Molecular imaging for cancer diagnosis and surgery

Abstract

Novel molecular imaging techniques have the potential to significantly enhance the diagnostic and therapeutic approaches for cancer treatment. For solid tumors in particular, novel molecular enhancers for imaging modalities such as US, CT, MRI and PET may facilitate earlier and more accurate diagnosis and staging which are prerequisites for successful surgical therapy. Enzymatically activatable “smart” molecular MRI probes seem particularly promising because of their potential to image tumors before and after surgical removal without re-administration of the probe to evaluate completeness of surgical resection. Furthermore, the use of “smart” MR probes as part of screening programs may enable detection of small tumors throughout the body in at-risk patient populations. Dual labeling of molecular MR probes with fluorescent dyes can add real time intraoperative guidance facilitating complete tumor resection and preservation of important structures. A truly theranostic approach with the further addition of therapeutic agents to the molecular probe for adjuvant therapy is conceivable for the future.

Evaluation of a Fluorescent and Radiolabeled Hybrid Somatostatin Analog In Vitro and in Mice Bearing H69 Neuroendocrine Xenografts

“…in DMF. After subsequent deprotection of the N terminus, DTPA (tBu) 4 (1.3 eq.) was coupled overnight using PyBOP (1.3 eq.…”

“…Nevertheless, radioguidance can neither determine tumor margins nor identify small metastases accurately (4,10). The poor visual discrimination between tumor and healthy tissues raises the chance of an incomplete resection, associated with disease progression or recurrence (10).…”

“…They have been used successfully in diagnosing patients with NET using nuclear imaging technologies, such as SPECT or PET, in combination with CT. They have also been used successfully for peptide receptor radionuclide therapy in patients with metastasized disease (2,3), although surgical resection of the tumor tissue, if possible, is the preferred treatment for NET (4,5).…”

Noninvasive Detection and Imaging of Matrix Metalloproteinases for Cancer Diagnosis

“…MRI offers high spatial resolution and excellent anatomical detail without any exposure to radiation, however, its sensitivity is inferior to that of optical and radiolabeled imaging. MRI contrast agents do not directly generate a signal but are detected through their ability to shorten the water proton relaxation time, that is, the longitudinal relaxation time (T 1 -weighted) and transverse relaxation time (T 2 -weighted) [59]. In a T 1 -weighted MRI image, T 1 -shortening results in positive contrast (bright spots), whereas in a T 2 -weighted MRI image, T 2 shortening generates negative contrast (dark areas).…”

Neuroradiology and Histopathology in Two Cases of Adult Medulloblastoma

“…The translation of this tissue-based molecular classification to molecular imaging strategies or techniques can bring therapeutic and prognostic knowledge prior to surgery, which can produce better treatment outcomes. The development of specific diffusible probes (antibodies or peptides), ligated to contrast agents, is under investigation 17,18 . Extension studies must be performed in the management of this high-grade CNS tumour due to its tendency to disseminate to cerebrospinal fluid (CSF) and different meningeal locations.…”