Audit template to assess compliance of low radiation dose CT used in the Targeted Lung Health Check Scans

This audit is intended to assess the quality of Computed Tomography (CT) scans of the thorax in the setting of Targeted Lung Health Check scans.

The NHSE Targeted Lung Health Check (TLHC) protocol recommends the implementation of standardised acquisition and reconstruction parameters for TLHC low dose CT scans, as described in the NHSE Standard Protocol[1] and Quality Assurance Standards[2].

The standard: 

All teams delivering NHSE TLHC programmes should use the standardised acquisition and reconstruction protocols for low dose CT as described in the protocol [1,2]. Involvement of the medical physics department is recommended to audit doses and investigate if median dose length product (DLP) consistently exceeds local DRL. In the absence of a national diagnostic reference level (NDRL) a maximum recommended local DRL is 74 mGy.cm, but it may be appropriate to set a lower value based on local setup. For average patients this will approximately equate to 2mSv.

Target: 

Image reconstruction is standardised and used for any subsequent follow-up examinations where possible with emphasis on ensuring that slice thickness, reconstruction increment, reconstruction algorithm is identical

• Median DLP for a sample of patients does not exceed the local DRL.
• 100% of reconstructed slice thickness of ≤ 1.25mm
• 100% of reconstructed slice increment of ≤ 0.7mm
• 100% scans reconstructed with correct standard lung algorithm.
• 100% of scans with correct anatomical coverage (i.e. entire lung parenchyma).

Indicators: 

• Median DLP (assess if this exceeds local DRL)
• Percentage of scans reconstructed with slice thickness ≤ 1.25mm
• Percentage of scans with  reconstructed slice increment of ≤ 0.7mm
• Percentage of scans correct reconstruction algorithm.
• Percentage of scans with correct anatomical coverage.

Data items to be collected: 

Number of scans included:

a) Total number of scans

Scan acquisition/reconstruction parameters:

b) DLP  

c) Slice thickness

d) Reconstruction increment

e) Reconstruction algorithm

f)  Area of interest covered

Suggested number: 

This will vary according to the size of the department. 100 examinations is recommended

• Present and discuss findings CT optimisation team meetings.
• Correct acquisition and reconstruction settings, if required.
• Discuss possible solutions for quality improvement and plan for a quality improvement cycle.

• List of eligible scans [may require support from PACS administration staff]
• Data collection from PACS (and RIS if required)
• Analysis and interpretation of data [which can be radiographer led]

1. [1] Standard Protocol prepared for the Targeted Lung Health Checks Programme, NHSE https://www.england.nhs.uk/publication/targeted-screening-for-lung-cancer/

2. [2] Quality Assurance Standards prepared for the Targeted Lung Health Checks Programme, NHSE https://www.england.nhs.uk/publication/targeted-screening-for-lung-cancer/

Peter Atiiga

Co-authors

Craig Moore

Tim Wood

Lizzie Barclay

Andrew Stephens

Oliver Byass

Nadia Jawad