Biological Effects of Acute Radiation Exposures by 65Y2XA4


              Acute Radiation Exposure
        Radiation Dose                                Effect
•   1 rad to bone marrow               • Risk of leukemia is 2 in 100,000
•   10 rad, whole body                 • Elevated number of chromosome
                                       abberations: No detectable injury or
•   100 rad, whole body                • Mild radiation sickness -- nausea,
                                       vomiting, fatigue are possible
•   400 rad, whole body                • Likely to result in death for 50%
                                       of exposed and untreated population
•   1,000 rad, whole body              • Erythema and blistering
•   4,000 rads or more, whole body     • Death within 48 hours from shock
                                       and vascular damage
•   1,000 - 6,000 rads, small volume   • Used to treat cancer over 6 weeks
    The Effects of Radiation
        Depends Upon

1. The energy of radiation
2. The dose rate
3. Time total dose is received
4. Part of the body exposed
Background radiation (average)       363 mrem/yr
Trans Atlantic Flight at 38,000 ft   5 mrem
Chest x ray                          10 mrem/film- 15
Nuclear Medicine Study               430 mrem
Nausea and Vomiting                  100,000 mrem
  (100% survival)                           (acute)
Lethal dose (bone marrow)            325,000 mrem
  50% in 60 days (LD50/60)                  (acute)
Cancer treatment series              6,000,000 mrem/
                                            6 wks
* An acute illness, which follows a roughly
  predictable course over a period of time ranging
  from a few hours to several weeks after exposure
  to ionizing radiation.

• It is characterized by the development of group of
  signs and symptoms which are manifestations of
  reactions of various body systems to irradiation of
  the whole body or to significant portion of it.

1. No nausea, vomiting or diarrhea
   Lymphocytes above 1500 cu mm at 48 hrs
   No erythema or local symptoms
   Probable no life threatening injury

2. Nausea, mild vomiting, possibly diarrhea
   Possibly conjunctival redness or erythema
   Lymphocytes 800 to 1500 at 48 hrs
   Probably serious injury. Plan for therapy.
3. Pronounced nausea and vomiting, possibly diarrhea
   Possible erythema and conjunctival redness
   Lymphocytes 100-800 cu mm at 48 hours
   Probable life threatening injury. Plan maximal

4. Prompt severe vomiting and bloody diarrhea
   Erythema, hypotension, lymphocytes below 100 cu
   mm at 48 hours
   Almost certainly lethal exposures. Supportive
    0-48 hours      Hours-28D        Hours-30D        Hours-60D

   PRODROMAL         LATENT          MANIFEST          DEATH /
                                      ILLNESS         RECOVERY
  •NAUSEA           Absent or    •INFECTION
  •VOMITTING        Diminished   •VOMITTING and
  •DIARRHEA                      DIARRHEA
  •FEVER                         •ELECTROLYTE
  •ERYTHEMA                      •HEMORRHAGE
                                 •BLOODY DIARRHEA
                                 •CV/CNS EFFECTS
    Treatment of Radiation Injuries
• * Standardized therapeutic protocols (treatment
    schemes) do not exist
•   1. Symptomatic treatment
•      IV Fluids, blood transfusion, analgesic,
•      antipyretic. antibiotics, antiemetic, etc.
•   2. Wound cleaning and prevention of infection
•   3. Improve local microcirculation
• 4. Reconstructive and plastic surgery
• 5. Amputation for very severe injuries
• 6. Long term and careful clinical
      observation and evaluation ( local
  injuries are characterized by excessively
  prolonged or incomplete healing)

     •   Sources of Medical Radiation

 1. Diagnostic and interventional x-rays
 2. Diagnostic and Nuclear Medicine application
 3. Radiation therapy from either external or
    internal sources
•   Difference of Medical Radiation from
           other Radiation Sources

1. Those exposed directly benefit from it
2. Dose received is over a short time only
3. Dose given to limited portion of the body
4. Exposed population is selected
            Medical Uses of X Rays
•   Biological Effects

    –   Affects all tissues of the body
    –   Affects rapidly growing tissues more than
        normal tissues
        •   Used in treatment of cancers
        •   Why it affects the fetus and the reproductive
1. Used in the diagnosis of diseases
   •   X ray of the different parts of the body to determine the
       presence, type and nature of diseases
   •   To localize foreign bodies
   •   Special procedures
        • Mammography – to determine presence of breast
        • GI series – determine diseases of the gastrointestinal
        • KUB-IVP – determine diseases of the kidneys
        • CT Scan – to determine disease of the brain
        • Cerebral angiography
        • Ventriculography, etc.
2. Used in the treatment of diseases like cancers and
   other tumors
3. Uses in pregnancy
  •   To demonstrate fetal parts in suspected pregnancy
  •   To demonstrate fetal abnormalities
  •   To demonstrate the lie, presentation, and maturity of the fetus
  •   To show presence of cephalo pelvic disproportion
  •   In suspected fetal death

4. For fertility work up
  •   Hysterosalphyngography
      –   Indication:
           » Infertility
           » Repeated abortions
           » Uterine bleeding
   •   Most common; it does not emit ionizing radiation,
       merely detects radiation emitted by patient

2. SPECT – Single Photon Emission Computerized Tomography
   •   Produces cross sectional images of radio tracer
       distribution in the body
   •   It has the ability to remove overlying structures which
       may obscure an abnormality
3. PET – Positron Emission Tomography
  •   Enables blood flow, metabolic rate and receptor
      density to be measured
  •   Projections are acquired simultaneously

4. CYCLOTRON – particle accelerators
  •   Linear accelerator, cyclic accelerator
  •   Bombardment of the target by a beam of particles
      created by the ionization of a gas
Proportion of Imaging Procedures
          Thyroid        -   40 %
          Cardiac        -   30 %
          Pulmonary      -   10 %
          Bones          -   7%
          Renal          -   3%
Liver and gall bladder   -   3%
   Gastrointestinal      -   1%
   Miscellaneous         -   1%
Gamma Camera – principal instrument for
imaging in Nuclear Medicine
1. Thyroid Imaging
   Radiopharmaceutical Used      Activity          Radiation Dose
     Tc 99m                      1-10 mCi          1.5 – 15 mGy
     I 123                       0.5-1 mCi         7.5-75 mGy

   :: Radiation dose given by IV then imaged with Gamma Camera

   Clinical Application
     •    To confirm the presence of nodule within the thyroid
     •    To identify the functional characteristic of the nodule
     •    To demonstrate the presence of multiple nodule
2. Cardiovascular Imaging
   Radiopharmaceutical Used          Activity            Radiation Dose
      Tc 99m                         10-20 mCi
      TI 201                         0.5-3 mCi           3-5.5 mGy

   :: Patient is made to exercise then the radiopharmaceutical is injected by IV
   then imaged with a gamma camera.

   Clinical Application:
      •    To evaluate patients with coronary artery disease
      •    To evaluate patients who had undergone coronary bypass
      •    To evaluate patients with Acute MI
      •    To monitor results of coronary artery angioplasty
      •    Shows the quantity, size and extent of lesion
3. Bone Imaging
   Radiopharmaceutical Used     Activity          Radiation Dose
     Tc 99m                     10-20 mCi         5.6 – 12 mGy

   Clinical Application
     •    For staging cancer
     •    Diagnosis of patients with breast cancer before surgery
     •    To determine the extent of metastasis
     •    To evaluate the result of therapy
     •    To investigate bone injuries
     •    To assess the size and extent of bone tumor
     •    To confirm the presence of osteomyelitis
     •    To investigate bone pains
4. Kidney Imaging

   Radiopharmaceuticals Used:
     •   Technitium 99m
     •   Iodine-125
     •   Chromium

   Clinical Application
     •   To evaluate extent of injury in kidney trauma
     •   To localize obstruction
     •   To evaluate kidney function
     •   To confirm presence of secondary kidney damage
5. Liver Imaging
    Radiopharmaceutical used        Activity adm.
              Tc 99m                7-15 mCi
    Clinical Application:
      •    To determine normal liver function
      •    To determine the presence of hepatic cirrhosis
      •    To determine the presence of fibrosis secondary to toxicity
      •    Chronic hepatitis

6. Diagnosis of the different types of cancers, the
   stages, the extent of metastasis, etc.
7. Diagnosis of rheumatoid arthritis and
      •    Shows grade of inflammation and degenerative process
1. If possible, defer study until later stage of
2. Give minimal dose (should not exceed I-2 mSv)
3. Hydrate patient and encourage to void
   frequently to decrease time of exposure of fetus
4. Pertechnitate and Gallium which concentrate in
   the placenta should be avoided
5. Limit the procedure to those which are
   absolutely necessary only
1. Risk of fetal cancer
   (1 in 100,000) - < 1-2 mSv
                      > 2 mSv (8 in 10,000)
2. Hypothyroidism
3. Cretinism
•  Diagnostic and Therapeutic
1. Posses a relatively short half life
2. Should not emit particulate radiation
3. Should emit gamma radiation with energy high
   enough to be detected
4. Not emit gamma radiation with energy so high
   as to make detection inefficient
5. Be available in the highest specific activity to
   avoid toxic response in patients
•    2, 300 radionuclides

Following are used in diagnosis:

1.   Technetium 99m – 80% used
2.   Thallium 201
3.   Gallium 67
4.   Indium 111
5.   Iodine 123
Following are used in treatment
1. Iodine 131
2. Phosphorus 32
3. Yttrium 90
4. Radium
5. Iridium
6. Argon 40
7. Cobalt 60
8. Cesium 137
9. Carbon 12
10. Neon 20
11. Silicon 28
TECHNECIUM 99M – ideal radionuclide for
use in Nuclear Medicine because:

1.   It is a pure gamma emitter
2.   It has a short physical half life
3.   It has a gamma ray energy of 140 kev
4.   It is carrier free (no stable isotope present)
5.   It can be produced cheaply
6.   It can exist in various valency states
                 Radiation Therapy
1.   Iodine 131 therapy in thyroid cancer 50-200 mSv at 3
     months interval for 3 years
2.   Radium needle treatment in tongue cancer
     Iridium 192 hairpin treatment in cancer of the tongue,
     palate and gums then subjected to intraoral electron
     beam at 40-50 Gy
3.   Treatment of cervical cancer with the use of: Co 60
                                                      Cs 137
4.   Heavy Particle radiation therapy for the different types
     of cancer using carbon 12, neon 20, silicon-28, argon 40
5.   Fast Neutron Therapy
6. Proton radiotherapy for the treatment of cancers
   of the head and neck, spine and tissues
7. Radiotherapy and Hyperthermia – heat treatment
   with radiation – also for the treatment of the
   different types of cancer
8. Intraoperative radiation therapy – used in deep
   seated tumors which are difficult to operate
9. Treatment of Breast cancer and other cancers
   after surgery with Co 60
  10 Leading Causes of Mortality in the
1.    Diseases of the Heart
2.    Diseases of the vascular system
3.    Malignant neoplasms
4.    Pneumonias
5.    Accidents
6.    Tuberculosis, all forms
7.    COPD & Allied Conditions
8.    Conditions pertaining to the perinatal period
9.    Diabetes Mellitus
10.   Nephritis, Nephrotic Syndrome and Nephrosis
Thank you

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