 greetings to everyone on the occasion of 125th anniversary of Ranjan. Konrad Ranjan was a physicist working on vacuum tubes where on 8th of November 1895, that is exactly 125 years back, he happened to accidentally find that all the films that he had stored in his dark room were getting spoiled and he thought that there must be something which led to the discovery of the so-called x-ray of today, which are invisible rays and this discovery, accidental discovery of Ranjan led to various imaging modalities that we are seeing and it has helped the patients tremendously and initially this only could image the bony structures because the soft tissue could not be appreciated that well and parallely there was also a development which was occurring using the radioisotopes which we call it as that is the nuclear medicine where they were administering radioactive material and trying to see or trace those material using initially a rectilinear scanner subsequently it developed into gamma camera where the large crystal was used to detect these radioisotopes where it was all going in the patient's body after it was injected or administered orally and they could trace it entry of the computers to medical field tremendously helped in imaging lot of pathologies in the patients in 1973 Hounsfield who was also an engineer working on various imaging processing he thought why not we bring the the nuclear medicine diagnostic scintillating crystal and the x-ray tube that is a nice marriage between the nuclear medicine and the radiology which led to the discovery of CT scanner and with CT scanner coming into medical field it has tremendously made things easy for diagnosis which was not possible earlier only on the operation table or on an autopsy table people used to see the pathologies subsequently people came out with positron emitters this particular positron emitters led to the discovery of PET scanner positron emission tomographic scanner and subsequently people thought why not we combine the benefit of CT scanner and the PET scanner which is today called as PET CT which helps both the anatomical diagnosis that is morphology and also functional aspect of the pathology how it is behaving and what are the effects all that can be seen today you have the PET CT scanner which is commonly used in diagnosis and management of various cancer patients or cancerous lesions which is helping both the functional and also the anatomical changes that we can see in the patients this is about the imaging techniques that are there using the ionizing radiation that is either the x-ray or the isotope which is emitting gamma rays but without these ionizing radiation there are also other modalities which have come up that is the MRI magnetic resonance imaging where one does not use any of the ionizing radiation here only patient is placed in a high field magnet and the patients own hydrogen atoms which are there in the body that is the water has got the hydrogen those atoms are imaged using the high field magnet and also trying to produce an image of the soft tissues which are of diagnostically very accurate and of great quality so the MRI is very beneficial and also to treat parallely there is also using the high frequency sound waves which are called as ultrasound they are also used in diagnosis and imaging of soft tissue pathologies in the patients so these two that is MRI and the ultrasound do not use ionizing radiation it is not that one imaging modality can replace the other all these are complementary to each other not competitive to one another a patient may come with a pain abdomen and the easily available and less expensive investigation is going to be an ultrasound and he may be advised to undergo an ultrasound and during the ultrasound one may find that a particular patient has got a tumor in his soft tissue that is either in the kidney or in the liver then he may be asked to undergo a CT scan so CT scan will give much more details compared to an ultrasound and if the suspicion becomes it is a malignancy then for treating that patient one may have to do a pet CT to see whether that particular tumor has got localized to that particular organ or it has spread to other parts of the body where you require a pet CT scan so the utilization of the appropriate imaging modality helps in diagnosis and management of the patients which is best decided by the treating clinician