Radiation Dose Summary for Diagnostic Procedures on FHIR, published by HL7 Imaging Integration Working Group. This is not an authorized publication; it is the continuous build for version 0.1.0). This version is based on the current content of https://github.com/HL7/fhir-radiation-dose-summary-ig/ and changes regularly. See the Directory of published versions

Background

This chapter describes the scope of this guide, provides background information about the radiation dose summary IG, key concepts, and describes the use cases supported by this implementation guide.

1. Problem - Description of the problem
2. Scope - Scope of the IG
3. Use cases - Key use cases covered by the IG
4. Minimal Radiation Information - Description of data shared through this IG
5. Underlying specifications - Description of the underlying specifications and resources.
6. Glossary - Glossary of terms used in this IG
7. References - Useful references

Problem

The IHE Dose Reporter actor from the IHE REM profile gathers Radiation information and dose reports from modalities. However, there is no standardization of the exposure of the gathered data to third parties in a light API based format.

Dose Management systems need to share information related to the exam to multiple third parties:

• RIS/EHR: many RIS/EHR systems do not have capabilities to read DICOM SR documents and prefer to contact the hospital dose management system in order to gather a summary of the dose report; and in order to include the radiation summary under the final imaging report.
• Third backend systems: some third backend applications may want to gather a summary of the exam’s radiations for some proprietary usage; gathering the complete RDSR is useless for most of the non Dose Management systems.

The RDSRs have a complete and a strong structure for sharing the dose information from the modalities to the Dose Consumer/Reporter actors, and also between the Dose Reporter and the Dose Registry systems. However, most of third party applications have a very light needs for the Dose report. For example, RIS systems in France need only, for CT exams, the Dose Length Product Total data from the CT RDSR, in order to fit local regulations.

The emergence of HL7 FHIR simplified the exchange between backend applications and third parties through the exchange of normalized resources having stable structures. This analysis allows to share minimal dose information through FHIR resources.

Scope

Scope:

• Share a summary of dose information by exam through FHIR
• Irradiations received by the patient
• The targeted modalities are CT/XA/RF/MG/NM

Out Of Scope:

• Share details of the radiation administration
• Share enhanced data (SSDE, Organ Dose, etc.) to third applications
• Cumulative calculation of radiation over time, and through multiple procedures or equipments
• Irradiations received by the practitioner

Dealing with sharing details of radiation procedures, like the X-Ray parameters, the modality configuration, etc., is out of scope. Also, sharing the details of enhanced dose data, like the size specific dose estimation, is also out of scope. Other means exist to share this detailed information, mainly the DICOM Radiation Structured Reports (RDSRs).

The defined profiles in this IG are describing radiation information within a unique irradiation act, which may contain multiple irradiation events. Calculating patient cumulative radiation over a period of time, and/or through multiple procedures and modalities, is out of scope, even if the current IG simplifies such computations. In parallel, the interpretation of radiation information is out of scope; this depends on facilities workflows, may be subject of interpretations, and may vary following regulations.

Radiotherapy procedures are not covered by the scope of this work, only diagnostic imaging radiations is covered by this work.

The FHIR profiles defined in this IG are engineering solution in order to simplify sharing the radiation summary information between heterogenous applications. This implementation guide is not meant to describe how the Radiation Data is treated, and who can access and interpret the radiation information. These details are site specific and follow the international and national regulations and recommendations; also, they follows facilities culture and workflows. For instance, facilities should follow recommendations from the AAPM/ACR/HPS Joint Statement on Proper Use of Radiation Dose Metric Tracking for Patients Undergoing Medical Imaging Exams; patient radiation history should not be used for decision making prior to exams.

Use case: Imaging report construction

The main use case identified for this implementation guide is the following:

• The Patient performs an irradiating exam within a modality.
• The modality shares the dose report to the Dose Management System, which may implement the IHE REM Dose Reporter actor. This dose information sharing can follow the REM profile schema.
• After analyzing the exam images, the radiologist sends its notes to the Radiology Information System (RIS).
• In order to construct the final imaging report, the RIS needs to gather a summary of the radiation received by the patient. The RIS send a query to the Dose management system and get minimal dose information report.
• The minimal dose information is then integrated to the final report, which can be a CDA report following the DICOM Imaging report specification in PS3.20.
• The final report is shared with the hospital EHR or with the regional/national radiology report repository, through IHE XDS-I.b for example.

This use case is very common within RIS systems not supporting dose management modules. In fact, gathering of dose information from modalities can be very complex:

• It is based on multiple sources of data: RDSR, MPPS, SC & OCR, and DICOM images header.
• The reporting of the dose information by the modalities may contain misinterpretations and errors

It is the role of the Dose management system to provide the RIS with the right information regarding the dose administered to the patients. Reporting the minimal dose information inside the final imaging report is recommended by many stakeholders and organizations, and sometimes it is a regulation. For example, in France there are the Order of 22 September 2006 relating to the radiation information to be included in an act report using ionizing radiation, from the French Minister of Health and Solidarity, and describing some dose information that needs to be present in the final report.

The same kind of regulations exists in California in the US about the CT exams, which is the Senate Bill No. 1237.

Minimal Radiation Information

Identification

In this paragraph, we analyze the mapping between the identified minimal dose information and some specifications on dose information reporting coming from multiple stakeholders:

• DICOM PS3.20: Imaging Reports using HL7 Clinical Document Architecture
• DICOM PS3.16: Content Mapping Resource
  • X-Ray Radiation Dose SR IOD Templates
  • CT Radiation Dose SR IOD Templates
  • Radiopharmaceutical Radiation Dose SR IOD Templates
  • TID 2008 - Radiation Exposure and Protection Information
• France guidelines
  • French Society of Radiology - SFR, Practical Guide for Interventional Radiology (Guideline - 2013)
  • High Authority of Health - HAS, Patient radiation protection and analysis of CPD practices and certification of healthcare establishments (Guideline - 2012)
  • Presentation of the main radiation protection regulatory provisions applicable in medical and dental radiology (Guideline: 2016)
  • French Minister of Health and Solidarity, Order of 22 September 2006 relating to the radiation information to be included in an act report using ionizing radiation, (Order - 2006)
• Finnish Imaging Report specification, KanTa Imaging CDA R2 document structures (2013)
• US, California State
  • AAPM, Computed Tomography Dose Limit Reporting Guidelines for Section 3 – 115113
  • Senate Bill No. 1237, CHAPTER 521
  • AAPM, Experience with California Law on Reporting CT Dose
  • Radiologist Compliance With California CT Dose Reporting Requirements: A Single-Center Review of Pediatric Chest CT
  • University of California Dose Optimization and Standardization Endeavor (UC-DOSE). Recommendations for compliance with California Senate Bill 1237 and related pending legislation.

The analysis of the different specifications allowed to obtain the following coverage between the minimal dose information and these specifications/guidelines:

Dose Information

Modality

PS3.20

PS3.16

Finland

France

USA California

CT

XA

RF

MG

NM

CT RDSR

X-Ray RDSR

RRDSR

TID 2008

Irradiation authorizing Person

Y

Y

Y

Y

Pregnancy Observation

Y

Y

Y

Y

Indication Observation

Y

Y

Y

Device

Y

Y

Y

Y

Y

Irradiation Issued Date

Y

Y

Y

Y

Y

Associated Procedure

Y

Y

Y

Y

Dose measurements - Study level

Dose (RP) Total

Y

Y

Y

Y

Y

Y

Accumulated Average Glandular Dose

Y

Y

Y

Y

Dose Area Product Total

Y

Y

Y

Y

Y

Y

Y

Fluoro Dose Area Product Total

Y

Y

Y

Y

Y

Acquisition Dose Area Product Total

Y

Y

Y

Y

Y

Total Fluoro Time

Y

Y

Y

Y

Y

Total Number of Radiographic Frames

Y

Y

Y

Y

CT Dose Length Product Total

Y

Y

Y

Y

Y

Y

Administered activity

Y

Y

Y

Y

Radiopharmaceutical Agent

Y

Y

Y

Y

Y

Radionuclide

Y

Y

Y

Radiopharmaceutical Volume

Y

Y

Route of administration

Y

Y

Y

Dose measurements - Irradiation Event level

Mean CTDIvol

Y

Y

Y

Y

Y

DLP

Y

Y

Y

Target Region

Y

Y

Y

Y

CTDIw Phantom Type

Y

Y

Y

Concepts mapping

The identified minimal dose information that should be collected by the dose management system and shared with third parties applications are divided into contextual information data and dose measurements data.

Contextual Information data:

Contextual Information	Identifier	Level
Irradiation Authorizing Person	EV (113850, DCM, Irradiation Authorizing)	Procedure
Pregnancy Observation	EV (82810-3, LN, Pregnancy status)	Procedure
Indication Observation	EV (18785-6, LN, Indications for Procedure)	Procedure
Irradiating Device	EV (113859, DCM, Irradiating Device)	Procedure
Irradiation Issued Date	EV (113809, DCM, Start of X-Ray Irradiation)	Procedure
Related Imaging Study	EV (110180, DCM, Study Instance UID)	Procedure

Dose measurements data:

Dose Measurements	Identifier	DICOM TID	Level	Type	Unit/ValueSet
Dose (RP) Total	EV (113725, DCM, Dose (RP) Total)	TID 10007	Procedure	Quantity	mGy
Accumulated Average Glandular Dose	EV (111637, DCM, Accumulated Average Glandular Dose)	TID 10005	Procedure	Quantity	mGy
Dose Area Product Total	EV (113722, DCM, Dose Area Product Total)	TID 10007	Procedure	Quantity	mGy.cm2
Fluoro Dose Area Product Total	EV (113726, DCM, Fluoro Dose Area Product Total)	TID 10004	Procedure	Quantity	mGy.cm2
Acquisition Dose Area Product Total	EV (113727, DCM, Acquisition Dose Area Product Total)	TID 10004	Procedure	Quantity	mGy.cm2
Total Fluoro Time	EV (113730, DCM, Total Fluoro Time)	TID 10004	Procedure	Quantity	s
Total Number of Radiographic Frames	EV (113731, DCM, Total Number of Radiographic Frames)	TID 10007	Procedure	Integer
CT Dose Length Product Total	EV (113813, DCM, CT Dose Length Product Total)	TID 10012	Procedure	Quantity	mGy.cm
Administered activity	EV (113507, DCM, Administered activity)	TID 10022	Administration	Quantity	MBq
Radiopharmaceutical Agent	EV (349358000, SCT, Radiopharmaceutical agent)	TID 10022	Administration	CodeableConcept	Radiopharmaceuticals Value Set
Radionuclide	EV (89457008, SCT, Radionuclide)	TID 10022	Administration	CodeableConcept	Isotopes Value Set
Radiopharmaceutical Volume	EV (123005, DCM, Radiopharmaceutical Volume)	TID 10022	Administration	Quantity	cm3
Route of administration	EV (410675002, SCT, Route of administration)	TID 10022	Administration	CodeableConcept	Route of Administration
Mean CTDIvol	EV (113830, DCM, Mean CTDIvol)	TID 10013	Irradiation Event	Quantity	mGy
DLP	EV (113838, DCM, DLP)	TID 10013	Irradiation Event	Quantity	mGy.cm
Target Region	EV (123014, DCM, Target Region)	TID 10013	Irradiation Event	CodeableConcept	Anatomy Imaged
CTDIw Phantom Type	EV (113835, DCM, CTDIw Phantom Type)	TID 10013	Irradiation Event	CodeableConcept	Phantom Devices

Remarks:

• We highlighted the “Dose (RP) Total” and not the “Entrance Exposure at RP”, as the latter one is related to the irradiation event level, and not the procedure level. Even if the PS3.20 is referencing the Entrance Exposure at RP, the IEC 61910-1 is referencing the Dose (RP) Total in the Basic Dose Documentation conformance.
• For NM, most of the minimal dose information related to procedure are described in the irradiation event level of the RRDSR structure. However, as there is only one irradiation event per RRDSR, we considered that this minimal dose information is related to the procedure level. However, this implies that for the same NM imaging procedure, multiple Radiation Dose Summaries can be reported. This should not be a problem, as in this case the Radiation Dose Summary is related to the administration act, more than the procedure act.
• The irradiation Issued Date has different significations, based on the targeted procedure type; in CT, it is the start date of the irradiation act, in XA/RF/MG, it is the Series Date Time, and in NM, it is the administration date time.
• The associated procedure is referenced through the related Imaging Study.
• The calibration factors are not reported as part of the minimal dose information. The generator of the Radiation Dose Summary resources shall take in consideration these calibration factors.
• Based on the analyzes performed, there is no minimal dose information related to the level Irradiation Event and part of the modalities XA/RF/MG.

Underlying specifications

This IG is based on HL7 FHIR standard, as well as DICOM standard, and its packaged value sets fhir.dicom. This IG uses also a profile from the specification International Patient Summary IG (IPS). Implementers of this specification must understand some basic information about the underlying specifications listed above.

FHIR

This IG uses terminology, notations and design principles that are specific to the HL7 FHIR standard. Before reading the page architecture and implementation, it is important to be familiar with the basic principles of FHIR and how to read FHIR specifications. Readers who are unfamiliar with FHIR are encouraged to review the following prior to reading the rest of this implementation guide.

• FHIR overview
• Developer’s introduction (or Clinical introduction)
• FHIR data types
• Using codes
• References between resources
• How to read resource & profile definitions
• Base resource

This implementation guide supports the recently published FHIR R4 version of the FHIR standard to ensure alignment with the current direction of the FHIR standard.

FHIR resources used

The table below identifies the specific FHIR Resources and their purposes that will be used in this IG. Implementers should familiarize themselves with these FHIR resources and their purposes.

FHIR Resource	Purpose
Observation	Used to describe the radiation dose summary and the collected minimal dose information
Patient	Used to reference the irradiated person
Practitioner	Used to reference the related irradiation authorizing person
Device	Used to describe the irradiating modality
ImagingStudy	Used to reference the performed exam
Composition	Used to create the irradiation report

DICOM® Standard

DICOM® is used as reference standard, as it provides a complete definition of the dose information that can be present in a radiation report. The DICOM® version used in this IG is the 2021d release. The packaged value sets coming from DICOM within fhir.dicom are referenced many times in the different profiles of this IG.

DICOM®

International Patient Summary IG (IPS)

Pregnancy Status Profile from International Patient Summary IG (IPS) is used within our IG ion order to report possible pregnancy of irradiated person.

International Patient Summary IG (IPS)

Glossary

The following terms and initialisms/acronyms are used within the Radiation Dose Summary IG:

Term	Definition
AAPM	American Association of Physicists in Medicine
ACR	American College of Radiology
ATNA	Audit Trail and Node Authentication
CDA	Clinical Document Architecture
CDS	Clinical Decision Support
CT	Computed Tomography
CTDI	Computed Tomography Dose Index
DAP	Dose Area Product
DICOM	Digital Imaging and Communications in Medicine
DLP	Dose Length Product
EHR	Electronic Health Record
EMR	Electronic Medical Record
FHIR	Fast Healthcare Interoperability Resources
HAS	French High Authority of Health
HL7	Health Level Seven
HPS	Health Physics Society
IEC	International Electrotechnical Commission
IG	Implementation Guide
IHE	Integrating the Healthcare Enterprise
IOD	Information Object Definition
IPS	International Patient Summary
MG	Mammography
MPPS	Modality Performed Procedure Step
NM	Nuclear Medicine
OCR	Optical Character Recognition
PHI	Personal Health Information
RDSC	Radiation Dose Summary Consumer
RDSP	Radiation Dose Summary Producer
RDSR	Radiation Dose Structured Report
REM	Radiation Exposure Monitoring
REM-NM	Radiation Exposure Monitoring for Nuclear Medicine
REST	Representational State Transfer
RF	Radio Fluoroscopy
RIS	Radiology Information System
RP	Reference Point
RRDSR	Radiopharmaceutical Radiation Dose Structured Report
SFR	French Society of Radiology
SR	Structured Report
SSDE	Size Specific Dose Estimation
TID	Template ID
TLS	Transport Layer Security
UID	Unique identifier
URL	Uniform Resource Locator
URN	Uniform Resource Name
VR	Value Representation
XA	X-Ray Angiography
XDS-I.b	Cross-enterprise Document Sharing for Imaging

References

1. DICOM, DICOM PS3.20: Imaging Reports using HL7 Clinical Document Architecture
2. DICOM, DICOM PS3.16: Content Mapping Resource
3. DICOM, X-Ray Radiation Dose SR IOD Templates
4. DICOM, CT Radiation Dose SR IOD Templates
5. DICOM, Radiopharmaceutical Radiation Dose SR IOD Templates
6. DICOM, TID 2008. Radiation Exposure and Protection Information
7. French Society of Radiology - SFR, Practical Guide for Interventional Radiology (Guideline - 2013)
8. French High Authority of Health - HAS, Patient radiation protection and analysis of CPD practices and certification of healthcare establishments (Guideline - 2012)
9. French nuclear safety authority, Presentation of the main radiation protection regulatory provisions applicable in medical and dental radiology (Guideline: 2016)
10. French Minister of Health and Solidarity, Order of 22 September 2006 relating to the radiation information to be included in an act report using ionizing radiation, (Order - 2006)
11. Finnish Imaging Report specification, KanTa Imaging CDA R2 document structures (2013)
12. Finnish Radiation and Nuclear Safety Authority, Röntgentutkimuksesta potilaalle aiheutuvan säteilyaltistuksen määrittäminen (X-ray examination of the patient radiation exposure determination)
13. AAPM, Computed Tomography Dose Limit Reporting Guidelines for Section 3 – 115113
14. Senate Bill No. 1237, CHAPTER 521
15. AAPM, Experience with California Law on Reporting CT Dose
16. Radiologist Compliance With California CT Dose Reporting Requirements: A Single-Center Review of Pediatric Chest CT
17. University of California Dose Optimization and Standardization Endeavor (UC-DOSE). Recommendations for compliance with California Senate Bill 1237 and related pending legislation
18. IEC, IEC 61910-1:2014 - Medical electrical equipment - Radiation dose documentation - Part 1: Radiation dose structured reports for radiography and radioscopy
19. IHE Radiology (RAD), Technical Framework Volume 1, Cross-enterprise Document Sharing for Imaging (XDS-I.b)
20. IHE Radiology (RAD), Technical Framework Volume 1, Radiation Exposure Monitoring (REM)
21. HL7 International, International Patient Summary Implementation Guide (IPS)
22. AAPM/ACR/HPS, AAPM/ACR/HPS Joint Statement on Proper Use of Radiation Dose Metric Tracking for Patients Undergoing Medical Imaging Exams