PET Scan Test in the Modern Oncology
In current medicine there is a growing need to identify (diagnose) the presence of a disease as soon as possible, even before the onset of symptoms or when these are minor. This serves to initiate or complete the diagnostic process and proceed with the initiation of treatment.
The next step in the therapeutic management of a process is to determine the level of the response reached with the treatment (s) and assess the patient's evolutive situation throughout the course of their illness, including the possibility of a subsequent relapse in case of responses positive The use of diagnostic imaging techniques that are based on morphological data, despite its high precision, often presents a limited diagnostic capacity, very specifically when the assessment of the response refers to oncological treatments.
These techniques define the response to treatment as a reduction in tumor size, without considering other elements of the malignant process, generally of earlier onset, such as functional changes or modifications at the cellular and / or molecular level, which may even be independent of the morphological changes.
In this line we have at present the positron emission tomography (PET), an imaging technique able to obtain non-invasive information about the cellular metabolism. There are also other molecular imaging techniques such as magnetic resonance (MR) spectroscopy, but with a diagnostic performance lower than PET.
The most widely used radiotracer in PET is 18F-fluoro-deoxyglucose (FDG), which shows the activity of intracellular glucose metabolism, highly useful information for the diagnostic identification of malignant processes and which can, at the same time, contribute to the forecast individually.
In Oncology, this ability to determine the metabolic activity of tissue glucose in vivo allows PET to identify malignant tumor lesions as hypermetabolic zones in areas with an increased concentration of the radiotracer.
There are numerous studies on the use of pet CT scan in Delhi with 18F-FDG that have shown that this technique has a diagnostic accuracy clearly superior to other conventional imaging techniques and the information obtained by PET leads to a change in the diagnostic-therapeutic attitude of patients in more than 30% of cases.
Recently, new equipment has been developed in which the PET technique is associated with the morphological image of the CT scan, called PET-CT that includes hybrid systems consisting of a PET camera with a multislice CT scan. This system is capable of acquiring images of the whole body more quickly, with a more accurate correction of attenuation and with a fusion of images of optimal quality.
In addition they allow to determine the anatomical location of the tumors in a more precise way, what au the accuracy of the technique. Since the first prototype of PET-CT was developed in 1998 and the first equipment for clinical use was launched, PET-CT has become the fastest growing image technique in the world, according to recent data provided by the industry, with nearly 1000 equipment installed in 2006.
PET is a technique widely implemented in clinical oncology for the diagnosis and staging of neoplastic diseases, but it is also very useful in the assessment of the response to treatment.
