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Radiology and Nuclear Medicine

20. Radiology and Nuclear Medicine. Learning Outcomes. Define radiology. Explain the dangers and safety precautions associated with x-rays. Identify the positions used in radiography.

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Radiology and Nuclear Medicine

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  1. 20 Radiology and Nuclear Medicine

  2. Learning Outcomes • Define radiology. • Explain the dangers and safety precautions associated with x-rays. • Identify the positions used in radiography. • Discuss diagnostic imaging as used by the radiologist and several computed-assisted x-ray machines that are described in this chapter.

  3. Learning Outcomes • Describe nuclear medicine and some of the general uses of this specialty. • Define interventional radiology and state some interventional procedures described in this chapter.

  4. Types and Characteristics • X-Rays • CT Scan • Sonogram- Ultra Sound • MRI • Nuclear Medicine • PET • Bone • Interventional Radiology

  5. Radiology • The scientific discipline of medical imaging • Career Pathways in Rad Tech http://www.asrt.org/home • http://www.bls.gov/ooh/Healthcare/Radiologic-technologists.htm • This medical specialty was developed after the discovery of an unknown ray in 1895 by Wilhelm Konrad Roentgen, who called his discovery x-ray.

  6. Radiology An invisible form of radiant energy with short wavelengths traveling at 186,000 miles per second. • Able to penetrate different substances to varying degrees.

  7. Radiology • Characteristics of X-Rays • Able to penetrate substances of different densities. • X-rays pass through air in the lungs, fluids such as blood and lymph, and fat around muscles. • Such substances are radiolucent. • X-rays are absorbed by substances such as calcium in bones, lead, or barium. • Such substances are radiopaque. • Can be used as a diagnostic tool by introducing a contrast medium into the body.

  8. Radiology • Characteristics of X-Rays • Cause ionization, a process resulting in the gain or loss of one or more electrons in neutral atoms. • The gain of an electron creates a negative electrical charge; the loss of an electron results in a positively charged particle. • These charged particles are called ions.

  9. Radiology • Characteristics of X-Rays • Allow the x-ray beam to be directed at a specific site during radiotherapy or to produce high-quality shadow images on film (radiographs).

  10. Radiology • Characteristics of X-Rays • X-rays can destroy body cells. • Radiation can be used to destroy malignant tumors. • Care must be exercised because x-rays can destroy healthy as well as abnormal tissue.

  11. Fluoroscopy is a study of moving body structures--similar to an X-ray "movie." A continuous X-ray beam is passed through the body part being examined. The beam is transmitted to a TV-like monitor so that the body part and its motion can be seen in detail. Figure 20.1The patient is positioned for a fluoroscopy.

  12. Radiology • Characteristics of X-Rays • Radiography • Fluoroscope: a device that projects x-ray images in a movielike sequence onto a screen monitor.

  13. Figure 20.6 X-ray technician in a lead apron positions a procedure. This apron is a protective shield of lead and rubber worn by a patient or those taking x-rays to protect the genitals and other vital organs from excessive exposure to x-rays.

  14. Radiology • Dangers and Safety Precautions • Precautions need to be taken to avoid unnecessary exposure. • Prolonged exposure • Can cause damage to gonads (testes or ovaries) and/or depress the hematopoietic system • Personnel involved with radiation therapy should limit their exposure by staying farther away from the source of radiation. • Infographic on radiology levels

  15. Radiology • Dangers and Safety Precautions • Secondary radiation • X-rays can scatter or be diverted from their normal straight paths when they strike radiopaque objects, adding unwanted density to the image. • Grid: a device positioned between the x-ray machine and the patient to absorb scatter before it reaches the x-ray film

  16. Radiology • Dangers and Safety Precautions • Safety precautions • Not all scatter or secondary radiation is absorbed by a grid. • Safety precautions for those working in areas adjacent to x-ray equipment include: • Film badge • Lead barrier • Lead-lined room • Protective clothing • Gonad shield

  17. Radiology • Dangers and Safety Precautions • Safety precautions • Film badge • Device pinned to medical workers' clothing to monitor an individual's exposure to beta and gamma rays.

  18. Figure 20.2Types of radiation badges to be worn by all staff around x-ray equipment.

  19. Radiology • Positions Used in Radiography • Anteroposterior (AP) position • Front part of body faces x-ray tube; back of body faces the film. • X-rays pass through the body from front to back to reach the film. • Posteroanterior (PA) position • Back of body faces x-ray tube; front of body faces the film. • X-rays pass through the body from back to front to reach the film.

  20. Radiology • Positions Used in Radiography • Lateral position • X-ray beam passes from one side of the patient's body to the opposite side to reach the film.

  21. Radiology • Positions Used in Radiography • Supine position • Patient rests on the back, face upward, allowing the x-rays to pass through the body from front to back. • Prone position • Patient lies face down with head turned to one side; x-rays pass from back to front side of body.

  22. Radiology • Positions Used in Radiography • Oblique position • Patient's body or body part is at an angle to the x-ray beam.

  23. Radiology • Diagnostic Imaging • Provides radiologist images of internal body organs and processes by using: • x-rays • ultrasound • radiopharmaceuticals • radiopaque media (contrast media) • computers

  24. Radiology • Diagnostic Imaging • These images are used to identify and locate: • tumors • fractures • hematomas • disease processes • other abnormalities within the body

  25. Radiology • Diagnostic Imaging • Computer-assisted x-ray machines enhance images obtained by the radiologist. • Noninvasive procedures are now possible in lieu of exploratory surgical procedures.

  26. Radiology • Mammography is the study of the breast using x ray. Pictured Normal mammogram obtained through the process of mammography.

  27. FYI • Breast cancer screening has reduced deaths from breast cancer in women 40–69 years of age. • A mammogram can detect changes in the breast, often before a lump can be felt. • Can also show calcifications, or mineral deposits, cysts or fluid-filled masses, leaking breast implants, and noncancerous tumors or growths.

  28. Figure 20.8Mammogram showing cancer with microcalcifications.

  29. Radiology • Computed Tomography (CT) • Sometimes referred to as a CAT scan (computerized axial tomography). • Combines an advanced x-ray scanning system with a powerful minicomputer.

  30. Radiology • Computed Tomography (CT) • CT scans reveal both bone and soft tissues, including organs, muscles, and tumors. • Aids diagnosis, surgery, and treatment, including radiation therapy, in which effective dosage depends highly on the precise density, size, and location of a tumor

  31. Figure 20.3Computed tomography system.

  32. Figure 20.43D CT scan, multiple facial fractures.

  33. Radiology • Magnetic Resonance Imaging (MRI) • A noninvasive imaging technique to view: • organs • bone • other internal body structures • The imaged body part is exposed to radio waves while in a magnetic field. • -SOUND OF MRI

  34. Radiology • Magnetic Resonance Imaging (MRI) • The picture is produced by energy emitted from hydrogen atoms in the body. • Patient is not exposed to radiation during this test.

  35. Radiology • Magnetic Resonance Imaging (MRI) • Can be used for a variety of purposes: • Cranial MRI: evaluates a person's tumor, seizure disorder, or headache symptoms • MRI of the spine examines a disk problem. • Is frequently used to study large joints such as the shoulder or knee • Is commonly used to evaluate disease of the heart, chest, abdomen, and pelvis

  36. Figure 20.5MRI of head showing large hemorrhagic lesion.

  37. Differences between CT and MRI • What are the differences between the two? • http://blog.image32.com/mri-vs-cat-scan/

  38. Radiology • Ultrasound • Means beyond sound • Sound frequency beyond the range of human hearing • Widely used in diagnostic imaging to evaluate a patient's internal organs • Ultrasonography: process of using ultrasound to produce a record of ultrasonic echoes as they strike tissues of different densities • The record is called a sonogram or echogram.

  39. Figure 20.13Ultrasound, left kidney, and spleen.

  40. Radiology • Ultrasound • Doppler echocardiography is a noninvasive technique for determining: • the blood flow velocity in different locations in the heart. • the uterine artery blood flow velocity during pregnancy, as well as the fetal heart rate.

  41. Nuclear Medicine • Subspecialty within the field of radiology that uses radioactive substances to produce images of body anatomy and function • Patient is given radioactive substance, either intravenously or by mouth. • Images are developed based on detection of energy emitted from radioactive substance.

  42. Nuclear Medicine • Positron Emission Tomography • Most commonly used to detect: • Cancer • Heart problems • Brain disorders • Other central nervous system disorders

  43. Nuclear Medicine • Positron Emission Tomography • Commonly called a PET scan • Helps physicians see how the organs and tissues inside the body are functioning • Detects and records the energy given off by the tracer substance injected into patient's arm vein • This energy is converted by a computer into three-dimensional pictures.

  44. PET Scans Video Click on the screenshot to view a video on the topic of PET scans. Back to Directory

  45. Figure 20.10PET scan comparing the metabolic activity levels of a normal brain and the brain of an Alzheimer's sufferer. Red and yellow colors indicate high activity levels; blue colors represent low activity levels.

  46. Bone Scans • Bone scans • A bone scan is a nuclear imaging test that helps diagnose and track several types of bone disease. • Shows specific areas of irregular bone metabolism • Detects abnormal blood flow to a particular bony region

  47. Figure 20.12Nuclear medicine bone scan.

  48. Interventional Radiology • Interventional Radiology is a medical sub-specialty of radiology utilizing minimally-invasive image-guided procedures to diagnose and treat diseases in nearly every organ system. Source:http://www.hopkinsmedicine.org/vascular/what_is_IR.html

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