TID 10013 CT Irradiation Event Data
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### TID 10013 CT Irradiation Event Data

This template conveys the dose and equipment parameters of a single irradiation event.

A CT irradiation event is the loading of X-Ray equipment caused by a single continuous actuation of the equipment's irradiation switch, from the start of the loading time of the first pulse until the loading time trailing edge of the final pulse. Any on-off switching of the radiation source during the event shall not be treated as separate events; rather the event includes the time between start and stop of radiation as triggered by the user, e.g., a single sequence of scanning comprised of multiple slices acquired with successive tube rotations and table increments shall be treated as a single irradiation event. Depending on the examination workflow and the anatomical target region the CT irradiation event data may split into multiple instances of this template for better dose estimation. The irradiation event is the "smallest" information entity to be recorded in the realm of Radiation Dose reporting. Individual Irradiation Events are described by a set of accompanying physical parameters that are sufficient to understand the "quality" of irradiation that is being applied. This set of parameters may be different for the various types of equipment that are able to create irradiation events.

Type:

  Extensible

Order:

  Significant

Table TID 10013. CT Irradiation Event Data

| NL | Rel with Parent | VT | Concept Name | VM | Req Type | Condition | Value Set Constraint
--- | --- | --- | --- | --- | --- | --- | --- | ---
1 |  |  | CONTAINER | EV (113819, DCM, "CT Acquisition") | 1 | M |  |
2 | > | CONTAINS | TEXT | EV (125203, DCM, "Acquisition Protocol") | 1 | U |  |
3 | > | CONTAINS | CODE | EV (123014, DCM, "Target Region") | 1 | M |  | DCID 4030 “CT, MR and PET Anatomy Imaged”
4 | > | CONTAINS | CODE | EV (113820, DCM, "CT Acquisition Type") | 1 | M |  | DCID 10013 “CT Acquisition Type”
4b | >> | CONTAINS | CODE | EV (113961, DCM, "Reconstruction Algorithm") | 1-n | U |  | DCID 10033 “CT Reconstruction Algorithm”
5 | > | CONTAINS | CODE | EV (G-C32C, SRT, "Procedure Context") | 1 | U |  | DCID 10014 “Contrast Imaging Technique”
6 | > | CONTAINS | UIDREF | EV (113769, DCM, "Irradiation Event UID") | 1 | M |  |
6b | > | CONTAINS | TEXT | EV (113605, DCM, "Irradiation Event Label") | 1 | U |  |
6c | >> | HAS CONCEPT MOD | CODE | EV (113606, DCM, "Label Type") | 1 | MC | IF the value of Row 6b is the value of an Attribute in the images. | DCID 10022 “Label Types”
7 | > | CONTAINS | CONTAINER | EV (113822, DCM, "CT Acquisition Parameters") | 1 | M |  |
8 | >> | CONTAINS | NUM | EV (113824, DCM, "Exposure Time") | 1 | M |  | UNITS = EV (s, UCUM, "s")
9 | >> | CONTAINS | INCLUDE | DTID 10014 “Scanning Length” | 1 | M |  |
10 | >> | CONTAINS | NUM | EV (113826, DCM, "Nominal Single Collimation Width") | 1 | M |  | UNITS = EV (mm, UCUM, "mm")
11 | >> | CONTAINS | NUM | EV (113827, DCM, "Nominal Total Collimation Width") | 1 | M |  | UNITS = EV (mm, UCUM, "mm")
12 | >> | CONTAINS | NUM | EV (113828, DCM, "Pitch Factor") | 1 | MC | IF row 4 equals (P5-08001, SRT, "Spiral Acquisition") or equals (113804, DCM, "Sequenced Acquisition") | UNITS = EV ({ratio}, UCUM, "ratio")
13 | >> | CONTAINS | NUM | EV (113823, DCM, "Number of X-Ray Sources") | 1 | M |  | UNITS = EV ({X-Ray sources}, UCUM, "X-Ray sources")
14 | >> | CONTAINS | CONTAINER | EV (113831, DCM, "CT X-Ray Source Parameters") | 1-n | M |  |
15 | >>> | CONTAINS | TEXT | EV (113832, DCM, "Identification of the X-Ray Source") | 1 | M |  |
16 | >>> | CONTAINS | NUM | EV (113733, DCM, "KVP") | 1 | M |  | UNITS = EV (kV, UCUM, "kV")
17 | >>> | CONTAINS | NUM | EV (113833, DCM, "Maximum X-Ray Tube Current") | 1 | M |  | UNITS = EV (mA, UCUM, "mA")
18 | >>> | CONTAINS | NUM | EV (113734, DCM, "X-Ray Tube Current") | 1 | M |  | UNITS = EV (mA, UCUM, "mA")
19 | >>> | CONTAINS | NUM | EV (113834, DCM, "Exposure Time per Rotation") | 1 | MC | IF row 4 does not equal (113805, DCM, "Constant Angle Acquisition") | UNITS = EV (s, UCUM, "s")
20 | >>> | CONTAINS | NUM | EV (113821, DCM, "X-Ray Filter Aluminum Equivalent") | 1 | U |  | UNITS = EV (mm, UCUM, "mm")
21 | > | CONTAINS | CONTAINER | EV (113829, DCM, "CT Dose") | 1 | MC | IF row 4 does not equal (113805, DCM, "Constant Angle Acquisition") |
22 | >> | CONTAINS | NUM | EV (113830, DCM, "Mean CTDIvol") | 1 | M |  | UNITS = EV (mGy, UCUM, "mGy")
23 | >> | CONTAINS | CODE | EV (113835, DCM, "CTDIw Phantom Type") | 1 | M |  | DCID 4052 “Phantom Devices”
24 | >> | CONTAINS | NUM | EV (113836, DCM, "CTDIfreeair Calculation Factor") | 1 | U |  | UNITS = EV (mGy/mA.s, UCUM, "mGy/mA.s")
25 | >> | CONTAINS | NUM | EV (113837, DCM, "Mean CTDIfreeair") | 1 | U |  | UNITS = EV (mGy, UCUM, "mGy")
26 | >> | CONTAINS | NUM | EV (113838, DCM, "DLP") | 1 | M |  | UNITS = EV (mGy.cm, UCUM, "mGy.cm")
27 | >> | CONTAINS | NUM | EV (113839, DCM, "Effective Dose") | 1 | U |  | UNITS = EV (mSv, UCUM, "mSv")
28 | >>> | HAS CONCEPT MOD | CODE | EV (G-C036, SRT, "Measurement Method") | 1 | MC | IF row 27 is present | DCID 10011 “Effective Dose Evaluation Method”
29 | >>>> | HAS PROPERTIES | NUM | EV (113840, DCM, "Effective Dose Conversion Factor") | 1 | MC | IF row 28 is present and equals (113800, DCM, "DLP to E conversion via MC computation") or equals (113802, DCM, "DLP to E conversion via measurement") | UNITS = EV (mSv/mGy.cm, UCUM, "mSv/mGy.cm")
30 | >> | CONTAINS | NUM | EV (113930, DCM, "Size Specific Dose Estimation") | 1-n | U |  | UNITS = EV (mGy, UCUM, "mGy")
31 | >>> | HAS CONCEPT MOD | CODE | EV (G-C036, SRT, "Measurement Method") | 1 | M |  | DCID 10023 “Size Specific Dose Estimation Method for CT”
32 | >>>> | INFERRED FROM | NUM | EV (113931, DCM, "Measured Lateral Dimension") | 1 | MC | IF row 31 equals (113934, DCM, "AAPM 204 Lateral Dimension") or (113936, DCM, "AAPM 204 Sum of Lateral and AP Dimension") | UNITS = EV (mm, UCUM, "mm")
33 | >>>> | INFERRED FROM | NUM | EV (113932, DCM, "Measured AP Dimension") | 1 | MC | IF row 31 equals (113935, DCM, "AAPM 204 AP Dimension") or (113936, DCM, "AAPM 204 Sum of Lateral and AP Dimension") | UNITS = EV (mm, UCUM, "mm")
34 | >>>> | INFERRED FROM | NUM | EV (113933, DCM, "Derived Effective Diameter") | 1 | MC | IF row 31 equals (113934, DCM, "AAPM 204 Lateral Dimension") or (113935, DCM, "AAPM 204 AP Dimension") or (113936, DCM, "AAPM 204 Sum of Lateral and AP Dimension") or (113937, DCM, "AAPM 204 Effective Diameter Estimated From Patient Age") | UNITS = EV (mm, UCUM, "mm")
35 | >> | CONTAINS | INCLUDE | DTID 10015 “CT Dose Check Details” | 1 | M |  |
36 | > | CONTAINS | TEXT | EV (113842, DCM, "X-Ray Modulation Type") | 1 | U |  |
37 | > | CONTAINS | TEXT | EV (121106, DCM, "Comment") | 1 | U |  |
38 | > | CONTAINS | INCLUDE | DTID 1020 “Person Participant” | 1-n | U |  | $PersonProcedureRole = EV (113851, DCM, "Irradiation Administering")
39 | > | CONTAINS | INCLUDE | DTID 1021 “Device Participant” | 1 | MC | Required if the irradiating device is not the recording device. | $DeviceProcedureRole = EV (113859, DCM, "Irradiating Device")

Content Item Descriptions

Row 2 | User-defined type of clinical acquisition protocol for creating images or image-derived measurements. May be taken from Protocol Name (0018,1030) or from Performed Procedure Step Description (0040,0254).
Row 3 | The target region is the anatomy exposed.
Row 4 | Description of the method used during acquisition of this CT irradiation event, may be derived from Acquisition Type (0018,9302).
Row 4b | Though not a characteristic of the acquisition per se, the type of reconstruction intended has a bearing on the technique used. If multiple types of reconstruction are performed, multiple values can be listed. These values should correspond to the values of Reconstruction Algorithm (0018,9315) in the reconstructed images.
Row 5 | The acquisition was performed with or without contrast medium application.
Row 8 | Total time the patient has received X-Ray exposure during the irradiation event.
Row 10 | The value of the nominal width (referenced to the location of the isocenter along the z axis) of a single collimated slice in mm.
Row 11 | The value of the nominal width (referenced to the location of the isocenter along the z axis) of the nominal total collimation in mm over the area of active X-Ray detection (z-coverage).
Row 12 | Pitch Factor: For Spiral Acquisition, the Pitch Factor is the ratio of the Table Feed per Rotation to the Nominal Total Collimation Width. For Sequenced Acquisition, the Pitch Factor is the ratio of the Table Feed per single sequenced scan to the Nominal Total Collimation Width.
Row 14 | CT X-Ray source parameters related to the acquisition. For each X-Ray source an item must be present. For multi-energy acquisitions, multiple items may be present for each X-Ray source, each item describing one energy level.
Row 15 | Identification of the X-Ray source. Identifies the particular X-Ray source (in a multi-source CT system) for which the set of X-Ray source parameter values is reported.
Row 16 | KVP value as measured/recorded by system.
Row 18 | Mean tube current as measured/recorded by system.
Row 19 | Exposure time as measured/recorded by the system per rotation.
Row 20 | Thickness of an equivalent filter constructed from aluminum, in case of multi-source CT systems AND if Row 4 is not present
Row 21 | CT Dose for one acquisition
Rows 5, 6 | "Mean CTDIvol" refers to the average value of the CTDIvol applied within this acquisition. CTDIvol is the volume CTDIw, where CTDIw is the weighted computed tomography dose index 100 as defined in IEC 60601-2-44. For Sequenced and Spiral scanning, CTDIvol = CTDIw / Pitch Factor. For Stationary and Free scanning, CTDIvol = CTDIw ✕ Cumulative Exposure Time/ Exposure Time Per Rotation. According to IEC 60601-2-44 Ed 3 for Constant Angle Acquisition may be calculated as CTDIvol = (CTDIw / Current Time Product (mAs)) ✕ X-Ray Tube Current (mA) x (Nominal Total Collimation Width (mm) / Table Speed (mm/s)). ### Note The ratio CTDIw / Current Time Product is evaluated independently of the Constant Angle Acquisition but with the same settings of tube voltage and Total Collimation Width as those of the Constant Angle Acquisition. See also CTDIvol (0018,9345) and Spiral Pitch Factor (0018,9311) in the “Enhanced Computed Tomography Image IOD” in PS3.3 .
Row 23 | The type of phantom used for CTDI measurement according to IEC 60601-2-44(e.g., Head 16 cm diameter PMMA, Body 32 cm diameter PMMA).
Rows 5, 6 | The CTDIfree air Calculation Factor is the CTDIfree air per mAs, expressed in units of mGy/mAs. The CTDIfree air Calculation Factor may be used in one method calculating Dose. For example, for this acquisition, Effective Dose = Mean X-Ray Tube Current ✕ Cumulative Exposure Time ✕ CTDIfree air Calculation Factor ✕ (Effective Dose/ CTDIfree air).
Rows 5, 6 | MeanCTDIfree air is the mean CTDI for this acquisition, evaluated free-in-air according to IEC 60601-2-44. MeanCTDIfree air = Mean X-Ray Tube Current ✕ Cumulative Exposure Time ✕ CTDIfree air Calculation Factor. The CTDIfree air may be used in one method of calculating Effective Dose.
Rows 5, 6 | For Spiral scanning, DLP = CTDIvol ✕ Scanning Length. For Sequenced scanning, DLP = CTDIvol ✕ Nominal Total Collimation Width ✕ Cumulative Exposure Time / Exposure Time per Rotation. For Stationary and Free scanning, DLP = CTDIvol ✕ Nominal Total Collimation Width (according to IEC 60601-2-44).
Row 27 | Effective Dose in mSv of the single continuous time-frame of the irradiation computed as described in TID 10012 “CT Accumulated Dose Data”.
Row 29 | The Effective Dose Conversion Factor is the ratio of the Effective Dose to the DLP, expressed in units of mSv/mGy.cm, and it is used as a factor in one method of estimating Effective Dose. Monte Carlo Simulations (or dosimetric measurements in an anthropomorphic phantom, e.g., the Alderson-Rando phantom) may be used as a basis for the evaluation of Effective Dose Conversion Factors.
Row 30 | More than one Size Specific Dose Estimation may be included, for example if different computation methods are used.
Row 31 | The methods of AAPM Report 204 are listed in CID 10023 “Size Specific Dose Estimation Method for CT”; other methods may be used. The phantom size (16cm or 32cm) used for the calculation is available from the phantom type defined in Row 23.
Row 32 | The condition specifies inclusion of the Measured Lateral Dimension if it was used in the calculation.
Row 33 | The condition specifies inclusion of the Measured AP Dimension if it was used in the calculation.
Row 34 | The Derived Effective Diameter is conditionally included, whether it was derived from measurements or estimated from age, but may not be used for other (non-AAPM Report 204) methods.
Row 35 | Record of details associated with using the NEMA Dose Check Standard (NEMA XR-25-2010).
Row 36 | The type of exposure modulation. May use the value of Exposure Modulation Type (0018,9323) from CT Exposure Macro or from CT Image Module.
Row 38 | People responsible for the administration of the radiation reported in the irradiation event. May include values that would appear in Performing Physicians' Name (0008,1050), Performing Physician Identification Sequence (0008,1052), Operators' Name (0008,1070) and/or Operator Identification Sequence (0008,1072).
Row 39 | The device that produced the irradiation in this Irradiation Event. I.e., the CT scanner. This is not required to be present if the information is the same as that already recorded in the TID 1004 “Device Observer Identifying Attributes” encoded via the inclusion of TID 1002 “Observer Context” in TID 10011 “CT Radiation Dose” Row 4, which in turn may be absent if identical to the content in the Enhanced General Equipment Module.

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