30459663 Radiology Physic Review

8/12/2019 30459663 Radiology Physic Review

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ADIOLOGY PHYSICS EVIEW



hat is a Photon? ,Under the photon theory of li ht a photon

( )is a dis!rete "#ndle or $#ant#% of ( ) .ele!tro%a neti! or li ht ener y Photons , ,are al&ays in %otion and in a 'a!##% ha'e a

,!onstant speed of li ht to all o"ser'ers at (the 'a!##% speed of li ht %ore !o%%only

) = .(#st !alled the speed of li ht of ! ) **+ , -. + / .% s

In physi!s , a $#ant#% ( :pl#ral $#anta ) is the

%ini%#% #nit of any physi!al entity in'ol'ed in an.intera!tion

A photon , , ,for e,a%ple is a sin le $#ant#% of li ht "and %ay th#s "e referred to as a li ht $#ant#% ".

http://en.wikipedia.org/wiki/Physics


http://en.wikipedia.org/wiki/Photon


http://en.wikipedia.org/wiki/Light_quantum








/#n Photon /a!ts ,0he photon is an ele%entary parti!le despite the fa!t that it . ,has no %ass It !annot de!ay on its o&n altho# h the ener y of ( )the photon !an transfer or "e !reated #pon intera!tion &ith

.other parti!les Photons are ele!tri!ally ne#tral and are one of ,the rare parti!les that are identi!al to their antiparti!le the

antiphoton

1asi! Properties of Photons , . . .A!!ordin to the photon theory of li ht photons

• , = .%o'e at a !onstant 'elo!ity ! ) **2* , -. + / ( . . "% s i e the speed of"),li ht in free spa!e

• .ha'e 3ero %ass and rest ener y

• ,!arry ener y and %o%ent#% &hi!h are also related to the fre$#en!y n# =and &a'elen th la%d"a of the ele!tro%a neti! &a'e "y E h n# and p

= / .h la%"da

• / / .!an "e destroyed !reated &hen radiation is a"sor"ed e%itted

• - ( . . )an ha'e part i! le li4e intera!t ions i e !ollis ions &ith le!trons and other par ti! les s#!h as in the Co%pton

.ffe!t



:E,pos#re 0he a%o#nt of ioni3ations -prod#!ed in air "y , ray or a%%a. ,photons 0he #nit is Roent en the SI #nit

.is the !o#lo%" per 4ilo ra%



:A!ti'ity A %eas#re of the intensity of radioa!ti'ity in a sa%ple of %aterial $#antified "y

the n#%"er of radioa!ti'e disinte rations o!!#rrin in a

i'en $#antity of %aterial per . ,#nit ti%e Unit is the !#rie the

.SI #nit is 1e!$#erel



( ):A"sor"ed Dose D 0he ener y i%parted to %atter "y ioni3in radiation per .#nit %ass of irradiated %aterial 0he

a"sor"ed dose is e,pressed in #nit

; ( ).rad the SI #nit is the ray Gy



( ):Dose e$#i'alent H 0he prod#!t of ( : )a"sor"ed dose in rads SI Gray in, ( )tiss#e a $#ality fa!tor 5 and other

( ).%odifyin fa!tors 6 Dose e$#i'alent

is e,pressed in the #nit re%( )ADIA0IO6 E5UIVALE60 7A6 , the SI #nit is the Sie'ert .

=Dose E$#i'alent rads , 5 , 6







:Photoele!tri! Effe!t O!!#rs "et&een

ti htly "o#nd inner shell ele!tron and - .in!ident , ray photon 0he inner shell ele!tron filled "y o#ter shell ele!tron

and e,!ess ener y is e%itted as

.!hara!teristi! radiation 0he photoele!tri! effe!t o!!#rs &hen photon is totally a"sor"ed "y the inner shell .ele!tron and a photoele!tron is e%itted



PHOTOELECTRIC

EFFECT

In%ident p oton

otoele%tron

C ara%teristi%x$ra'



:Co%pton S!atter In Co%pton s!atter in!ident photon intera!t &ith loosely

"o#nd o#ter shell ele!tron res#ltin

.is s!attered photon 0his is a !a#se of %ost s!attered radiation in

.dia nosti! radiolo y



C34 T35 SC&TTERI5-

In%ident p oton

Compton Ele%tron

S%attered oton



:Coherent s!atter - a ter% so%eti%es #sed for Raylei h;s!atterin In!ident photon !han es

.dire!tion &itho#t losin ener y

i%ilar &ith that of 1re%sstrahl#n-ray prod#!tion



Rayleigh Scattering

In%ident p oton

S%attered p oton



:Pair Prod#!tion Hi h ener y photon intera!t &ith the n#!le#s of an

.ato% 0he photon disappear and ener y is !on'erted in to an

.ele!tron and positron



&IR R3,6CTI35

In%ident p oton

e$

e7

ele%tron

positron



:Photodisinte ration When a hi h ener y photon is a"sor"ed "y a n#!le#s res#ltin in i%%ediate

.disinte ration of the n#!le#s



-Dia nosti! , rays are prod#!ed &hen

ele!trons &ith hi h ener ies of ). .to -8. 9e' are stopped in %atter-: rays are prod#!ed "y t&o

:different pro!ess 4no&n as

.- 1re%sstrahl#n. -) Chara!teristi! , ray prod#!tion



( )1re%sstrahl#n 1rea4in or General-: rays are prod#!ed &hen in!ident

ele!trons intera!t &ith n#!lear ele!tri! fields &hi!h slo& the% do&n

.and !han e their dire!tion So%e of the

-4ineti! ener y is e%itted as , ray

. -photon 1re%sstrahl#n , ray prod#!e .!ontino#s spe!tr#% of radiation

-1re%sstrahl#n , ray prod#!tion

in!reases &ith the a!!eleratin

( ) ( )'olta e 9V and ato%i! n#%"er 3 of.anode



:Chara!teristi! radiation Chara!teristi! radiation is prod#!ed &hen the inner shell

ele!tron of the anode tar et are e(e!ted "y

.the in!ident ele!tron 0he inner shell 'a!an!y are filled "y o#ter shell ele!trons and the ener y differen!e is e%itted as !hara!teristi!

.radiation E,!ess ener y %ay also "e e%itted as A# er

.ele!tron-9 shell ele!tron is e%itted only if in!ident

-ele!tron ha'e ener ies reater than 9 shell ."indin ener y

= =/or t#n sten 2. 4' 7oly"den#% ). 4'- -L shell ele!tron also nor%ally a!!o%panies 9 . - -shell radiation L shell !hara!teristi! , rays

ha'e 'ery lo& ener ies and are a"sor"ed "y the -lass of the , ray t#"e .



22

X Ray tube components

• Cathode : heated filament which is thesource of the electron beam directedtowards the anode

• tungsten filament

• Anode ( stationary or rotating ): impactedby electrons, emits X Rays• Metal tube housing surrounding glass (or

metal) X Ray tube (electrons are

tra eling in acuum)• !hielding material (protection againstscattered radiation)





arts o8 8ixed &node x$ra' Tube

.ig Tension -enerator Cat ode&node

T e -lass Envelope and 9a%uumT e Tube s ieldCooling me% anism0iltration me% anism







2"

Cathode structure

• Cathode includes filament(s) andassociated circuitry • tungsten material : preferred because of

its high melting point (3370 C)• slow filament e!aporation• no arcing (spar")• minimum deposit of # on glass en!elope

• #o reduce e aporation the emissiontemperature of the cathode is reached $ustbefore the e%posure

• in stand$by% temperature is "ept at &' 00 C so that 700 C emissiontemperature can be reached within a

second



2&

• Modern tubes ha e two filaments• a long one : higher current'lower resolution

• a short one : lower current'higherresolution

• Coulomb interaction ma es the electronbeam di ergent on the tra el to theanode

• focal spot increased low r m =>r solut on • o l s t on o@= =

l trons s ru l ! @ @ @ =

Cathode structure



T e &node& pie%e o8 tungsten in a 8orm o8 plate o8 2mm t i%k ;re%tangular or %ir%ular in s ape larger t an t e 8o%al area isembedded on a t i%k %opper rod

T is is essentiall' a metal plate to re%eive t e ele%tron< i% bombard itIt is so designed t e t at bombarded ele%tron gives greatamount o8 eat(AAB) and small amount o8 x$ra'(1B)&node as relativel' larger sur8a%e area so produ%ed eat%an be dissipated and tube damage %an be prevented

Tungsten and %opper is used 8or t is purpose but < '



Tungsten D &s a target $.ig melting point; ig atomi% number (e88i%ientto produ%e x$ra'); good %ondu%tor o8 eat; %an be s aped andmade smoot as re uired&s a 8ilament $.ig t ermioni% emission; %an be %onvertedinto <ire; ig melting point and does not vapori@e easil'

Copper$-ood %ondu%tor o8 eat so dissipates eat to outside to outsideo8 tube and also serves as ele%trode o8 positive pole (anode)< ere ig :9 %urrent is %onne%ted



-H o & to p rod # !e fa ste r an d p o& e rf# l , ray?

0h e la r e r th e d iffe re n !e " e t& e en in th e ( )!h a r e p o ten tia ld iffe re n !e " e t& een a n od e

an d !a th o d e th e fa ste r th e e le !tro n .a !!e le ra te to & a rd s th e a n o d e

,0h e fa ste r th e e le !tron o es th e h a rd e r th e y -!o llid e & ith th e a n o d e a n d % o re p o& e rf# l ,

.ra y a re p ro d # !e d



- W h a t is th e e ffe !t o f 4V P a n d % A s on , ray

p rod # !tio n ?

–% A s In !rea sin th e % A s it in !rea se th e - .$ # an tity of th e , ra y p ro d # !tion

—4V p In !rea se in 4V P it in !rea se s th e $ # a lity - .of th e , ra y p rod # !tion



X Ray tube characteristics

• Anode mechanical constraints• Μα τ ε ρ ι α λ : τ υ ν γ σ τ ε ν ,ρ η ε ν ι υ µ , µ ο λ ψ β δ ε ν υ µ ,γ ρ α π η ι τ ε

• *ocal spot : surface of anode impacted by

electrons• Anode angle• +is and annular trac diameter (rotation

fre uency φ ρ ο µ 3,000 τ ο 10,000ρ ε ο λ υ τ ι ο ν σ /µ ι ν υ τ ε )

• *hic"ness µ α σ σ α ν δµ α τ ε ρ ι α λ ο λ υ µ ε )

η ε α τ χ α π α χ ι τ ψ• Anode thermal constraints

• -nstantaneous power load (heat unit)• .eat loadin time cur e



0o%using o8 t e ele%tron beam

T e ele%tron spreading a<a' 8rom t e 8ilament are broug t toget er b' means o8 an ele%tri% 8ield < i% exist bet<een anode and %at ode

T e 8ilament sits in a slot in t e %at ode

T e 8ilament and slot are %are8ull' designed in s ape; si@e and position so t at t e emitted ele%tron %an onl' leave t e 8ilament

t roug t e slot

' t is ele%tron leaving t e 8ilament %omes toget er in a beam so asto %over small area on t e anode; also %alled 03C& S 3T o8 x$ra'tube

0o%al Spot T e exa%t area o8 t e anode < ere t e ele%tron it t eanode

oca spo s e an mag ng



/

oca spo s ,e an mag nggeometry

• *ocal spot 0arge image unsharpened• -mpro ing sharpness small focal spot si1e

• *or mammography focal spot si1e ≤ 0.4 µ µ ν ο µ ι ν α λ

• !mall focal spot si1e ρ ε δ υ χ ε δ τ υ β εο υ τ π υ τ (λ ο ν γ ε ρ ε ξ π ο σ υ ρ ετ ι µ ε )

• 0arge focal spot allows high output (shorter

e%posure time)• alance depends on organ mo ement (fast mo ing

organs may re uire larger focus)



3

-node angle

• #he 0ine4*ocus principle• Α ν ο δ ε τ α ρ γ ε τ π λ α τ ε η α σ ασ η α π ε τ η α τ ι σ µ ο ρ ερ ε χ τ α ν γ υ λ α ρ ο ρε λ λ ι π σ ο ι δ α λ τ η α νχ ι ρ χ υ λ α ρ

• τ η ε σ η α π ε δ ε π ε ν δ σ ο ν :• φ ι λ α µ ε ν τ σ ι ζ ε α ν δ

σ η α π ε• φ ο χ υ σ ι ν γ χ υ π σ α ν δ

π ο τ ε ν τ ι α λ• δ ι σ τ α ν χ ε β ε τ ω ε ε ν

χ α τ η ο δ ε α ν δ α ν ο δ ε• Ι µ α γ ε ρ ε σ ο λ υ τ ι ο ν

ρ ε θ υ ι ρ ε σ α σ µ α λ λ φ ο χ α λσ π ο τ

• Η ε α τ δ ι σ σ ι π α τ ι ο ν

ρ ε θ υ ι ρ ε σ α λ α ρ γ ε σ π ο τ





&

• #he heel effect is not always a negati e factor• -t can be used to compensate for different

attenuation through parts of the body• *or e%ample:

• thoracic spine (thic er part of the patient towardsthe cathode side of the tube)

• mammography

-node heel effect



Conditions necessary for theproduction of .$rays

• #here must be a .igh 7oltage (potentialdifference)

•• #here must be *ast Mo ing 8lectrons9•• #here must be a #arget9

•• -t must be in 7acuum9







Production of.$ray

anodecathode





T e gas envelope and va%uumT e ele%tron t at leave t e %at ode ave unimpeded passage tot e anode

I8 t ere is no va%uum it %ollide <it t e gas <it in t e tube asa result o8 < i% t e' loose t e energ' be8ore %olliding <it

t e anodeT e end result <ould be produ%tion o8 less intense and less

penetrating x$ra'



T e tube s ield4ade up o8 %'lindri%al aluminum or aluminum$lead allo'

It <ill not allo< an' x$ra' to es%ape out o8 t e x$ra' tube expe%tt roug t e glass <indo< < i% is provided to allo< onl' t e

primar' beam 8rom 8o%al spot

4etalli% %asearound t e x$ra' tube t at provides prote%tionagainst radiation risk and ele%tri%al risk T eoreti%all' it s ould

be ra' proo8 and s o%k proo8

Ra' proo8 is impossible a%%ording to p 'si% o8 x$ra'

absorption but signi8i%antl' redu%es amount o8 radiation%oming t roug t e absorber <it in e sa8et' limit

C li 4 % i 8 $ ' t b



Cooling 4e% anism o8 x$ra' tube&mount o8 eat produ%tion=:9 x m& x Se%onds

T e greater t e 8a%tor are used t e more eat are produ%edI8 t e dissipation o8 eat <ere not to take pla%e simultaneousl'<it eat produ%tion; t e melting point o8 tungsten(**F#?%)<ill

be soon rea% ed

.eat dissipation o%%urs b'$1 Condu%tion$t roug t e solid part o8 anode$%opper

2 Conve%tion$t roug t e oil surrounding t e tube(glass and%opper blo%k transmit t e eat to oil in < i% tube is immersed

* Radiation$o%%ur t roug t e va%uum o8 t e tube to glassenvelope



0iltration in t e x$ra' tube

G$ra' beam %omprises man' <avelengt in it & 8ilter a%ts b'

absorbing pre8erabl' t e useless but arm8ul longer<avelengt s in t e beamT ere b' onl' s orter <avelengt x$ra' leaves t e tube < i%<ould %ast s arp radiograp i% image

T is use8ul beam still as to pass t roug1 T in <indo< in t e glass envelope2 3il <it in t e s ield* ead lined plasti% %over aperture %all t e portal(t ese are also %alled in erent 8iltration o8 x$ra' tube )





S%attered Radiation> en x$ra' strikes t e bod' part ;se%ondar' radiation are

produ%ed < i% ave longer <avelengt t an t e primar' beamT ese se%ondar' radiations are s%attered in all dire%tion and

produ%e a veil o8 8og on t e diagnosti% x$ra' 8ilmS%attered radiation a88e%t t e image o8 part at a distan%e 8rom t e8ilm b' 8ogging

Small parts like ands and 8eet s o<s negligible s%attering but pelvi% and trunk s o<s maximum s%attering

Control o8 s%attered radiation



Control o8 s%attered radiationSome radiograp i% a%%essories are used to %ut do<n t e se%ondar'radiation 8og1 S utters/diap ragms $T e s utter diap ragm ave lig tingarrangement above t em; in%orporated inside t e tube s ield < i%s o<s t e 8ield si@e (a8ter operating t e s utters) on t e patientHs bod'2 Cones Cones o8 di88erent si@es and s apes are available to restri%t 8ieldo8 radiograp ' to t e obsolete re uired si@e eg$mastoid %one ; 5S %one



. : G rid 0 h ese a re th e d e ' i!e s & h i!h !o n sist o f ( )se rie s o f a lte rn a te strip e s o f le a d o r t# n sten an d

( ). -& o od o r si% ila r rad io l# !e n t % a te ria l 0 h e , ray p en e tra te s rid an d fa llon th e fil% to p ro d # !e

. -i% a e 0 h e s!a tte red , ra y a re !# t o ff " y le ad.strip e s

- : “ ” (0yp i!a lly ) 8 ti% es 1 # !4y fa !to r o r rid ra tio 0h e re la tion o f th e h e i h t o f th e le ad strip s to th e & id th .o f th e n o n o p a $ # e % a te ria l" e t& e en th e%

: , : , : )C o % % on rid ra tio s a re ) + ) - ) a n d ) -

:G rid s are % a in ly t& o typ e s. : ( )- S ta tin o n a ry rid s LY S H O L7 G rid. : . - .) 7 o ' in G rid a Po tte r " # !4y rid " O s!illa tin rid.! C ross rid



A S%attered and primar' x$ra' p otons rea% ingt e same point P on 8ilm B S%attered p oton isremoved b' antis%atter grid; < ile primar'

p oton gets t roug





G$ra' 0ilm Cassette ,iagram demonstrating as eet o8 x$ra' 8ilm bet<een t<o 8luores%ents%reens <it in a lig t$proo8 %assette



:E%#lsion /il% !onsist of an appro,i%ately -. %i!ro%eter thi!4 e%#lsion s#pported "y %ylar

."ase &hi!h is -8. %i!ro%eter thi!4 0he e%#lsion !ontains sil'er halide rains

&hi!h !an "e sensiti3ed "y radiation or

.li ht to hold a latent i%a e ( )Se'eral li ht photon appro,i%ately B %#st ."e a"sor"ed to sensiti3e ea!h rain

% i 8 0il



ro%essing o8 0ilms1 ro per mixing o8 t e % emi%al solutiona%%ording to manu8a%ture instru%tion2 6nloading o8 t e exposed 8ilm 8rom t e%assette; <riting patient I, <it %op'ing pen%iland t en mounting it on to proper anger

* ,eveloping ro%ess" Rinsing pro%ess! 0ixing pro%essF >as ing ro%ess+ ,r'ing pro%ess



:De'elopin De'elop%ent of radio raphi! fil% -is a !he%i!al pro!ess &hi!h red#!es , ray

-e,posed sil'er "ro%ide of the , ray fil% into

,plain %etalli! sil'er in a finely di'ided .for% to "rin o#t the latent i%a e

Sensiti3ed rains are red#!ed in the .de'eloper "y the addition of ele!tron

A de'eloped rain res#lts in a spe!4 of .sil'er that appears "la!4 on the fil% Grains &ith no latent i%a e are also de'eloped "#t

at a %#!h slo&er rate

Contains B %ain !he%i!al %i,ed &ith



distilled &ater. / :- De'elopin Red#!in a ent ) %ain !he%i!als. -a Hydro$#inone slo&ly "#ild #p "a!4 tones

and !ontrast. –" Elon $#i!4ly "#ilds #p ray tones.) Preser'ati'e a ent !ontains sodi#%

s#lfite &hi!h prote!ts the rapid o,idation

of the de'elopin a ent. : , A!ti'ator Contains sodi#% !ar"onate also

!alled al4ali3er &hi!h pro'ides ne!essary .al4aline %edi#%

. :B Restrainer Contain potassi#% "ro%ide

restrain the de'elopin a ent fro% de'elopin the #ne,posed sil'er halide.!rytals

:0he fi,in Stops f#rther de'elop%ent th#s



:, p p ,esta"lishin a per%anent i%a e on the fil%

,re%o'es dissol'ed sil'er halide !rystals .hardens the e%#lsion

:0here are B %ain !he%i!als. / :- /i,in a ent !learin a ent A%%oni#%

–thios#lfate or sodi#% thios#lfate Re%o'es the #ne,posed and any re%ainin #nde'eloped sil'er

.halide !rystals. : –) Preser'ati'e Sodi#% s#lfide slo&s the rate of o,idation and pre'ents deterioration of the

.fi,in a ent. : : Hardenin a ent Potassi#% al#% Shrin4s and

.hardens the elatin e%#lsion. :B A!idifer Contain a!eti! a!id &hi!h f#rther

stops de'elop%ent "y ne#trali3in the al4ali of .the de'eloper

O h )!h %i! l



:Other ) !he%i!als. :- Wettin a ent A for% of deter ent

&hi!h red#!es s#rfa!e tension and helps the fil% to dry faster

. :) C#ttin a ent A !o%"ination of potassi#% ferro!yanide and fi,er

&hi!h !an "e #sed in an e%er en!y to li hten fil% that ha'e "een

a!!identally o'ere,posed or

.o'erde'eloped

Whatisdifferen!e"et&eenSpatialresol#tionand



What is differen!e et&een Spatial resol#tion and !ontrast resol#tion?

Spatial resol#tion is a %eas#re of the a"ility of an i%a in te!hni$#e to de%onstrate that t&o near"y

, , .o"(e!ts are indeed separate o"(e!ts It is %eas#red " ,"in line pairs per %illi%eter referrin to the a"ility of a %odality to de%onstrate that 'ery s%all

pairs of lines are indeed separate lines and not a . - ,sin le line Of the di ital !ross se!tional %odalities

.C0 has the hi hest spatial resol#tion - Contrast resol#tion 0he density differen!e "et&een the .t&o ad(a!ent area on the radio raph

Refers to the a"ility of an i%a in %odality to render different o"(e!ts or tiss#es as different

. -shades of ray Of the di ital !ross se!tional

, .%odalities 7RI has the hi hest !ontrast resol#tion

R di ti f / t l



32

• ormally ;4 m! 'year• -n areas of high bac ground, 4;

m! 'year•0+ /6'36 < = >y (#he LD50/60 isthat dose at which /6?of the

e%posed population will die within36 days)•

Radiation from /aturalources



3

1ccupational% medical and publice.posures

• 1ccupational e.posure• All e%posures of wor ers incurred:

• in the course of their wor , with the e%ception ofe%posures e%cluded from the !tandards

•• e%posures from practices or sources e%empted by the

!tandards



3=


• 2edical e.posure:• 8%posure incurred by patients

• as part of their own medical or dental diagnosis ortreatment@

• by persons, other than those occupationally e%posed,nowingly while oluntarily helping in the support andcomfort of patients@

• by olunteers in a programme of biomedical researchin ol ing their e%posure



3/


• Public e.posure: • 8%posure incurred by:

• members of the public from radiation sources,• e%cluding any occupational or medical e%posure and

the normal local natural bac ground radiation• but including e%posure from authori1ed sources and

practices and from inter ention situations9



33

ose limits (occupationale.posure)

• #he occupational e%posure of any wor er shouldbe controlled so that the following limits be note%ceeded:

•

500 mSvThe hands and feet500 mSvThe skin150 mSvThe lens of the eye

Annual equivalent dose in:

20 mSv per year, averaged overdefined periods of 5 years50 mSv in any single year

ffe!tive dose

"!!upational dose limit Appli!ation

$ d



3"

P456 C $ 1ptimi,ation underConstraints

• 1 8 6 2 *• effecti e dose of ; m! in a year• in special circumstances, effecti e dose of / m!

in a single year, pro ided that the a erage o er

fi e consecuti e years in less than ;m! peryear• e ui alent dose to lens of the eye ;/ m! in a

year• e ui alent dose to s in of /6 m! in a year9



3&

ose limits (public)

50 mSvThe skin15 mSvThe lens of the eye

Annual equivalent dose in:

1 mSv in a year #$%ffe!tive dose&u'li! dose limit Appli!ation

#$%In special circumstances, an effective dose of up to 5 mSvin a single year provided that the average dose over fiveconsecutive years does not exceed 1 mSv per year .



3

ose 6imits ( CRP 90)• 1ccupationalPublic•8ffecti!e dose 0 m ! yr a!eraged; ' m ! in a

yr• o!er yrs<•-nnual e=ui!alent•dose to• 6ens of eye ' 0 m ! ' m !• "in 00 m ! 0 m !• >ands ? +eet 00 m !•

•B with further pro ision that dose in any single yr 6m! (A8R ) and </6 m! (-CRD)

• 9 9: M9D9+9 ; ; < /66 m! , ; ="<;/6 m! , ; ""</6m! E

•

in ; 6<26 m!



"6

(e live )ith1*+ mSv

an kill-000 mSv

Radiation

Where to stop, where is the safe point?What are the effects of radiation?



";

Radiation health effects

!"!R#I$IS"I%Somatic%linically attri&uta&lein the exposedindividual

%!'' !(")S"*%)(S"I%somatic + hereditaryepidemiologicallyattri&uta&le in largepopulations

($"!$("('somatic andhereditary expressedin the foetus, in the live&orn or descendants

*")

"- !*/

!//!%"S

%!'' "R($S/*R#("I*$

o og ca e ec s o on , ngradiation



"2

radiation

•eterministic• e9g9 0ens opacities,

s in in$uries,• infertility,

epilation(hairremo al), etc

• tochastic• Cancer, genetic

effects9

eterministic effects



"

F eterministic0"hreshold non2stochastic3

F .isten!e of a dosethreshold value #'elo)this dose, the effe!t is noto'serva'le%

F Severity of the effe!tin!reases )ith dose

F A large num'er of !ells areinvolved

adiation in(#ry fro% an ind#strial so#

eterministic effects

*hreshold oses for eterministic8ffects



"=

F atara!ts of the lens of the eye 2*10 /y

F&ermanent sterility

Fmales + 5* /y

Ffemales 2 5* /yFTemporary sterility

Fmales 0 15 /yFfemales 0 /y

dose

e'er ity ofeffe!t

threshold

8ffects



Radiosensiti!ity



"3

Radiosensiti!ity

us!le3ones4ervoussystem

Skinesodermorgans #liver,

heart, lungs %

3one arro)SpleenThymus6ymphati!nodes/onads

ye lens6ympho!ytes#e.!eption to the 7S la)s%

6o) 7Sedium 7S8igh 7S





8ffects of antenatal e posure



"

8ffects of antenatal e.posure

• Mental retardation:• -CRD establishes that mental retardation can be

induced by radiation (-ntelligence Nuotient scoreO ;66)9

• -t occurs during the most R! period: &42/ wee ofpregnancy9

• Ris s of antenatal e%posure related to mentalretardation are:

•Severe mental retardation

)ith a risk fa!tor of

0 19Sv

Severe mental retardation)ith a risk fa!tor of

0 -9Sv

152 5 wee89215 wee8

8 am<



&6

7elative ose 7e!eived

num&er of chest x2rays6 56 166 156 66

( )r% head a n4le foot - ( )ead 6e!4

( )ead C0 - . ( )hora!i ! Spine -+

( )a%%o raphy Cysto raphy ) . ( )el ' i s )B

( )"do%en Hip Upper lo&er fe%#r )+ ( )a S&al lo& .

( )"ster i ! a"do%en B- ( )#%"o sa!ra l area B

( )holan io raphy 8) ( )#%"er 7yelo raphy .

( )o&er a"do%en C0 %ale 2) ( )pper A"do%en C0 2

( )a 7eal 2- - ( )n io head An io per iphera l +.

( )ro raphy +2

- ( )n io a"do%inal - ) .

( )hest C0 - . . ( )o&er A"d C0 fe% -B)

( )a ene%a -8B. ( )y%phan -+.

mSv.650 156.:;6.;1.61.1.:1.5

1.<.15.5;=.6=.>1=.><=.9:.6

:.=>>.6>.9<.1=<.>;;.6

8.am< (as multiple of chest .$ray)





*ypical effecti!e doses from



&

*ypical effecti!e doses fromdiagnostic medical e.posures

iagnosti!

pro!edure

Typi!al effe!tive

dose #mSv%

quiv no of

!hest .*rays

Appro. equiv period of

natural 'a!kgroundradiation

8ip 0 + 15 ; )eeks

&elvis 0 ; +5 - months

A'domen 1 0 50 months

<=> 2 5 125 1- months

: . ,/ro % R e fe rra lC rite ria /o r I% a in C E.) . . .





&/

>ow to measure doses

A'solutemethods

7elativemethods

alorimetry

hemi!al#?ri!ke dosimeter%

<onometry#ioni@ation !ham'er%

&hotography

S!intillation

T6

<onometry

"hey needto 8now a

characteristic

parameter

!!han4yo#



!!han4yo#

!!.

Documents

30459663 Radiology Physic Review