Boron detection from blood samples by ICP-AES and ICP-MS during boron neutron capture therapy

Objective. The concept of boron neutron capture therapy (BNCT) involves infusion of a ¹⁰B containing tracer into the patient's bloodstream followed by local neutron irradiation(s). Accurate estimation of the blood boron level for the treatment field before irradiation is required. Boron concentration can be quantified by inductively coupled plasma atomic emission spectrometry (ICP‐AES), mass spectrometry (ICP‐MS), spectrofluorometric and direct current atomic emission spectrometry (DCP‐AES) or by prompt gamma photon detection methods. Material and methods. The blood boron concentrations were analysed and compared using ICP‐AES and ICP‐MS to ensure congruency of the results if the analysis had to be changed during the treatment, e.g. for technical reasons. The effect of wet‐ashing on the results was studied in addition. Results. The mean of all samples analysed with ICP‐MS was 5.8 % lower than with ICP‐AES coupled to wet‐ashing (R² = 0.88). Without wet‐ashing, the mean of all samples analysed with ICP‐MS was 9.1 % higher than with ICP‐AES (R² = 0.99). Conclusions. Boron concentration analysed from whole blood samples with ICP‐AES correlated well with the values of ICP‐MS with wet‐ashing of the sample matrix, which is generally considered the reference method. When using these methods in parallel at certain intervals during the treatments, reliability of the blood boron concentration values remains satisfactory, taking into account the required accuracy of dose determination in the irradiation of cancer patients.