Lung perfusion scintigraphy with 99mTc-MAA and ventilation scintigraphy with Technegas (V/Q SPECT/CT) has been the cornerstone for the detection of pulmonary embolisms (PE) for many decades. In last two decades after the introduction of pulmonary CTA, general PE detection has shifted towards CTA and V/Q SPECT/CT has become the modality of choice for specific patient populations (iodine contrast allergy, poor kidney function, pregnancy, etc.) or indications (pre-operative risk stratification, chronic embolism detection, pulmonary hypertension). V/Q SPECT/CT acquisition is performed on a gamma camera, but this technique has distinct challenges and/or disadvantages. A potential alternative is the nowadays broadly available. 68Ga as a positron emitter allows PET/CT imaging. Replacing 99mTc with 68Ga in both MAA and aerosol suspension is easy and requires no modifications. However, 68Ga-V/Q with PET/CT will resolve many of the disadvantages of V/Q SPECT/CT. International studies have proven safety and feasibility of replacing 99mTc with 68Ga and preliminary work by international colleagues and our institute have shown validated preparations of the radiopharmaceuticals. However, in our institution, clinical translation is hampered by lack of data on technical acquisition parameters for our scanners. The aim of this small study is to get more insights into technical parameters for image acquisition, logistical feasibility of V/Q PET/CT, and confirm preliminary non-inferiority of this new technique over the current clinical standard (V/Q SPECT/CT).

Inclusion Criteria:

• Adult ≥18 years and declared competent
• Provided written informed consent
• Referred to the Nuclear Medicine Department for a conventional V/Q-SPECT/CT
• Indication for conventional V/Q-SPECT/CT includes known or suspected pulmonary embolism

Exclusion Criteria:

- Pregnancy