Nuclear Medicine

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Diagnostics imaging of lungs, brain, thyroid, stomach, salivary glands, liver, kidney, bone, heart adrenal glands as well as sites of occult infection is achieved using a sophisticated Gamma Camera with tomographic facilities linked to the computer system department offers both diagnostic and therapeutic services. Nuclear Medicine increases the depth of diagnostic orkup to accurately and precisely monitor treatment and patient progress.

THE MOST MODERN MEDICAL SPECIALITY, WHICH IS SAFE, PAINLESS, NON INVASIVE AND COST EFFECTIVE, USING RADIO NUCLIDES OF ADEQUATE HALF LIFE SUCH AS 99MTC 123 I, 131 I ETC. NOT ONLY FOR DIAGNOSTIC PURPOSE BUT ALSO FOR THERAPPY

The way it developed

-Originated from notably the discovery of artificial radioactivity in 1934 - first clinical use of artificial radioactivity was in 1937 for a patient of leukemia (blood cancer) at the UNIVERSITY OF CALIFORNIA in UNITED STATE OF AMERICA. -and in 1946 it was used for thyroid patients with amazing results.

Salient features

• safe ,painless and cost effective .
• unique in giving physiological details.
• almost all organs can be imaged.
• early detection of fractures and tumors are possible .
• even hairline fractures can be easily detected.
• therapy is simple procedure and very much cost effective.
• the dose for therapy can be easily determined using nuclear scan itself.
• the most developing field in imaging procedures.
• the most used field in cancer evaluation and follow-up.

Salient features

• One of the first Nuclear scanning centers in India
• Carrying out almost all procedures available in nuclear medicine field
• One of the few centers which do “venogram “ to study the blood flow and hence potency of superficial and deep veins and to find out thrombosis
• One of the few centers which carry out RIA &IRMA technique with thyroid scinti scan for accurate diagnosis and quantitative study
• Diagnosis is cost effective
• Availability of service at any time as the patient’s requirement
• Widely accepted quality of scan and of reporting
• Availability of facilities like x ray ,MRI,CT etc if any comparative study required
• Availability of therapy facilities for thyroid cancer, thyrotoxicosis ,hyperthyroidism ,bone pain in cancer patients etc.

We are equipped with

• DICOM camera of SIEMENS, America
• Various types of collimator facilities for iodine scan, technetium scan, gallium scan etc
• Apple Macintosh computer for acquisition -Well equipped RIA lab to do T3,T4, TSH, FreeT3,FreeT4 and also PSA,LH,FSH etc. etc.

Tc 99 m - Technetium-99

chemical symbol Tc-99, is a silver-gray, radioactive metal. It occurs naturally in minute amounts in the earth's crust, but is primarily man-made. All isotopes of technetium are radioactive. The most commonly available isotope is Tc-99m (called metastable Tc-99) and is the shorter-lived parent of Tc-99.

Technetium in the form of technetium-97 was discovered in 1937 by Emilio Segré and Carlo Perrier at the University of California - Berkeley. Technetium-99m, one of the most common isotopes used in modern
medicine, was developed by Glenn T. Seaborg and Emilio Segré.

properties of technetium-99

Technetium-99 is silver-gray, radioactive metal. It occurs naturally only in very small amounts. Its melting point is 3,942 °F and its boiling point is 8,811 °F. It is also a very dense material--at room temperature, a measure
of technetium-99 weighs 11.5 times as much as an equal volume of water. Technetium-99 has a radioactive half-life of 212,000 years. Technetium- 99m (called metastable Tc-99) decays to Tc-99 primarily by gamma
emission, and has a half-life of only about 6 hours. Technetium-99 decays to form ruthenium-99, which is stable, by emitting beta and gamma radiation.

uses of technetium-99

Technetium-99 has no significant industrial use. Technetium-99 is found in the radioactive wastes from defense-related government facilities, nuclear reactor and fuel cycle facilities, academic institutions, hospitals, and research establishments. Its short-lived parent, Tc-99m, however, is the most widely used
radioactive isotope for medical diagnostic studies.

Different radiopharmaceuticals are used to produce images from almost all regions of the body:

Part of the Body	Example Radiotracer
Brain	99mTc-HMPAO
Thyroid	Na99mTcO4
Lung (Ventilation)	133Xe gas
Lung (Perfusion)	99mTc-MAA
Liver	99mTc-Tin Colloid
Spleen	99mTc-Damaged Red Blood Cells
Pancreas	75Se-Selenomethionine
Kidneys	99mTc-DMSA

Note that the form of information obtained using this imaging method is mainly related to the physiological functioning of an organ as opposed to the mainly medicine therefore provides a different perspective on a disease condition and generates additional information to that obtained from X-ray images.

Early forms of imaging system used in this field consisted of a radiation detector (a scintillation detector for example) which was scanned slowly over a region of the patient in order to measure the radiation intensity emitted from individual points within the region. One such device was called the Rectilinear Scanner. Such imaging systems have been replaced since the 1970s by more sophisticated devices which produce images much more rapidly. The most common of these modern devices is called the Gamma Camera and we will consider its construction and mode of operation below.

GAMMA CAMERA

The basic design of the most common type of gamma camera used today was developed by an American physicist, Hal Anger and is therefore sometimes called the Anger Camera. It consists of a large diameter NaI(Tl) scintillation crystal which is viewed by a large number of photomultiplier tubes. A block diagram of the basic components of a gamma camera is shown below:

The crystal and PM Tubes are housed in a cylindrical shaped housing commonly called the camera head and a cross-sectional view of this is shown in the figure. The crystal can be between about 25 cm and 40 cm in diameter and about 1 cm thick. The diameter is dependent on the application of the device. For example a 25 cm diameter crystal might be used for a camera designed for cardiac applications while a larger 40 cm crystal would be used for producing images of the lungs. The thickness of the crystal is chosen so that it provides good detection for the 140 keV gamma-rays emitted from 99mTc - which is the most common radioisotope used today.

Scintillations produced in the crystal are detected by a large number of PM tubes which are arranged in a two-dimensional array. There is typically between 37 and 91 PM tubes in modern gamma cameras.

The gamma camera can therefore be considered to be a sophisticated arrangement of electronic circuits used to translate the position of a flash of light in a scintillation crystal to a flash of light at a related point on the screen of an oscilloscope. In addition the use of a pulse height analyser in the circuitry allows us to translate the scintillations related only to photoelectric events in the crystal by rejecting all voltage pulses except those occurring within the photopeak of the gamma-ray energy spectrum.

Some photographs of gamma cameras and related devices are shown below:

A single-headed gamma camera	Another single-headed gamma camera	The NaI crystal of a gamma camera
The cathode ray oscilloscope (CRO) of a gamma camera	The image processing system of a gamma camera	A dual-headed gamma camera
Another view of a dual-headed gamma camera	The image acquisition and processing console of a dual-headed gamma camera

We will continue with our description of the gamma camera by considering the construction and purpose of the collimator.

COLLIMATION

The collimator is a device which is attached to the front of the gamma camera head. It functions something like a lens used in a photographic camera but this analogy is not quite correct because it is rather difficult to focus gamma-rays. Nevertheless in its simplest form it is used to block out all gamma rays which are heading towards the crystal except those which are travelling at right angles to the plane of the crystal:

Diagram of parallel-hole collimator attached to a crystal of a gamma camera. Obliquely incident gamma-rays are absorbed by the septa.

A representative selection of nuclear medicine images is shown below

A SPECT slice of the distribution of 99m-Tc Ceretec within a patient's brain	A SPECT slice through a patient's liver	Images from a patient's bone scan.
A PET slice of a patient's brain, with a region of interest drawn to indicate the skin surface.	Images from a ventilation (V) and perfusion (Q) scan of a patient's lungs.	A 201Tl study of the whole body of a patient.
A series of planar images acquired every 10 seconds during a renogram of a patient with a stone blocking their right kidney	Selected images from a renogram series.	A graphical display showing the number of counts in each kidney versus time for a renogram
A SPECT slice of a patient's heart.	A blood pool study covering the whole body of a patient.	A series from a SPECT study of a patient's brain.
Images from a SPECT study of a patient's heart.	A thyroid uptake study.	A gastric-emptying study evaluating a patient's digestive system.

EMISSION TOMOGRAPHY

The form of imaging which we have been describing is called Planar Imaging. It produces a two-dimensional image of a three-dimensional object. As a result images contain no depth information and some details can be superimposed on top of each other and obscured or partially obscured as a result. Note that this is also a feature of conventional X-ray imaging.

The usual way of trying to overcome this limitation is to take at least two views of the patient, one from the front and one from the side for example. So in chest radiography a posterio-anterior (PA) and a lateral view can be taken. And in a nuclear medicine liver scan an antero-posterior (AP) and lateral scan are acquired.

This limitation of planar X-ray imaging was overcome by the development of the CAT Scanner about 1970 or thereabouts. CAT stands for Computerized Axial Tomography or Computer Assisted Tomography and today the term is often shortened to Computed Tomography or CT scanning

The equivalent nuclear medicine imaging technique is called Emission Computed Tomography. We will consider two implementations of this technique below.

1. Single Photon Emission Computed Tomography (SPECT) This SPECT technique uses a gamma camera to record images at a series of angles around the patient. These images (click here for an example) are then subjected to a form of digital image processing called Image Reconstruction in order to compute images of slices through the patient.

A comparison of these image reconstruction techniques is shown below for a slice through a ventilation scan of a patient's lungs:

OUR FEW PROCEDURES

We are one of the few centers in India doing almost all the nuclear scanning modalities and our quality of scans and reporting is widely accepted as the best

We are carrying out Dynamic –Static Imaging Procedures ,SPECT Procedures, RIA &IRMA Techniques for T3,T4,TSH>Free T3, Free T4, L.H etc, etc. to make our reports the best both quantitatively and qualitatively

NUCLEAR CARDIOLOGY

• Nuclear Cardiology is one of the3b fast developing field in nuclear medicine to Diagnosis Myocardial Perfusion, Myocardial ischemia ,infract, cardiac blood pool etc
• We are one among the few centers in India using 201 TL (thallous chloride) Red9istribution property for Myocardial imaging ,Which is highly physiological compared to other radio-nuclides in use.
• We have the facility of 99m Tc- labeled Tetrofosmin or sesta MIBI for Cardiac wall motion abnormality detection.
• SPECT imaging procedure which can be further processedvand quantitative values like Ejection Fraction (both Regoional and Global ) can be calculated
• First pass study of heart to detect the potency and size of right ventricle
• MUGA or Multi gated Analysis is another technique in use to evaluate cardiac blood pool and to calculate Ejection Fraction.
• Cardiac Shunt ,is one of the commonest disease in children which is duiagn9oosed by us using First Pass study
• Stress-Rest protocol, is available both using 201 TL and 99m Tc radio-pharmaceuticals to differentiate Myocardial ischemia and Infract ,which 9s unique of Nuclear Medicine
• Common procedure which we are using to exercise patients is T.M.T(Tread Mill Test) which is helpful in determining Rest and stress ECG, Heart Rate ,Myocardial Oxygen Demand etc.
• For those patients who are unable to exercise or are known case of coronary artery disease (CAD) we have the provision of Pharmacological stress using Adenosine, Dypyramidole, Dobutamine etc.

RADIONUCLIDES IN ASSESSING RENAL DISORDERS

It is well known about the use of radio-nuclides in assessing renal function, position, shape and size and it is one of the most commonly used technique in nuclear medicine

• Renal cortical Scan can evaluate not only the size, shape and position of the kidney but the scars in the cortex and quantitatively the renal differential function can be accurately determined.
• The physiology of Kidneys can be evaluated by renogram analysis both quantitatively and qualitatively which will give the GFR of each Kidneys ,Global GFR etc.
• The excretory phase of renogram is valuable to assess the obstruction in VUJ (Vesico Ureteric Junction) and PUJ(Pelvic Ureteric Junction)
• Diuretic Renogram Analysis which is used by us is a provocative method to evaluate dilation with out Obstruction and obstructed Nephropathy.
• We evaluate the renal hypertension using Captopril Renogram Method
• To evaluate the volume of Residual urine and Vesico –Ureteric Reflux common in babies, we are carrying out Direct Micturation Renogram // Direct Radio nuclide Cysto urography which is known for its higher sensitivity compared to other similar scans.

LUNG VENTILLATION_PERFUSION STUDIES

Using Radio-nuclides we are carrying out both ventilation study to know the airways to lung and perfusion study to know the perfusion of blood to the lobes of lungs and also Lung ventilation-Perfusion Study which is the most helpful method to evaluate PULMONARY ENMBOLISM (P.E) ,one of the three commonest cause of death due to disease in European Countries ,for the evaluation of which no other tests are possible. We are proud to say that which is being carried out by as here and have accurately diagnosed the cases .

• Not only Pulmonary Embolism but also Parenchymal Lung Disease, Pulmonary Odema , Tuberculosis are being diagnosed by this non-invasive technique.
• The scan is also helpful to calculate quantitatively the Ventilation- Perfusion Ratio.

WHOLE BODY AND REGIONAL SKELETAL SCINTIGRAPHY

Nuclear Medicine procedures are the common methods in detecting bone tumors either benign or malignant .bone metastasis ,bone fracture which we are carrying out in our center

• With the aid of this procedure the whole body skeleton can be imaged easily and the spot views if required of the suspected area scan also be acquired
• Bone Scan is helpful to find out even hairline fractures which is unique of our procedure.
• Nuclear Medicine bone scan is kn0own for early detection of lesion and fracture.
• Bone scan helps to assess the response to therapy in cancer patients to know the spread of disease.
• Three phase bone scan procedure is also available to differentiate Cellulitis and Sinusitis from actual bone lesions
• Quantitative approaches are being used in bone scan and also in Joint Imaging such as Whole body Retention (W.B.R) if Renal Function is proper, Segmental Comparison for accurate idea about Growth Plate Pathology, Sacro-Iliac Joint Index Calculation etc.

LIVER – SPLEEN IMAGING & CHOLESCINTIGRAPHY

• Liver, the largest solid organ in body, having two types of vascular supply such as Hepatic and Portal supply and Spleen consisting of Reticulo Endothelial cells can be easily imaged using various techniques available in Nuclear Medicine.
• The size,shape ,position and omas of liver and spleen like Hepatoma, Hematoma, Spleenomegal;y etc. etc. can be easily detected
• The blood perfusion to the liver by Hepatic and Portal supply can be studied using Dynamic Imaging Techniques that we are using here.
• Not only the potency of Kuffer Cells or Reticulo endothelial cells but also Hepatic cells efficiency can also be detected
• Imaging of the working ability of hepatis Cells usually termed as Cholescintigraphy , detects function aspects of hepatocites, biliary tree potency ,Gtall bladder ejection fraction, biliarry atresia etc.
• Using quantitative methodes even the differentiation of neonetal hepatitis and biliary atresia is possible.
  
• The working condition of gall bladder is being evaluated and quantitatively the Ejection Fraction of Gall Bladder is calculated.

IMAGING OF CENTRAL NERVOUS SYSTEM INCLUDING BLOOD BRAIN BARRIER,BLOOD FLOW TO

• BRAIN AND CEREBRO -–SPINAL FLUID (C.S.F)

Blood Brain barrier is the name given yto the junction of capilliary walls , Neuroglea and Nerve Cells ,which constitute a barrier to the passage of compounds unnecessary to brain metabolism and thus limit the movement of potentially toxic substansae from blood to brain.hence the potency determination of B>B>B is very important which will be disturbed in many caqses such as fracture , brain tumor etc.