$Introduction:$ Solitary pulmonary nodules (SPNs) are common on CT. The most cost-effective investigation algorithm is still to be determined. Dynamic contrastenhanced CT (DCE-CT) is an established diagnostic test not widely available in the UK currently.

$Methods\; and\; analysis:$ The SPUtNIk study will assess the diagnostic accuracy, clinical utility and cost-effectiveness of DCE-CT, alongside the current CT and 18-flurodeoxyglucose-positron emission tomography) ($\mathrm{<mrow\; data-mjx-texclass="ORD">18</mrow>}$FDG-PET)-CT nodule characterisation strategies in the National Health Service (NHS). Image acquisition and data analysis for $\mathrm{<mrow\; data-mjx-texclass="ORD">18</mrow>}$FDG-PET-CT and DCE-CT will follow a standardised protocol with central review of 10% to ensure quality assurance. Decision analytic modelling will assess the likely costs and health outcomes resulting from incorporation of DCE-CT into management strategies for patients with SPNs.

$Ethics\; and\; dissemination:$ Approval has been granted by the South West Research Ethics Committee. Ethics reference number 12/SW/0206. The results of the trial will be presented at national and international meetings and published in an Health Technology Assessment (HTA) Monograph and in peer-reviewed journals.