Imaging Instrumentation Trends In Clinical Oncology
Introduction
The second leading cause of death worldwide is attributable to cancer, with 17 million new cases per year. One in three people gets impacted by cancer and just under 10 million succumb to cancer every year. The increasing trend of cancer is causing a significant burden on healthcare as the cost is driven by complex and long-lasting therapies. Diagnosis, treatment, patient workup, and care in addition to the loss of workforce are constantly rising and account for 10% or more of gross GDP with variations across countries. Hence the focus on early and accurate diagnosis in clinical oncology. Non-invasive detection of cancerous tissue through patient-specific morphology and functional molecular pathways has become the mainstay for referring oncologists to support therapy management decisions. Stand-alone anatomical and functional oncology imaging has moved towards integrating molecular image information through various methods, including anatometabolic imaging (PET/CT), advanced MRI, and optical or ultrasound imaging. There has been a steep increase in imaging compared to other physician-provided services.
Hybrid imaging methods
Non-invasive imaging yields anatomical information that enables the detection of cancerous tissue in vivo. If there is no morphological alteration, it is difficult to detect oncological diseases from plain anatomical images and can be identified by virtue of molecular and metabolic perturbations.
Nuclear medicine techniques, that rely on the tracer principle such as Positron Emission Tomography (PET) or Single Photon Emission Computed Tomography (SPECT) have taken center stage in the diagnostic management of cancer. Labelling minute amounts of a biomolecule of choice such as glucose with a radioactive isotope enable labelled biomolecules to be traced by means of emitted radiation without disturbing normal tissue function. Optical imaging makes use of fluorescent molecular probes and ultrasound of targeted microbubbles to highlight signaling pathways and differential anatomies respectively. Even though nuclear medicine imaging is highly sensitive and specific they yield images of tracer distribution that are of lower spatial resolution than CT or MRI owing to fundamental differences in detection principles of molecular and anatomical imaging. This has led to the emergence of hybrid imaging methods, that include the physical combination of PET and CT (PET/CT), SPECT and CT(SPECT/CT), or PET and MRI (PET/MRI). General practice is to support imaging with bioptic sampling to confirm the diagnosis. Time and accuracy of diagnosis and full understanding of cancer phenotype with a minimally invasive procedure is ideal and desired for precision medicine that enables the choice of appropriate therapy depending on the stage and biological features of the disease.
PET imaging and instrumentation trends
Noninvasive imaging technique such as PET provides visual and quantitative information on molecular pathways. Imaging is done following the injection of a radiotracer (biomolecule labelled with a neutron-deficient radioisotope). The positron travels a short distance before it annihilates termed the positron range. The spatiotemporal distribution and absolute concentration of the tracer are determined through the detection and reconstruction of annihilation events. PET detectors can now be manufactured with very fast scintillation materials and produced in modules for use in PET/CT and PET/MRI combinations. When designed with SiPM, it can improve spatial resolution and partial volume effects. TOF and advanced image reconstruction algorithms create flexibility in image protocol designs and help push the image quality even in low count situations which help in signifying even early time point measurements shortly after tracer injection and with parametric imaging. PET imaging in combination with CT and MRI, PET/CT, and PET/MRI provides suitable information augmenting clinical practice. The latest PET/CT permit shorter acquisition times, lower administered radiotracer amount, and easily repeated imaging of any region of the body. Therefore, transform PET imaging from a diagnostic tool to a screening tool. PET/MRI comparatively is evolving slowly. Read more here about Clinical Oncology