Radiographic Film Dosimetry
Indra JJ. Das,, Ph
hD,, FACR
Department of Radiiation Oncology
Indiana University of School of
Medicine & Midwe
est Proton
Radiation Therapy Institute (MPRI)
Indianapolis, IN
ID/AAPMSS-Film/09
Learning Objectives
O
As described
d in TG-66
ID/AAPMSS-Film/09
Historical Peerspective
1826
1836
1889
1890
1895
1896
1913
1918
1933
1942
1960
1965
1972
1983
1992
1994
2000
Joseph Niepce
J. M. Daguerre
Eastman Kodak
Hurter & Driffield
Roentgen
Carll Schlussner
hl
Kodak
Kodak
Dupont
Pako
Dupont
Kodak
Kodak
Fuji
CEA
3M
Kodak
First Photogrraph
Concept of developer
d
Cellulose nittrate base for emulsion
Defined the term
t
optical density
First Radiograph
First
i glass
l pllate
l for
f radiography
di
h
Film on Celllulose nitrate base
Double emullsion film
X-ray
X
ray film w
with blue base
Automatic fiilm processor
Polyester base introduced
Rapid film processing
p
XTL and XV
V film for therapy
Computed raadiography system
Vacuum paccked TLF AND TVS film
D process laser
Dry
l
imaging
i
i
Extended doose range (EDR) film
ID/ARS/09
Radiograp
phic Film

Base (Cellulose nitrate or
o Polyester)
(t i ll 200 m))
(typically
 Emulsion (10-20 m; 2--5 mg/cm3)
 Gelatin (derivative frrom bone)
 grain (size: 0.13 m
m diameter)
o
o
o
Emulsion
Base
AgBr (cubic crystal with lattice
l
distance of 28 nm
AgI
KI
 There are 109-1012 grrains/cm2 in a x-ray films

Coating
 Very sensitive whichh may determine X &
Y direction uniformitty
ID/ARS/09
Photograph
hic Process
 Sil
Silver halides
h lid (A
A
AgBr,
A
AgCl,
Cl A
AgI)) are
sensitive to radiaation.
 Radiation event (latent
(
image) can be
magnified by a billion fold (109 ) with
developer.
ID/ARS/09
Emulsion of Fiilm/Radiograph
The heart of a film is emulsion whichh contains grains (crystals of silver
h lid ) in
halides)
in gelatin
l i





Gelatin is suitable due to
it keeps grains well dispersed
it prevents clumping and sedimentatio
on
of grains
it protects the unexposed grains from
reduction by a developer
it allows easy processing of exposed
grains
it is neutral to the grains in terms of
fogging, loss of sensitivity
Electron micrograph of grain in gelatin
ID/ARS/09
Unusual Grain Morpho
ologies of Films
Eastman Kodak Company, 2001
Cheng & Das, Med. Phys. 23, 1225, 1996
ID/AAPMSS-Film/09
Laten
nt image
 The change which causes the grains to be
rendered developablle on exposure is
considered to be the formation of latent
image.
 It
I iis composedd off an
n aggregate off a few
f
silver atoms (4-10).
 On average 1000 Ag
g atoms are formed per
x-ray quantum absorrbed in a grain.
 Gurney & Mott prov
vided a clear picture of
latent image
ID/ARS/09
Gurney & Mott Theory of Latent Image
X-ray
Graiin
Silv
ver
Speck
ID/AAPMSS-Film/09
Film Pro
ocessing
 Developing [(Metol; methylll-p-aminophenol
p aminophenol sulphate or Phenidone;
1phenol 3pyrazolidone)]
 Converts all Ag+ attoms to Ag. The latent image
Ag + are developed
d much more rapidly.
rapidly
 Stop Bath
 dilute acetic acid sttops all reaction and further
development
 Fixer,, Hypo
yp ((Sodium Thiossulphate)
p
)
 it dissolves all undeeveloped grains.
 Washing
g
 Drying
ID/ARS/09
Temperature Dependencce of Various Films
1.6
Dupont
Kodak MRM
Fuji
j
Kodak MR5
Optical Denssity
1.4
1.2
1.0
0.8
08
0.6
0.4
84
86
88
90
92
94
96
98
100
102
Developer Temperaature (degree F)
ID/AAPMSS-Film/09
Ch
hange in O
OD per Deegree Processor Tem
mperature
(OD/
OD/T)
Koodak Films
.10
OD=K0T +K1T2
.08
Min R M
.06
Ektascan HN
.04
T-Mat G/RA
02
.02
Ektascan IR
0.0
91
92
93
94
95
96
97
98
Processor Temperatuure (degree F)
Bogucki et al, Med.Phys., 24, 581, 1997
ID/AAPMSS-Film/09
99
Temperaturee Dependence of Kodak films
3.0
y = 0.0244x + 0.13
R² = 0.8782
R
Optical D
Density (O
OD)
2.5
XV, 100 cGy
y = 0.0176x + 0.532
R² = 0.8951
0 8951
20
2.0
EDR, 400 cGy
1.5
y = 0.0204x
0 0204x - 0.606
0 606
R² = 0.8856
y = 0.0046x - 0.035
R² = 0.9653
XV 40 cGy
XV,
cG
1.0
0.5
05
EDR 80 cGy
EDR,
0.0
80
82
84
86
Srivastava & Das Med Phys 34:2445-46, 2007
88
90 92 94 96 98
Temperature (deg F)
100 102 104 106
ID/AAPMSS-Film/09
40
Speed
S d
% change
Standard Processsing Cycle
20
0
-20
3.6
3.4
Contrast
Average
Gradient
32
3.2
3.0
2.8
Base
+
Fog
0.22
0.20
0.18
0.16
91 F
33 C
95 F
35 C
Tempeerature
99 F
37 C
103 F
39 C
ID/AAPMSS-Film/09
Hurter & Drriffield (1890)
Optical Density
D
(OD)
OD= log10(Io/I)
OD=log10 (T) where T is transmittance
T=ean
a= average area/grain; n iss number of exposed grains/cm2;
N is number of grains/cm2
OD = log (T) = an log10
0 4343 an
1 e = 0.4343
n/N = awhere  electron fluence
OD = 0.4343
0 4343 a2N
OD is proportional to annd hence dose and square
of grain area
ID/ARS/09
Characteriistic curve
H&D Curve
C
Gradient, gamma, slop
pe = (D2-D1)/Log(E2/E1)
Speed (sensiti
(sensitivity)=
it ) 1/RRoentgens for OD equal to unity
Latitude (Contrast): raange of log exposure to
give an
a acceptable density range
shoulder
slope
base
Log (expposure)
ID/ARS/09
Various types of ploots for film response
(a)
(b)
Sensittometricc
Log (exposure)
(c)
( )
DX
Log (exposure, dose)
Tx
(d)
Exposure, Dose
ID/AAPMSS-Film/09
Optical Density = OD((D,Dr,
D Dr, E,
D,Dr
E T,
T d,
d FS,
FS )
D = Dose
Dr = Dose rate
E = Energy
T = type of radiation (x(x-rays,
r
electrons etc)
d = depth of measuremennt
FS= Field Size
 = Orientation: parallel or perpendicular
ID/AAPMSS-Film/09
Optimum Opticcal Density
7.0
Range
6.0
21 film types
yp
Contrasst
5.0
4.0
3.0
2.0
1.0
0
0
1.0
2.0
3.0
4.0
5.0
Opticaal Density
ID/AAPMSS-Film/09
Inciddent light
Film
Fil
Specular
Diffuse
Double diffuse
Transmiitted light
ID/AAPMSS-Film/09
Densitometerrs/ Digitizers
 Visual type
yp densitomeeter ((Dobson,, Griffith &
Harrison, 1926)
 Photoelectric type
 light densitometer (widde spectrum)
 Standard: McBeth, Xriite, Nuclear Associate etc
 Light source coupled w
with CCD digitizer
 Fluorescent light sourcce – Vidar VXR-16 Digitizer
 LED light source - Howtek MultiRAD 460 Digitizer
 Laser densitometer (sinngle wavelength)
 Lumysis scanning systtem
ID/ARS/09
Digiti
g izers
 Scanning film Digitizeer Artifacts:
 Drift in OD; warm-up effect
e
of fluorescent lamp
 Use first 20-30 minutes as warm-up time
 Scanner spatial distortioon
 Validated in both dimennsions using known test patterns
 Interference artifacts - at the
t interface of film and the glass
plate/film support. (Multiple reflection due to changes in
the index of refraction)
 Use of diffused glass or anttireflective coated glass
Reinstein et. al., Dempsey et.al.
ID/ARS/09
Optimum Film Properties
 Linear with dose (dosee dependence)
 Linear with dose rate (dose rate independence)
 Radiation type (indepeendent of photon and
electron)
 Energy independent
 Uniformity in x & y (ccoating artifact)
 Processing condition
 F
Fading
di
 Delayed processing
 Atmospheric conditiion, temperature, humidity
ID/ARS/09
Dose Ratte Dependence
6
5
4
62R/sec
1100R/sec
3
0
0.033R/sec
2
1.31R/sec
1
0
10-2
10-1
100
101
102
103
104
Exppposure,, R
Ehrlich, J.Opt.Soc.Am. 46,801, 1956
ID/AAPMSS-Film/09
105
Dose rate (film)
1 10
1.10
1.08
6 MV, EDR Film
1.06
18 MV, EDR Film
Dose rattio
1.04
1.02
1.00
0.98
0.96
0.94
0.92
1
10
100
Dose raate (cGy/min)
1000
10000
Srivastava and Das Med Phys 33:2089 , 2006
ID/AAPMSS-Film/09
Energy Dependence of
o Radiographic Film
28 keV
2.5
44 keV
79 keeV
Net O
Optical Deensity
2.0
1.71 MeV
977 keV
1.5
142 keV
1.0
0.5
Kodak XV Film
0
0
10
20
30
40
50
60
70
80
Dosse (cGy)
Muench et al, Med. Phys. 18, 769, 1991
ID/AAPMSS-Film/09
Energy Dependence of CEA TVS film
50
5.0
Opptical Deensity
4.0
Gamma rays
G
y
X-rays
OD = 0.054 Dose
3.0
ODx = 0.047 Dose
Cs-137
CsCo--60
Co
4 MV
6 MV
10 MV
18 MV
2.0
1.0
0.0
0
20
40
60
80
100
Dosee (cGy)
Cheng & Das, Med. Phys. 23, 1225, 1996
ID/AAPMSS-Film/09
Effect of film air gaap on depth dose
0 75 mm
0.75
0.50
0.25
100
0
Air gap
Film
50
0
5
Dutreix et al, Ann NY Acad Sci, 161, 33, 1969
10
Depth (cm)
ID/AAPMSS-Film/09
Effect of film misalignnment on depth dose
100
0
2
5 mm
Air gap
Film
50
0
5
Dutreix et al, Ann NY Acad Sci, 161, 33, 1969
10
Depthh (cm)
ID/AAPMSS-Film/09
Effect of film under alignnment on depth dose
100
4
7 mm
0 mm
Air gap
Film
50
0
5
Dutreix et al, Ann NY Acad Sci, 161, 33, 1969
10
Depth (cm)
ID/AAPMSS-Film/09
Methods to eliminaate problems with Film
 To eliminate air trapped
d inside jacket
jacket, vacuum
packing could be used (C
CEA film)
 To keep identical positio
on and press
pressure,
re RMI
sells film cassettes for dosimetry
d
 U
Use fil
film in
i water
t as sugggested
t d by
b van Battum
B tt
ett
al, Radiother.Oncol. 34, 152, 1995
 Special phantom; Bova, Med. Dos. 15, 83, 1990
 Modern films come withh vacuum packed
ID/ARS/09
CEA Film
ms (TLF,
(TLF TVS)
Kodak TL
Opticaal Density
y
4
CEA TVS
CEA TLF
Kodak XV
3
2
1
0
0
20
40
60
80
100
120
Doose (cGy)
Cheng & Das, Med. Phys. 23, 1225, 1996
ID/AAPMSS-Film/09
OD vs Dose
Dose = a+b(OD) +cc(OD)2
PDD = [a+b(OD) +c(OD))2]d / [a+b(OD) +c(OD) ]
2
max
OAR=[a+b(OD) +c(OD)2]x / [a+b(OD) +c(OD)2]cax
For limited range and linear film
D = m(OD)
(OD) th
thenn
D2/D1 = OD2/O
OD1
ID/ARS/09
Sensitivity of film to scatter
Depth and field size dependdence of OD
V B
Van
Battum et al,
l fil
film in
i water
w
Burch et al, lead filter
Yeo et al , Lead filter
m
Skyes et al, against filter method
“although scatter filtering method appears to have the desired
effect it seems intuitively wrrong to introduce a high Z filter in
order to make an inadequate dosimeter, film, behave as if it is
water equivalent”
Suchowerska et al MC simuulation to prove scatter as a
problem
ID/ARS/09
30
25
20
15
10
6x6, 5 cm depth
25x25, 5 cm depth
6x6,
6 6 15 cm ddepth
th
25x25, 15 cm depth
5
0
0
0.2
0.4
0.6
0.8
1.0
Net Opptical Density
Sykes et al, Med.Phys., 26, 329, 1999
ID/AAPMSS-Film/09
1.2
Opticaal Densitty (Norm
malized)
Effect of depth and field size on OD
108
106
30 30
30x30
104
102
20x20
100
10x10
98
4x4
96
94
0
5
10
15
20
Depth (cm)
Van Battum et al , Radiother Oncol, 34, 152, 1995
ID/AAPMSS-Film/09
25
Ion Chamber
100
Rellative Doose (%)
Film
80
20x20
60
4x4
10x10
40
20
0
0
2
4
6
8
10
12
14
16
18
20
Depppth ((cm))
Van Battum et al , Radiother Oncol, 34, 152, 1995
ID/AAPMSS-Film/09
Phooton
Movable position
t= 0.15, 0.30,
.0.46, 0.76 mm
Parallel film Orientation
X 6, 12, 19 mm
X,
Film
Lead filter
Yeo et al Med. Phys. 24, 1943, 1997
Burch et al, Med. Phys. 24, 775, 1997
ID/AAPMSS-Film/09
1.22
1.00
Relattive dose ((ratio)
Film no filter
Film with filter
Ion Chamber
0.88
0.66
0.44
0.22
-10
-5
0
5
10
Distance from central
c
axis (cm)
Ju et al, Med. Phys., 29, 351351-355, 2002
ID/AAPMSS-Film/09
MC simulation of photon speectrum at various depths
Relativve Fluennce (%)
10.0
1 5 cm
1.5
m
8.0
10 cm
6.0
30 cm
4.0
2.0
0.0
0
4
2
8
6
Energgy (MeV)
Suchowerska et al, Phys. Med. Biol. 44, 1755, 1999
ID/AAPMSS-Film/09
200
4 MV, 25x25 cm2
180
0.76 mm Pb
X=0 mm
160
140
120
100
80
X=6 mm
60
X=12 mm
40
Ion chamber
20
0
0
5
10
15
20
25
30
35
40
Depth (cm)
(
Burch et al,
al Med.
Med Phys.,
Phys 24,
24 775,
775 1997
ID/AAPMSS-Film/09
Effect of Pb filteer on depth dose
120
120
4 MV, 6x6
100
cm2
4 MV, 25x25 cm2
100
80
80
60
60
No Pb
No Pb
40
40
Ion Chamber
Ion Chamber
20
20
Film+.46 mm Pb
Film+.46 mm Pb
0
0
0
5
10
15
20
Depth (cm)
25
30
35
40
0
5
10
15
20
25
Depth (cm)
Burch et al, Med. Phys., 24, 775, 1997
ID/AAPMSS-Film/09
30
35
40
Sensitometric curves for
fo 15x15 cm2 field
with perpendicularr film exposure
3.0
2.5
2.0
20
1.5
Depth
1.0
0.5g/cm3
4 g/cm3
9 g/cm3
0.0
0.5
0
2.5
2.0
20
1.5
Depth
1.0
0.5g/cm3
4 g/cm3
9 gg/cm3
0.0
1.0
1.5
2.0
1.0
1.5
2.0
Dose (Gy)
3.0
18 MV
Kodak
0.5
0
Dose (Gy)
3.0
6 MV
Kodak
Net Optical D
Density
Net Optical D
Density
3.0
C0--60
C0
Kodak
2.5
2.5
2.0
2.0
1.5
45 MV
Kodak
Depth
p
1.5
Depth
p
1.0
0.5g/cm3
4 g/cm3
9 g/cm3
0.5g/cm3
g/cm3
1.0
4
9 g/cm3
0.0
0.0
0
0.5
1.0
Dose (Gy)
1.5
2.0
0
0.5
1.0
1.5
D
Dose
(G
(Gy))
Danciu et al, Med. Phys. 28, 972, 2001
ID/AAPMSS-Film/09
2.0
Agfa
3.0
3.5
Co--60
Co
Parallel
Perpendicular
2.5
2.0
20
1.5
Kodak
1.0
Parallel
Perpendicular
3.0
2.5
2.0
20
1.5
Kodak
1.0
0
2
4
6
8
10
12
14
16
0
2
4
Depth (cm)
Net Optical Dennsity
Parallel
Perpendicular
3.0
2.5
2.0
1.5
Kodak
1.0
0
2
4
6
8
8
10
3.5
15 MV
Agfa
6
12
14
16
Depth (cm)
3.5
Net Optical Deensity
6 MV
Agfa
Net Opptical Density
Net Opptical Density
3.5
10
12
Depth (cm)
14
45 MV
3.0
Parallel
Perpendicular
2.5
2.0
Kodak
1.5
1.0
16
0
2
4
6
8
10
12
Depth (cm)
Danciu et al, Med. Phys. 28, 972, 2001
ID/AAPMSS-Film/09
14
16
Phootons
ew
ew
(ew)n
ew
ew
elecctrons
(ew)n+(ef)m
P
Perpendicular
ef
ew
P
Parallel
fillm
# ew<<
< # ef
ODperpendiculaar < ODparallel
ID/AAPMSS-Film/09
120
100
95
90
110
100
90
80
70
60
80
70
60
50
50
40
40
Ion Chamber
30
30
Williamson et al , Med. Phys. 8, 94,
9 1981
Film
ID/AAPMSS-Film/09
IMRT Veriification
ID/AAPMSS-Film/09
Advantage of film
f
dosimetry
 Unrivaled spatial distribuution of dose or energy
imparted.
me film: permanent record
 Repeated reading of sam
 2-D distribution with sinngle exposure
 Small detector size
 Wide availability: Kodakk, Agfa, Fuji, Dupont, CEA
 Large area dosimetry: Esspecially for electron beam
 Linearity of dose (over a short dose range, OD can be
treated linear with dose for
f most films)
 Dose rate independence
ID/AAPMSS-Film/09
Film Dosimeetry - Caution
 Strong energy depen
ndence (high sensitivity to
low energy photons due to photoelectric
interactions in grainss)
 Film plane orientatio
on with respect to the beam
direction
 Emulsion differences amongst films of
diff
different
t bbatches,
t h fil
film
ms off th
the same batch
b t h or
even in the same film
m
 Densitometer/Digitizzer artifacts
ID/AAPMSS-Film/09
-Cautioon
 OD depends on:
 Chemical processinng
 developer chemistrry and temperature
 Processingg time
 drying conditions
 Sensitivity to environ
nment
 High temperature & humidity creating fading
 Storage stability
 0.05-0.1 OD in (6( -60mR)) among
g various films (ref
Soleiman et al Med. Phyy. 22, 1691, 1995)
 Microbiological grow
wth in gelatin
 Solarization: At extreemely higher doses,
doses OD
decreases
ID/AAPMSS-Film/09
Sum
mmary
 Film is ideal detecto
or for relative dose
measurement
 Best suited for planaar dose distribution
 Dependent on type, batch, exposure
condition,
diti beam
b
eneergy, dose,
d
ddose rate,
t
processor condition, digitizer etc.
 Film is a dying tech
hnology with a uncertain
future. It is being rep
placed with electronic
devices
ID/AAPMSS-Film/09
ID/AAPMSS-Film/09