Audit Trail and Node Authentication - Radiology Option

The Radiology Option for Audit Trail and Node Authentication (ATNA) specifies basic security measures for protecting patient confidentiality and assuring traceability in the imaging environment.

Summary

The IT infrastructure domain (ITI) has already established ATNA as a profile for the information exchange (see ITI Technical Framework, Volume 1 - Section 9 documents the ATNA profile :http://www.ihe.net/Technical_Framework/upload/IHE_ITI_TF_4_0_Vol1_FT_2007_08_22.pdf). This is the Radiology option.

ATNA provides institutions with a mechanism to consolidate audit trail events on user activity across several imaging and information systems throughout the enterprise systems interconnected in a secure manner. The Radiology option defines further requirements for the ATNA profile, which are specific for this domain.

The Radiology Audit Trail Option defines the specific requirements of the IHE Radiology transactions for supporting the IHE ITI Audit Trail and Node Authentication profile. This option deals largely with the details of the Record Audit Event transaction in the IHE ITI Technical Framework. The option details the required audit events for each of the IHE Radiology transactions, based on the different trigger events.

Benefits

Having an ATNA implementation allows healthcare professionals and patients have a greater confidence in the system and prevents improper access or tampering with the medical information.

For example:

• User identification: the users will have to be identified in order to gain access to the system.

• Authentication/Access control: network access is limited between information systems (the access is restricted to secure systems only) and between each sytem to authorized users (depending on local authentication and access control policy).

• Audit trail: allows detection of abnormal behavior, such as improper creation, access, modification and deletion of Protected Health Information (PHI).

• The audit records are centralized, allowing an easier implementation of security requirements.

Details

Securing the exchange of patient healthcare information, and logging key events during the processing of healthcare data increases the reliability of the underlying information systems and provides accountability for users of these systems. This is achieved by combining the ATNA requirements with the relevant IHE profiles, using industry standards like TLS and Syslog.

Node authentication gives a means to control network access by:

• Using, from and to each node, a mandatory bi-directional certificate-based node authentication,

• Allowing, for each node, the use of the user’s authentication and access control policy of its choice.

Audit Trails are based on the production of audit records, that provide a record of actions such as queries, views, additions, deletions and changes that are processed within the Security Domain covered by ATNA.

Records are triggered by trigger events described in this profile.

Some of the trigger events described in ATNA are not relevant in the ATNA Radiology option. These trigger events are:

• Health-service-event

• Medication

• Patient-care-assignment

• Patient-care-episode

• Patient-care-protocol

More details concerning the ATNA profile can be found on the: Audit Trail and Node Authentication. For an in-depth explanation the reader is directed to the ITI technical framework (ITI Technical Framework, Volume 1 - Section 9 documents the ATNA profile

• http://www.ihe.net/Technical_Framework/upload/IHE_ITI_TF_4_0_Vol1_FT_2007_08_22.pdf).

Systems Affected

All systems which participate in Radiology Framework transactions with corresponding audit events are affected. See Table 5.1-2, page 161-163 listed in volume 3 of the IHE Radiology technical framework(http://www.ihe.net/Technical_Framework/upload/ihe_tf_rev8-3.pdf).

Some examples are: ADT systems, HIS, RIS, PACS, imaging modalities

• ADT systems - recording patient demographics and events
• Modalities - storing instances (exams and their associated information)
• Image manager/Image archive - handling images
• Reporting workstations - retrieving, processing and including details from exams in reports.

Actors & Transactions:

ATNA is security domain that involves all kind of Information Systems that could be used within a department up to a XDS-I Affinity Domain.

Specification

Profile Status: Final Text

Documents:

ITI Technical Framework:

• Vol. 1 - Section 9 (ATNA profile)
• Vol. 1 - Section 10 (Cross-Enterprise Document Sharing profile - XDS)
• Vol. 2a - Section 3.20 (Record Audit Event)

IHE Radiology Technical Framework:

• Vol. 1 - Appendix H (Security considerations for XDS-I (informative)
• Vol. 1 - Section 7 (Access to Radiology Information (ARI)
• Vol. 1 - Section 18 (Cross-enterprise Document Sharing for Imaging (XDS-I)
• Vol. 3 - Section 5 (Transaction Options on other Domain Profiles)

Underlying Standards:

• http://www.ietf.org/rfc/rfc4346.txt - TLS
• http://www.ietf.org/rfc/rfc3881.txt - Security Audit and Access Accountability Message XML Data Definitions for Healthcare Applications
• http://medical.nema.org/Dicom/2011/11_15pu.pdf - DICOM PS 3.15: Audit Trail Message Format Profile

See Also

Related Profiles

• Most part of the radiology integration profiles are affected by the ATNA profile, since it pertains to privacy and security of the personal healthcare information.

Consumer Information

• The ATNA Profile FAQ answers typical questions about what the profile does.

• Audit Trail and Node Authentication Purchasing describes considerations when purchasing equipment to deploy this Profile. For the moment there is no page describing the Trail and Node Authentication Purchasing.

Implementer Information

• Audit Trail and Node Authentication Implementation provides additional information about implementing this Profile in software.]

Reference Articles

• Creating an IHE ATNA-Based Audit Repository, Gregg, B. et al, Journal of Digital Imaging, Vol. 19, Number 4, 2006, pp. 307-315 - http://www.springerlink.com/content/a587222402764162/