DICOM PS3.3 2016d - Information Object Definitions

C.8.8.14 RT Beams Module
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#### C.8.8.14 RT Beams Module

The RT Beams Module contains information defining equipment parameters for delivery of external radiation beams.

Table C.8-50. RT Beams Module Attributes

Attribute Name | Tag | Type | Attribute Description
--- | --- | --- | ---
Beam Sequence | (300A,00B0) | 1 | Sequence of treatment beams for current RT Plan. One or more Items shall be included in this Sequence.
>Beam Number | (300A,00C0) | 1 | Identification number of the Beam. The value of Beam Number (300A,00C0) shall be unique within the RT Plan in which it is created. See Note 1.
>Beam Name | (300A,00C2) | 3 | User-defined name for Beam. See Note 1.
>Beam Description | (300A,00C3) | 3 | User-defined description for Beam. See Note 1.
>Beam Type | (300A,00C4) | 1 | Motion characteristic of Beam. See Note 5. Enumerated Values: STATIC All Control Point Sequence (300A,0111) attributes remain unchanged between consecutive pairs of control points with changing Cumulative Meterset Weight (300A,0134). DYNAMIC One or more Control Point Sequence (300A,0111) attributes change between one or more consecutive pairs of control points with changing Cumulative Meterset Weight (300A,0134).
>Radiation Type | (300A,00C6) | 2 | Particle type of Beam. Defined Terms: PHOTON ELECTRON NEUTRON PROTON
>Primary Fluence Mode Sequence | (3002,0050) | 3 | Sequence defining whether the primary fluence of the treatment beam uses a non-standard fluence-shaping. Only a single item is permitted in this Sequence.
>>Fluence Mode | (3002,0051) | 1 | Describes whether the fluence shaping is the standard mode for the beam or an alternate. Enumerated Values: STANDARD Uses standard fluence-shaping NON_STANDARD Uses a non-standard fluence-shaping mode
>>Fluence Mode ID | (3002,0052) | 1C | Identifier for the specific fluence-shaping mode. Required if Fluence Mode (3002,0051) has value NON_STANDARD.
>High-Dose Technique Type | (300A,00C7) | 1C | Type of high-dose treatment technique. Defined Terms: TBI Total Body Irradiation HDR High Dose Rate Required if treatment technique requires a dose that would normally require overriding of treatment machine safety controls.
>Treatment Machine Name | (300A,00B2) | 2 | User-defined name identifying treatment machine to be used for beam delivery. See Note 2.
>Manufacturer | (0008,0070) | 3 | Manufacturer of the equipment to be used for beam delivery.
>Institution Name | (0008,0080) | 3 | Institution where the equipment is located that is to be used for beam delivery.
>Institution Address | (0008,0081) | 3 | Mailing address of the institution where the equipment is located that is to be used for beam delivery.
>Institutional Department Name | (0008,1040) | 3 | Department in the institution where the equipment is located that is to be used for beam delivery.
>Manufacturer's Model Name | (0008,1090) | 3 | Manufacturer's model name of the equipment that is to be used for beam delivery.
>Device Serial Number | (0018,1000) | 3 | Manufacturer's serial number of the equipment that is to be used for beam delivery.
>Primary Dosimeter Unit | (300A,00B3) | 3 | Measurement unit of machine dosimeter. See Section C.8.8.14.1. Enumerated Values: MU Monitor Unit MINUTE minute
>Referenced Tolerance Table Number | (300C,00A0) | 3 | Uniquely identifies Tolerance Table specified by Tolerance Table Number (300A,0042) within Tolerance Table Sequence in RT Tolerance Tables Module. These tolerances are to be used for verification of treatment machine settings.
>Source-Axis Distance | (300A,00B4) | 3 | Radiation source to Gantry rotation axis distance of the equipment that is to be used for beam delivery (mm).
>Beam Limiting Device Sequence | (300A,00B6) | 1 | Sequence of beam limiting device (collimator) jaw or leaf (element) sets. One or more Items shall be included in this Sequence.
>>RT Beam Limiting Device Type | (300A,00B8) | 1 | Type of beam limiting device (collimator). Enumerated Values: X symmetric jaw pair in IEC X direction Y symmetric jaw pair in IEC Y direction ASYMX asymmetric jaw pair in IEC X direction ASYMY asymmetric pair in IEC Y direction MLCX multileaf (multi-element) jaw pair in IEC X direction MLCY multileaf (multi-element) jaw pair in IEC Y direction
>>Source to Beam Limiting Device Distance | (300A,00BA) | 3 | Radiation source to beam limiting device (collimator) distance of the equipment that is to be used for beam delivery (mm).
>>Number of Leaf/Jaw Pairs | (300A,00BC) | 1 | Number of leaf (element) or jaw pairs (equal to 1 for standard beam limiting device jaws).
>>Leaf Position Boundaries | (300A,00BE) | 2C | Boundaries of beam limiting device (collimator) leaves (in mm) in IEC BEAM LIMITING DEVICE coordinate axis appropriate to RT Beam Limiting Device Type (300A,00B8), i.e., X-axis for MLCY, Y-axis for MLCX. Contains N+1 values, where N is the Number of Leaf/Jaw Pairs (300A,00BC), starting from Leaf (Element) Pair 1. Required if RT Beam Limiting Device Type (300A,00B8) is MLCX or MLCY. May be present otherwise. See Note 3.
>Referenced Patient Setup Number | (300C,006A) | 3 | Uniquely identifies Patient Setup to be used for current beam, specified by Patient Setup Number (300A,0182) within Patient Setup Sequence of RT Patient Setup Module.
>Referenced Reference Image Sequence | (300C,0042) | 3 | Reference images used for validation of current beam. One or more Items are permitted in this Sequence.
>>Include Table 10-11 “SOP Instance Reference Macro Attributes” |
>>Reference Image Number | (300A,00C8) | 1 | Uniquely identifies Reference Image within Referenced Reference Image Sequence (300C,0042).
>>Start Cumulative Meterset Weight | (300C,0008) | 3 | Cumulative Meterset Weight within current Beam at which image acquisition starts.
>>End Cumulative Meterset Weight | (300C,0009) | 3 | Cumulative Meterset Weight within current Beam at which image acquisition ends.
>Planned Verification Image Sequence | (300A,00CA) | 3 | Sequence of planned verification images to be acquired during current beam. One or more Items are permitted in this Sequence. See Section C.8.8.14.2.
>>Start Cumulative Meterset Weight | (300C,0008) | 3 | Cumulative Meterset Weight within current Beam at which image acquisition will start.
>>Meterset Exposure | (3002,0032) | 3 | Meterset duration over which image is to be acquired, specified in Monitor units (MU) or minutes as defined by Primary Dosimeter Unit (300A,00B3).
>>End Cumulative Meterset Weight | (300C,0009) | 3 | Cumulative Meterset Weight within current Beam at which image acquisition will end.
>>RT Image Plane | (3002,000C) | 3 | Describes whether or not image plane is normal to beam axis. Enumerated Values: NORMAL image plane normal to beam axis NON_NORMAL image plane non-normal to beam axis
>>X-Ray Image Receptor Angle | (3002,000E) | 3 | X-Ray Image Receptor Angle i.e., orientation of IEC X-RAY IMAGE RECEPTOR coordinate system with respect to IEC GANTRY coordinate system (degrees). See Section C.8.8.14.3.
>>RT Image Orientation | (3002,0010) | 3 | The direction cosines of the first row and the first column with respect to the IEC X-RAY IMAGE RECEPTOR coordinate system.
>>RT Image Position | (3002,0012) | 3 | The x and y coordinates (in mm) of the upper left hand corner of the image, in the IEC X-RAY IMAGE RECEPTOR coordinate system. This is the center of the first pixel transmitted.
>>RT Image SID | (3002,0026) | 3 | Radiation machine source to image plane distance (mm).
>>Imaging Device-Specific Acquisition Parameters | (300A,00CC) | 3 | User-specified device-specific parameters that describe how the imager will acquire the image.
>>Referenced Reference Image Number | (300C,0007) | 3 | Uniquely identifies Reference Image to which planned verification image is related, specified by Reference Image Number (300A,00C8) within Referenced Reference Image Sequence (300C,0042).
>Treatment Delivery Type | (300A,00CE) | 3 | Delivery Type of treatment. Defined Terms: TREATMENT normal patient treatment OPEN_PORTFILM portal image acquisition with open field TRMT_PORTFILM portal image acquisition with treatment port CONTINUATION continuation of interrupted treatment SETUP no treatment beam is applied for this RT Beam. To be used for specifying the gantry, couch, and other machine positions where X-Ray set-up images or measurements are to be taken
>Referenced Dose Sequence | (300C,0080) | 3 | Related instances of RT Dose (for grids, isodose curves, and named/unnamed point doses). One or more Items are permitted in this Sequence.
>>Include Table 10-11 “SOP Instance Reference Macro Attributes” |
>Number of Wedges | (300A,00D0) | 1 | Number of wedges associated with current Beam.
>Wedge Sequence | (300A,00D1) | 1C | Sequence of treatment wedges. Required if Number of Wedges (300A,00D0) is non-zero. One or more Items shall be included in this Sequence.
>>Wedge Number | (300A,00D2) | 1 | Identification number of the Wedge. The value of Wedge Number (300A,00D2) shall be unique within the Beam in which it is created.
>>Wedge Type | (300A,00D3) | 2 | Type of wedge (if any) defined for Beam. Defined Terms: STANDARD standard (static) wedge DYNAMIC moving beam limiting device (collimator) jaw simulating wedge MOTORIZED single wedge that can be removed from beam remotely
>>Wedge ID | (300A,00D4) | 3 | User-supplied identifier for Wedge.
>>Accessory Code | (300A,00F9) | 3 | An identifier for the accessory intended to be read by a device such as a bar-code reader.
>>Wedge Angle | (300A,00D5) | 2 | Nominal wedge angle (degrees).
>>Wedge Factor | (300A,00D6) | 2 | Nominal wedge factor under machine calibration conditions at the beam energy specified by the Nominal Beam Energy (300A,0114) of the first Control Point of the Control Point Sequence (300A,0111).
>>Wedge Orientation | (300A,00D8) | 2 | Orientation of wedge, i.e., orientation of IEC WEDGE FILTER coordinate system with respect to IEC BEAM LIMITING DEVICE coordinate system (degrees).
>>Source to Wedge Tray Distance | (300A,00DA) | 3 | Radiation source to wedge tray attachment edge distance (in mm) for current wedge.
>>Effective Wedge Angle | (300A,00DE) | 3 | Effective wedge angle (degrees). See Section C.8.8.14.14.
>Number of Compensators | (300A,00E0) | 1 | Number of compensators associated with current Beam.
>Total Compensator Tray Factor | (300A,00E2) | 3 | Compensator Tray transmission factor (between 0 and 1), at the beam energy specified by the Nominal Beam Energy (300A,0114) of the first Control Point of the Control Point Sequence (300A,0111).
>Compensator Sequence | (300A,00E3) | 1C | Sequence of treatment compensators. One or more Items shall be included in this Sequence. Required if Number of Compensators (300A,00E0) is non-zero.
>>Compensator Description | (300A,02EB) | 3 | User defined description for the compensator.
>>Compensator Number | (300A,00E4) | 1C | Identification number of the Compensator. The value of Compensator Number (300A,00E4) shall be unique within the Beam in which it is created. Required if Number of Compensators (300A,00E0) is non-zero.
>>Compensator Type | (300A,00EE) | 3 | Type of compensator (if any). Defined Terms: STANDARD physical (static) compensator DYNAMIC moving Beam Limiting Device (collimator) simulating physical compensator
>>Material ID | (300A,00E1) | 2C | User-supplied identifier for material used to manufacture Compensator. Required if Number of Compensators (300A,00E0) is non-zero.
>>Compensator ID | (300A,00E5) | 3 | User-supplied identifier for compensator.
>>Accessory Code | (300A,00F9) | 3 | An identifier for the Compensator intended to be read by a device such as a bar-code reader.
>>Compensator Tray ID | (300A,00EF) | 3 | User-supplied identifier for compensator tray.
>>Tray Accessory Code | (300A,0355) | 3 | An identifier for the Tray intended to be read by a device such as a bar-code reader.
>>Source to Compensator Tray Distance | (300A,00E6) | 2 | Radiation source to compensator tray attachment edge distance (in mm) for current compensator.
>>Compensator Divergence | (300A,02E0) | 3 | Indicates presence or absence of geometrical divergence of the compensator. Enumerated Values: PRESENT the compensator is shaped according to the beam geometrical divergence. ABSENT the compensator is not shaped according to the beam geometrical divergence.
>>Compensator Mounting Position | (300A,02E1) | 3 | Indicates on which side of the Compensator Tray the compensator is mounted. Enumerated Values: PATIENT_SIDE the compensator is mounted on the side of the Compensator Tray that is towards the patient. SOURCE_SIDE the compensator is mounted on the side of the Compensator Tray that is towards the radiation source. DOUBLE_SIDED the compensator has a shaped (i.e., non-flat) surface on both sides of the Compensator Tray.
>>Compensator Rows | (300A,00E7) | 1 | Number of rows in the compensator. A row is defined to be in the X direction of the IEC Beam Limiting Device Coordinate system.
>>Compensator Columns | (300A,00E8) | 1 | Number of columns in the compensator. A column is defined to be in the Y direction of the IEC Beam Limiting Device Coordinate system.
>>Compensator Pixel Spacing | (300A,00E9) | 1 | Physical distance (in mm) between the center of each pixel projected onto machine isocentric plane. Specified by a numeric pair - adjacent row spacing (delimiter) adjacent column spacing. See Section 10.7.1.3 for further explanation of the value order.
>>Compensator Position | (300A,00EA) | 1 | The x and y coordinates of the upper left hand corner (first pixel transmitted) of the compensator, projected onto the machine isocentric plane in the IEC BEAM LIMITING DEVICE coordinate system (mm).
>>Compensator Transmission Data | (300A,00EB) | 1C | A data stream of the pixel samples that comprise the compensator, expressed as broad-beam transmission values (between 0 and 1) along a ray line passing through the pixel, at the beam energy specified by the Nominal Beam Energy (300A,0114) of the first Control Point of the Control Point Sequence (300A,0111). The order of pixels sent is left to right, top to bottom, i.e., the upper left pixel is sent first followed by the remainder of the first row, followed by the first pixel of the 2nd row, then the remainder of the 2nd row and so on) when viewed from the radiation source. Required if Material ID (300A,00E1) is zero-length. May be present if Material ID (300A,00E1) is non-zero length. See Section C.8.8.14.10 and Section C.8.8.14.11. ### Note Compensator Transmission Data may not be properly encoded if Explicit VR transfer syntax is used and the VL of this attribute exceeds 65534 bytes.
>>Compensator Thickness Data | (300A,00EC) | 1C | A data stream of the pixel samples that comprise the compensator, expressed as thicknesses (in mm). The order of pixels sent is left to right, top to bottom, i.e., the upper left pixel is sent first followed by the remainder of the first row, followed by the first pixel of the 2nd row, then the remainder of the 2nd row and so on) when viewed from the radiation source. Required if Material ID (300A,00E1) is non-zero length. May be present if Material ID (300A,00E1) is zero length. See Section C.8.8.14.9 and Section C.8.8.14.10 and Section C.8.8.14.11, “Block and Compensator Precedence for Dosimetric Calculations”. ### Note Compensator Thickness Data may not be properly encoded if Explicit VR transfer syntax is used and the VL of this attribute exceeds 65534 bytes.
>>Source to Compensator Distance | (300A,02E2) | 1C | A data stream of the pixel samples that comprise the distance from the radiation source to the compensator surface closest to the radiation source (in mm). The order of pixels sent is left to right, top to bottom (upper left pixel, followed by the remainder of row 1, followed by the remainder of the columns). Required if Material ID (300A,00E1) is non-zero length, and Compensator Mounting Position (300A,02E1) is DOUBLE_SIDED. May be present if Material ID (300A,00E1) is zero length and Compensator Mounting Position (300A,02E1) is DOUBLE_SIDED. See Section C.8.8.14.9 and Section C.8.8.14.11.
>Number of Boli | (300A,00ED) | 1 | Number of boli associated with current Beam.
>Referenced Bolus Sequence | (300C,00B0) | 1C | Sequence of boli associated with Beam. Required if Number of Boli (300A,00ED) is non-zero. One or more Items shall be included in this Sequence.
>>Referenced ROI Number | (3006,0084) | 1 | Uniquely identifies ROI representing the Bolus specified by ROI Number (3006,0022) in Structure Set ROI Sequence (3006,0020) in Structure Set Module within RT Structure Set in Referenced Structure Set Sequence (300C,0060) in RT General Plan Module.
>>Bolus ID | (300A,00DC) | 3 | User-supplied identifier for the Bolus.
>>Bolus Description | (300A,00DD) | 3 | User-defined description for the Bolus.
>>Accessory Code | (300A,00F9) | 3 | An identifier for the accessory intended to be read by a device such as a bar-code reader.
>Number of Blocks | (300A,00F0) | 1 | Number of shielding blocks associated with Beam.
>Total Block Tray Factor | (300A,00F2) | 3 | Total block tray transmission for all block trays (between 0 and 1) at the beam energy specified by the Nominal Beam Energy (300A,0114) of the first Control Point of the Control Point Sequence (300A,0111).
>Block Sequence | (300A,00F4) | 1C | Sequence of blocks associated with Beam. One or more Items shall be included in this Sequence. Required if Number of Blocks (300A,00F0) is non-zero.
>>Block Tray ID | (300A,00F5) | 3 | User-supplied identifier for block tray.
>>Tray Accessory Code | (300A,0355) | 3 | An identifier for the Tray intended to be read by a device such as a bar-code reader.
>>Accessory Code | (300A,00F9) | 3 | An identifier for the Block intended to be read by a device such as a bar-code reader.
>>Source to Block Tray Distance | (300A,00F6) | 2 | Radiation Source to attachment edge of block tray assembly (mm).
>>Block Type | (300A,00F8) | 1 | Type of block. Enumerated Values: SHIELDING blocking material is inside contour APERTURE blocking material is outside contour
>>Block Divergence | (300A,00FA) | 2 | Indicates presence or otherwise of geometrical divergence. Enumerated Values: PRESENT block edges are shaped for beam divergence ABSENT block edges are not shaped for beam divergence
>>Block Mounting Position | (300A,00FB) | 3 | Indicates on which side of the Block Tray the block is mounted. Enumerated Values: PATIENT_SIDE the block is mounted on the side of the Block Tray that is towards the patient. SOURCE_SIDE the block is mounted on the side of the Block Tray that is towards the radiation source.
>>Block Number | (300A,00FC) | 1 | Identification number of the Block. The value of Block Number (300A,00FC) shall be unique within the Beam in which it is created.
>>Block Name | (300A,00FE) | 3 | User-defined name for block.
>>Material ID | (300A,00E1) | 2 | User-supplied identifier for material used to manufacture Block.
>>Block Thickness | (300A,0100) | 2C | Physical thickness of block (in mm) parallel to radiation beam axis. Required if Material ID (300A,00E1) is non-zero length. May be present if Material ID (300A,00E1) is zero length. See Section C.8.8.14.4 and Section C.8.8.14.11.
>>Block Transmission | (300A,0102) | 2C | Transmission through the block (between 0 and 1) at the beam energy specified by the Nominal Beam Energy (300A,0114) of the first Control Point of the Control Point Sequence (300A,0111). Required if Material ID (300A,00E1) is zero length. May be present if Material ID (300A,00E1) is non-zero length. See Section C.8.8.14.4 and Section C.8.8.14.11.
>>Block Number of Points | (300A,0104) | 2 | Number of (x,y) pairs defining the block edge.
>>Block Data | (300A,0106) | 2 | A data stream of (x,y) pairs that comprise the block edge. The number of pairs shall be equal to Block Number of Points (300A,0104), and the vertices shall be interpreted as a closed polygon. Coordinates are projected onto the machine isocentric plane in the IEC BEAM LIMITING DEVICE coordinate system (mm). See Note 4.
>Applicator Sequence | (300A,0107) | 3 | Sequence of Applicators associated with Beam. Only a single item is permitted in this Sequence.
>>Applicator ID | (300A,0108) | 1 | User or machine supplied identifier for Applicator.
>>Accessory Code | (300A,00F9) | 3 | An identifier for the accessory intended to be read by a device such as a bar-code reader.
>>Applicator Type | (300A,0109) | 1 | Type of Applicator. Defined Terms: ELECTRON_SQUARE square electron applicator ELECTRON_RECT rectangular electron applicator ELECTRON_CIRC circular electron applicator ELECTRON_SHORT short electron applicator ELECTRON_OPEN open (dummy) electron applicator PHOTON_SQUARE square photon applicator PHOTON_RECT rectangular photon applicator PHOTON_CIRC circular photon applicator INTRAOPERATIVE intraoperative (custom) applicator STEREOTACTIC stereotactic applicator (deprecated)
>>Applicator Geometry Sequence | (300A,0431) | 3 | Describes the applicator aperture geometry. Only a single Item is permitted in this Sequence.
>>>Applicator Aperture Shape | (300A,0432) | 1 | Aperture shape of the applicator. Defined Terms: SYM_SQUARE A square-shaped aperture symmetrical to the central axis. SYM_RECTANGLE A rectangular-shaped aperture symmetrical to the central axis. SYM_CIRCULAR A circular-shaped aperture symmetrical to the central axis.
>>>Applicator Opening | (300A,0433) | 1C | Opening (in mm) of the applicator's aperture in IEC BEAM LIMITING DEVICE coordinate system. In case of square-shaped applicator contains the length of the sides of the square. In case of circular-shaped applicators, contains the diameter of the circular aperture. Required if Applicator Aperture Shape (300A,0432) is SYM_SQUARE or SYM_CIRCULAR.
>>>Applicator Opening X | (300A,0434) | 1C | Opening (in mm) of the applicator's aperture in IEC BEAM LIMITING DEVICE coordinate system in X-Direction. Required if Applicator Aperture Shape (300A,0432) is SYM_RECTANGLE.
>>>Applicator Opening Y | (300A,0435) | 1C | Opening (in mm) of the applicator's aperture in IEC BEAM LIMITING DEVICE coordinate system in Y-Direction. Required if Applicator Aperture Shape (300A,0432) is SYM_RECTANGLE.
>> Source to Applicator Mounting Position Distance | (300A,0436) | 3 | Radiation source to applicator mounting position distance (in mm) for current applicator.
>>Applicator Description | (300A,010A) | 3 | User-defined description for Applicator.
>General Accessory Sequence | (300A,0420) | 3 | Introduces a Sequence of General Accessories associated with this Beam. One or more Items are permitted in this Sequence.
>>General Accessory Number | (300A,0424) | 1 | Identification Number of the General Accessory. The value shall be unique within the sequence.
>>General Accessory ID | (300A,0421) | 1 | User or machine supplied identifier for General Accessory.
>>General Accessory Description | (300A,0422) | 3 | User supplied description of General Accessory.
>>General Accessory Type | (300A,0423) | 3 | Specifies the type of accessory. Defined Terms: GRATICULE Accessory tray with a radio-opaque grid IMAGE_DETECTOR Image acquisition device positioned in the beam line RETICLE Accessory tray with radio-transparent markers or grid
>>Accessory Code | (300A,00F9) | 3 | Machine-readable identifier for this accessory
>>Source to General Accessory Distance | (300A,0425) | 3 | Radiation source to general accessory distance (in mm) for current accessory.
>Final Cumulative Meterset Weight | (300A,010E) | 1C | Value of Cumulative Meterset Weight (300A,0134) for final Control Point in Control Point Sequence (300A,0111). Required if Cumulative Meterset Weight is non-null in Control Points specified within Control Point Sequence (300A,0111). See Section C.8.8.14.1.
>Number of Control Points | (300A,0110) | 1 | Number of control points in Beam. Value shall be greater than or equal to 2.
>Control Point Sequence | (300A,0111) | 1 | Sequence of machine configurations describing treatment beam. The number of Items in this Sequence shall equal the value of Number of Control Points (300A,0110). See Section C.8.8.14.5 and Section C.8.8.14.6.
>>Control Point Index | (300A,0112) | 1 | Index of current Control Point, starting at 0 for first Control Point.
>>Cumulative Meterset Weight | (300A,0134) | 2 | Cumulative weight to current control point. Cumulative Meterset Weight for the first item in Control Point Sequence shall always be zero. Cumulative Meterset Weight for the final item in Control Point Sequence shall always be equal to Final Cumulative Meterset Weight. See Section C.8.8.14.1.
>>Referenced Dose Reference Sequence | (300C,0050) | 3 | Introduces a sequence of Dose References for current Beam. One or more Items are permitted in this Sequence.
>>>Referenced Dose Reference Number | (300C,0051) | 1 | Uniquely identifies Dose Reference specified by Dose Reference Number (300A,0012) in Dose Reference Sequence (300A,0010) in RT Prescription Module.
>>>Cumulative Dose Reference Coefficient | (300A,010C) | 2 | Coefficient used to calculate cumulative dose contribution from this Beam to the referenced Dose Reference at the current Control Point. See Section C.8.8.14.7.
>>Referenced Dose Sequence | (300C,0080) | 1C | Sequence describing related instances of RT Dose (for grids, isodose curves, and named/unnamed point doses). One or more Items shall be included in this Sequence. Required if RT Dose is being sent, and Dose Summation Type (3004,000A) equals CONTROL_POINT.
>>>Include Table 10-11 “SOP Instance Reference Macro Attributes” |
>>Nominal Beam Energy | (300A,0114) | 3 | Nominal Beam Energy at control point (MV/MeV).
>>Dose Rate Set | (300A,0115) | 3 | Dose Rate to be set on treatment machine for segment beginning at current control point (e.g., MU/min).
>>Wedge Position Sequence | (300A,0116) | 1C | A Sequence of Items describing Wedge Positions for the current control point. Required for first item of Control Point Sequence if Number of Wedges (300A,00D0) is non-zero, and in subsequent control points if Wedge Position (300A,0118) changes during Beam. See Section C.8.8.14.5. The number of items in this Sequence shall equal the value of Number of Wedges (300A,00D0).
>>>Referenced Wedge Number | (300C,00C0) | 1 | Uniquely references Wedge described by Wedge Number (300A,00D2) in Wedge Sequence (300A,00D1).
>>>Wedge Position | (300A,0118) | 1 | Position of Wedge at current Control Point. Enumerated Values: IN OUT
>>Beam Limiting Device Position Sequence | (300A,011A) | 1C | Sequence of beam limiting device (collimator) jaw or leaf (element) positions. One or more Items shall be included in this Sequence. Required for first item of Control Point Sequence, or if Beam Limiting Device changes during Beam.
>>>RT Beam Limiting Device Type | (300A,00B8) | 1 | Type of beam limiting device (collimator). The value of this attribute shall correspond to RT Beam Limiting Device Type (300A,00B8) defined in an item of Beam Limiting Device Sequence (300A,00B6). Enumerated Values: X symmetric jaw pair in IEC X direction Y symmetric jaw pair in IEC Y direction ASYMX asymmetric jaw pair in IEC X direction ASYMY asymmetric pair in IEC Y direction MLCX multileaf (multi-element) jaw pair in IEC X direction MLCY multileaf (multi-element) jaw pair in IEC Y direction
>>>Leaf/Jaw Positions | (300A,011C) | 1 | Positions of beam limiting device (collimator) leaf (element) or jaw pairs (in mm) in IEC BEAM LIMITING DEVICE coordinate axis appropriate to RT Beam Limiting Device Type (300A,00B8), e.g., X-axis for MLCX, Y-axis for MLCY. Contains 2N values, where N is the Number of Leaf/Jaw Pairs (300A,00BC) in Beam Limiting Device Sequence (300A,00B6). Values shall be listed in IEC leaf (element) subscript order 101, 102, … 1N, 201, 202, … 2N. See Note 3.
>>Gantry Angle | (300A,011E) | 1C | Gantry angle of radiation source, i.e., orientation of IEC GANTRY coordinate system with respect to IEC FIXED REFERENCE coordinate system (degrees). Required for first item of Control Point Sequence, or if Gantry Angle changes during Beam. See Section C.8.8.14.13.
>>Gantry Rotation Direction | (300A,011F) | 1C | Direction of Gantry Rotation when viewing gantry from isocenter, for segment following Control Point. Required for first item of Control Point Sequence, or if Gantry Rotation Direction changes during Beam. See Section C.8.8.14.8. Enumerated Values: CW clockwise CC counter-clockwise NONE no rotation
>>Gantry Pitch Angle | (300A,014A) | 3 | Gantry Pitch Angle. i.e., the rotation of the IEC GANTRY coordinate system about the X-axis of the IEC GANTRY coordinate system (degrees). If used, must be present for first item of Control Point Sequence, or if used and Gantry Pitch Rotation Angle changes during Beam, must be present. See Section C.8.8.25.6.5. See Section C.8.8.14.13.
>>Gantry Pitch Rotation Direction | (300A,014C) | 3 | Direction of Gantry Pitch Angle when viewing along the positive X-axis of the IEC GANTRY coordinate system, for segment following Control Point. If used, must be present for first item of Control Point Sequence, or if used and Gantry Pitch Rotation Direction changes during Beam, must be present. See Section C.8.8.14.8 and Section C.8.8.25.6.5. Enumerated Values: CW clockwise CC counter-clockwise NONE no rotation
>>Beam Limiting Device Angle | (300A,0120) | 1C | Beam Limiting Device angle, i.e., orientation of IEC BEAM LIMITING DEVICE coordinate system with respect to IEC GANTRY coordinate system (degrees). Required for first item of Control Point Sequence, or if Beam Limiting Device Angle changes during Beam. See Section C.8.8.14.13.
>>Beam Limiting Device Rotation Direction | (300A,0121) | 1C | Direction of Beam Limiting Device Rotation when viewing beam limiting device (collimator) from radiation source, for segment following Control Point. Required for first item of Control Point Sequence, or if Beam Limiting Device Rotation Direction changes during Beam. See Section C.8.8.14.8. Enumerated Values: CW clockwise CC counter-clockwise NONE no rotation
>>Patient Support Angle | (300A,0122) | 1C | Patient Support angle, i.e., orientation of IEC PATIENT SUPPORT (turntable) coordinate system with respect to IEC FIXED REFERENCE coordinate system (degrees). Required for first item of Control Point Sequence, or if Patient Support Angle changes during Beam. See Section C.8.8.14.13.
>>Patient Support Rotation Direction | (300A,0123) | 1C | Direction of Patient Support Rotation when viewing table from above, for segment following Control Point. Required for first item of Control Point Sequence, or if Patient Support Rotation Direction changes during Beam. See Section C.8.8.14.8. Enumerated Values: CW clockwise CC counter-clockwise NONE no rotation
>>Table Top Eccentric Axis Distance | (300A,0124) | 3 | Distance (positive) from the IEC PATIENT SUPPORT vertical axis to the IEC TABLE TOP ECCENTRIC vertical axis (mm).
>>Table Top Eccentric Angle | (300A,0125) | 1C | Table Top (non-isocentric) angle, i.e., orientation of IEC TABLE TOP ECCENTRIC coordinate system with respect to IEC PATIENT SUPPORT coordinate system (degrees). Required for first item of Control Point Sequence, or if Table Top Eccentric Angle changes during Beam. See Section C.8.8.14.13.
>>Table Top Eccentric Rotation Direction | (300A,0126) | 1C | Direction of Table Top Eccentric Rotation when viewing table from above, for segment following Control Point. Required for first item of Control Point Sequence, or if Table Top Eccentric Rotation Direction changes during Beam. See Section C.8.8.14.8. Enumerated Values: CW clockwise CC counter-clockwise NONE no rotation
>>Table Top Pitch Angle | (300A,0140) | 1C | Table Top Pitch Angle, i.e., the rotation of the IEC TABLE TOP coordinate system about the X-axis of the IEC TABLE TOP coordinate system (degrees). If required by treatment delivery device, shall be present for first item of Control Point Sequence. If required by treatment delivery device and if Table Top Pitch Angle changes during Beam, shall be present in all subsequent items of Control Point Sequence. See Section C.8.8.14.12 and Section C.8.8.14.13.
>>Table Top Pitch Rotation Direction | (300A,0142) | 1C | Direction of Table Top Pitch Rotation when viewing the table along the positive X-axis of the IEC TABLE TOP coordinate system, for segment following Control Point. If required by treatment delivery device, shall be present for first item of Control Point Sequence. If required by treatment delivery device and if Table Top Pitch Rotation Direction changes during Beam, shall be present in all subsequent items of Control Point Sequence. See Section C.8.8.14.8 and Section C.8.8.14.12. Enumerated Values: CW clockwise CC counter-clockwise NONE no rotation
>>Table Top Roll Angle | (300A,0144) | 1C | Table Top Roll Angle, i.e., the rotation of the IEC TABLE TOP coordinate system about the IEC Y-axis of the IEC TABLE TOP coordinate system (degrees). If required by treatment delivery device, shall be present for first item of Control Point Sequence. If required by treatment delivery device and if Table Top Roll Angle changes during Beam, shall be present in all subsequent items of Control Point Sequence. See Section C.8.8.14.12 and Section C.8.8.14.13.
>>Table Top Roll Rotation Direction | (300A,0146) | 1C | Direction of Table Top Roll Rotation when viewing the table along the positive Y-axis of the IEC TABLE TOP coordinate system, for segment following Control Point. If required by treatment delivery device, shall be present for first item of Control Point Sequence. If required by treatment delivery device and if Table Top Roll Rotation Direction changes during Beam, shall be present in all subsequent items of Control Point Sequence. See Section C.8.8.14.8 and Section C.8.8.14.12. Enumerated Values: CW clockwise CC counter-clockwise NONE no rotation
>>Table Top Vertical Position | (300A,0128) | 2C | Table Top Vertical position in IEC TABLE TOP coordinate system (mm). Required for first item of Control Point Sequence, or if Table Top Vertical Position changes during Beam. See Section C.8.8.14.6.
>>Table Top Longitudinal Position | (300A,0129) | 2C | Table Top Longitudinal position in IEC TABLE TOP coordinate system (mm). Required for first item of Control Point Sequence, or if Table Top Longitudinal Position changes during Beam. See Section C.8.8.14.6.
>>Table Top Lateral Position | (300A,012A) | 2C | Table Top Lateral position in IEC TABLE TOP coordinate system (mm). Required for first item of Control Point Sequence, or if Table Top Lateral Position changes during Beam. See Section C.8.8.14.6.
>>Isocenter Position | (300A,012C) | 2C | Isocenter coordinates (x,y,z) in the patient based coordinate system described in Section C.7.6.2.1.1 (mm). Required for first item of Segment Control Point Sequence, or if Segment Isocenter Position changes during Beam.
>>Surface Entry Point | (300A,012E) | 3 | Patient surface entry point coordinates (x,y,z) in the patient based coordinate system described in Section C.7.6.2.1.1 (mm).
>>External Contour Entry Point | (300A,0133) | 3 | External Contour entry point coordinates (x,y,z) in the patient based coordinate system described in Section C.7.6.2.1.1 (mm). See Section C.8.8.14.15.
>>Source to Surface Distance | (300A,0130) | 3 | Source to Patient Surface (skin) distance (mm).
>>Source to External Contour Distance | (300A,0132) | 3 | Source to External Contour distance (mm) including devices associated with the patient anatomy model. For dosimetric purposes this value may differ from the Source to Surface Distance (300A,0130). See Section C.8.8.14.15.

### Note

1. Beam Number (300A,00C0) is provided to link related information across modules, and its value should not be required to have any real-world interpretation. Beam Name (300A,00C2), a Type 3 attribute, is intended to store the primary beam identifier (often referred to as "field identifier"). Beam Description (300A,00C3), a Type 3 attribute, is intended to store additional beam identifying information (often referred to as "field name"). Equipment supporting both these attributes should state this clearly in the Conformance Statement.

2. The DICOM standard does not support the transmission of treatment unit modeling information such as depth doses and beam profiles.

3. Implementers should take note that Leaf Position Boundaries (300A,00BE) are the positions of the mechanical boundaries (projected to the isocentric plane) between beam limiting device (collimator) leaves, fixed for a given beam limiting device (collimator). Leaf/Jaw Positions (300A,011C) are values specific to a given beam control point, specifying the beam limiting device (collimator) leaf (element) openings.

4. Block coordinates may not be transmitted when such data is not available from the transmitting system. However, the receiving system may not have internal mechanisms to use or store such data. For example, a plan sent from an treatment planning system to a Record and Verify (R&V) system will contain the block data for blocked beams. Subsequent transfer of beam data from the R&V system may omit this data since the R&V system may not have stored it.

5. Refer to Section C.8.8.14.5 for examples of STATIC and DYNAMIC Beam Type. Note that beams having Wedge Type = DYNAMIC as the only moving parameter are not considered DYNAMIC according to the definition of Beam Type (300A,00C4).

6. Attributes Beam Dose Point Depth (300A,0088), Beam Dose Point Equivalent Depth (300A,0089), Beam Dose Point SSD (300A,008A) were previously included in this Module but have been retired. See PS3.3-2011.

##### C.8.8.14.1 Meterset Calculations

The Meterset at a given Control Point is equal to Beam Meterset (300A,0086) specified in the Referenced Beam Sequence (300C,0004) of the RT Fraction Scheme Module, multiplied by the Cumulative Meterset Weight (300A,0134) for the Control Point, divided by the Final Cumulative Meterset Weight (300A,010E). The Meterset is specified in units defined by Primary Dosimeter Unit (300A,00B3). If the calculation for Meterset results in a Meterset value that is not an exact multiple of the primary Meterset resolution, then the result shall be rounded to the nearest allowed Meterset value (i.e., less than a half resolution unit shall be rounded down to the nearest resolution unit, and equal or greater than half a resolution unit shall be rounded up to the nearest resolution unit).

Note also that if Final Cumulative Meterset Weight (300A,010E) is equal to 100, then Cumulative Meterset Weight (300A,0134) becomes equivalent to the percentage of Beam Meterset (300A,0086) delivered at each control point. If Final Cumulative Meterset Weight (300A,010E) is equal to Beam Meterset (300A,0086), then the Cumulative Meterset Weight (300A,0134) at each control point becomes equal to the cumulative Meterset delivered at that control point.

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DICOM PS3.3 2016d - Information Object Definitions