Policies: Introduction

General concept

In QAWeb Enterprise, policies are used to control how the display components of a workstation are calibrated and how QA tests are executed.

There are three types of policies in QAWeb Enterprise:

  • QA policies: QA (Quality Assurance) policies define which QA tests should be run, and the frequency of their execution. QA policies are used to determine the QA status of a workstation.

  • Calibration policies: Calibration polices define the settings and features of a display. They also control the calibration schedule and calibration method

  • Ambient light policies: These policies are used to define the expected room ambient light condition. This is used to calculate the amount of reflected light during DICOM GSDF calibration and QA tests.

Tip

New users may find the difference between QA policies and calibration policies can be confusing. In short: QA policies determine the tests, while calibration policies determine the settings of a display

There are a set of non-modifiable Barco-managed policies available, which are applied initially when setting up your organization. It is also possible to create your own custom policies; which is explained later in this guide.

About the ‘use’ of a display

In order to correctly understand how policies are applied to specific displays, it is necessary to understand the concept of the use of a display as configured in QAWeb Enterprise.

The concept of display use has been created to provide a flexible yet practical way to control which calibration settings and QA tests should be applied to a display, irrespective of the model of that display. The use of a display can be set to one of the following values:

  • Reviewing

  • General radiology

  • Mammography

  • Breast Tomosynthesis

  • Non-clinical (No QA tests can be associated with this use)

  • Pathology

  • Dentistry

When new displays are added to your QAWeb Enterprise organization (either new workstations being added, or by connecting a display to an already registered workstation), the use is automatically initialized based on the model of the display. However, it is possible to modify the use using the web client (see Modifying the ‘use’ of a display) .

For example, due to aging a display in the fleet may no longer conform to the site luminance requirements for mammography. By switching the use to ‘Reviewing’ and only using that display for clinical review, the flexibility of the use-based policy engine can be leveraged.

Policy hierarchy for the organizational structure

In addition to the configured use of a display, the organizational structure provides a second dimension of flexibility to define policies on your displays. Policies should be assigned to the desired level of the organizational tree so that they are applied to the desired displays.

Whenever the QAWeb Enterprise agent is active on a workstation, it will retrieve the matching policies starting at the room level and ascending the tree until the first matching policy is found.

The Policies Hierarchy provides a read-only overview of the policies that are currently assigned to the entire organization. To access this view:

  1. Navigate to the ‘QA’ section in the top menu

  2. On the left navigation menu, open Policies -> Hierarchy

_images/policies_hierarchy.png

Summary: How the QA tests and calibration settings are determined for individual displays

The effective QA tests and calibration settings for a workstation and the connected displays are determined by combining the mechanisms described above (use and policy - organizational structure assignment). The following logic is applied to each workstation:

  1. Retrieve the room to which the workstation is assigned

  2. Find the policy assigned to the organizational tree, starting at the room level, and then ascending each node until a policy is encountered.

  3. Apply the policy / settings for each display:

    • Retrieve the configured use of the display

    • For the use, retrieve the QA tests and calibration settings from the policy

    • Apply these QA tests and settings to the display

  4. Evaluate the tests and settings context of multiple displays with the same use, if applicable. For example, a multi-display uniformity test will only become available when there is more than one dispay.

If multiple policies are assigned to different nodes in the organizational structure, then only the policy assigned to the lowest node level will be taken into account. For example, if in the organizational structure a policy is assigned to a room node and another policy is assigned to a hospital node, then only the policy assigned to the room node will be applied.