Computed tomography with adjusted dose for body mass index may be superior to whole-body radiography especially in elderly patients with multiple myeloma.

BACKGROUND: Whole-body skeletal radiography has traditionally been used in the management of multiple myeloma for defining treatment strategies. For several reasons, radiography has been replaced by computed tomography (CT) covering the same regions.

PURPOSE: To evaluate the body mass index (BMI) adjusted effective radiation dose from two different methods of whole-body radiologic imaging for multiple myeloma assessment.

MATERIAL AND METHODS: The current investigation analyses the dose to patients resulting from the two methods, conventional radiography supplemented with tomosynthesis (203 examinations) and CT (264 examinations). All patients subject to myeloma staging for 4.5 years were included in the study. Exposure parameters were collected from the PACS and conversion factors were calculated using the software packages PCXMC and VirtualDose enabling the calculation of the effective dose to each patient based on BMI. The Mann-Whitney U test was used for comparisons between groups.

RESULTS: Patients were subject to a median effective dose of 2.5 mSv for conventional radiography and 5.1 mSv for CT, a statistically significant difference.

CONCLUSION: The effective dose for whole-body CT in assessing multiple myeloma is twice as high as for whole-body skeletal survey with modern digital radiography, but at a low level and considerably less than the levels quoted in the earlier studies of ∼30 mSv when the technique was first explored.