swastika Renal Scan nuclear medicine .pptx

renal scan

1. Nuclear Medicine Procedure o f Renal Scan Swastika pandit B.Sc.MIT 3 rd year NAMS, Bir hospital

2. Contents Introduction Terminologies Anatomy Indications Contraindications Radiopharmaceuticals Different types of Renal studies Patient preparation Procedure Aftercare References

3. Introduction Nuclear Medicine is “The branch of medicine that deals with the use of radioactive substances in research, diagnosis, and treatment .”It  is a specialized area of radiology that uses very small amounts of radioactive materials, or radiopharmaceuticals, to examine organ function and structure.( https :// www.dictionary.com )   N uclear medicine renal scan  uses radiopharmaceuticals ( radioactive  medications) injected into a vein, usually in the arm, to provide clear images of the  kidneys  taken with a special camera called a gamma camera.

4. Terminologies Isotopes : same atomic number but different atomic mass. Radioisotopes : Radioisotopes are the molecules that contain radioactive atoms. When those atoms decay, they emit energy in the form of gamma rays or alpha or beta particles that are detected by the nuclear medicine camera. Radiopharmaceutical : radioisotopes + pharmaceuticals. Radioactive tracers are made up carrier molecule that are bonded tightly to a radioactive atom.

5. Anatomy Kidneys A pair of bean-shaped organs approximately 12 cm long, extending from vertebral level T12 to L3 when the body is in the erect position. The right kidney is positioned slightly lower than the left because of the mass of the liver . The kidneys are encased in complex layers of fascia and fat. They are arranged as follows (deep to superficial): Renal capsule –  tough fibrous capsule. Perirenal fat  – collection of extraperitoneal fat. Renal fascia  (also known as Gerota’s fascia or perirenal fascia) – encloses the kidneys and the suprarenal glands. Pararenal fat  – mainly located on the posterolateral aspect of the kidney.

6. Internal Structures -the outer cortex and inner medulla Cortex-contains glomeruli, Bowman's capsules, and proximal and distal convoluted tubules. It forms renal columns, which extend between medullary pyramids. The cortex extends into the medulla, dividing it into triangular shapes – these are known as  renal pyramids .

7. Medulla-consists of 10 to 18 striated pyramids and contains collecting ducts and loops of Henle. The apex of each pyramid ends as a papilla where collecting ducts open. Calyces-the minor calyces receive one or more papillae and unite to form major calyces, of which there are two to three per kidney. Renal pelvis-the dilated upper portion of the ureter that receives the major calyces . The medial margin of each kidney is marked by a deep fissure, known as the  renal hilum . This acts as a gateway to the kidney – normally the renal vessels and ureter enter/exit the kidney via this structure.

8. Anatomy

9. Relations

10. Blood supply The kidneys are supplied with blood via the  renal arteries , which arise directly from the abdominal aorta, immediately distal to the origin of the  superior mesenteric artery . The renal artery enters the kidney via the renal hilum. At the hilum level, the renal artery forms an  anterior  and a  posterior  division, which carry 75% and 25% of the blood supply to the kidney, respectively. The kidneys are drained of venous blood by the left and right  renal veins . They leave the renal hilum anteriorly to the renal arteries, and empty directly into the inferior vena cava.

11. Radiopharmaceuticals Radiopharmaceuticals are biologically active molecules labeled by  radionuclides  which provide a beneficial source of  ionizing radiation  mainly applied in diagnostic imaging and therapy. Radiopharmaceuticals emit radiation themselves and emitted radiation are detected by specific devices.

12. 99mTc Currently, Technetium-99 (99mTc) is most widely used diagnostic radionuclide. emits Gamma rays of energy 140 Kev half life of 6.01 hours. Source: moly generator Activity: 2-10 mci Radiation dose : 0.13 rad/mci

13. I 131 Physical half life:8.1 days Emits:364 Kev gamma rays for scanning Source: nuclear fission in nuclear reactor . Activity : 50-200microci Radiation dose :1-2 rads / uci Application: As NaI in diagnosis and treatment of thyroid disease .

14. Different types of renal studies DTPA (Diethylenediamine Penta acetic acid): for measuring GFR MAG3 ( Mercaptoacetyl triglycine ) and OIH  ( orthoiodohippurate ) for measuring ERPF(effective renal plasma flow) DMSA ( Dimercaptosuccinic Acid): for measuring cortical scarring

15. Indications Evaluations for renal artery stenosis Obstructions Evaluations for renal perfusion and tubular function Evaluations for renal vascular flow Detection of acute tubular necrosis. Congenital anomalies, Infection , masses. Pre-surgical quantization (nephrectomy) Renal transplant

16. Choice of radiotracer Perfusion MAG3, DTPA Morphology DMSA Obstruction MAG3, DTPA, OIH Relative function All GFR quantization DTPA 

17. DTPA ( Diethylenetriamine pentaacetic acid) DTPA is cleared by glomerular filtration. Filtered agents are used in evaluating vascular supply, measuring renal function (filtration rate), drainage (detects obstruction). Dynamic studies are usually used .  Recommended agent for GFR measurement. Peak renal activity : (3 to 4) mins Cheap and widely available

18. Equipment Camera: large field of view Collimator: low energy, high resolution Computer set up: flow: 1-5 sec/frame for 1 min dynamic: 20-60 sec/frame for 30 min

19. Radionuclide : Tc 99m: t1/2: 6 hrs energies: 140 keV type: gamma emission, generator Radiopharmaceuticals: Tc-99m DTPA Method of administration: intravenous injection if study includes a diuretic use iv cannula (furosemide 20-40 mg) Dose range: Tc-99m:3-20 mCi

20. Patient preparation Well hydrated (2 – 3) cups of water 30 mins prior to the injection Void before injection Void after injection Consent History

21. Procedure Count the syringe before and after injection for 1 min at 20-30 cm from camera face. Place patient in supine position , camera under table or posterior. Position camera by point source over xiphoid, umbilicus, pubis symphysis and sides in field of view. Give intravenous injection, and start image acquisition simultaneously. Image for 20-30 min.

22. If no excretion is seen during this time, a diuretic (furosemide 0.5 mg/kg) may be administered slowly with further imaging up to 15 min. or a diuretic may be given 15 min before administration of the radiopharmaceutical. Filming : all posterior Acquire 5-10 s images over the first min, then 2-3 min images for 20-30 min.

23. Processing Generate kidney time/activity curve graphs Generate percent uptake of each kidney. Select frames of dynamic study or static that has most counts. Generate pictures of dynamic or static images. Calculate GFR. Calculate parenchymal and whole kidney transit

24. Diuretic renogram Done mainly for obstructions Lasex induces increased urine flow (furosemide ) If obstructed “will not wash out “ Radiotracer: Tc-99m MAG3(5-10mci) Normal T1/2 is< 12 min .if kidney doesn’t reach T1/2 by 20 min,the kidney is considered to be obstructed . T1/2 from 12-20min is considered to be intermediate.

25. Normal results Assuming two kidneys, both kidneys visualizing about the same size and intensities. Both graphs peaking with parallel up slope and within 3 sec of aortic peak and dropping off at the same rate. Static images should yield a smooth renal contour. Time- to- peak concentration is 3-5 min. Clearance t1/2 is 12-15 min Furosemide suggested normals:t1/2 washout time from injection is suggested at less than 15 min GFR=125 ml/min

26. Aftercare The patient is warned that the effects of diuresis may last a couple of hours. The patient may feel faint because of hypotension when adopting the erect posture at the end of the procedure. Complication : none

27. Tc99m-MAG3 It is supplied as a sterile, lyophilized powder. Each vial contains betiatide . After reconstitution with sterile sodium pertechnetate Tc 99m injection, the Tc 99m mertiatide which is formed, is suitable for intravenous administration. Mainly cleared by tubular secretion. Fast clearance and greater kidney/background ratio than Tc99m DTPA therefore better for poor renal function, but currently more expensive.

28. photon energy: 140 KeV physical half life: 6 hours biological half life: 4 hours good quality images with renal insufficiency cannot measure GFR as it is cleared almost entirely by tubular secretion Uses , doses, timings and storage adult dose: 8 mCi IV ( adults) pediatric dose: 0.10 mCi /kg 60 sec flow study be stored at controlled room temperature 20° to 25°C (68° to 77°F)

29. OIH 131I Labelled OIH has a significantly higher clearance than other radiopharmaceutical.  In patients with normally functioning kidneys, 85% of the OIH may be found in the urine 30 minutes after intravenous injection. It is eliminated mainly by tubular secretion. High kidney background ratio. Its use has greatly improved the diagnostic potential of renal studies. The only factor limiting its widespread use is restricted availability and the expense involved in its production

30. DMSA 60% TF It is for morphology or structure To detect renal scar or acute pyelonephritis and provide accurate differential renal function. The rapid transits of other (DTPA , MAG3) doesn't allow high resolution imaging of true cortex. Max . Activity _ ( 3-4) hrs. Images taken at (2 to 4) hrs since , poor target to background ratio = poor renal function

31. Indication 1.Renal ectopia and anomalies(Fusion or horseshoe , Multicystic dysplastic kidney) 2.Renal masses and pseudo masses 3.Infection and scarring 4.Renal transplant

32. Kit preparation Radionuclide: Tc 99m: t1/2: 6 hrs energies: 140 keV type: gamma emission, generator Radiopharmaceuticals: Tc-99m DMSA Method of administration: Direct intravenous injection or IV catheter with saline flush. Dose range: Tc-99m DMSA:1-6 mCi

33. Procedure Place patient in supine position, camera under table, except for kidney replacement patients for whom camera is placed above the abdomen centered in FOV. Position camera with upper abdomen centered in field of view . Images are acquired at any time 1-6 hours later. Imaging in the first hour is to be avoided because of free Tc-99m in the urine.

34. Filming Posterior RPO LPO RLAT L LAT Anterior (for horseshoe kidney ,kidney transplant)

35. Processin g Generate percent uptake for each kidney. Select posterior static taken at least at 1 hr. Generate pictures of static images . Aftercare : none Complications : none

36. Normal results Assuming two kidneys, both kidneys visualising about the same size and intensities. Static images should yield bilateral smooth renal contour. Hepatic uptake visualised, varies with degree of renal function. Because of extremely slow rate of clearance of DMSA, collecting system may not visualise.

37. Functional imaging Perfusion imaging : - evaluation of renal blood flow and function of native kidneys. Renal   perfusion  and functional imaging examines blood flow to the kidneys and identifies potential narrowing of the renal arteries. Through a series of images taken over 20 to 30 minutes immediately after radiopharmaceutical injection. -10-20 mci of radiopharmaceutical is injected Ivly . -imaging for renal perfusion usually begins as soon as bolus is seen in abdominal aorta .

38. In normal renal blood flow By 3 sec , aorta is fully visualized. By ( 5 to 6) both kidneys are seen Maximal kidney activity is reached in ( 30 – 60 ) sec In bladder by about 4-8 min

39. Advantages It is useful in evaluating the physiology/functioning of the kidney by monitoring flow of radioisotope and how efficiently the kidneys absorb and pass it. Form of information obtained using this imaging method is mainly related to the physiological functioning of an organ as opposed to the mainly anatomical information which is obtained using X-ray imaging systems. The radioisotope material helps to differentiates between passive dilation and obstruction.

40. It is important to be done before and after renal transplantation to check for the vascularity of the kidney to be transplanted, success of kidney treatment, rejection of a kidney transplant. It is a good option if the patient has had an allergic reaction to the contrast dye used in KUB X-rays.

41. Disadvantages It produces lower contrast images than KUB X-ray, CT and MRI, and may require further tests to clarify a diagnosis. Renography may not reliably differentiate between cysts (abnormal sac filled with fluid) and tumors (abnormal mass of tissue/swelling) Time consuming. A typical scan takes 30 mins – 2 hours. Requires nuclear reactor producing radionuclide to be used.

42. References Nuclear medicine technology: procedures and quick references 2 nd edition, Pete Shackett www.ncbi.nlm.nih.gov (Nuclear Renal Scan ; Hiral Banker; Eugene G. Sheffield; Harris L. Cohen. https ://en.wikipedia.org/wiki/Renal_physiology https :// www.slideshare.net/airwave12/renal-scintigraphy Previous slides

43. Thank You

44. 1.Why is patient asked to void before the injection of radiotracer in renal scan? 2.Which radiotracers are to be used for perfusion ,GFR and cortical scarring ? 3.What are the phases of renogram ? 4 .Advantages and disadvantages of NM renal scan over other modalities 5.Why is DTPA preferred over other radiotracers for GFR measurement ?