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University of South Carolina School of Medicine. RADIOLOGY. ICM. Introduction To Clinical Medicine. Francis Neuffer M.D. U.S.C. School of Medicine. Radiology Website : http://radiology.med.sc.edu. Overview . GOALS. Image creation Different modalities

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radiology

University of South Carolina

School of Medicine

RADIOLOGY

ICM

Introduction To Clinical Medicine

Francis Neuffer M.D.

U.S.C. School of Medicine

Radiology Website: http://radiology.med.sc.edu

goals

Overview

GOALS

  • Image creation
  • Different modalities
  • Strengths and weakness
radiology tools
RADIOLOGY TOOLS

X- RAY

ULTRASOUND

NUCLEAR MEDICINE

MAGNETIC RESONANCE

COMPUTED TOMOGRAPHY

how is imaging done
HOW IS IMAGING DONE?
  • IONIZING RADIATION

X-ray, CT, Nuclear Medicine

  • SOUND WAVES

Ultrasound

  • MAGNETIC FIELDS / RADIO WAVES

Magnetic Resonance

slide5

X-ray, visible light and radio waves are all electromagnetic radiation and only vary in frequency.

slide6

X-RAY

  • High Energy Photon

--Kilo Electron Volts

  • Ionizing Radiation
  • Exposes Film / Detector
  • Projection Data

X-ray beam

detector

slide7

X- RAY

  • Bone
  • Soft

tissue

  • Fat
  • Air
slide8

UPPER GI--(GASTRO INTESTINAL)

ORAL BARIUM CONTRAST

STOMACH

WITHOUT CONTRAST-plain or scout film

ARTERIOGRAM

INTRAVASCULAR IODINE CONTRAST

slide9
HIGH ENERGY PHOTON

IONIZING RADIATION

EXPOSES DETECTOR

TOMOGRAPHIC DATA

COMPUTED

TOMOGRAPHY

9

slide11

THE

HOUNSFIELD SCALE

-1000

1000

0

-20 - -80

+20 - +80

AIR

BONE

WATER

FATTY TISSUE

SOFT TISSUE

slide13

ARTERIOGRAM

CT WITH INTRAVENOUS IODINE CONTRAST

WITHOUT CONTRAST

INTRA-ARTERIAL IODINE CONTRAST

slide14

AXIAL

SAGITTAL

slide15

ENHANCING RING LESION

NON-CONTRAST

STUDY

IV IODINE CONTRAST

STUDY

nuclear medicine
NUCLEAR MEDICINE
  • High Energy Photon
  • Ionizing Radiation

--Radiopharmaceutical

  • Dynamic / Physiologic
slide17

Normal Bone Scan

Metastatic bone disease

slide18

NORMAL

LUNG SCAN

nuclear medicine exposure
NUCLEAR MEDICINE Exposure
  • Physical half-life
  • Biological half-life
  • Effective half-life
  • Definitions:
  • The effective half-life for a radionuclide is the time needed for the compound to be decreased by 50%. This is the combined biological half-life and the physical half-life .
  • • The biological half-life is excretion dependent.
  • • The physical half-life is due to nuclear decay.
radiation
RADIATION

Ionizing radiation:

X-Ray

CT

Nuclear Medicine / PET

Non-ionizing radiation:

US

MR

slide21

WHICH

ONE

DOESN’T

THAT’S MORE LIKE IT.

FIT?

radiation risk
RADIATION RISK

CT scans contribute approximately 45% of the U.S. population's collective radiation dose from all medical x-ray examinations.

CT is the LARGEST contributor to medical exposure to the U.S. population.

Estimated Number of CT Scans Performed

Annually in the United States

increased ct utilization
Increased CT Utilization
  • Indications
  • Availability
  • Certainty
  • Speed
  • Demand—patient / physician / insurance

Emergency Radiology 2006 Oct: 13(1); 25-30

radiation risk1

RADIATION RISK

IONIZING RADIATION

Ionizing radiation can cause free radicals which can break DNA.

Incomplete DNA repair can be lethal to cell or increase cancer risk or increase genetic defects in fetus.

radiation dosage
RADIATION DOSAGE

RADS

REMS

GRAYS

SIEVERTS

ncrp 160 report 2009 background population radiation
NCRP 160 Report (2009)Background Population Radiation

Adapted from: Radiology 2009;253:293-296 Figure 2

radiation dosage1
RADIATION DOSAGE

CXR= 1/100 Background Radiation/Yr.

CT Scan= 1-4x Background Radiation/Yr.

Denver = 2x Background Radiation/Yr.

radiation risk2
RADIATION RISK

Deterministic effects—dose dependent.

Stochastic effects—probability of event

deterministic threshold dose related
DETERMINISTICTHRESHOLD - DOSE RELATED

Cataracts, Skin Erythema & Burns,

(very rare -interventional procedures)

Acute Radiation Sickness-(Radiation accidents)

Bone marrow-depression

GI tract sloughing

Cerebral edema

Death

stochastic effects
STOCHASTIC EFFECTS

LOWER DOSE:

probability increase - population effect

Cancer incidence

Hiroshima Nuclear Bomb survivors

slide32

Excess Risk of Cancer

50-100 mSv exposure

Nuclear Bomb Survivors

small statistical increased risk
Small Statistical Increased Risk

The estimated lifetime cancer mortality risks from a single full-body CT examination at age 45.

ct dose is in range of hiroshima bomb survivors dose
CT DOSE IS IN RANGE OF HIROSHIMA BOMB SURVIVORS DOSE

There is an excess cancer risk seen in

large groups of Hiroshima survivors.

Statistically CT scans WOULD increase

risk of cancer.

pediatric exposure
PEDIATRIC EXPOSURE

Children are considerably more sensitive to radiation than adults by about 3 times.

Children also have alonger life expectancy than adults, resulting in a larger opportunity for effect.

Radiation-induced cancers effects delayed1 to 2 decades or longer after exposure.

Children can receive a higher dose( ADULT SCAN) than

necessary.

Thus risk for developing a radiation-related cancer can be several times higher for a pediatric patient.

slide37

FOR MORE PHYSICS…

www.youhavenolife.com

radiology1

University of South Carolina

School of Medicine

RADIOLOGY

ICM

Introduction To Clinical Medicine

Francis Neuffer M.D.

U.S.C. School of Medicine

Radiology Website: http://radiology.med.sc.edu

no ionizing radiation
NO IONIZING RADIATION
  • SOUND WAVES

Ultrasound

  • MAGNETIC FIELDS / RADIO WAVES

Magnetic Resonance

ultrasound
ULTRASOUND
  • Sound Wave - high Frequency-megahertz
  • No Ionizing Radiation
slide41

B Mode-brightness

    • Most common use
    • Presents “real time”image
  • Ultrasound Sector Scanning
slide44

CAROTID ARTERY

color doppler

magnetic resonance
MAGNETIC RESONANCE
  • HYDROGEN PROTONS ALIGN IN MAGNETIC FIELD
  • RADIO FREQUENCY

EXCITATION and

TRANSMISSION

  • NO IONIZING RADIATION
t1 scan
T1 SCAN

MR SIGNAL

T2 SCAN

SCANS ARE MADE TO SEPARATE TISSUE BASED ON THEIR T1 AND T2 TIMES.

mr angiography with gadolinium
MR ANGIOGRAPHY WITHGADOLINIUM

Standard catheter

Angiogram

imaging prosand cons
IMAGING PROSAND CONS
  • IONIZING RADIATION

X-ray, CT, Nuclear Medicine

  • SOUND WAVES

Ultrasound

  • MAGNETIC FIELDS / RADIO WAVES

Magnetic Resonance

slide53

X-RAY

PRO’S

  • Available
  • Inexpensive
  • General Skills

CON’S

  • Ionizing Radiation
  • Contrast Issues
  • Projection Data
slide54

IODINE and BARIUM

Contrast Issues

IODINATED AGENTS are WATER SOLUABLE and can be given by oral or vascular routes.

With IODINE, there is a potential for RENAL TOXICITY in certain patients and ALLERGIC REACTIONS can occur.

BARIUM is a GI CONTRAST. It is a particulate inert material. Therefore it is not a vascular agent. It could be a problem if it perforated into the peritoneum.

slide55

CT SCANNING

PRO’S

  • Available
  • Fast
  • Sectional data
  • Soft tissue detail

CON’S

  • Radiation
  • IV Contrast
  • Cost
slide56

NUCLEAR MEDICINE

CON’s

  • PRO’s
  • Physiologic data
  • Quantifiable
  • Tissue specific
  • Limited anatomy
  • Radiation
  • Speed / Motion limited
  • Cost
slide57

Ultrasound

  • non-ionizing radiation
  • not motion limited
  • portable / multiplanar
  • lower cost

PRO’S

CON’S

  • operator dependent
  • Limited FOV
magnetic resonance imaging
MAGNETIC RESONANCE IMAGING

PRO’S

  • Soft tissue resolution
  • No iodine toxicity
  • No ionizing radiation
magnetic resonance imaging1
MAGNETIC RESONANCE IMAGING

CON’S

  • Cost / Availability
  • Motion
  • Air- lungs / bowel
  • Bone- skeleton / calcium
  • Hemorrhage /
  • hemoglobin
magnetic resonance imaging2
MAGNETIC RESONANCE IMAGING
  • RF Energy – pacemaker overide
  • Magnetic field - aneurysm clips –
  • Occular metal -missile effect
  • Nephrogenic Systemic Fibrosis
  • Gadolineum toxicity in renal failure

CON’S

  • ICU patients and Claustrophobia
  • Metal artifact
slide61

GADOLINIUM CONTRAST

  • Physiology similar to iodine
  • Blood pool and tissue enhancement
  • MINIMAL allergic issue
  • TOXICITY in patients with renal failure
  • Nephrogenic Systemic Fibrosis
radiation1
RADIATION

Ionizing radiation:

X-Ray

CT

Nuclear Medicine / PET

Non-ionizing radiation:

US

MR