CT%20Dose%20Reporting%20with%20DICOM%20Structured%20Report%20(SR)

1
(No Transcript)
2
CT Dose Reporting with DICOM Structured Report
(SR)

• A new supplement has been created based on the
  request of IEC MT30 CT
• The CT Dose Report, as defined in the supplement
  is based on supplement 94 concerning X-Ray
  radiation.
• The requirements of the CT SR dose reporting were
  presented on the RSNA and distributed in WG21
  (see the following slides).
• The Supplement was discussed by DICOM WG21 CT in
  July and shall be released in the near future
  (March of 2007).

3
DICOM Structured Report Dose

• The Radiation Dose reporting shall be defined
  through a DICOM Structured Report (SR) object
  template and SOP Class. This SR object could be
  routed to an appropriate Radiation Safety
  Reporting System. A system that claims
  conformance to such a SR object would then be
  expected to appropriately deal with such data
  items.
• The proposal for CT Dose Reporting is derivated
  from the Supplement 94 Diagnostic X-Ray
  Radiation Dose Reporting (Dose SR)

4
Irradiation Event and Structured Report

• An irradiation event is the occurrence of
  radiation being applied to a patient in a single
  continuous time-frame between the start (release)
  and the stop (cease) of the irradiation.
• A differentiation is made between dose relevant
  data that has to be provided per event and
  those data that represent accumulations.
• 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 pulsed fluoro X-Ray
  acquisition shall be treated as one single
  irradiation event.
• An amount of additional data to describe the
  physical context and the quality of the
  irradiation exposure has to be recorded along
  with the dose values.
• The irradiation event is the smallest
  information entity to be recorded in the realm of
  Radiation Dose reporting. Patient Information and
  study information shall be stored with the DICOM
  Dose SR object.
• An event resulting in creation of a DICOM Image
  SOP Instance or SOP series shall be included as a
  reference.

5
X-Ray SR Dose IOD Modules and Structure
IE Module Reference Description
Patient Patient C.7.1.1 Describes the identity of patient
Clinical Trial Subject C.7.1.3 Identify clinical trial subject
Study General Study C.7.2.1 Describes the study performed upon patient
Patient Study C.7.2.2 Describes information about study
Clinical Trial Study C.7.2.3 Identify context of clinical trial
Series SR Document Series C.17.1 Defines attributes of the SR document
Clinical Trial Series C.7.3.2 Identify context of clinical trial
Frame of Reference Synchronization C.7.4.2 Synchronization to patient study
Equipment General Equipment C.7.5.1 Attributes to identify the equipment
Document SR Document General C.17.2 General context of SR document
SR Document Content C.17.3 Specifies the attributes contained in the SR
SOP Common C.12.1 DICOM basic for definition of object
CT Accumulated Irradiation Dose Study template Accumulated irradiation for an entire examination
CT Irradiation Event template 1 to n separate irradiation events
6
Summary of Accumulated Dose

• The report summary shall give an overview of the
  whole patient examination and the accumulated
  dose applied.
• The patient information, the patient study
  information and the general equipment information
  is stored within the general part of the SR
• The total DLP of a patient examination is
  required.
• The accumulated irradiation effective dose in mSv
  may stated. This is optional!
• The method of evaluation is stated
• The measuring devices are stated, if applicable
• The generation, the relationship and the dose of
  each event are stated in separate sequences.

7
Content of the CT Irradiation Event

• The clinical character of the examination shall
  be stated
• The type of acquisition shall be stated
• The relation to the DICOM study and image objects
  shall be stated.
• The relation to the patient region shall be given
  by body part examined
• The parameters of dose evaluation shall be given
• The parameters of the generation of the
  irradiation and acquisition shall be stated.
• The dose of a single event shall be stated.

8
CT Acquisition Sequence

• The acquisition type is stated sequenced or
  spiral.
• Fluoroscopy flag is stated if applicable.
• A reference id (Radiation event UID) is stated to
  identify related series and images within this
  patient study.

9
CT Acquisition Parameters

• The tube voltage and the tube current are stated.
• The effective exposure in mAs is stated.
• The exposure time and the scanning length are
  stated.
• Acquisition parameters related to the volume
  acquisition are stated (collimation, pitch
  factor).

10
CT Irradiation Event Dose Summary

• A comment related to exam and dose can be
  appended.
• For each CT Acquisition (irradiation event)
• The CITDIvol and DPL are stated.
• The corresponding CTDIfreeair is stated.
• The effective dose may be stated, optional.
• The detection method and the parameters used are
  stated.
• The reference values for dose estimation and
  calculation are stated, e.g. calibration factor,
  effective dose type

11
What happens
12
History of Versions
01 May 31, 2006 Created, draft distributed 02
August 01, 2006 Correctives included FDA (S.
Stern), GE Healthcare (D. Littlejohn), Philips
(S. Gotman), Siemens (B. Hassold) 03 September
20, 2006 Correctives included Position of IEC/SC
62B Position of IEC/SC 62, GEHC Comments (D.
Littlejohn), Position of the 10th Meeting of the
Maintenance Team IEC/62B/MT30 04 October 20, 2006
Correctives included FDA (S. Stern), GE
Healthcare (D. Littlejohn, Harry Solomon), 05
January 08, 2007 Correctives included GE
Healthcare (D. Littlejohn, Harry Solomon), 06
January 25, 2007Correctives include WG
13
Who was Involved

• IEC WG 30 Norbert Bischof, Stanley Stern,
  Christoph Suess
• FDA Stanley Stern,
• Nema Stephen Vastagh,
• DICOM Stephen Vastagh, WG21
• Response of Manufactures GE, Philips, Siemens