Lecture 1_Basic concepts and Conventional Nuclear Medicine.pdf

NUCLEAR MEDICINE AND MOLECULAR IMAGING Basic Concepts and Conventional Nuclear Medicine Dra. Lidia Sancho Rodríguez, MD, PhD Nuclear Medicine Department (Clínica Universidad de Navarra - Madrid) [email protected] WHAT IS NUCLEAR MEDICINE? “NUCLEAR MEDICINE IS A MEDICAL IMAGING SPECIALITY THAT USES...

NUCLEAR MEDICINE AND MOLECULAR IMAGING Basic Concepts and Conventional Nuclear Medicine Dra. Lidia Sancho Rodríguez, MD, PhD Nuclear Medicine Department (Clínica Universidad de Navarra - Madrid) [email protected] WHAT IS NUCLEAR MEDICINE? “NUCLEAR MEDICINE IS A MEDICAL IMAGING SPECIALITY THAT USES SMALL AMOUNTS OF RADIOACTIVE MATERIAL (RADIOPHARMACEUTICAL) FOR THE DIAGNOSIS OR TREATMENT OF DIFFERENT PATOLOGIES” WHAT IS A RADIOPHARMACEUTICAL? Pharmaceutical (Drug) Determines the biological behavior Radioisotope Determines the physical characteristics of the radiopharmaceutical. It allows detection (diagnosis) or damage (treatment). PHARMACEUTICAL • Determines the biological behavior • It is the non-radioactive part of the radiopharmaceutical. • It is the vehicle of the radiopharmaceutical within the body. • Some pharmaceuticals are designed to bind specifically to a cellular receptor, usually overexpressed in tumor cells. • Other pharmaceuticals use normal cells channels to get into them. • In some cases the pharmaceutical serve only as a support for the radioisotope because the radiopharmaceutical is deposited directly on the object of study (for instance: intra-arterial administration). RADIOISOTOPES ≠ A (neutrons): PHYSICAL = Z (protons): CHEMICAL • Isotopes can be stable or unstable (radioisotopes): their nuclei emit energy in the form of ionizing radiation while searching for a more stable configuration. • It determines the physical characteristics of the radiopharamceutical. Depending on the ionizing radiation produced, it is used for diagnosis or treatment. TYPES OF IONIZING RADIATION RADIOACTIVITY: disintegration of an unstable atomic nucleus accompanied by the emission of radiation. • Alpha particles have the advantage of very high amount of energy and a short path length. Due to the amount of energy is only a small number of particles lead to lethal damage to cells. They need to be delivered into or right next to tumor cell because only a piece of paper (skin) is enough to block them. • Beta particles are more penetrating than alpha particles, can travel further distances, but they are less harmful due to their lower energy. • Gamma photons are more penetrating than beta particles but less ionizing. • Neutronic radiation: neutrons are very penetrating, hazard for the body. A material rich of hydrogen (water block or concrete is required to stop them. QUESTION If it were necessary to select a radiopharmaceutical to detect a spinal injury, what type of radiation would be advisable to emit ?: 1. 2. 3. 4. 5. Alpha radiation, due to its low penetration Neutronic radiation, due to its low penetration Gamma radiation, due to its greater penetration None Anyone RADIOPHARMACEUTICAL Pharmaceutical (Drug) Determines the biological behavior Radioisotope Determines the physical characteristics of the radiopharamceutical. It allows detection (diagnosis) or damage (treatment). DIAGNOSIS TREATMENT THERAGNOSIS THERAPY+DIAGNOSIS (same pharmaceutical, different radioisotope) RADIOPHARMACEUTICALS IN CLINICAL PRACTICE DIAGNOSTIC  IMAGE PET: POSITRON EMISSION 18F, 11C, 68Ga… (β+ ) FOR INSTANCE: 18F-FDG 68Ga-DOTATOC Gammacamera or SPECT:  EMITTERS 99mTc, 123I, 111In… FOR INSTANCE: 99mTc-MDP THERAPY: α o β- EMITTERS 131I, 90Y, 177Lu… FOR INSTANCE: 90Y-microsperes BASIC PHYSICAL BASES OF THE IMAGES TRANSMISSION IMAGES A source emits radiation that passes through the patient and hits a support (plate or detectors) RADIOLOGY EMISSION IMAGES • RX • TAC The patient is the source of radiation. The radiation emitted by the patient is detected (SPECT or PET). NUCLEAR MEDICINE • PLANAR IMAGES • SPECT (Single photon emission computed tomography) • PET (Positron emission tomography) NUCLEAR MEDICINE INSTRUMENTATION GAMMACAMERA (Scintigraphy) / SPECT (Single Photon Emission Tomography) or SPECT/CT PET (Positron Emission Tomography) or PET/CT NUCLEAR MEDICINE INSTRUMENTATION GAMMACAMERA (Scintigraphy) PLANAR STUDY ANTERIOR VIEW POSTERIOR VIEW NUCLEAR MEDICINE INSTRUMENTATION GAMMACAMERA (Scintigraphy) SPECT STUDY It allows the visualization of the three dimensional distribution of the radiopharmaceutical. 3 AXES OF THE PATIENT´S SPINE NUCLEAR MEDICINE INSTRUMENTATION • Multimodality cameras: SPECT/CT CT SPECT/CT TYPICAL PROCEDURES IN NUCLEAR MEDICINE BONE SCINTIGRAPHY 99mTc-MDP (99mTechnetium – Biphosphonates) The injected radiolabelled bisphosphonates are adsorbed by the surface of hydroxyapatite crystals in proportion to local bone vascularization and osteoblastic activity (bone remodeling). Most pathological bone conditions (infectious, traumatic, neoplastic or other origin) are associated with an increase in vascularization and local bone remodeling. TYPICAL PROCEDURES IN NUCLEAR MEDICINE BONE SCINTIGRAPHY NORMAL DISTRIBUTION There is a physiological increased uptake in joints, sternum and spine. To mask bladder uptake 323478858 TYPICAL PROCEDURES IN NUCLEAR MEDICINE BONE SCINTIGRAPHY Multiphase bone scan: planar images of the vascular inflow (during intravenous injection), the soft tissue phase (first 5-10 min after injection) and early images (10-15 min after injection) over a given area of the skeleton. Delayed phase images (2-4 h after injection) of the entire skeleton. Dedicated planar images or SPECT/CT images if necessary. DELAYED PHASE IMAGES OF THE ENTIRE SKELETON GROWTH CARTILAGES TYPICAL PROCEDURES IN NUCLEAR MEDICINE BONE SCINTIGRAPHY Multiphase bone scan: planar images of the vascular inflow (during intravenous injection), the soft tissue phase (first 5-10 min after injection) and early images (10-15 min after injection) over a given area of the skeleton. Delayed phase images (2-4 h after injection) of the entire skeleton. Dedicated planar images or SPECT/CT images if necessary. DELAYED PHASE IMAGES OF A GIVEN AREA OF THE SKELETON DEDICATED PLANAR IMAGES SPECT/CT IMAGES TYPICAL PROCEDURES IN NUCLEAR MEDICINE THYROID SCINTIGRAPHY NIS: Sodium iodide symporter and 123I  Iodine is involved in thyroid hormonogenesis. RADIODINE follows the iodine metabolism in the thyroid gland. 131I  Pharmacologic mimic of iodine which is concentrated within the thyroid cells by NIS activity. However it does not take part in hormonogenesis and therefore washout from thyroid cells occurs after 30 min of radiotracer injection. Most common tracer used for thyroid scintigraphy. 99mTc-pertechentate TYPICAL PROCEDURES IN NUCLEAR MEDICINE THYROID SCINTIGRAPHY 131Iodine, 123Iodine 99mTechnetium-Pertechnetate To determine:  Size  Localization  Function TYPICAL PROCEDURES IN NUCLEAR MEDICINE 99mTechnetium-MAG3, RENAL SCINTIGRAPHY 99mTechnetium-DTPA DYNAMIC STUDIES are a sequence of images acquiere during a period of time(from seconds to minutes). Acquired data are processed to produce activity-time curves describing organ uptake/excretion rates. TYPICAL PROCEDURES IN NUCLEAR MEDICINE RENAL SCINTIGRAPHY Renal function curves express the transit of the radiopharmaceutical through the 3 renla compartmentes (vascular, parenchymal and excretory phases). - Vascular phase: It study renal vascularization (1st min after injection). - Parenchymal phase: evaluates renal function (max peak: 3 - 6 min). - Excretory phase: Reflects the permeability of the pelvic-ureteral excretory pathway and the degree of excretion (50% after 10 min and 60% after 15 min). TYPICAL PROCEDURES IN NUCLEAR MEDICINE VENTILATION/PERFUSIONSCINTIGRAPHY VENTILATION PERFUSION 99mTc-Technegas: aerosol comprising extremely small 99mTc-labelled solid graphite particles generated at high temperature. Carbon particles in argon carrier gas. It is inhaled by the patient to explore lung ventilation. 99mTc-MAA (99mTc-macroaggregated albumin): intravenous injection to explore lung perfusion. Main indication: the detection of acute pulmonary thromboembolism due to acute obstruction of a pulmonary artery or one of its sub-branches by a venous thrombus. TYPICAL PROCEDURES IN NUCLEAR MEDICINE VENTILATION/PERFUSIONSCINTIGRAPHY Anterior, posterior, oblique and lateral images of the lungs THERAPY FROM IONIZATION EVENTES CAUSED BY ALPHA OR BETA PARTICLES The two main radiation particles used for therapy are alpha and beta particles. • Alpha particles have the advantage of very high amount of energy and a short path length. The amount of energy is very high so that only a small number of particles lead to lethal damage to cells. They need to be delivered into or right next to tumor cell because only a piece of paper is enough to block them. • Beta particles are more penetrating than alpha particles, can travel further distances, but they are less harmful due to their lower energy. 131-I THERAPY FOR THYROID CANCER 131-I THERAPY FOR THYROID CANCER HEPATIC RADIOEMBOLIZATION with labelled with Ytrio-90 or Holmio-166 (β-) microspheres Treatment of primary or metastatic liver tumors HEPATIC RADIOEMBOLIZATION with labelled with Ytrio-90 or Holmio-166 (β-) microspheres Treatment of hepatocellular carcinoma DIAGNOSTIC MRI 99mTc-MAA 9OY SPECT/CT PET/CT MRI  EXCELLENT TREATMENT RESPONSE NUCLEAR MEDICINE AND MOLECULAR IMAGING Basic Concepts and Conventional Nuclear Medicine Dra. Lidia Sancho Rodríguez, MD, PhD Nuclear Medicine Department (Clínica Universidad de Navarra - Madrid) [email protected]