On SPECT imaging of five patients with haematologic malignancies, [99mTc]Tc-PentixaTec showed good tolerability, biodistribution, and dosimetric profile (2.1–3.4 mSv per 500 MBq) and a favourable TBR.155 In a 65-year-old female patient with relapsed MM, SPECT/CT imaging with [99mTc]Tc-PentixaTec revealed significant CXCR4 expression in the skin and muscle lesions, which may help guide the therapeutic approach. This evidence concerns the gene CXCR4 and Miyoshi myopathy.