RADIATION PROTECTION & RADIOBIOLOGY

RADIATION PROTECTION & RADIOBIOLOGY

RT 244 – 2006 WEEK 7

CD# 3CH. 6 STAT

CELLULAR RADIATION EFFECTS

• # 3 APPLICATIONS OF DOSE-RESPONSE RELATIONSHIPS

• THERAPTEUTIC USE IN TREATING

• MALIGNANT DISEASES

• UNDERSTANDING BIOLOGIC EFFECTS OF LOW DOSE RADIATION

RESPONSE DIRECTLY PROPORTIONAL TO DOSE

SOMATIC & GENETICSTOCHASTIC VS NON STOCHASTIC

• A = STOCHASTIC• “CHANCE” EFFECTS GENETIC, LEUKEMIA,

CANCERDIAGNOSTIC RADIOLOGY

B= NON-STOCHASTICTHRESHOLD EFFECTSDETERMINISTICSOMATIC EFFECTSSKIN ERYTHEMA,

CATARACTS, STERILITYRAD -MALIGNANCIES

PG 137

# 7 – Dose Response Relationships

LINEAR NON THRESHOLD

• ASSUMES ANY AMOUNT OF RADIATION IS CAPABLE OF CAUSING A BIOLOGIC RESPONSE

• THE RELATIONSHIP BETWEEN THE RADIATION DOSE AND BIOLOGIC RESPONSE IS CONSIDERED TO BE DIRECTLY PROPORTIONAL

Acute Radiation Syndrome

• To see a response quickly – doses must be very high

• Early or Acute Effect

• Early Pioneers - Late Somatic Effects discovered

• 1912 X-ray Dermatits

# 8 ACUTE EFFECTS (XRAY DERMATITIS)EFFECTS SEEN WITHIN MINUTES, HOURS, DAYS WEEKS

# 9 4 STAGES OF ACUTE RADIATION SYNDROME (ARS)

• Occurs from accidents or nuclear weapons

• Results from HIGH DOSES :

• Nausea • Blood disorders• intestinal disorders• fever• fatique

• depression of the sperm count

• temporary or permanent sterility in both sexes,

• Cardiovascular• CNS• shedding of skin layer

# 9 4 STAGES OF ACUTE RADIATION SYNDROME (ARS)

• PRODROMAL

• LATENT PERIOD

• MANIFEST ILLNESS

• RECOVERY OR DEATH

• The graph depicts the stages of acute radiation syndrome following a whole-body reception of large doses of ionizing radiation delivered over a short period of time. The length of time involved for the syndrome to run its course and the final outcome of the syndrome depends on the dose received.

PRODROMAL

• OCCURS WITHIN HOURS OF 1 GY (100 rad)• NAUSEA, VOMITING, DIARRHEA, FATIQUE• DECREASED IN WBC’S• LASTS A FEW HOURS – TO SEVERAL DAYS

LATENT

• NOT FEEL ANY SYMPTOMS

• LASTS ABOUT 1 WEEK

MANIFEST ILLNESS

• WIDE RANGE OF SYMPTOMS LEADING TO : • APATHY, • CONFUSTION, • EPILATION , • WBC & RBC DECREASE, • DIARREHEA, VOMITING • HEADACHES, • TO CARDIOVASCULAR COLLAPSE

RECOVERY OR DEATH

• DEPENDS OF AMOUNT OF DAMAGE

• DEATH WILL NOT USUALLY OCCUR UNDER 1 GY (100 RAD)

• SUB LEATHAL 2 – 3 GY (May have recovery)

• SUPERLEATHAL 6 –10 GY

• SURVIVAL DOES NOT MEAN END OF EFFECTS –

• CAN EFFECT THE FUTURE GENERATIONS (GENETIC EFFECTS)

• OR RESULT IN CANCER

CHERYNOBYL POWER PLANT IN RUSSIA

• One such accident occurred in April 26, 1986, at the Chernobyl Plant outside Kiev in Ukraine in 1986.

• This was the most serious accident at a nuclear plant that the world has seen so far.

• The accident occurred when an improperly conducted experiment in one of the reactors caused an explosion.

• The explosion blew off the top of the reactor, releasing 100 million curies of radionuclides into the atmosphere. More than thirty people who were at the site of the reactor when it exploded died immediately or shortly after the accident.

CHERYNOBYL POWER PLANT IN RUSSIA

EXPLODED 1986• 2 PEOPLE DIED INSTANTLY• 29 PEOPLE DIED WITHIN 3 MONTHS FROM

BURNS AND SEVERE INJURIES – WHOLE BODY DOSE OF 6+ GY

• 200 HAD ACUTE RADIATION ILLNESS – DOSE EXCEEDING 1 SV

• MASS EVAUCATIONS OF OVER 100,000 PEOPLE• MAY RESULT IN OVER 20,000 MALIGNANCIES• 10 YEARS LATER MANY THYROID CANCERS

HAVE BEEN SEEN IN CHILDREN

• An area around the site with a 30-mile radius was evacuated.

• Since the accident doctors have found a striking increase of thyroid cancer among people, especially children, living in contaminated regions in Ukraine and Belarus.

The child is a victim of the 1986 nuclear power plant explosion at Chernobyl suffering from

leukemia

• Five-year-old Alec Zhloba from a town in Belarus is suffering from leukemia.

• Some 70 percent of the fallout from the 1986 Chernobyl disaster fell on Belarus.

These children live in a village not far from the Chernobyl nuclear plant.

Four years after the 1986 Chernobyl accident, these children are suffering intestinal problems from exposure to radiation.

• Annya was born in 1990 in a village highly contaminated by the Chernobyl nuclear meltdown of 1986.

• A cancerous brain tumour at the age of four marked the end of Annya's childhood and the beginning of a life of pain and illness.

• Annya, now 15 and bed-ridden, has spent her life in and out of hospital, between tumours and life support.

Recovery

• EXPLOSION

• Burns – infection = septicemia

• Other injuries

• Bone Marrow Transplant 13 / 1

Radiation protection was primarily a non-governmental function until the late 1940s. After World War II, the development of the atomic bomb and nuclear reactors caused the Federal government to establish policies dealing with human exposure to radiation. In 1959, the Federal Radiation Council was established

THE PLUTONIOUM FILES

Japan Bombing

• August 6, 1945 • An atomic bomb

exploded over the Japanese city of Hiroshima.

• A second bomb was dropped on Nagasaki

• Between 70,000 and 80,000 people died right away; perhaps as many died from radiation or injuries.

TOTAL BODY RADIATION DOSE

RHB NOTIFICATION (EXP IN 24 HOURS)

• IMMEDIATE – WITHIN 24 HOURS

• TOTAL DOSE OF 25 rems

• Eye dose – 75 rem

• Extremity – 250 RADS

• OVEREXPOSURE – WITHIN 30 DAYS

• TOTAL DOSE OF 5 rems

• Eye dose – 15 rem

• Extremity - 50 REMS

• “Unexpected Radiation raises the dead”

ACUTE RADIATION SYNDROME – TOTAL BODY EXPOSURE

• HEMATOPOIETIC SYNDROME (BONE MARROW)

• GASTROINTESTINAL SYNDROME

• CEREBROVASCULAR SYNDROME

HEMATOPOIETIC SYNDROME (BONE MARROW)

• Most radiosensitive organ system in body

• RESPONSIBLE FOR MANUFACTURING THE RED BLOOD CELLS

• 1 – 10 gy ( 100 – 1000rad)

• SURVIVE 6 - 8 WEEKS

• All blood cells are not the same – so vary in sensitivity

BLOOD CELLS – 4 TYPES

• Red blood cells ( Erythrocytes – most numerous , most mature)

• 2 types of white blood cells

• platelet cells

• Originate from a “special type of stem cell”

• stem cells are the most radiosensitive

Red blood cells• Erythrocytes – most numerous mature• Spend 8 – 10 days in bone marrow • 4 month life span makes them more

radioresistant• Red blood cells carry oxygen to organs (lungs +

Body)• 0.5 gy (50 rad) can decrease # of RBC’s =

anemia • Prevents them from transporting oxygen

effiecently• RBC contain no nucleus • mature cells least radiosensitive

2 types of White blood cells (leukocytes)

•# 15 lymphocytes – produce antibodies

• (small amt of antibodies from spleen and thymus)

• live about max 24 hours• defense against disease • more susceptible to infections• damage seen at .25 gy (25 rad)• at 200 rad – recovery can take several months

# 16 - Granulocytes

• neutorphilic and eosinophilic

• act to protect the body from disease

• damage can lower the body’s defenses and increase infection

# 17 -Platelet cells – thrombocytes

• (blood clotting) stops hemmorage

• 5 days in bone marrow

• live about 30 days

• most resistant to radiation

• Numbers can be lessened by doses

• of 50 rads and take several months to recover

• MOST PROBLEMS DO NOT OCCUR IN DIAGNOSTIC RADIATION

• ALTHOUGH THERE ARE STUDIES THAT SHOW CHROMSOME ABBERATIONS IN PATIENTS THAT UNDERWENT DIAGNOSTIC RADIOGRAPHY PROCEDURES

• IN THERAPY

• PATIENT CAN HAVE A DROP IN BLOOD CELL COUNT – AND ARE MONITORED

• Several cases of lens injuries, caused by occupational radiation exposure, have occurred in two X-ray rooms devoted to vascular and visceral interventional radiology procedures.

• Both laboratories were equipped with overcouch X-ray systems not designed for interventional radiology and without specific tools for radiation protection of the eyes.

• Typical workloads ranged from between two and five procedures per day.

• For the two radiologists affected, estimates for the dose to eye lens ranged from 450 to 900 mSv per year, over several years

RADIATION

THERAPY

Protracted &

Fractionated doses

Protracted• LG doses• shorter time

Fractionated • Smaller doses • spread out

HEMATOPOIETIC SYNDROME (BONE MARROW)

• MOST RADIOSENSTIVE ORGAN SYSTEM IN BODY

• DEATH OCCURS WITH WHOLE BODY – 20 GY (2000 RAD) EXPOSURE

• EXPOSURES BELOW 1 GY –

• CAN HAVE RECOVERY WITHIN A FEW WEEKS

GASTROINTESTINAL SYNDROME • 6- 10 GY - SURVIVE 3 TO 10 DAYS• Symptoms: same as hematopoietic• DEATH OCCURS - immature cells of the

epithelial lining of intensine (GI tract)• 3- 5 day lifespan- damaged cells impairs body

homeostasis causing electrolyte imbalance, lethargy, fatigue, emaciation

• SMALL INTESTINE MOST SENSITIVE• 6 gy kills the crypt cells – no new cells to replace-causing the lining

of the intestine to wear away – fluids can pass through• Before Cherynobyl – only 1 reported death

Gastrointestinal

CEREBROVASCULAR SYNDROME

• ABOVE 50 GY

• SURVIVAL HOURS TO 3 DAYS

• Prodromal stage occurs within minutes– Nervousness, confusion, skin burning,LOC

• Latent (about 12 hours)- Symptoms lessen

• Manifest – symptoms worsen – Coma– Increase intracranial leak / pressure

• Death – within minutes

Doses above 50 gy

CEREBROVASCULAR SYNDROME

• Nerve cells relay messages to and from the brain

• Damage results in a loss of control to systems

• Above 50 gy death occurs in hours or days

Carlton Ch 13 - p. 208 & 210 & 214

• “AVE” CHEST EXPOSURE - 2 IMAGES• (Ave – Pt meas 23cm pa 40cm lat)• PA 110 KVP 5 MAS 16:1 GRID 400RS

72”• LAT 110 KVP 20 MAS 16:1 GRID 400 RS 72”

• WHAT IS THE PATIENT’S DOSE??

LD 50/30

HIGH DOSES RECEIVED

50% OF THE POPULATION WOULD DIE IN 30 DAYS

# 35 LD 50/30

• NO RESPONSE AT 1 GY (100 RAD)

• RESPONSE SEEN AT 3 GY - 300 RAD

• AT 6 GY – NO ONE IS EXPECTED TO SURVIVE

# 36 CHART OF SPECIES SURVIVAL RATES

Fluoroscopic Procedures Analyzed• (PTCA) Percutaneous transluminal coronary angioplasty • 608,000 procedures per year in U.S. (1997) • effective (whole-body) dose per procedure 5.0 ± 1.9 mSv • Cardiac catheterization, coronary arteriography &

angiography (CA)• may include ventriculography, left- and/or right-heart

studies • 3,870,000 procedures per year in U.S. (1997) • effective (whole-body) dose per procedure 3.1 ± 1.3 mSv

• Upper gastrointestinal series fluoroscopy and radiography (UGI)

• excludes barium swallow examinations • 16,500,000 procedures per year in U.S. (1996) • effective (whole-body) dose per procedure 2.8 ± 1.7 mSv

www.fda.gov/

Proposed Amendments FDA

• would require that new fluoroscopy equipment

• Display the rate, time, and cumulative total of radiation emission

• Filter out more of the lower energy x-rays to reduce dose to patient skin

• Collimate the x-ray field more “tightly” so that it’s used more efficiently

Display Amendment

Collimation Amendment