Estimation of effective dose for the diagnosis and follow-up of multiple myeloma using conventional radiology

Background and objective: Multiple myeloma (MM) is a haemolytic neoplasm which produces osteolytic lesions and necessitates the periodical radiological examination of the skeleton for monitoring the disease progression. This involves the acquisition of multiple radiographs every 3 to 6 months, depending on the extent and the stage of the disease. Our objective was to estimate the cumulative patient dose during the radiographic investigation of MM. Materials and methods: Sixty eight MM radiographic examinations performed with a digital X-ray unit were recorded on a CD-rom in DICOM format. The DICOM data were extracted using appropriate software (DICOM Info Extractor) and were input into a Microsoft Excel based spreadsheet, containing embedded algorithms for the identification of the radiological examination type and the estimation of entrance surface air kerma (ESAK), dose area product (DAP) and effective dose (E) in each radiograph. The DAP to E conversion coefficients for each examination type were derived using the PCXMC 2.0 Monte Carlo simulation software for the case of a standard adult patient utilizing the irradiation geometry as this was perceived from the images and the DICOM data. Results: The mean values [and ranges] were: for number of radiographs= 14 [7-23], for cumulative ESAK 13 [2-44] mGy, for cumulative DAP= 6 [1.35-16.5] Gycm2 and for E= 0. [0.14-2.4] mSv. Conclusion: The average E value calculated is smaller than the values of 1.7 and 2.4 mSv reported in the literature and even smaller than the values of 4.8 and 4.1 mSv reported for MM diagnosis using whole-body CT. (authors)