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Abstract: A 73-year-old man with metastatic pancreatic neuroendocrine tumor was evaluated with 68 Ga-DOTATATE PET/CT for peptide receptor radionuclide therapy. Both PET-positive and negative lesions were seen in the liver, along with extrahepatic metastases. Histopathology was obtained from one of the PET-negative liver lesions to exclude secondary malignancy. Histology confirmed a well-differentiated (G2) metastasis of pNET with high somatostatin receptor expression. We initiated peptide receptor radionuclide therapy with close monitoring of the PET-negative liver metastases. We present a rare case, where posttherapeutic scintigraphy revealed vigorous uptake of 177 Lu-DOTATATE even in the 68 Ga-DOTATATE PET-negative liver metastases. Follow-up PET/CT showed a partial response to therapy., Competing Interests: Conflicts of interest and sources of funding: none declared., (Copyright © 2023 Wolters Kluwer Health, Inc. All rights reserved.)

Prostate-specific membrane antigen (PSMA)-targeted PET/CT has become a fundamental tool in the management of patients with prostate cancer, especially to rule out local recurrence after surgery or radiation. However, the assessment of the prostatic fossa is difficult due to the renal excretion of PSMA-targeted radionuclides. PET/CT studies using Ga-PSMA-11 PET/CT and F-PSMA-1007 of a 61-year-old man after radical prostatectomy are presented. This case illustrates that F-PSMA-1007 is an ideal radionuclide for the detection of local recurrence of prostate cancer and is superior to Ga-PSMA-11, especially in case of pelvic lesions.

PET using the radiotracer F-fluorodeoxyglucose (FDG) was performed in a patient who presented with elevated thyroglobulin (Tg) levels several years after initial therapy of follicular thyroid carcinoma (oncocytic variant) and in whom high-dose radioiodine (I) failed to locate recurrent tumor or to decrease Tg levels. A focal fluorodeoxyglucose uptake in the apical septum of the heart did not have a discernible correlate in echocardiography or MRI for more than 12 months. Finally, a metastasis of the follicular thyroid carcinoma with partly squamous cell differentiation was confirmed and treated by resection and stereotactic body radiotherapy.

Radiolabeled ligands targeting prostate-specific membrane antigen (PSMA) are currently being established. Prostate-specific membrane antigen radioligand therapy with Lu-PSMA-617 is a promising treatment in metastasized castration-resistant prostate cancer with high efficacy and safety and seems to prolong progression-free survival and overall survival. We present Ga-PSMA PET/CT images during and after 2 therapy courses, including each 4 cycles of Lu-PSMA-617, and prostate-specific antigen-level history of a 77-year-old heavily pretreated patient with metastasized castration-resistant prostate cancer.

Meningiomas are typically benign solitary intracranial tumors. Atypical (World Health Organization [WHO] grade II) or malignant/anaplastic (WHO grade III) meningiomas are seldom, and distant metastases occur only in rare exceptions. We present a case of a 54-year-old male patient with atypical (WHO grade II) meningioma who underwent 1 cycle of peptide receptor radionuclide therapy. Previous imaging studies were confined to the head, but posttherapeutic whole-body Lu-DOTATATE scintigraphy revealed thoracic uptake arising from previously undetected pulmonic meningioma metastases. The case highlights the importance of consideration of rare/untypical metastatic sides and the value of radiotracer whole-body imaging in identifying these.

The classification of thyroid nodules in children is often difficult, especially in pretreated patients with metastatic disease. In osteosarcoma patients, Tc-MDP SPECT/CT is used for primary and follow-up staging. Bone and soft tissue metastases can be revealed because of Tc-MDP imaging of osteoid-producing metastases. We present Tc-MDP SPECT-CT, CT, and ultrasound images of a highly suspicious calcified thyroid lesion in a 17-year-old boy with osteosarcoma. High uptake in Tc-MDP SPECT-CT provides diagnosis of thyroid metastasis of osteosarcoma, which was proven by histopathology.

Recently radiolabeled ligands targeting prostate specific membrane antigen (PSMA) have been introduced for diagnostics and treatment of prostate cancer. Labeled with Lutetium, PSMA radioligand therapy (RLT) is one of the most promising new treatments of metastatic castration refractory prostate cancer. We present images of Ga-PSMA PET/CT and parameters of response of a 75-year-old heavily pretreated metastatic castration refractory prostate cancer patient with extended bone metastases, showing an extraordinary biochemical response in PSA-levels concordant to SUV decline in bone metastases. Furthermore, this case shows that CT is of no use in assessing response in bone metastases of prostate cancer.

A 66-year-old man with castration-resistant prostate carcinoma and multiple symptomatic bone mestastases was considered for Ra-dichloride (Xofigo) therapy. Staging with Ga-PSMA-PET/CT revealed additional extensive tumor involvement of the spine without relevant uptake in bone scintigraphy. Based on this imaging result, the patient was rescheduled for a PSMA-targeted therapy. Additional Ga-PSMA-PET/CT may have a considerable benefit for patients considered for Xofigo.

A 65-year-old man with disseminated bone metastases of prostate cancer was referred for Ga-PSMA-HBED-CC-PET/CT (short PSMA-PET/CT) to exclude visceral metastases before treatment of bone metastases with Ra-dichloride. Apart from disseminated bone metastases, PSMA-PET/CT revealed a focal cerebral tracer uptake in the right frontal lobe highly suspicious for cerebral spread. According to patient history, a cerebral infarction occurred 14 days before PSMA imaging in corresponding localization confirmed by MRI scanning. This case demonstrates the possibility of false-positive finding of cerebral metastases in PSMA-PET early after stroke.

Background: Despite progress in treatment of metastatic castration-resistant prostate cancer (mCRPC), new approaches are urgently needed. Recently theranostic concepts using radiolabeled ligands of the prostate-specific membrane antigen (PSMA) have been developed for diagnostics and therapy of patients with advanced mCRPC. The aim of this study was to evaluate tumor response, adverse effects, and survival in patients undergoing radioligand therapy with Lu-PSMA-617., Methods: Fifty therapies using Lu-PSMA-617 were performed in 28 consecutive patients with mCRPC and exhausted conventional therapeutic options (median age, 73.4 years; range, 45-87 years). Data were retrospectively analyzed with focus on response, safety, and survival. The median overall survival was compared with that of a recent historical patient cohort treated with best supportive care prior to availability of Lu-PSMA-617., Results: Any PSA decline occurred in 59% and 75% of patients after 1 and 2 therapies. Moreover, a PSA decline of 50% or greater occurred in 32% and 50%. Therapies were well tolerated. Hematologic and renal parameters changed insignificantly; permanent xerostomia or other safety-related toxicity did not occur. The estimated median survival was 29.4 weeks, significantly longer than survival in the historical best supportive care group (19.7 weeks [hazard ratio, 0.44; 95% confidence interval, 0.20-0.95]; P = 0.031)., Conclusions: Results from 50 therapies show that radioligand therapy with Lu-PSMA-617 is effective and well tolerated and seems to increase overall survival. A future randomized controlled prospective study will be necessary to confirm these results.

Acute renal failure (ARF) due to bilateral parenchymal infiltration of a high grade malignant non-Hodgkin B-cell lymphoma is exceptional. Early identification of this pathology causing ARF is critical as early induction therapy with cyclophosphamide and prednisone often leads to a substantial recovery of kidney function. This striking case illustrates the usefulness of noninvasive fluoro-deoxy-glucose positron emission tomography/computed tomography as a functional imaging modality demonstrating not only the cause of unexplained ARF but also its convenience for the restaging management of non-Hodgkin lymphomas during complete remission.