RAD PROTPT 2Radiobiologyand Cells

WEEK 7 9RT 2442006

RADIOBIOLOGYRadiation Protection & BiologyCD SERIES 2 - 6RADIATION PROTECTIONAND EFFECTS

CD # 2CELLULAR RADIATION+ STAT CH 4, 5 & 6

# 2 CELLS MADE OF PROTOPLASM

RESPONSIBLE FOR THE METABOLISM OF THE CELLSCOMPOSED MOSTLY OF WATER (80-85%)

CD 2 - # 2

A quick review of interactionsStat Ch 1 & 2

PHOTOELECTRICABSORBTION IS WHAT GIVES US THE CONTRAST ON THE FILM

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DNA IN THE NUCLEUSCONTAINS THE GENETIC MATERIALCONTROLS CELL DIVISION + MULITPLICATIONAND BIOCHEMICAL REACTIONS THAT OCCUR IN THE LIVING CELL

6 DNA IS THE ESSENTIAL INGREDIENT IN THE 46 HUMAN CHROMOSOMESDNA CARRIES THE GENETIC CODE FOR CELL REPRODUCTION AND CELL ACTIVITYDNA EXISTS MOSTLY IN THE NUCLEUS OF THE CELLRADIATION INDUCED CHROMOSOME DAMAGE IS ONE OF THE MOST IMPORTANT REASONS FOR LIMITING RADIATION EXPOSURE.

Repair EnzymesSOME CHROMOSOME DAMAGE CAN BE REVERSED BY REPAIR ENZYMES - ( 5 RADS)IF REPAIR IS NOT POSSIBLE CELL DEATH OCCURS TOO MANY CELLS DIE TISSUE OR ORGAN DAMAGE OCCURS(Rad Therapy therapeutic ratio (p 66)

WHEN DNA DAMAGE RESULTS IN ABNORMAL METABOLIC ACTIVITY THERE CAN BE UNCONTROLLED CELL GROWTH THIS IS WHAT OCCURS IN RADIATION INDUCED MALIGNANT DISEASE. WHEN DNA DAMAGE OCCURS THE EFFECTS MAY NOT SHOW UP UNTIL FUTURE GENERATIONS

CD 2 - # 6

21- CELL DAMAGE FROM RADIATION

CD2 # 21

23 Cell Division How and why radiation effects the human body HITS NUCLEUS DAMAGE TO DNAHITS WATER RADIOLYSIS OCCURS CAN SET OFF A REACTION RESULTING IN CELL DEATHA BREAK IN THE CELL MEMBRANE CAN EXPOSE THE CELL TO OUTSIDE ELEMENTS

CD2 - # 24

CELL DIVISION (#24) Multiplication process where cells divide

MITOSIS SOMATIC CELLS EVERY CELL THAT IS NOT GENETICMEIOSISREPRODUCTIVE CELLSGERM CELLSsperm + eggs

4 PHASES OF MITOSIS

INTERPHASE THE PROCESS BEFORE MITOSIS BEGINSPROPHASE nucleus swells DNA takes structureMETAPHASE MOST SENSITIVE STAGE FOR DAMAGEChromosomes line up in the center ANAPHASETELOPHASE cells split to daughter cells

METAPHASEDURING THIS PHASE CELL DIVISION CAN BE STOPPED AND EVALUATEDCHROMOSOME DAMAGE CAUSED BY RADIATION DAMAGE CAN BE SEEN

CD2 - #28 CELL DIVISION

CD 2 # 33

CELL DIVISION FROM

1 2 481632641282565121024never ending

# 32 MEIOSIS THE SPERM AND OVUM46 Chromosone reduced to 23 for Females +23 for Males to unite during reproduction

34 * CELLULAR EFFECTS OF RADIATION Vulnerability of all cells to Radiation CD 2 - # 34

36 CELL THEORY TARGET THEORY MASTER MOLECULE (DNA Molecule) If this is destroyed the cell can die (Direct or Indirect hit)CD 2 - # 36

CD 2 - # 37 MASTER MOLECULE

CD 2 # 37

CELL DEATH -MASTER MOLECULEUSUALLY DNA HIT

CD 2 # 35

Radiolysispoison water theory

H 2 O molecules -

Ejection of electron = free radical

H2 0 2 = hydrogen peroxide

LET linear energy transfer

The amount of energy that may be deposited in tissue as radiation passesFactor in assessing potential damage to organs/tissues from exposure to ionizing radiation ENERGY = LET - passes through

Damage from LETHigh LET (alpha particles radon)Internal contamination implanted, ingested or inhaledPotiental for irreparable damge

RBE WITH O2Relative Biologic EffectivenessDescribes the capabilities of radiation with differing LETs to produce a particular biologic reaction Weighting factor (EqD) equivalent dose

TYPES OF RADIATON(ALL CAUSE IONIZATION)PARTICULATE(HIGH LET)ALPHABETAFAST NEUTRONS

More destructiveELECTROMAGNETIC(LOW LET)XRAY GAMMA(damaged caused by indirect action = free radicals can be repaired)

Quality (Weighting) FactorHow dangerous the type of radiation isAlpha + fast neutrons = 20X-ray, Beta, Gamma = 1(why fluffy died!)

OER Oxygen Enhancement RatioOXYGEN IN CELL INCREASES LET PT IN HYPERBARIC TREATMENT AND ON OXYGENLET IS AFFECTED BY OXYGEN

CD 2 - # 38

SLIDE # 39

# 39 RADIAITON DAMAGE TO DNAEFFECTS OF RADIATION DAMAGEDNA LOSS OF CONTROL OVER CELL FUNCTIONPRODUCTION OF DAUGHTER CELLS WITH GREATER LOSS OF CELL FUNCTION Inablity to divide or reproduceOTHER CELL COMPONENTSLOSS OF IMPORTANT CELL FUNCTIONSPRODUCTION OF TOXIC WASTESCELL DEATH

CD 2 # 40

#40 RADIATION DAMAGE TO CELLS NUCLEUS

INSTANT DEATHREPRODUCTIVE DEATHAPOPTOSIS- PROGRAMMED CELL DEATHMITOTIC, OR GENETIC DEATH OR DELAYINTERFERENCE OF FUNCTIONCHROMOSOME BREAKAGE

INSTANT DEATH 1000 GY (100,000 RAD)

REPRODUCTIVE DEATH - 1 10 GY ( 100 1000)APOPTOSIS CELL DEATH BEFORE DIVISIONMITOTIC/ GENETIC DEATH CELLS DEATH AFTER DIVISIONOR DELAY JUST BEFORE CELL DIVISIONINTERFERENCE OF FUNCTIONMAY BE REPARIED BY ENZYMESOR PERMANENTYLY DAMAGE CELL FUNCTIONCHROMOSOME BREAKAGE CAUSE GENETIC MUTATIONS IN FUTURE GENERATIONS

# 43 IONIZING RADIATION CANPERMANENTLY DAMAGE CELL FUNCTIONSTEMPORARILY INTERFERE WITH CELL FUNCTIONSCAUSE CHROMSOME BREAKAGECAUSE GENEITC DAMAGE IN FUTURE GENERATIONS

ALL CELLS ARE NOT EQUAL# 44 CELL RADIOSENSITIVITY

SOME CELLS ARE MORE:SENSITIVE TO DAMAGEMORE EAISLY REPAIREDMORE QUICKLY REPLACEDAll of these factors affect the radiosensitivity of the cell

The Law of Bergonie & Tribondeaux

Cells that are most sensitive to radiationYoung immature cellsStem CellsHighly dividing (mitotic) cells CD 2 #45

RADIOSENSITIVY IS REALTED TO CELL FUNCTION, CELL MATURITY AND CELL DIVISION RATECONVERSLY CELLS LEAST SENSITIVE ARE:CELLS THAT REPRODUCE SLOWLYSHORT MITOTIC CYCLELEAST DEGREE OF SPECIALIZATIONMOST MATURE

CELLS THAT REPRODUCE THE MOST SPEND THE MOST TIME IN THEIR REPRODUCTIVE STATE

CD 2 - #47

CELLS MOST SENSITIVE:

WHITE BLOOD CELLS LYMPHOCYTESRED BLOOD CELLS ERYTHOROCYTESBASAL CELLS OF THE SKININTESTINAL CELLSDEVELOPING NERVE CELLS OF EMBRYOIMMATURE REPRODUCTIVE CELLSEPITHELIAL CELLS THAT LINE BLOOD LYMPHATIC VESSELLS (80% BODY)

LYMPHOCYTE PG.103SUBGROUP OF WBCONLY LIVE FOR 24 HOURSARE MANUFACTURED IN BONE MARROWMOST RADIOSENSITIVE BLOOD CELL25 RADS CAN DEPRESS # OF CELLSLESS ABILITY TO FIGHT INFECTIONS

RADIOINSENSTIVE MATURE BONE CELLSMATURE NERVE CELLSMUSCLE CELLSMATURE REPRODUCTIVE CELLSMATURE RED BLOOD CELLSSCAR TISSUE CELLS

CD 2 - # 48

RHB SYLLABUS PG 47MOST LEAST SENSITIVELYMPHOCYTES (WBC)ETHROCYTES (RBC)EPITHELIAL CELLS (SKIN)ENDOTHELIAL CELLS (LINE BLOOD VESSELSCONNECTIVE TISSUE CELLSBONE CELLSMUSCLE CELLSNERVE CELLSBRAIN CELLS

5-4 pg 101

Muscles & Nerve CellsHIGHLY SPECIALIZEDDO NOT DIVIDE SO ARE REALTIVELY INSENSITIVE TO RADIATION

GERM CELLS in malesHIGHLY RADIOSENSITIVE = DEPENDS OF STAGE OF DEVELOPMENTMATURE SPERM LESS SENSITIVEUNDEVELOPED VERY SENSITIVE 200 RADS CAN CAUSE TEMP STERILITY FOR 12 MONTHS (500- 600 permanent)10 rads possible genetic mutations (future generations) wait a few months

GERM CELLS in Females(present at birth)HIGHLY RADIOSENSITIVE = DEPENDS OF STAGE OF DEVELOPMENTMature ovum do not divide frequently (20-30 yrs old - least sensitive)Immature very sensitiveIf exposed ova meets sperm may contain damaged chromosomes passing genetic damage to offspring =CONGENTIAL ABNORMALITIES

RADIATION DAMAGECHROMOSOME ABBERATION SEENWITH HLC FLUOROSCOPYLONG STUDIES (CARDIAC CATH)

RAD PROTECTION & RADIOBIOLOGY CDS3456NOT YET ON POWERPOINTIn class highlights of CH 4/5/6 Stat Nice to know vs Need to know!

The use of higher kilovoltage (kVp) and lower milliamperage and exposure time in seconds (mAs) reduces patient dose. A, The use of high kVp and low mAs results in a high-energy, penetrating x-ray beam and a small patient absorbed dose. B, The use of low kVp and high mAs results in a low-energy x-ray beam, most of which is easily absorbed by the patient. C, Example of a higher-kVp, lower mAs technique resulting in a 70% reduction in patient exposure without significantly compromising radiographic quality

More to follow ..Ch. 6 STATCD 3 /4 / 5/ 6