Utilidad de 11C-metionina PET/CT en neurooncología / Utility of 11C-methionine PET/CT in neuro-oncology

La tomografía por emisión de positrones con metionina carbono 11 (11C-metionina PET/TC) se utiliza en la evaluación de los tumores primarios del sistema nervioso central. Describimos nuestra experiencia sobre los primeros 4 pacientes con tumores de la serie glial estudiados con 11C-metionina PET/TC. Este es un estudio descriptivo, observacional y prospectivo. Se presentan 4 pacientes entre 38-50 años de edad con diagnóstico de gliomas (clasificación de la OMS). A todos se les realizó RM y 11C-metionina PET/TC para evaluar actividad tumoral y diferenciar progresión tumoral de pseudoprogresión. Caso 1, gliomatosis cerebri grado II posradioterapia. Caso 2, glioblastoma grado IV postratamiento RT + temozolomida. Caso 3, oligodendroglioma grado II posradioterapia en 1993. Caso 4, oligoastrocitoma anaplásico grado III postratamiento RT + temozolomida. El patrón de captación de la 11C-metionina comparativamente con la RM, demostró progresión tumoral en los casos 1, 3 y 4; en el caso 2 mostró captación aunque el diagnóstico final fue pseudoprogresión. A diferencia del PET con 18fluordeoxiglucosa, la captación de 11C-metionina en el tejido cerebral normal y en la pseudoprogresión es baja, y los gliomas se visualizan como áreas metabólicamente activas. En los casos presentados, el 11C-metionina PET/TC proveyó información valiosa sobre el comportamiento y extensión de la lesión, aunque en uno de los casos presentados no diferenció progresión tumoral de pseudoprogresión. El 11C-metionina PET/TC sería una herramienta útil en el estudio y seguimiento de los pacientes con gliomas.(AU)

Positron emission tomography (PET) with 11C-methionine (11C-methionine PET/CT) is a new technique used to evaluate primary central nervous system (CNS) tumors. We describe our experience regarding the first 4 patients with glial tumors and 11C-methionine PET/CT. This is a descriptive, observational and prospective study of 4 patients between 38-50 years of age, with different gliomas (WHO classification). MRI and 11C-methionine PET/CT were performed in all cases. Case 1, gliomatosis cerebri grade II post-radiotherapy. Case 2, oligodendroglioma grade II diagnosed and treated with radiotherapy in 1993. Case 3, glioblastoma grade IV post-radiotherapy + temozolomide. Case 4, anaplastic oligoastrocytoma grade III post-radiotherapy + temozolomide. The pattern of 11C-methionine uptake compared with MRI showed tumor progression in cases 1, 3 and 4, and in case 2 showed uptake although the final diagnosis was pseudoprogression. Unlike 18fluordeoxiglucose PET/TC, 11C-methionine uptake in normal brain tissue and pseudoprogression is low, and gliomas are displayed as metabolically active areas. The 11C-methionine PET/CT provided valuable information on the tumoral behavior and extension, although in one case presented did not differentiate tumor progression from pseudoprogression. 11C-methionine PET/CT could be a useful tool in the study and follow-up to patients with gliomas.(AU)

Utilidad de 11C-metionina PET/CT en neurooncología. / [Utility of 11C-methionine PET/CT in neuro-oncology].

Positron emission tomography (PET) with 11C-methionine (11C-methionine PET/CT) is a new technique used to evaluate primary central nervous system (CNS) tumors. We describe our experience regarding the first 4 patients with glial tumors and 11C-methionine PET/CT. This is a descriptive, observational and prospective study of 4 patients between 38-50 years of age, with different gliomas (WHO classification). MRI and 11C-methionine PET/CT were performed in all cases. Case 1, gliomatosis cerebri grade II post-radiotherapy. Case 2, oligodendroglioma grade II diagnosed and treated with radiotherapy in 1993. Case 3, glioblastoma grade IV post-radiotherapy + temozolomide. Case 4, anaplastic oligoastrocytoma grade III post-radiotherapy + temozolomide. The pattern of 11C-methionine uptake compared with MRI showed tumor progression in cases 1, 3 and 4, and in case 2 showed uptake although the final diagnosis was pseudoprogression. Unlike 18fluordeoxiglucose PET/TC, 11C-methionine uptake in normal brain tissue and pseudoprogression is low, and gliomas are displayed as metabolically active areas. The 11C-methionine PET/CT provided valuable information on the tumoral behavior and extension, although in one case presented did not differentiate tumor progression from pseudoprogression. 11C-methionine PET/CT could be a useful tool in the study and follow-up to patients with gliomas.

S35 methionine uptake in protein-depleted Jamaican children

There is no reliable test of the severity of protein depletion or indicator as to prognosis. The absence of such a test makes therapeutic trails hazardous and difficult to interpret. In experimentally protein-depleted dogs and in malnourished children, a change from the normal distribution of protein anabolism has been demonstrated by use of radioactive methionine as a tracer. It is suggested that such tracer studies may provide information not otherwise obtainable concerning the essential physiology of protein depletion, and thereby assist in the deveploment and assessment of new methods of treatment (AU)