General Concepts in Theranostics.

Theranostics describes the pairing of diagnostic biomarkers and therapeutic agents with common specific targets. Nuclear medicine is the greatest theranostics protagonist, relying on radioactive tracers for imaging biologic phenomena and delivering ionizing radiation to the tissues that take up those tracers. The concept has gained importance with the growth of personalized medicine, allowing customized management for diseases, refining patient selection, better predicting responses, reducing toxicity, and estimating prognosis. This work provides an overview of the general concepts of the theranostics approach in nuclear medicine discussing its background, features, and future directions in imaging and therapy.

Prostate-specific Membrane Antigen PET: Therapy Response Assessment in Metastatic Prostate Cancer.

Therapy response assessment is a critical step in cancer management, leading clinicians to optimize the use of therapeutic options during the course of the disease. Imaging is a pivotal biomarker for therapy response evaluation in oncology and has gained wider use through the development of reproducible data-based guidelines, of which the Response Evaluation Criteria in Solid Tumors is the most successful example. Disease-specific criteria have also been proposed, and the Prostate Cancer Working Group 3 criteria are the mainstay for prostate cancer (PC). However, conventional imaging evaluation in metastatic PC has several limitations, including (a) the inability to detect small-volume disease, (b) the high prevalence of bone (nonmeasurable) lesions at imaging, and (c) the established role of serum prostate-specific antigen (PSA) levels as the biomarker of choice for response assessment and disease progression. In addition, there are an increasing number of newer treatment options with various effects on imaging features. Prostate-specific membrane antigen (PSMA) PET has improved patient selection for newer treatments, such as metastasis-directed therapy (MDT) or radionuclide therapy. The role of PSMA PET in response assessment for many metastatic PC therapeutic options (MDT, androgen deprivation therapy, chemotherapy, radionuclide therapy, and immunotherapy) is an evolving issue, with emerging data showing good correlation with PSA levels and clinical outcome. However, there are specific implications of each therapy (especially androgen deprivation therapy and immunotherapy) on PSMA expression by PC cells, leading to potential pitfalls and inaccuracies that must be known by radiologists. Despite some limitations, PSMA PET is addressing gaps left by conventional imaging methods (eg, CT and bone scanning) and nonimaging biomarkers (PSA levels) in metastatic PC therapy response assessment, a role that can be improved with advances like refinement of interpretation criteria and whole-body tumor burden quantification.© RSNA, 2020See discussion on this article by Barwick and Castellucci.

Revisiting Prostate Cancer Recurrence with PSMA PET: Atlas of Typical and Atypical Patterns of Spread.

The introduction of prostate-specific membrane antigen (PSMA) in clinical practice has revolutionized evaluation of biochemical recurrence of prostate cancer after curative-intent treatment. The high expression of this glycoprotein in prostate cancer cells makes PSMA imaging superior to the current conventional staging methods, namely bone scanning and CT. The high capability of PSMA imaging for identifying very small previously undetected lesions has been widely demonstrated in the literature, leading to a rethinking of patient management by oncologists, urologists, and radiation oncologists. The typical and predictable patterns of spread in prostate cancer are still more prevalent, such as spread to pelvic lymph nodes and bone metastasis, but different patterns of disease spread are becoming more commonly recognized with higher reliability because PSMA imaging allows detection of more typical and atypical lesions than conventional imaging. Furthermore, it is important for the reading physician to recognize and understand the typical disease spread and the most prevalent atypical prostate cancer relapses, not only to heighten the relevancy of reports but also to improve imaging consultancy in multispecialty oncologic practice. ©RSNA, 2019.

Initial results on the use of mechanical devices for proximal saphenous vein graft anastomoses: a clinical and angiographic evaluation

OBJETIVO: Relatar nossa experiência inicial com utilização do dispositivo mecânico para realização de anastomose aorta-safena. MÉTODO: Entre junho/2002 e maio/2003, 17 pacientes (pts) foram selecionados para emprego de anastomose mecânica, sendo 13 homens, com idade média de 64,4ñ9,4 anos, portadores de doença arterial coronariana. Foram realizadas 2,9ñ0,5 anastomoses/paciente, totalizando 49, sendo 19 com utilização de enxertos arteriais e 30 com veia safena. Dentre as pontes de veia safena, 11 (36,7 por cento) foram convencionais e 19 (63,3 por cento) utilizaram sutura mecânica (SM) aorto-safena. No período pós-operatório, foram analisados evolução clínica, alteraçäes enzimáticas e eletrocardiográficas, bem como estudo angiográfico das anastomoses. RESULTADOS: Dos 17 pts, a SM foi empregada em 16 (94,1 por cento). Utilizou-se circulação extracorpórea em 6 (37,5 por cento) dos 16 pts que receberam SM, com tempo médio de 102,9 ñ 16,9 minutos. A evolução pós-operatória foi satisfatória em todos os pts. No pós-operatório, não foram observadas alteraçäes isquêmicas ou IAM em nenhum paciente. O estudo angiográfico das anastomoses foi realizado em 9 (52,9 por cento) pts. As anastomoses da artéria torácica interna esquerda para ramo interventricular anterior apresentavam-se pérvias em 100 por cento dos casos. Das 15 anastomoses de veia safena estudadas, 11 (73,3 por cento) eram de SM e 9 (81,8 por cento) apresentavam-se pérvias. Todas anastomoses convencionais de veia safena estavam pérvias. Não se observou óbito hospitalar. No seguimento tardio, 88,2 por cento dos pacientes apresentam-se livres de eventos cardiovasculares. CONCLUSåES: A SM mostrou-se factível, mas é necessária uma análise mais ampla dos benefícios de sua utilização em relação ao tempo operatório, agressão ao paciente, perviabilidade do enxerto e custo final.

[Initial results on the use of mechanical devices for proximal saphenous vein graft anastomoses: a clinical and angiographic evaluation].

OBJECTIVE: To report on our initial clinical experience of the utilization of a mechanical anastomotic device (MAD) to perform saphenous vein graft to aorta anastomosis. METHOD: Between June 2002 and May 2003, 17 patients, including 13 male, with a mean age of 64.4 +/- 9.4 years, were selected for coronary artery bypass grafting using MAD. A total of 49 anastomoses, 19 arterial and 30 vein grafts, were performed with a mean of 2.9 +/-0.5 anastomoses per patient. Eleven (36.7%) vein-graft anastomoses were performed with conventional sutures and 19 (63.3%) using MAD. The clinical evolution, enzymatic and electrocardiographic alterations as well as an angiographic study were analyzed in the postoperative period. RESULTS: Of the 17 patients, the mechanical device was used on 16 (94.1%). Six (37.5%) patients were operated on under cardiopulmonary bypass with a mean time of 102.9 +/-16.9 minutes. The postoperative evolution was satisfactory in all patients. No patient presented with enzymatic, myocardial infarction or other ischemic electrocardiographic alterations in the immediate postoperative period. Early postoperative angiography was performed in 9 (52.9%) patients. The anastomoses of the left internal thoracic artery to left anterior descending artery were patent in all cases. Of the 15 saphenous vein grafts studied, 11 (73.3%) were performed using MAD, 9 (81.8%) of which were patent. All the 4 conventionally sutured vein anastomoses were patent. No hospital deaths occurred. In the late follow-up, 88.2% of the patients were free of cardiac-related events. CONCLUSIONS: MAD for vein graft-to-aorta anastomoses proved to be feasible, but a wider analysis of the benefits of its utilization regarding operative time, aggression to the patient, patency of the grafts and final cost are necessary.