OBJECTIVES The National Institute of Health and Care Excellence (NICE) issued diagnostic guidance on new generation computed tomography (CT) scanners recommending them as an option for the first-line imaging of coronary arteries in patients with suspected low-risk coronary artery disease (CAD) in whom imaging with old generation scanners is difficult (e.g. obese patients). The capital investment for a new generation scanner is considerably more than a standard scanner, which could hamper implementation. Based on the NICE guidance, a model was designed for use as a planning tool for rapid access chest pain clinics (RACPCs) looking to replace their current scanner with a new generation scanner. METHODS  An Excel^® model was developed to estimate up to a 10-year impact of acquiring a new generation scanner. It was assumed that under standard care low-risk, difficult-to-image patients would be referred for a diagnostic invasive coronary angiography (ICA). Under the new diagnostic pathway these patients can be scanned with a new generation scanner. Whenever possible the NICE guidance was used to guide assumptions and populate default values. RESULTS The model estimates that for each difficult-to-image patient a new generation scanner has the potential to save approximately £946.62 in diagnostic costs. Considering the capital investment required, a RACPC looking to replace their standard scanner and considering implementing a new generation CT scanner only need 53 difficult-to-image patients per year to see a positive return on investment over a 10-year period. CONCLUSIONS The model is likely to be conservative as it focuses on difficult-to-image patients only, yet the scanner is available for all patients who will likely benefit from the better sensitivity and specificity associated with the new scanners. However, it highlights that even a low number of these difficult-to-image patients will result in a positive return on investment over the expected life-time of the scanner.