SAFETY AND RISK OF RADIATIONCONTRAST MEDIA, RISK, PRECAUTION AND MANAGEMENT

DR Riaz Mohammad

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. The average background dose is 3mSv/year

WHAT IONIZING RADIATION DO ?

Cancer

Genetic effects

Skin injuries

Cataracts

Infertility

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

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

SAFETY AND RISKS OF X-RAYS

RISK AND SAFETY IN NUCLEAR MEDICINE1. Nuclear medicine is not safe

for the use of human beings, so therefore should not be used on healthy people.

2. 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

`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.

RADIATION SAFETY AND RISKS

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• 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.

• Natural ionizing radiation include cosmic rays and gamma rays from space, and natural radioactivity.

• Risk of radiation from fluoroscopy and CT scan are not entirely negligible, so these examination should be done when necessary.

RADIATION EFFECTS

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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.

Somatic effects and genetic effects show no immediate symptoms

But it may manifest in future generations

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.

HOW TO MINIMIZE THE RISK

1. Time

2. Distance

3. Shielding

General Rule

(ALARA Principle) As Low As Reasonably Achievable

Longer usage

more exposure

DISTANCE- One step back from

tableside: cuts exposure by factor of 4

- Move Image Int. close to patient:

less patient skin exposure less

scatter

SHIELDINGIncreasing 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

-+

• SHIELDING

- Lead aprons: cut exposure by factor of 20

distant scatter: 0.25 mm Pb eqdirect involvement: 0.5 mm Pb eq

Proper storage (hanging vs. folding)

PROTECTION TOOLS

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CURTAIN THYROIDGOGGLES THYROID

RADIATION INJURIES

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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.

A SUMMARY

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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.

Quantities of radiation, absorbed doses, and biological effective doses must be expressed in units.

Exposure limits for workers are guidelines, and limits for the general public are 100th of those for workers.

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

IDEAL CONTRAST AGENT

1. An ideal contrast agent should be :

2. Non toxic.

3. Painless to patient.

4. Low osmolar.

5. It should not be expensive

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

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.

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

ENEMA DOUBLE CONTRAST WHICH IS BARIUM + AIR

BA MEAL

CT MYELOGRAM. INJECT IODINE CONTRAST IN TO THE SUBARACHNOID SPACE TO SEE THECAL SAC OF SPINAL CORD

AXIAL AND CORONAL CT CHEST WITH CONTRAST. THROMBUS IN THE PULMONARY ARTERY

MORE INVESTIGATIONS ARE

Sailogram. Contrast examination of salivary gland.

Sino gram. Contrast examination of sinus tract

Ductogram. Imaging of the breast duct

INTRAVENOUS PYELOGRAPHY

TAKE PRECAUTIONS BEFORE GIVING CONTRAST MEDIA

1-Previous reaction

2-Asthmatic patient

3-Renal impairment >> 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) >> so we give antihistamine and epinephrine immediately

TYPE OF REACTION Mild

Signs and symptoms appear self-limited without evidence of progression

Nausea, vomiting Altered taste Sweats

Cough Itching Rash, hives

Warmth (heat) Pallor Nasal stuffiness

Headache Flushing Swelling: eyes, face

Dizziness Chills Anxiety

Moderate.

Reactions which require treatment but are not immediately life-threatening

Tachycardia/bradycardia Hypotension Bronchospasm, wheezing

Pronounced cutaneous edema

Treatment: Prompt treatment with close observation

SEVERE

Life-threatening with more severe signs or symptoms including:

Laryngeal edema Profound hypotension Unresponsiveness

(severe or progressive) Convulsions Cardiopulmonary arrest

Clinically manifest

arrhythmias

Treatment: Immediate treatment. Usually requires hospitalization.

ADVERSE REACTIONS CONTINUE-------

Fortunately, most reactions are classified as mild. Within this category, itching, flushing, hives, nasal congestion, and swelling about the eyes and face are common. Nausea and vomiting have become less common with the use of low osmolar and iso-osmolar agents.

Among the moderate reactions, bronchospasm and laryngeal edema are encountered most frequently; patients must also be monitored carefully for changes in cardiac rate and blood pressure.

Severe:

These are nfrequent, can rapidly escalate to a life-threatening situation.

Need prompt treatment and even hospitalization.

HOW TO TREAT?

Give atropine, anti-histamine and if needed adrenaline

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.

SUMMARY1. 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.

THANK YOU

Thank you