ForfinalExam• Introduction• MeasurementsandUnits• ElectricalPhenomenaIntheBody• Fluids• Haemodynamics• WavesandSounds• OpticsandVision• EnergyandMetabolism• RadiationPhysics• IdealGasLaw,andRespiration

Themostsensitivecelltoradiationisthe:

RedbloodCellNeuron

Fibroblast(connectivetissue,collogen)Intestinalepithelialcell X

Musclecells

- inMedicalDevices

• X-rays :ionizingradiationandareusedformanytypesofdiagnostictestsMedicalx-raysgenerallydeliverlessthan100mrem

Riskofexposuretoradiationdeceaseswithage

Theriskoffoetaldeathinuteroduetoradiationisgreatestin

ThefirsttwoweeksofpregnancyThesecondtrimesterThethirdtrimesterThroughouttheentirepregnancyThereisnorisk

Thepotentialriskforacutelymphocyticleukaemia(ALL)tobecausedbyradiation

DoesnotdependonageIncreaseswithageDecreaseswithageIsunknown

RadiationinMedicalDevices

• X-rays :ionizingradiationandareusedformanytypesofdiagnostictestsMedicalx-raysgenerallydeliverlessthan100mrem (rem(roentgenequivalent man )iscgs unitofequivalentdose)

x-raytestscanleadtocancerespecially,inchildren,youngadultsandfetusesofpregnantwomen.

• MagneticResonanceImaging(MRI):Usesnon-ionizingradiation(strongmagneticfieldsandradiowaves)andhavenotbeenfoundtoincreasetheriskofcancer,i.e.,saferalternativetox-rays.

InteractswithhydrogennucleusspinintheHionofthewatercontentinthebody

A patient suffers from severe brain damage. He is referred to Al-Salmaniya Medical Complex (Manama) for evaluation of his brain function. You will recommend

CT of the head is not recommended because ……..

EEG exam,, maybe if …..

MRI of the head, why ?

fMRI of the head (Functionalmagneticresonanceimaging)measuresbrainactivity:makinguseofthefactthatblood flow is coupled with the neurological activity of the brain

Nuclear Radiology: uses radioactive methods for imaging

PET study positronemissiontomographyusessmallamountofradioactivematerials/drugs(usuallyinjectedIV)calledradiotracerswhichlocalizesatdiseasedareaswithabnormaltissue(earlystagesofcancers,heartandbraindiseasesinearlystage)-Cancercellsneedmoreenergy,thereforetheradioactivedrug(e.g.radioactiveglucose,Fludeoxyglucose(18F)/fluorodeoxyglucose)accumulatesinit

-PETcameraisusedtodetecttheseareas(β emittingareas)

-benefit:Byidentifyingbodychangesatthecellularlevel,PETmaydetecttheearlyonsetofdiseasebeforeitisevidentonotherimagingtests

UsuallyPETscanisaccompaniedwithCT-scanPET/CT

Not recommended for pregnant women, why

Radiation therapy

• Using high doses of radiation to treat various types of cancer• i.e., Beams of radiation are directed at the cancer to kill of cancerous cells

• X-rays, sometimes protons or other types of energy.

• It kills cancer cells by damaging DNA

• Magnetic Resonance Imaging (MRI): Uses non-ionizing radiation (strong magnetic fields and radio waves) and have not been found to increase the risk of cancer, i.e., safer alternative to x-rays.

- Other Manufactured Devices based on radiation

• Airport and building x-ray scans

• Microwaves, Cell phones and other similar manufactured devices : Long exposure is not recommended to high energy non-ionizing radiation which can damage cell contents, neurological and reproductive harms ( with low probability ).However, debates about harmful low energy non-ionizing radiation such as

microwaves is unsubstantiated, but generally it is safer than ionizing radiation.