PET WITH ~(18)FDG AND SPECT WITH ~(99)Tc~m-SESTAMIBI FOR THERAPY MANAGEMENT IN PATIENTS WITH TREATED MALIGNANT LYMPHOMAS

摘要

Therapy management in patients with recurrent malignant lymphoma requires functional methods to differentiate between residual soft tissue masses. Furthermore, one of the main problems in patients receiving chemotherapy is the occurrence of multidrug resistance (MDR). Experimental studies gave evidence of a correlation between the accumulation of 6-methoxyisobutyl isonitrile (SESTAMIBI) and the expression of P-glycoprotein, which is dependent on the mdrl gene. While positron emission tomography (PET) studies with ~(18)F-deoxyglucose (~(18)FDG) reflect primarily tumour viability, single photon emission computed tomography (SPECT) examinations with ~(99)Tc~m-SESTAMIBI may help to predict MDR in patients. PET with ~(18)FDG was used in patients with recurrent Hodgkin's lymphoma (HL) (20 patients, 68 malignant lesions and 3 benign lesions) and non-Hodgkin's lymphoma (NHL) (26 patients, 46 malignant lesions and 1 benign lesion) prior to second line chemotherapy. Dynamic acquisitions were performed and standardized uptake values were calculated from the regions of interest data. In 14 patients, SPECT studies with ~(99)Tc~m-SESTAMIBI were performed immediately prior to PET in order to evaluate the presence of MDR. Furthermore, in 10 of the 14 patients, PET ~(18)FDG follow-up studies were performed after one chemo-therapeutic cycle. The change in 18FDG metabolism, as well as the Tc-SESTAMIBI accumulation, were compared with the restaging data. All malignant lesions showed an enhanced ~(18)FDG uptake. The ~(18)FDG uptake exceeded that of blood background activity in 90.4% of the malignant lesions. ~(18)FDG accumulation was increased in two patients with an abscess. The change in ~(18)FDG uptake prior to and after chemotherapy correlated with the restaging data. An increase in ~(18)FDG uptake was also noted in one patient classified as having a stable disease. Positive SESTAMIBI accumulation was observed in 3/5 patients with complete response and partial response and 2/5 with stable disease. No SESTAMIBI accumulation was noted in two patients with progressive disease. The results show that ~(18)FDG provides a highrnlevel of sensitivity for the detection of residual tumour tissue. Changes in the ~(18)FDG uptake prior to and after one chemotherapeutic cycle reflect early response to treatment and correlate with the restaging data. An accumulation of ~(99)Tc~m-SESTAMIBI was only observed in patients with at least stable disease.