Inclusion Criteria:

- Patient is able to read and understand the Informed Consent Form and he/she will
provide written Informed Consent.

- Male or female in the age range of 18-85 years.

- The patient will undergo V/Q scan (up to ONE WEEK from the VRI recording)

- The patient presented for evaluation of COPD.

- Body Mass Index >21.

Exclusion Criteria:

- Unstable clinical status such as fever, acute shortness of breath, cough, hemoptysis,
cheat pain, or acute chest illness.

- Chest wall deformation;

- Spine deformation (including severe scoliosis);

- Hirsutism;

- Potentially contagious skin lesion on the back;

- Skin lesion that would interfere with sensor placement;

- Any additional chronic lung disease of any findings such as past tuberculosis,
visualized on CXR.

8. Previous resection lung surgery and history of lung tumor; 9. Cardiac pacemaker or
implantable defibrillator