Wajima lung cancer screening program using annual chest radiographs with computed radiography (CR)

It has been shown that chest radiography and sputum cytology are the only tests of proved value in detecting preclinical lung cancer. In the Wajima Lung Cancer Screening Program, computed radiography (CR) was utilized in a new chest radiography trial. A total of 3965 male cigarrete smokers over 45 years of age from Wajima City volunteered for this study between June 1984 and December 1989. A total of 11 lung cancers had been diagnosed by March 1990. Of these patients, 7 were detected through routine screening radiographs and 4 were detected only by sputum cytology. The radiographs which led to the diagnosis were carefully reviewed and compared to previous studies. Previous CR films showed no evidence of cancer. Therefore, it was considered that the error rate could be decreased by chest radiographs with CR. Single exposure dual-energy subtraction by means of CR was also utilized in some cases from June 1989. Subtraction images markedly improved the detection of nodules hidden under the ribs and calcifications. The dual energy subtraction technique appears promising for lung cancer screening. (author)