scheme​ Designator, not simply a different Coding Scheme Version.​

8.3 Code Meaning​

Code Meaning (0008,0104) is text that has meaning to a human and conveys the meaning of the term defined by the combination of​ Code Value (0008,0100) (or Long Code Value (0008,0119) or URN Code Value (0008,0120)), and Coding Scheme Designator​ (0008,0102). Though such a meaning can be "looked up" in the dictionary for the coding scheme, it is encoded for the convenience​ of applications that do not have access to such a dictionary.​

It should be noted that for a particular Coding Scheme Designator (0008,0102) and Code Value (0008,0100) or Long Code Value​ (0008,0119), or URN Code Value (0008,0120), several alternative values for Code Meaning (0008,0104) may be defined. These may​ be synonyms in the same language or translations of the Coding Scheme into other languages. Hence the value of Code Meaning​ (0008,0104) shall never be used as a key, index or decision value, rather the combination of Coding Scheme Designator (0008,0102)​ andCodeValue(0008,0100),LongCodeValue(0008,0119),orURNCodeValue(0008,0120)maybeused.CodeMeaning(0008,0104)​ is a purely annotative, descriptive Attribute.​

This does not imply that Code Meaning (0008,0104) can be filled with arbitrary free text. Available values from the Coding Scheme​ or translation in the chosen language shall be used.​

8.4 Mapping Resource​

The value of Mapping Resource (0008,0105) denotes the message/terminology Mapping Resource that specifies the Context Group​ that specifies the Value Set. The Defined Terms for the value of Mapping Resource (0008,0105) shall be:​

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Defined Terms:​

DCMR​DICOM Content Mapping Resource​

SDM​SNOMED DICOM Microglossary (Retired)​

PS3.16 specifies the DICOM Content Mapping Resource (DCMR).​

Note​

Unless otherwise specified, the DCMR is the source of all Context Groups and Templates specified in this Standard.​

Mapping Resources may be uniquely identified by Mapping Resource UID (0008,0118).​

Private Mapping Resources (those not listed amongst the Defined Terms in this section), may be identified by the prefix "99".​

Mapping Resource Name (0008,0122) may contain the name of the Mapping Resource. The value may e.g., denote the Institution​ or organization that has specified the Value Set.​

8.5 Context Group Version​

Context Group Version (0008,0106) conveys the version of the Context Group identified by Context Identifier (0008,010F). This At-​ tribute uses VR DT, but for Context Groups defined in PS3.16 the precision of Context Group Version is limited to the day, and the​ time zone offset is not used.​

8.6 Context Identifier and Context UID​

The value of Context Identifier (0008,010F) identifies the Context Group defined by Mapping Resource (0008,0105) from which the​ valuesofCodeValue(0008,0100)(orLongCodeValue(0008,0119)orURNCodeValue(0008,0120))andCodeMeaning(0008,0104)​ were selected, or to which Code Value (0008,0100) (or Long Code Value (0008,0119) or URN Code Value (0008,0120)) and Code​ Meaning (0008,0104) have been added as a private Context Group extension (see Section 8.7). The Context Identifier Attribute uses​ VR CS, and for Context Groups defined in PS3.16 the value shall be the Context Group Identifier as a string of digits without leading​ zeros, and does not include the string "CID".​

The value of Context UID (0008,0117) uniquely identifies the Context Group. See PS3.6.​

Note​

Privately defined Context Groups may be identified by Context Identifier and Mapping Resource.​

8.7 Context Group Extensions​

Context Group Extension Flag (0008,010B) may be used to designate a pair of Code Value (0008,0100) (or Long Code Value​ (0008,0119) or URN Code Value (0008,0120)) and Code Meaning (0008,0104) as a selection from a private extension of a Context​ Group. If the Context Group Extension Flag is present, and has a value of "Y", Context Group Extension Creator UID (0008,010D)​ shall be used to identify the person or organization who created the extension to the Context Group. Context Group Local Version​ (0008,0107) conveys an implementation-specific private version DateTime of a Context Group that contains private extensions​

Note​

1.​These Attributes provide the means for implementations to extend code sets conveniently, while preserving referential​ integrity with respect to the original Context Group Version.​

2.​The locally-defined (private) value of Context Group Local Version (0008,0107) typically would be a more recent date​ than the standard value of Context Group Version (0008,0106) specified in the standard message/terminology Mapping​ Resource that defines the Context Group.​

8.8 Standard Attribute Sets for Code Sequence Attributes​

Table 8.8-1 specifies the default set of Attributes encapsulated in the Items of Code Sequence Attributes. These Attributes comprise​ the Code Sequence Macro.​

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