A 52-year-old male stone quarry worker presents with progressive dyspnea and dry cough for 3 years. He has a 25-year history of exposure to silica dust without adequate respiratory protection. Physical examination reveals bilateral fine crackles at lung bases. Chest X-ray shows bilateral upper and mid-zone nodular opacities with 'eggshell' calcification of hilar lymph nodes. Which investigation is most appropriate to confirm silicosis and assess for associated complications?