This clinical trial is focused on studying the effects of a treatment for pulmonary embolism, a condition where one or more arteries in the lungs become blocked by a blood clot. The study will use two treatments: Pulmocis, which is a suspension for injection containing human albumin as macroaggregates, and Pulmotec, an inhalation powder containing graphite. These treatments are used to help assess lung function after a pulmonary embolism.

The purpose of the study is to evaluate how these treatments affect lung function using a special imaging technique called PET/CT, which combines positron emission tomography and computed tomography to create detailed images of the lungs. Participants will receive either the treatment or a placebo and will undergo several imaging sessions to monitor changes in lung function over time. The study aims to understand how well the lungs are working after treatment and to identify any improvements in breathing and overall lung health.

Throughout the study, participants will have regular check-ups and imaging tests to track their progress. The study will last for a period of time, during which participants will be closely monitored by healthcare professionals. The goal is to gather information that could help improve treatment options for people with pulmonary embolism in the future.