Radiation Dose Summary for Diagnostic Procedures on FHIR
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## 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. Problematic - Description of the problematic
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. Glossary - Glossary of terms used in this IG
6. References - Useful references

### Problematic

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:

- Mobile Applications: like patients related mobile applications, where a patient may want to centralize the report of doses injected to him
- 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
- 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).

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

### Use cases

Three use cases were identified.

#### Use case 1: Imaging report construction

- 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.

#### Use case 2: Mobile applications access

The exposure of the Dose Summary as FHIR resources opens the doors to the mobile applications to gather the dose information from the Dose management systems, or from the EMR if the Dose Summary is propagated to the EMR. Many applications may benefit from this additional patient data in order to add tracking of the patient dose information. Some patient facing applications can track the dose summary through multiple facilities. Other practitioner mobile applications can benefit from the Dose Summary data in order to collect more data for practitioner, or to improve their Clinical Decision Support (CDS) component.

#### Use case 3: Business Intelligence

The exposure of the Dose Summary as a FHIR resources is beneficial for Business Intelligence applications exposing metrics on dose data. In fact, multiple metrics can be normalized within a FHIR server collecting the Dose Summary resources, like:

- Comparison of average of Dose between modalities
- Comparison of average of Dose between facilities/hospital
- Comparison of dose administration characteristics between patient cohorts
- Comparison between dose administration levels between regions within a national FHIR server

### 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
--- | --- | --- | --- | --- | ---
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 |
Radionuclide | EV (89457008, SCT, Radionuclide) | TID 10022 | Administration | CodeableConcept |
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 |
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 |
CTDIw Phantom Type | EV (113835, DCM, CTDIw Phantom Type) | TID 10013 | Irradiation Event | CodeableConcept |

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.

### Glossary

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

Term | Definition
--- | ---
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
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
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
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)