Are therapeutic radiographers able to achieve a clinically acceptable match for stereotactic lung radiotherapy treatment (SBRT)?

This audit aimed to prospectively assess the accuracy of radiographer verification of CBCT images for SBRT treatment delivery and the feasibility of local implementation of radiographer-led on-line image verification for SBRT.

SBRT for treatment of early stage peripheral non-small cell lung cancer (NSCLC) improves outcomes [1]. However, daily on-line imaging is essential to ensure accuracy in delivery of these hypo-fractionated high-dose treatments [2,3]. Currently in the department on-line verification of cone beam computerised tomography (CBCT) images for SBRT is performed by a clinical oncologist. The National Radiotherapy Advisory Group (NRAG) recommends more effective use of the skilled multi-professional workforce to meet the demands of an ever expanding radiotherapy service [4]. Utilising therapeutic radiographers to perform on-line verification improves efficiency but requires competency to be assessed before implementation.

The standard: 

• 3D images (CT, MRI) should be used to localise target volume and OAR

• 3D images (CT) should be used to plan SBRT treatment

• CBCT images should be acquired and used for verification purposes

• The clinical oncologist’s original online verification match is taken as the audit standard

Target: 

90% of therapeutic radiographers to be within 2mm of the audit standard in all three planes (left/right, superior/inferior, anterior/ posterior).

Indicators: 

The indicator was defined as a radiographer match within 2 mm of the clinician’s original verification with a target of 90% agreement.

Data items to be collected: 

• CT localisation image data set

• CBCT data set images from the first fraction of each SBRT treatment

• Age

• Stage of disease

• Size of tumour

• Position of tumour within lung

Suggested number: 

All patients receiving SBRT for mobile, peripheral lung tumours since the introduction of hypofractionated lung radiotherapy within the department in 2009.

• Identify reasons for not meeting required agreement; look at staff training and experience. Where there any recurring themes such as tumour size and location for example?

• Provide CBCT training workshops specific for SBRT verification imaging

• After SBRT specific training radiographers to retrospectively verify CBCT images replicating the initial guidelines and targets

• Personnel required: Clinical director, audit lead, clinical oncologist, therapeutic radiographers

• Time: 2.5 hours for each radiographer to complete verifications and associated paperwork, 20 hours for all data to be collated and reviewed

1. Grills IS, Hope AJ, Guckenberger M, et al. A collaborative analysis of stereotactic lung radiotherapy outcomes for early-stage non-small-cell lung cancer using daily online cone-beam computed tomography image-guided radiotherapy. J Thorac Oncol.2012;7(9):1382-93.

2. Guckenberger M, Krieger T, Richter A, et al. Potential of image-guidance, gating and real-time tracking to improve accuracy in pulmonary stereotactic body radiotherapy. Radiother Oncol. 2009;91(3):288-95

3. Burnett SS, Sixel KE, Cheung PC, Hoisak JD. A study of tumor motion management in the conformal radiotherapy of lung cancer. Radiother Oncol. 2008;86(1):77-85.

4. Radiotherapy: Developing a world class service for England. Report to Ministers from National Radiotherapy Advisory Group. 2007

Merina Ahmed, Jacqui Hudson