IHE Profile Proposal (Brief)

1. Proposed Profile: Radiation Dose Profile

Proposal Editor: Joel Chabriais/Bernard Aubert/Kevin O'Donnell
Date: N/A (Wiki keeps history)
Version: N/A (Wiki keeps history)
Domain: Radiology (SFR, ACR, AAPM, IRSN, RSNA, FDA)

2. The Problem

Tracking radiation dose delivered to patients for medical purposes is gathering increasing attention from professional societies and regulatory groups. Publications include: European directive Euratom 97/43, ACR Dose Whitepaper and some Japanese regulations.

Many such groups have expressed a desire to establish standards of practice based first on a quantitative understanding of current practice, however they have found it prohibitively difficult to collect such data. Needs have been expressed to track both dose to individual patients and to assemble population data.

Physicians are asked to follow guidelines, like constraining their patients dose to As Low As Reasonably Achievable (ALARA), but it can be difficult for them to see what their patient dose actually was, and almost impossible to assemble comparison values as to what is reasonably achievable.

In most of the world, although it should be, it is not possible to do things like:

view the dose a patient (or particuar organs) received for a certain exam, hospital stay or course of treatment
view a patients cumulative dose history
determine if a given patient dose exceeds maximum guidelines or is otherwise an "outlier" requiring investigation
compute the population "dose profile" for a certain hospital or region
compute the population "dose profile" for a certain pathology
compare "dose profiles" against other sites/regions, against local policy targets or against standards of practice

In the vast majority of medical procedures involving radiation, the potential benefit to the patients health far outweighs the potential risk, but the tradeoff should not be forgotten, and without the support of technological mechanisms, a concious evaluation if the tradeoff is seldom done.

The problem is that although standards exist (see below) such dose tracking has not been widely deployed due to:

difficulty coordinating the roles of the different equipment involved (which actors should do what)
difficulty coordinating tracking across multiple departments and multiple institutions
the need to converge on one of the available standard approaches
a chicken-egg situation between the dose record producers, the dose record receivers and the dose record consumers

These are, of course, many of the typical problems that IHE is used to addressing.

3. Key Use Case

First use case scenario

Frank Smith is hospitalized following an automobile accident.

The ER doctor sends him for an abdominal CT. Later, his attending physician sends him to Radiology once for a chest X-ray and twice for a right arm and left leg X-ray. A referral to Cardiology results in a coronarography (fluoroscopy and radiographies were done).

The hospital would like to believe its doctors are following site policy and its practices are in line with national norms, but doesn't know if that is actually true and has little or no data to back it up. It has little or no tools for implementing a dose management or reduction plan and no tools to measure progress towards its targets.

Some of the modalities included a few dose details in the headers of the images. Those images are distributed across the Radiology and Cardiology PACS systems. A few of the Reporting workstations display dose values some of the time when the details in the image header match what it expects to find. Other systems put dose details in some of the MPPS messages sent to the RIS and the CIS. All the HIS knows is the names of the radiology procedures ordered. No system has a complete picture and due to inconsistency of data format and distribution, none of them attempt to compile a dose record.

Correlation with Mr. Smiths radiotherapy earlier this month and again next month at the clinic across town is completely out of the question.

Second use case scenario

When Frank Smith's order is placed, the system provides guidance to the physician, taking into account the dose of considered procedures and current patient dose.

At the end of the stay, the HIS knows all ionizing radiation events that occurred during the stay of Mr. Smith, keeps track of all data and calculates and archives the total dose delivered during the stay. Mr. Smith had several visits to this hospital before. The HIS consolidates the total radiation dose delivered through all visits. Data is sent to the regional EHR sytem to be consolidated with other enterprises Mr. Smith visits during his life. Data is also transmited, after anonymization, to a national radiation dose registry. The registry provides periodic reports back to the facility with regional and national benchmarks of radiation dose. Using this report, Mr. Smith’s hospital can compare its dose profile by modality, exam type, and pathology to facilities of the same type, in the same region, and to the nation as a whole.

4. Standards & Systems

Some existing systems that might be involved include:

Systems that schedule studies (RIS), administer radiation (modalities, and therapy systems), and store and report the results (PACS?, HIS?, EHR?)

Some standards which might be relevant to the solution include:

DICOM SR Dose objects (PS3.3 A.35.8 X-Ray Radiation Dose, Supp 127 CT Radiation Dose)
DICOM IOD’s attributes (CT IOD, XR IOD, etc.)
DICOM MPPS attributes
Other standards in radiotherapy and nuclear medicine? (PS 3.3 A.18 RT Dose?)
Dose measurement protocols and guidelines from professional and/or regulatory bodies

5. Discussion

Why would IHE be a good venue to address this? See the last part of Section 2.

What should IHE do? Consider a Radiation Dose Management Profile. At the very least, coordinate how systems that deliver dose should electronically report it, and how that information can be archived and accessed.

Controversies do exist over what are the most relevant/useful measurements to make and how those should be be interpreted. An IHE Profile will need to limit requirements to common denominator measurements and to empower analysis but not to dictate interpretation/policy.

First priority is to begin capturing the data using standards. Later it may be useful to tie this into the National Registry Submission work being done in IHE Cardiology and IHE Quality.

Since a number of national/professional/regulatory groups have an interest in "consuming" this data, IHE will need to figure out how best to involve them so we enable their work.

Some additional background

CR Dose Tracking Article in Aunt Minnie

Final report by The UK Clinical Advisory Committee on diagnostic imaging on the safety and efficacy of CT screening - July 2007 expresses a need for an integrated framework for policing and compliance of national and international protocols for radiation exposure.

The French Ministry of Health (Roselyne Bachelot), decided in July that Radiation Dose Follow-up is now a major work item for the ministry. The ASN (Autorité de Sûreté Nucléaire - Nuclear Safety Authority) is now in charge to develop the necessary infrastructure. On September 10, ASN and IRSN (Institut de Radioprotection et de Sûreté Nucléaire - Radioprotection and Nuclear Safety Institute) will meet at SFR (Société Française de Radiologie - French Radiological Society) to work on "Integration of Radiation Dose delivery for medical imaging examinations and links to the Patient Folder".

Radiation Dose Profile - Brief Proposal