Radiation Biology Objectives Test 1 2024 PDF

 Radiobiologythestudyoftheaction of ionizingradiation onliving organisms specifically howradiation interactswithbiologicaltissues at thecellularandmolecularlevels 2 Early LateEffects Earlyeffectsoccurshortlyafterexposure toradiationsuch as skinburnsor acuteradiationsyndrome Lateeffectsappearmonth...

 Radiobiologythestudyoftheaction of ionizingradiation onliving organisms specifically howradiation interactswithbiologicaltissues at thecellularandmolecularlevels 2 Early LateEffects Earlyeffectsoccurshortlyafterexposure toradiationsuch as skinburnsor acuteradiationsyndrome Lateeffectsappearmonths oryears after exposure andcanincludecancercataracts andgeneticmutations 3 Macromolecules intheHumanBody thefivetypesofmacromolecules are carbohydra lipidsproteinsnucleicacids andwaterEachplaysa crucialroleinthe body'sstructure andfunction 4 MostSensitive andAbundant Macromolecules nucleic acids DNA RNA are themost sensitivetoradiationWateristhemost abundant macromolecule makingup about60 of the humanbody 5 Definitions Homeostasis thebody'sabilitytomaintain astableinternal environmentdespite changes inexternalconditions Catabolism thebreakdown ofcomplexmoleculesintosimplieronesreleasingenergy Anabolism the synthesis of complexmoleculesfromsimplieronesrequiringenergy Metabolism the sum of all chemical reactions inthebody including catabolism and anabolism 6 TwoTypesofNucleicAcids DNA deoxyribo nucleicacid andRNA ribonucleicacid DN carriesgeneticinformationwhileRNA isinvolved inproteinsynthesisandothercellularprocesses 7 Radiation Sensitivity ofcells HighSensitivity Lymphocytes spermatogoniaerythroblastsandintestinalcryptcells Intermediatesensitivity endothelialcells osteoblasts fibroblastsand spermatocytes Sensitivity  1 I 1 8 LawofBergonie Tribondeauthislawstatesthatcellsaremore radiosensitive if theyare less differentiatedhavea highermetabolic ratedividerapidlyandare intheembryonicorimmature stage 9 Factors AffectingRadiosensitivity PhysicalFactors LinearEnergyTransfer ET Relative biologicaleffectivenessRBEandDos Rate BiologicalFactors cellcyclestageoxygenpresence oxygenenhancementratio OER andage of the organism 10 LinearEnergyTransfer ET theamountofenergytransferredbyionizingradiation tothematerial it passesthroughperunitdistance HigherLETradiation likealphaparticles causesmoredamageto biologicaltissuesthanlowerLETradiation likex rays 11 Relative BiologicalEffectivenessRBE RBEcomparesthe effectiveness ofdifferenttypes ofradiation inproducingbiologicaleffectsIt'sdefined astheratioofthedoseofreference radiation likex rays tothedoseoftheradiation inquestionneededtoproducethesame biologicaleffect 12.1Fractionation andProtraction Fractionation dividingthetotalradiationdoseintomultiplesmallerdosesgivenover a period oftimeThisallowsnormaltissuestorepairbetweendoses reducingsideeffects Protraction extendingthedurationoverwhich a radiationdose isdelivered whichalso allowstimefortissuerepair 13 Recovery theprocessbywhichcellsrepairdamage causedbyradiationexposure leading to recovery of normaltissuefunction 14 OxygenEnhancementRatioOER thepresence ofoxygenenhancestheeffectsofradiationOERis theratiooftheradiationdoserequiredtocause a particular biologicaleffectin a oxygendeprived environmenttothedoserequired in an oxygenrichenvironment 15 Dose Response RelationshipCurves thesecurvesillustratehowthe biological responsechangeswithvaryingradiationcloses Differenttypesofcurvesincludelinearlinear quadratic andthreshold curves 16 Effect ofAge Sexon Radiosensitivity Ageyoungerindividuals aregenerallymoreradiosensitiveduetotheirhigher rate ofcelldivisionElderlyindividualsmayalso bemore sensitivedue to reduced repai mechanisms Sev therecan bedifferences in radiosensitivitybetweenmales andfemalesoften dueto hormonal differences 17 Combinations ofDoseResponse Relationships differenttypesoftissuesandeffectscan havevarying dose response relationshipsUnderstandingthese combinations helpsinpredictingand managingradiationeffects 18 Extrapolationestimatingtheeffectsofradiationatdosesthatarenotdirectlyobservedby extendingtheknowndoseresponse data 19MostImportantDoseResponseRelationshipinDiagnosticRadiology thelinearnonthreshold LNT modelisoftenusedwhichassumesthatanyamountofradiationexposurecarriessomeriskofcausing harm 20.1Stochastic vs Deterministic Effects Stochastic Effects randomeffectsthatoccur chance anddonothave a thresholdsuch by ascancer Deterministic Effects effectsthathave a thresholddosebelowwhich theydonot occursuch asskinburnsandradiationsickness 21 AcuteRadiationSyndrome aconditioncausedbyahighdose ofradiationoverashort periodleadingto symptomssuchas nauseavomitingdiarrhea anddecreasedbloodcellcounts 22 InverseSquareLaw aphysicalprinciplestatingthattheintensity ofradiationdecreases distance Formula I istheintensity Io istheinitialintensity and d isthe I E distance where 23 AlphaRadiation atypeofionizingradiationconsistingofalphaparticles It hashighionizing powerbutlowpenetrationdepthmeaningitcanbestoppedbyasheetofpaperorhumanskin Study ws book and notes Test Review Thursday89questionslong allmultiplechoice What's an example ofhighLETradiation AlphaParticle LowLETradiation DiagnosticV Rays WhatistheLET of an x ray 3 Arexrayspenetration orionizing Penetrating Whatare thetwomostsensitivecellsinyourbody LymphocytesandSpermanigonia themostsensitive cellinyourbodyis Lymphocytes sensitivetoradiation if itgoes throughmitosis KnowLaw of Bergionie Theoxygeneffectdoesoxygenplay arolewithhighorlowradiation LowLETradiation ifitshighLETradiationoxygendoesn'treallymatter WhatarethetwotypesoflowLETradiation X diagnostic andGamma AlphaandbetaishighLET Aremusclecellssensitive toradiation No arenervecellare lymphocytes Yes Fractionation inradiationtherapy a break betweendoses Protraction isalowdoseover a longtimeperiod Whatarethethreethingsthat contribute to LETradiation HighMAsHighCharge andlow velocity Cancellsrecoverfromradiation Yesthatswhy we dofractionation  Thedoseresponserelationship ifyousawanydoseregardlessofthesizewhatproduced an effectisthatthresholdor non threshold Nonthreshold ifyouhavetohave a certainamountforanyeffecttoshowupthen it is Threshold What isthe differencebetweenlinearandnonlinearwhatdoesittellus Predictwhat gonnahappen linear nonlinearweknowsomethingisgonnahappenbutcan'tpredict what If wehave a linearcurve ifwehave a steeponeand a flatonethenwhichone is gonnabemoredamaging to our body Steep Thesteepcurvetakeslessof the dose increment and thex axisimprovesmore of th effect Whichdose response relationship are ourdosebasedon Linearnonthreshold intercets x yaxisatzerozero Astherateofgrowthorproliferationincreases isitgoingtobecomemoreorlesssensitive toradiation ifitshighproliferationitsmoresensitiveto radiation Whatsprotraction lowdoseover a longperiodoftime What the termfor a maturecell Differentiated immature stemcell undifferentiated Whats the mostsensitivemacromoleculeinourbody NucleicAcids What is the differencebetweenAnabolism andcatabolism Catabolism isbreaking downinto smallerways Anabolism isbuildinguptogetherthey make metabolism Earlyoccurs in fewhours lateeffectoccursyearslater Whatdoes itmean to extrapolate information takeinformationfrom inlastslides inournotes  Arelymphocytes highor low sensitivity High musclecells low spermatids intermediate RBEfor diagnosticradiation I LET 3 If it has ahigh metabolicrate is it sensitive Yes 3things determine LET masschargevelocity DoesLETexpressquantity or quality Quality Thelateeffects of diagnostic x raysare theylinear or nonlinear Linear nonthreshold InverseSquare law anotherterm forimmature cell undifferentiated or stemcells if acellis highlymitotic is itsensitive toradiation yes Whenare alpha particlesmovedangerous to our body Whenthey are internal when in annoxycommunity no oxygen andlowoxygen and mosttissue ismoresensitive when it isoxygen Whenisradiationexposurethemostdamagingto us highdosewhole body are diagnostic trayhighor lowLET Low and lowenergy doescataracts have a threshold Yes and the cross v avisabove zero Scatter partialtransferof energy to matter Absorption absorbed in the body Attenuation decrease in intensity at the exitsurface of the bodyversusthe entrance ESEor entryskinexposurethats the part of the body that gets the most exposure to radiation doesradiationquality haveanythingto do withbiologicdamage Yes doesthesize ofthe irradiatedarea have anythingtodo withdamage yes alphaparticlesdon'tpenetrateverydeepstopat theskin are youngcellsresistant or sensitive Sensitive are stemcells sensitive iftheyhave a low proliferation rate resistant proliferation reproducingcells if let increases what happens to RBE increases would increase filtration or short SID cause more skindose ShortSID is the rectumor smallbowelmore sensitive Small bowel nervoussystem is resistant Stochastic all ornothing nonthreshold arereproductive organs andbloodformingorganssensitive Yes closelimitto eyes 150 doesthequality of radiation haveanything todowithdamage yes doestypeoftissue yes doesfractionation yes Whatare thetwotypesof electromagneticradiation V andgamma particulates alpha and beta isneuroblast and retroblastsensitive yes on the doseresponse curvehowdoyouknowthethreshold itsabove 0 on the x axis  i l r I istissuemoresensitiveunderoxygenated or unoxygenated oxygenated if we increasegridratiodoesthiscausemore orlessptexposure more 16 1 6 5 1 2 Whatis the mainsource ofscatter the patient knowtissuetable Whatdoyouclassifylivercells intermediate 3 cardinalprinciples of radiationsafety timeshieldinganddistance Somaticeffect justtheindividualpersongetsexposed canbe a fetus fluoremovecloserto pt onlaptop portable fluore 12inches minimumsourceof the skin distance stationary isinches leastpt exposure lowMAs highkup andlowgrid ratio deterministic doeshave a threshold themostsensitive part of any humanbody Nucleus and the chromosome Learn dose response curve lookonlaptop dogammarays have a charge no nomasslow let what doeshave a charge electron if photonabsorptionincreases whatdoesthat mean toptdose it goes up radiation weightingfactor qualityof radiation Laptop review Comptonour exposure outer photoelectric inner highenergy photoelectric lowenergy