Objective  To evaluate the benefits of chest SPECT/CT in the diagnosis of bone metastasis after whole-body bone scan in lung cancer patients and to screen the optimal beneficiaries of SPECT/CT.

  Methods  A total of 150 lung cancer patients who underwent routine whole-body bone scan and chest SPECT/CT in Affiliated Cancer Hospital and Institute of Guangzhou Medical University from January 2019 to October 2019 were enrolled in the study. The extent of benefit of SPECT/CT was stratified into no benefit, general benefit, and significant benefit based on the diagnostic results of whole-body bone scan and chest SPECT/CT, changes in the number of lesions, qualitative diagnosis, and follow-up results. General data, clinical information, and lesion imaging findings were collected for all patients. Finally, the relationship between these variables and the benefit from SPECT/CT was analyzed using the χ² test.

  Results  In terms of the extent of benefit of SPECT/CT, among the 150 patients with lung cancer, 41 patients showed no benefit, 58 patients showed general benefit, and 51 patients showed significant benefit. The chi-square test confirmed that symptoms(χ²=7.849, P=0.020), number of lesions (χ²=19.567, P < 0.001), type of distribution (χ²=17.053, P < 0.001), site of involvement (χ²=7.643, P=0.022), and imaging agent intake level (χ²=17.601, P=0.001) were found to be related to the benefit from SPECT/CT.

  Conclusion  The necessity for thoracic SPECT/CT after whole-body bone scan in lung cancer patients should be evaluated by benefit assessment. The symptoms, number of lesions, type of distribution, site of involvement, and site of involvement were effective factors for evaluating the benefit of SPECT/CT.