Hello and hope you are doing well.
PTB is Pulmonary Tuberculosis, or TB, is an infectious bacterial disease caused by Mycobacterium tuberculosis, which most commonly affects the lungs. It usually affects the apical portion of the lungs. It is transmitted from person to person via droplets from the throat and lungs of people with the active respiratory disease. Undetermined activity means, the findings identified in imaging studies could be due to an active infection or due to an old infection. Only further investigations can help diagnose if it is an active or an old infection.
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It would help to better describe your question, starting with what "PTB" is, spell it out.