Various diagnostic assessments are required for detection and administration of most cancers of which imaging performs an necessary (pivotal) function in most cancers administration. Imaging has made fast strides previously few years with newer modalities and new indications getting added as time progresses. Molecular and metabolic imaging with 18F Flurodeoxyglucose Positron Emission Tomography (FDG PET) and different non-FDG isotopes has revolutionized oncologic imaging and adjusted our method in the direction of most cancers analysis, staging and surveillance. Newer indications get added to the literature. The main focus is to grasp the essential ideas of FDG PET imaging and know few of its medical functions in oncology Previously few a long time oncologists and oncosurgeons have tried to remedy many varieties of cancers or a minimum of present sufferers with an extended disease-free life, there was a spectacular parallel and supportive revolution in imaging analysis know-how. Presently, imaging performs a central function within the administration of all cancers. It’s used for screening, for preliminary analysis, to ascertain the extent and distribution of illness, for biopsy steerage, staging, prognostication, therapeutic planning, judging response to remedy and restaging. In oncology, the function of imaging has shifted from merely offering anatomical data to offering perception into tumor biology utilizing strategies similar to Computerized Tomography (CT) and Magnetic Resonance Imaging (MRI) perfusion imaging, MR spectroscopy and Positron Emission Tomography (PET) imaging. These strategies can show metabolic response to remedy which precedes anatomical adjustments. If there’s lower than optimum response to therapy then an earlier evaluation guides a change within the administration regime, thus avoiding the potential morbidities. PET-CT utilizing18 F-Flurodeoxyglucose (FDG) PET has in the previous couple of years has turn into a longtime modality within the administration of a number of cancers. It’s an imaging method that gives details about the useful and metabolic adjustments related to most cancers. PET scanning requires using molecules which might be labeled with radio nuclides. Quite a few such positron-emitting radio-isotopes exist and are utilized in medical experiments and analysis. Nevertheless, in medical follow the principal radio-isotope used is the positron-emitting 18 F-FDG which is a glucose analogue labeled with 18 F. The positron emitters together with 18 F FDG have brief half lives and are produced in cyclotrons. FDG is injected intravenously and is transported from the plasma to the cells by glucose transporters (GLUT 1 and GLUT 4). It then undergoes phosphorylation throughout the cell by the enzyme hexokinase and is transformed to FDG-6-phosphate. FDG-6-phosphate just isn’t metabolized and will get trapped within the cell. Most cancers cells show elevated glycolysis which is believed to be resulting from upregulation of glucose transporters and hexokinase and diminished ranges of glucose-6-phosphatase thus limiting additional metabolism of the tracer in most cancers cells. FDG PET and PET-CT play an necessary function within the 1. Preliminary analysis/analysis, particularly in malignancies/metastatic secondaries most significantly Lymphoma, Carcinoma Breast, Carcinoma Lung, Colorectal Most cancers; Malignant Melanoma
An FDG avid tissue visualized on the PET-CT scan helps us to localize metabolically lively lesion and act as information for FNAC/biopsy
2. Staging of the illness, 3. Assess response to therapy /Monitor response to remedy by semiquantitative SUV worth e.g affected person responding to therapy and people who don’t reply
Non Responder
Responder 4. Help in restaging of illnesses
5. Radiation therapy planning
6. Sooner or later assist in improvement of newer molecules for therapeutic function e.g
(newer anti most cancers medication) As with every different non invasive diagnostic modality PET-CT scan carried out with 18F-FDG too has its limitations as enumerated beneath. 1. Altered biodistribution of FDG associated to hyperglycemia and accompanying insulin improve within the physique causes regular glucose to competes with FDG for uptake in tumoral tissue thus causes lower uptake in tumor and improve background. Enhance insulin ranges within the physique following meals or insulin injection as in diabetics trigger insulin to push glucose and FDG in the direction of skeletal muscular tissues and myocardium inflicting lower uptake within the tumor and improve background. Therefore it is vitally necessary that affected person stays fasting for six – eight hours previous to the scan, as even a small amount of meals consumption previous to the scan can alter biodistribution of the FDG and trigger better diploma of false unfavorable scan. For diabetic sufferers on medicine require stringent protocol for an optimum scan outcomes, Bone marrow activation encountered in sufferers receiving bone marrow stimulating medication trigger FDG distribution in bone marrow considerably with little uptake within the tumoral tissue. 2. Mind sometimes reveals intense FDG uptake because it makes use of glucose solely, therefore lesions will be missed, thus PET-CT scans are normally carried out from base of cranium to mid thigh until indicated in any other case. 3. FDG is excreted by way of the kidneys into ureters and into the bladder,with the next tracer focus at these websites, lesions can’t be assessed with confidence at these anatomical websites. Not all malignancies and tumors are FDG avid .Poorly avid FDG tumors are Prostate, Bronchoalveolar carcinoma, neuroendocrine tumors, low grade sarcomas and NHL (Non Hodgkins Lymphoma). Additionally not all FDG avid tissue are malignant e.g. 1. An infection
2. Granulamatous lesions
3. Arthritis
4. Publish surgical procedure/radiotherapy
