In recent years, the introduction of PET/CT tomographs (which have now almost completely replaced tomographs equipped with PET alone), has allowed a significant increase in diagnostic accuracy in the majority of tumors. However, in order to reduce the radiation doses, administering CT images are acquired for patients at a low dose (generally 60mA 120kV) without the use of contrast agents. This prudential attitude, however, makes it essential to carry out "diagnostic" CT investigations which, at the end of the diagnostic process It leads to an increase in the dose administered for the patient rather than to savings.

This study aims to evaluate the possible advantages in diagnostic, economic and quality of life terms of PET/CT performed with diagnostic CT with intravenous contrast medium, with the aim of benefiting the neoplastic patient in the diagnostic process by optimizing (from a temporal and dosimetric point of view ) the diagnostic procedures to which it is subjected.

It is expected that the integrated PET/CT procedure can facilitate the process of staging the neoplasm and that this procedure can have a positive impact on the patient's quality of life while also reducing the costs incurred in terms of time and money.

Inclusion Criteria:

• Established lymphoma (non-Hodgkin's lymphoma and Hodgkin's disease) being staged;
• Performing the PET/CT examination within two weeks of diagnosis and before treatment;
• Signing of the Informed Consent.

Exclusion Criteria:

• patients <18 years;
• Patients who have not signed the Informed Consent;
• Execution of previous anti-inflammatory or anti-inflammatory therapies in the 4 weeks preceding the PET exam.

patients with malignant lymphoma subjected to diagnostic examination by PET/CT with contrast medium in a single session, instead of on two different dates, as occurs in normal clinical practice.