Low-dose Computer Tomography in Follow-up of Soft Tissue Sarcomas

The goal of this interventional study is to compare sensitivity of regular chest x-ray to ultra-low-dose computed tomography to find pulmonary relapse in follow-up of soft tissue sarcoma. The main question\[s\] it aims to answer are: * Is ultra-low-dose computed tomography more sensitive than regular chest x-ray to find pulmonary relapse? * Does ultra-low-dose computed tomography detect the most fast-growing pulmonary metastases earlier than regular chest x-ray? Participants will have seven ultra-low-dose computed tomography imagings in addition to simultaneous routine protocol of chest x-rays. Participants therefore work as their own controls.