RESUMO
Treatment activity for yttrium-90 ((90)Y) radioembolization when calculated by using the manufacturer-recommended technique is only partially patient-specific and may result in a subtumoricidal dose in some patients. The authors describe the use of quantitative (90)Y positron emission tomography/computed tomography as a tool to provide patient-specific optimization of treatment activity and evaluate this new method in a patient who previously received traditional (90)Y radioembolization. The modified treatment resulted in a 40-Gy increase in absorbed dose to tumor and complete resolution of disease in the treated area within 3 months.
Assuntos
Neoplasias dos Ductos Biliares/radioterapia , Ductos Biliares Intra-Hepáticos/efeitos da radiação , Colangiocarcinoma/radioterapia , Embolização Terapêutica/métodos , Neoplasias Hepáticas/radioterapia , Imagem Multimodal , Tomografia por Emissão de Pósitrons , Compostos Radiofarmacêuticos/administração & dosagem , Tomografia Computadorizada por Raios X , Ítrio/administração & dosagem , Idoso , Neoplasias dos Ductos Biliares/diagnóstico por imagem , Neoplasias dos Ductos Biliares/patologia , Ductos Biliares Intra-Hepáticos/diagnóstico por imagem , Ductos Biliares Intra-Hepáticos/patologia , Colangiocarcinoma/diagnóstico por imagem , Colangiocarcinoma/secundário , Humanos , Neoplasias Hepáticas/diagnóstico por imagem , Neoplasias Hepáticas/secundário , Masculino , Valor Preditivo dos Testes , Dosagem Radioterapêutica , Fatores de Tempo , Resultado do TratamentoRESUMO
Substance P receptor (SPR) and its naturally occurring splice-variant, lacking the C-terminal tail, are found in brain and spinal cord. Whether C-terminally truncated SPR desensitizes like full-length SPR is controversial. We used a multivaried approach to determine whether human SPR (hSPR) and a C-terminally truncated mutant, hSPRDelta325, differ in their desensitization and internalization. In HEK-293 cells expressing either hSPRDelta325 or hSPR, SP-induced desensitization of the two receptors was similar when measured by inositol triphosphate accumulation or by transient translocation of coexpressed PKCbetaII-GFP to the plasma membrane. Moreover, translocation of beta-arrestin 1 or 2-GFP (betaarr1-GFP or betaarr2-GFP) to the plasma membrane, and receptor internalization were also similar. However, hSPR and hSPRDelta325 differ in their phosphorylation and in their ability to form beta-arrestin-containing endocytic vesicles. Unlike hSPR, hSPRDelta325 is not phosphorylated to a detectable level in intact HEK293 cells, and whereas hSPR forms vesicles containing either betaarr1-GFP or betaarr2-GFP, hSPRDelta325 does not form any vesicles with betaarr1-GFP, and forms fewer vesicles with betaarr2-GFP. We conclude that truncated hSPR undergoes agonist-dependent desensitization and internalization without detectable receptor phosphorylation.
