Benefits Study of Respiratory-gated PET Acquisition in Lung Disease (PneumoTEP)

Benefits Study of a Respiratory Gating Protocol for Positron Emission Tomography: Application on the Lungs

Fluorodeoxyglucose (FDG) positron emission tomography (PET) is now widely used for cancer imaging purpose, notably for preoperative work-up. It aims at visualizing organs metabolism. In case of cancer, metabolism is, classically, increased and some hot spots are visible on PET images. Because of respiratory motion some lung tumours (especially the smallest ones) can be falsely interpreted by the clinician. The investigators developed a respiratory-gated PET method in order to reduce the motion issue. The investigators designed a study to investigate its effect on lung cancer (primary or metastasis) to check if it improves the sensitivity/specificity of PET imaging of the lungs. To that aim, patients presenting a lung nodule on a CT examination can be proposed to participate this study. After the standard PET acquisition (acquired in free-breathing), an additional 10 minutes respiratory-gated PET acquisition is performed without additional injection. After that, a breath-hold (~10s) CT is performed.

After fasting for at least 6 hours, normal glucose blood level was checked and each patient received an intravenous injection of 18F-FDG (5MBq/kg). After a 60-minute uptake phase in a quiet environment, patients underwent the PET/CT examination. Whole-body PET/CT (Ungated session) The Ungated acquisition consisted in a whole-body, free-breathing CT followed by standard multistep PET, used as routine clinical practice in the department. Respiratory-gated PET/CT (CT-based session) The CT-based method consisted in an additional single-step, 10-minute List Mode respiratory gated PET acquisition followed by an end-expiration breath-hold CT added to the end of the clinical protocol, with continuous respiratory signal recording during these examinations.

For each CT nodule, observer has to report the corresponding (maximum Standardized Uptake Value)SUVmax on ungated and CT-based images (even if there is no obvious uptake)

Patients undergo lung function test including measures of: total lung capacity residual volume forced expiratory volume forced vital capacity

Inclusion Criteria: patient has one or more lung lesion(s) less than 35 mm visible on a CT image age : over 18 years patients gave their written informed consent Exclusion Criteria: pregnancy patient has at least one lesion more than 35 mm in its great axis

Daouk J, Leloire M, Fin L, Bailly P, Morvan J, El Esper I, Saidi L, Moullart V, Francois G, Jounieaux V, Meyer ME. Respiratory-gated 18F-FDG PET imaging in lung cancer: effects on sensitivity and specificity. Acta Radiol. 2011 Jul 1;52(6):651-7. doi: 10.1258/ar.2011.110018. Epub 2011 Apr 21.

Daouk J, Bailly P, Kamimura M, Sacksick D, Jounieaux V, Meyer ME. Positron emission tomography-based evidence of low-amplitude respiratory motion in patients with chronic obstructive pulmonary disease. Ann Nucl Med. 2015 May;29(4):319-24. doi: 10.1007/s12149-014-0945-3. Epub 2015 Jan 8.