Responsible for monitoring and treating patients with temporary or chronic respiratory conditions like asthma, COPD, pneumonia, bronchitis or emphysema. Patients range from premature infants with undeveloped lungs to elderly patients who have diseased lung Job Requirements : ARRT - American Registry Radiologic Technologists. Depending on what state you plan to work in, you may also need to obtain a state license in order to become a radiation therapist. Pennsylvania is currently a state that does not require license exams, but New Jersey is a state that does.