Association between gastrin-releasing peptide receptor expression as assessed with [Ga]Ga-RM2 PET/CT and histopathological tumor regression after neoadjuvant chemotherapy in primary breast cancer.

Introduction: The gastrin-releasing peptide receptor is overexpressed in breast cancer (BC) tissue and can be visualized by positron emission tomography (PET) using the GRPR antagonist [Ga]Ga-RM2. This study assessed tumor binding of RM2 before and after neoadjuvant chemotherapy (NAC) in primary BC with reference to residual tumor size in the resected specimen.

Materials And Methods: In this retrospective study, five female patients with biopsy-confirmed estrogen receptor (ER)-positive primary BC (one with bilateral tumors) underwent [Ga]Ga-RM2 PET/CT before and after NAC.

Detection of Insulinomas Using Dual-Time-Point 68Ga-DOTA-Exendin 4 PET/CT.

Purpose: Insulinomas are predominantly benign neuroendocrine tumors originating from beta cells within the islets of Langerhans of the endocrine pancreas. Because surgical resection represents the only curative therapy option, exact tumor localization and discrimination of insulinomas from focal or diffuse manifestations of congenital hyperinsulinism are crucial for optimal treatment strategies. We investigated the diagnostic value of glucagon-like peptide 1 receptor PET/CT using Ga-DOTA-exendin 4 for detecting insulinomas and compared the diagnostic value of PET scans performed at 2 time points.

Results from extended lymphadenectomies with [In]PSMA-617 for intraoperative detection of PSMA-PET/CT-positive nodal metastatic prostate cancer.

Purpose: Identification of suspicious PSMA-PET/CT-positive lymph node (LN) metastases (LNM) from prostate cancer (PCa) during lymphadenectomy (LA) is challenging. We evaluated an In-labelled PSMA ligand (DKFZ-617, referred to as [In]PSMA-617) as a γ-emitting tracer for intraoperative γ-probe application for resected tissue samples in PCa patients. Forty-eight hours prior to LA, [In]PSMA-617 was administered intravenously in 23 patients with suspected LNM on PSMA-PET/CT (n = 21 with biochemical relapse, n = 2 at primary therapy).

Correction to: Effect of radiochemotherapy on T2* MRI in HNSCC and its relation to FMISO PET derived hypoxia and FDG PET.

Following the publication of this article [1], the authors noticed that figures 2, 3, 4 and 5 were in the incorrect order and thus had incorrect captions.

Effect of radiochemotherapy on T2* MRI in HNSCC and its relation to FMISO PET derived hypoxia and FDG PET.

Background: To assess the effect of radiochemotherapy (RCT) on proposed tumour hypoxia marker transverse relaxation time (T2*) and to analyse the relation between T2* and F-misonidazole PET/CT (FMISO-PET) and F-fluorodeoxyglucose PET/CT (FDG-PET).

Methods: Ten patients undergoing definitive RCT for squamous cell head-and-neck cancer (HNSCC) received repeat FMISO- and 3 Tesla T2*-weighted MRI at weeks 0, 2 and 5 during treatment and FDG-PET at baseline. Gross tumour volumes (GTV) of tumour (T), lymph nodes (LN) and hypoxic subvolumes (HSV, based on FMISO-PET) and complementary non-hypoxic subvolumes (nonHSV) were generated.

Performance of In-labelled PSMA ligand in patients with nodal metastatic prostate cancer: correlation between tracer uptake and histopathology from lymphadenectomy.

Purpose: Intraoperative identification of lymph node (LN) metastases (LNM) detected on preoperative PSMA PET/CT may be facilitated by PSMA radioguided surgery with the use of a gamma probe. We evaluated the uptake of In-labelled PSMA ligand DKFZ-617 (referred to as In-PSMA-617) in unaffected LN and LNM at the level of single LN.

Methods: Six patients with prostate cancer (PCa) with suspicion of LNM on preoperative PSMA PET/CT underwent In-PSMA-617-guided lymphadenectomy (LA; four salvage LA and two primary LA).

The somatostatin receptor 2 antagonist 64Cu-NODAGA-JR11 outperforms 64Cu-DOTA-TATE in a mouse xenograft model.

Copper-64 is an attractive radionuclide for PET imaging and is frequently used in clinical applications. The aim of this study was to perform a side-by-side comparison of the in vitro and in vivo performance of 64Cu-NODAGA-JR11 (NODAGA = 1,4,7-triazacyclononane,1-glutaric acid,4,7-acetic acid, JR11 = p-Cl-Phe-cyclo(D-Cys-Aph(Hor)-D-Aph(cbm)-Lys-Thr-Cys)D-Tyr-NH2), a somatostatin receptor 2 antagonist, with the clinically used sst2 agonist 64Cu-DOTA-TATE ((TATE = D-Phe-cyclo(Cys-Tyr-D-Trp-Lys-Thr-Cys)Thr). In vitro studies demonstrated Kd values of 5.

Morphologically 'invisible' proinsulin - secreting adenoma detected by Ga-68 Exendin-4 (GLP-1 Receptor) positron emission tomography/CT.

This case report of a young man suffering from recurring hypoglycaemia illustrates a rare condition of a neuroendocrine tumour, predominantly secreting proinsulin and invisible to conventional imaging approaches. Only a GLP-1 receptor PET/CT using Exendin-4 visualized the pancreatic lesion and enabled curative therapy, confirming the diagnostic value of this tracer for detection of neuroendocrine tumours. As only few publications on this topic are available, an overview of the available data is also given.

Strong PSMA Radioligand Uptake by Rectal Carcinoma: Who Put the "S" in PSMA?

We present a case of a 71-year-old patient with newly diagnosed rectal adenocarcinoma and hepatic metastases. Restaging after chemotherapy revealed a good response of the rectal primary while liver metastases were progressive. As the patient also had a history of prostate cancer, a Ga-PSMA-HBED-CC PET/CT scan was performed to noninvasively further assess hepatic metastases.

Gastrin-releasing Peptide Receptor Imaging in Breast Cancer Using the Receptor Antagonist (68)Ga-RM2 And PET.

Introduction: The gastrin-releasing peptide receptor (GRPR) is overexpressed in breast cancer. The present study evaluates GRPR imaging as a novel imaging modality in breast cancer by employing positron emission tomography (PET) and the GRPR antagonist (68)Ga-RM2.

Methods: Fifteen female patients with biopsy confirmed primary breast carcinoma (3 bilateral tumors; median clinical stage IIB) underwent (68)Ga-RM2-PET/CT for pretreatment staging.

Evaluation of intraocular pressure elevation in a modified laser-induced glaucoma rat model.

The main drawbacks of currently described pressure induced glaucoma animal models are, that intraocular pressure (IOP) either rises slowly, leading to a heterogeneous onset of glaucoma in the treated animals or that IOP normalizes before significant damage occurs, necessitating re-treatment. Furthermore, a variable magnitude of IOP increase often results when particles are introduced into the anterior chamber. In order to develop a simple and reproducible rat glaucoma model with sustained IOP elevation after a single treatment we induced occlusion of the chamber angle by anterior chamber paracentesis and subsequent laser coagulation of the limbal area with 35, 40 or 45 laser burns.

Preconditioning with inhalative carbon monoxide protects rat retinal ganglion cells from ischemia/reperfusion injury.

PURPOSE. Retinal ischemia/reperfusion (I/R) injury damages retinal neurons. Carbon monoxide (CO) recently attracted attention as cytoprotective because of its anti-inflammatory and antiapoptotic effects.