Safety and Risk In Radiation Contrast media, Precaution, risk and management

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Safety and Risk In RadiationContrast media,
Precaution, risk and management
Dr. Riaz Mohammad
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Radiation risk and safety.

• Types of radiation
• 1 Alpha.
• 2 Beta.
• 3 Gamma and ( X-rays)
• We are all exposed to radiation from sun, rock
  and other natural sources. These include cosmic
  rays and gamma rays from the space, and natural
  resources
• The average background dose is 3mSv/year

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What ionizing radiation do ?

• Cancer
• Genetic effects
• Skin injuries
• Cataracts
• Infertility

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• It is important to weigh the benefit of every
  examination against the potential risk of
  performing test

RISK
BENEFIT
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Safety and risks of x-rays

• Risk
• Ionizing radiation has enough energy to
  potentially cause damage to cell and DNA. Risks
  from exposure to ionizing radiation include
  cancer.
• Radiation dose is high in fluoroscopy due to
  continuous x-rays use

• Benefits
• Noninvasive and painless, help to diagnosis
  disease and monitor therapy
• support medical and surgical treatment planning.
• guide medical personnel as they insert
  catheters, stents, or other devices inside the
  body, treat tumors, or remove blood clots or
  other blockages

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Risk and safety in nuclear medicine

• Nuclear medicine is not safe for the use of human
  beings, so therefore should not be used on
  healthy people.
• Also the procedure is not recommended for
  pregnant women because unborn babies have a
  greater sensitivity to radiation than children or
  adults.

1. Radioactive substances emit gamma rays in to the
   body so the safest way is to use a radio nuclide
   which has a short half life, so it can decay to a
   safe level as soon as possible
2. But the half life should not be too short because
   it will decay before the test is completed

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• Safety precautions . when a patient has been
  injected with radioactive substance. Wear a gown
  and disposable gloves maximize the distance from
  the patient.
• Most of the administered radioactive isotopes is
  excreted as urine via the kidney and bladder but
  some is excreted as perspiration and saliva. This
  means that the patient has radio active
  substances on their skin and should take extra
  care when around other people. If accidents like
  urination and vomiting happen, it must be assumed
  that the material is radioactive unless proved
  other wise.

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Radiation safety and risks

• Accidental and avoidable exposure to ionizing
  radiation is a risk.
• Effects of ionizing radiation on life depend on
  types of radiation, rates of receiving, and
  dosages received.
• Risk of radiation from fluoroscopy and CT scan
  are not entirely negligible, so these examination
  should be done when necessary.

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Radiation Effects
Somatic effects damages to cells passed on to
succeeding cell generations.
Genetic effectsdamages to genes that affect
future generations. Genes are units of
hereditary information that occupy fixed
positions (locus) on a chromosome. Genes achieve
their effects by directing the synthesis of
proteins.
Genetic effects show no immediate symptoms But
it may manifest in future generations
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Radiation doses
Investigation Radiation dose Equal to background radiation
X-ray chest 0.1-0.3 mSv 10 days Negligible
CT head 4mSv 16 months low
CT abdomen and pelvis 10 mSv 3 years low
Intravenous pyelography 3mSv 1year low

CT abdomen and pelvis repeated with and with out contrast 20 mSv 7 years (Moderate)



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Important points to remember

• Every effort should be made to keep radiation low
  and when ever possible to use ultrasound and MRI.
• The radiation doses mentioned are small, but some
  procedure like fluoroscopy and CT are not
  entirely negligible.
• We must keep records of radiological
  investigations
• The risk is lower for older people and higher in
  children and pregnant women

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How to minimize the risk

• Time
• 2. Distance
• 3. Shielding

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Radiation Protection.

• General Rule
• (ALARA Principle)
• As
• Low
• As
• Reasonably
• Achievable

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Radiation Protection in Fluoroscopy
more exposure
Longer usage
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Radiation Protection in Fluoroscopy

• DISTANCE
• - One step back from tableside
• cuts exposure by factor of 4

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Shielding
Radiation Protection in Fluoroscopy
Increasing the amount of shielding around a
source of radiation will decrease the amount of
radiation exposure.
To avoid scatter Be sure to shield all directions.
Shielding
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Radiation Protection in Fluoroscopy

• SHIELDING
• - Lead aprons cut exposure by factor of 20

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Protection tools
Radiation Protection in Fluoroscopy
CURTAIN
THYROID
GOGGLES
Body
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Radiation Injuries
Whole-body radiation victims mostly suffer from
injuries to the hemopoietic, gastrointestinal
(GI), and central nervous (CN) systems. Injuries
to the hemopoietic system lead to bone morrow
syndromes with low red and white cells and
platelet counts. The GI syndromes are anorexia,
fatigue, nausea, vomiting, and diarrhea. GI
system failures weakens body defence. Damages to
the isolated and non-renewable CN system show
ataxia (loss of motion control), disorientation,
apathy, depression, prostration (exhaustion),
convulsions, and shock. Organs such as skin,
gonads, and eyes are sensitive to radiation.
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A Summary
Early experiences led to the discoveries of
radiation effects. Radiation causes delayed
somatic and genetic effects due to damages to
cells and the DNA molecules. There are guidelines
regarding exposure limits for workers and
patients which must be followed.
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Contrast media. Types, benefits and risk

• Contrast media are chemical substances that due
  to its high attenuation of x-rays or differential
  absorption of x-rays from the surrounding tissues
  permit clear demonstration of organs or tubular
  structures.
• Type of contrast
• Oral contrast. Barium sulphate.
• Intravascular contrast. Iodine containing-
• 1. Low osmolar
• 2. High osmolar
• Contrast agent used in KSA are low osmolar, it
  is expensive but safe
• Intravascular contrast used in MRI Gadolinium
  DTPA

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Ideal contrast agent

• An ideal contrast agent should be
• Non toxic.
• Painless to patient.
• Low osmolar.
• It should not be expensive

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Patient who need special care when using contrast

• Extreme age ( infants and elderly)
• DM
• Hypertension
• Asthma
• Sickle cell anemia and multiple myeloma
• Liver failure
• Renal failure

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Contrast continue

• Radiographic contrast agents are used to
  visualize structures or disease processes that
  would otherwise be invisible or difficult to see
• Barium is widely used to outline
  gastrointestinal tract.All the other radio-opaque
  media rely on iodine in solution to absorb
  x-rays. Iodine containing solutions are used for
  urography, angiography and intravenous contrast
  enhancement at CT.

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Barium

• Barium contrast (not water soluble) usually we
  use it for upper GI study (orally) or lower GI
  study ( as enema ) because it is available, easy
  to use, gives good images, rarely cause allergy
  and cheap but it is contraindicated if there is
  perforation ( in case of perforation e.g.
  duodenal ulcer or post op leakage we use
  gastrografin (water soluble) - If there is
  perforation barium contrast used , the end
  result will be chemical peritonitis.
• How do I know if there is perforation? - We know
  it if we see air under the diaphragm in x-ray -
  Contrast agents could be used orally , enema , IV

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Enema double contrast which is barium air
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Ba meal
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CT myelogram. Inject iodine contrast in to the
subarachnoid space to see thecal sac of spinal
cord
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Axial and coronal CT chest with contrast.
Thrombus in the pulmonary artery
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More investigations are

• Sailogram. Contrast examination of salivary
  gland.
• Sino gram. Contrast examination of sinus tract
• Ductogram. Imaging of the breast duct

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Intravenous pyelography
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Take precautions before giving contrast media

• 1-Previous reaction
• 2-Asthmatic patient
• 3-Renal impairment gtgt contrast might cause
  acute renal failure
• 4-dm-atopic dermatitis
• 5-Pregnant (contrast is contraindicated)
• 6-Sickle cell anemia and multiple myeloma
  (contrast is
• contraindicated).
• Probably the patient will get anaphylactic
  shock from your contrast (skin erythema, etching,
  tachycardia, tachypnea, BP drop, bronchospasm) gtgt
  so we give antihistamine and epinephrine
  immediately ?

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Type of reaction

• 1-Mild (only nausea and vomiting)
• 2-Moderate (bronchospasm and skin reaction)
• 3-Sever (tachycardia hypotension) .
• How to treat? Give atropine, adrenalin and
  anti-histamine
• To protect the patient give him steroid prior
  to the study,
• cancel and change the modality if he has a
  special
• condition.
• When you write radiographic request form, make
  sure the
• patient has no contraindications.
• Write a detail clinical history for the
  radiologist.

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Patients with angioedema and anaphylactic reaction
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Summary

1. Barium contrast is contraindicated if there is
   perforation and we use gastrografin instead.
2. If there is perforation barium contrast used ,
   the end result will be chemical peritonitis
3. Sialogram A sialogram is an x-ray of the
   salivary ducts and glands. Myelogram is an x-ray
   examination of the spinal canal.
4. A contrast agent is injected through a needle
   into the space around the spinal cord to display
   the spinal cord, spinal canal, and nerve roots on
   an x ray.
5. Contrast is contraindicated with pregnant women,
   sickle cell anemia and multiple myeloma.

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Thank you