68Ga-DOTATATE PET/CT versus 111In-octreotide scintigraphy in patients with neuroendocrine tumors: a prospective study / PET/CT com 68Ga-DOTATATE versus cintilografia com 111In-octreotide em pacientes com tumores neuroendócrinos: estudo prospectivo

Abstract Objective: To compare 68Ga-DOTA-DPhe1,Tyr3-octreotate (68Ga-DOTATATE) positron-emission tomography/computed tomography (PET/CT) findings with those of conventional 111In-octreotide scintigraphy in patients with neuroendocrine tumors (NETs). Materials and Methods: This was a single-center prospective study including 41 patients (25 males; mean age, 55.4 years) with biopsy-proven NETs who underwent whole-body 111In-octreotide scintigraphy and whole-body 68Ga-DOTATATE PET/CT. The patients had been referred for tumor staging (34.1%), tumor restaging (61.0%), or response evaluation (4.9%). Images were compared in a patient-by-patient analysis to identify additional lesions, and we attempted to determine the impact that discordant findings had on treatment planning. Results: Compared with 111In-octreotide scintigraphy, 68Ga-DOTATATE PET/CT revealed more lesions, the additional lesions typically being in the liver or bowel. Changes in management owing to the additional information provided by 68Ga-DOTATATE PET/CT occurred in five patients (12.2%), including intermodal changes in three (7.3%) and intramodal changes in two (4.9%). In addition, 68Ga-DOTATATE PET/CT yielded incidental findings unrelated to the primary NET in three patients (7.3%): Hürthle cell carcinoma of the thyroid, bowel non-Hodgkin lymphoma, and a suspicious breast lesion. Conclusion: We conclude that 68Ga-DOTATATE PET/CT is superior to conventional 111In-octreotide scintigraphy for the management of NETs because of its ability to determine the extent of the disease more accurately, which, in some cases, translates to changes in the treatment plan.

RESUMO Objetivo: Comparar os achados da PET/CT com 68Ga-DOTATATE em relação aos da cintilografia com 111In-octreotide em pacientes com tumores neuroendócrinos (TNEs). Materiais e Métodos: Estudo prospectivo unicêntrico incluindo 41 pacientes (25 homens; média de idade: 55,4 anos) com TNEs comprovados por biópsia submetidos a cintilografia de corpo inteiro com 111In-octreotide e PET/CT com 68Ga-DOTATATE. Os pacientes incluídos foram encaminhados para estadiamento do tumor (34,1%), reestadiamento (61,0%) ou avaliação da resposta (4,9%). As imagens foram comparadas para identificar lesões adicionais e o impacto dos achados discordantes no planejamento terapêutico. Resultados: Na comparação com a cintilografia com 111In-octreotide, a PET/CT com 68Ga-DOTATATE revelou mais lesões, mais frequentemente localizadas no fígado e intestino. Mudanças no tratamento devidas às informações adicionais reveladas pela PET/ CT ocorreram em 5/41 pacientes (12,2%), incluindo mudanças intermodalidade em três casos (7,3%) e intramodalidade em dois casos (4,9%). A PET/CT também identificou achados incidentais não relacionados ao TNE em 3/41 pacientes (7,3%), incluindo um carcinoma de células de Hürthle da tireoide, um linfoma não Hodgkin de intestino e uma lesão mamária suspeita. Conclusão: A PET/CT com 68Ga-DOTATATE é superior à cintilografia convencional com 111In-octreotide para o manejo de pacientes com TNEs, em virtude da sua capacidade de detectar a extensão da doença com mais precisão, o que se traduz, em alguns casos, em alterações terapêuticas.

Impacto do PET-CT com 68Ga-DOTATATE versus cintilografia em gama camera com 111In-OCTREOTIDE nos pacientes portadores de tumores neuroendócrinos / Impact of 68Ga-DOTATATE PET-CT versus conventional 111In-octreotide scintigraphy in neuroendocrine tumors patients carrier

Objetivo: Comparar as modalidades diagnósticas do PET-CT com 68Ga-DOTATATE versus cintilografia em gama camera com 111In-octreotide nos pacientes portadores de tumores neuroendócrinos e a avaliação da medida do seu impacto na mudança de terapia. Método: Quarenta e um pacientes com tumores neuroendócrinos confirmados histologicamente foram incluidos e foram submetidos a cintilografia convencional com 111In-octreotide e PET-CT de corpo inteiro com 68Ga-DOTATATE. Imagens de ambas as modalidades foram comparadas em uma análise paciente a paciente com avaliação do impacto da detecção de lesões adicionais na mudança de conduta. Resultados: Significativamente mais lesões foram detectadas no PET-CT com 68Ga-DOTATATE quando comparado a cintilografia convencional com 111In-octreotide. Lesões adicionais foram mais frequentemente visualizadas no fígado e nos implantes em alças intestinais. Mudanças na conduta devido a informações adicionais oferecidas pelo PET-CT com 68Ga-DOTATATE ocorreram em cinco dos 41 pacientes (12,2%). Três dos 41 pacientes (7,3%) apresentaram mudança de conduta intermodalidade e dois dos 41 (4,9%) mudança intramodalidade. Conclusão: O PET-CT com 68Ga-DOTATATE demonstrou-se superior para a detecção de tumores neuroendócrinos comparativamente à cintilografia convencional com 111In-octreotide, traduzida em parte na mudança de conduta terapêutica

Purpose: Compare the detectability of the 68Ga-DOTATATE PET-CT with conventional 111In-octreotide scintigraphy in neuroendocrine tumors patients carrier and the measure of its impact in therapy change. Method: Forty one patients with a histologically confirmed diagnosis of neuroendocrine tumors were included and underwent conventional 111In-octreotide scintigraphy and whole body 68Ga-DOTATATE PET-CT. Images of both modalities were compared in a patient by patient analysis determining aditional lesions and the impact of detecting additional lesions in the therapy change. Results: Significantly more lesions were detected on 68Ga-DOTATATE PET-CT versus conventional 111In-octreotide scintigraphy. Additional lesions were mostly frequent visualized in liver and implants in intestinal loops. Change in management due additional information given by 68Ga-DOTATATE PET-CT occured in 5 of 41 patients (12.2%). Three of 41 patients (7.3%) presented a intermodality change and 2 of 41 (4.9%) had a intramodality change. Conclusion: 68Ga-DOTATATE PET-CT is superior for the detection of neuroendocrine tumors compared to conventional 111In-octreotide scintigraphy with impact in the therapy change

Anatomical location of cervical uptake areas after total thyroidectomy with 131Iodine - SPECT-CT

Objective: The purpose of this study was to evaluate the use of SPECT-CT for the determination of the anatomical locations of the cervical 131Iodine uptake areas during 131Iodine-whole body (131I-WB) scans. Methods: One hundred fifty-four patients who had undergone total thyroidectomyfor differentiated thyroid carcinoma (DTC) and had 131I-WB scan with cervical uptake images were studied with SPECT-CT, from March 2003 to October 2006. Results: From the 154patients included, 124 were women (80.5%) and the mean age of 46.09 ± 14.77 years. 131I-WB was performed 1-2 months after surgery in 137 patients (89.0%). The percentage of cervical uptake found varied between 0.1 and 15.0% and its mean was 1.42 ± 2.05%. Using SPECT-CT, 223 foci of cervical 131Iodine uptake (CIU) were identified in 154 patients. CIU foci were localized to the thyroid bed in 17 patients, while 29 patients presented with CIU in the thyroid bed and the extra thyroid tissue and in both the thyroid bed and extra thyroid tissues in another 29 patients. Inthe remaining 108 subjects, the CIU were located outside of the thyroid bed, of which the most common locations were the sternothyroid muscle and the thyroid cartilage. Conclusions: The useof SPECT-CT demonstrated significant diversity in the anatomical locations of CIU foci observed during 131I-WB scans after thyroidectomy for DTC

Definition of gross tumor volume with FDG-18F PET-CT in patients with head and neck cancer: comparison of different delineation methods

Objective: Besides the high sensitivity and specificity of positron emission tomography (PET) for head and neck tumors, there is still a lack of consensus about how to use this method inradiotherapy planning. The aim of this study is to compare different gross tumor volume (GTV) obtained with PET images in comparison to the size of the target volume generated with CT scanalone, for treated and untreated head and neck lesions. Methods: Sixty lesions in fifty patients with head and neck squamous cell carcinoma were included in the study. Delineation of the GTV was achieved using computed tomography (CT) images alone (GTV-CT) and PET-CT images with the visual assessment method (GTVPET-CT) and standard uptake value (SUV) thresholds of 40, 50, 60 and 75 percent (GTV40%, GTV50%, GTV60%, GTV75%, respectively). Correlations were measured by the Spearman test and the Friedman test was used to verify differences between GTVs. Results: For all lesions (treated and untreated), only the GTVPET-CT showed a strong correlation with GTV-CT. For only the untreated lesions, GTVPET-CT and GTV75% showed a strong correlation with GTV-CT. The GTV50%, GTV60% and GTV75% showed statistically significant difference in relation to GTV-CT, while GTVPET-CT and GTV40% were similar to GTV-CT. Conclusion: The use of PET-CT changes the volume of the final target in head and neck tumors,depending on the methodology used to calculate the GTV. The results presented here showed that the GTV40% and the GTVPET-CT are those who are closer to the target volumes delineated by conventional CT

Evaluation of therapeutic response with 18-FDG PET-CT for non-small cell lung cancer case report and literature review

Positron Emission Tomography / Computed Tomography (PET-CT) is increasingly being used as to complement conventional imaging methods and improve the management of patients with non-small cells lung cancer (NSCLC). The objective of this work is to report on a case in which PET-CT was used as a complementary method to evaluate the therapeutic response in a patient with NSCLC, and to carry out a literature review of the theme. Female patient, 65 years-old, with NSCLC, stage IIIA (T2N2M0), was submitted to exclusive neoadjuvant chemotherapy and presented good response to the treatment, classified by the morphological criteria of the RECIST (Response Evaluation Criteria in Solid Tumors) as a partial response (reduction equal to or greater than 30 percent in the sum of the widest diameter of all the target lesions in the computed tomography). The metabolic evaluation by PET-CT showed a complete response (reduction equal to or higher than 80 percent at maximum SUV of the lesions), which was confirmed in the histopathological analysis of the surgical samples. In the case presented, and through the literature review, we show that the evaluation of response with metabolic criteria, associated with morphological criteria, may be more accurate than the use of morphological criteria alone.