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ICRU recommendations
Citation preview
ICRrecommedations
David Sjöström,Herlev Hospital,
RUon volume and dose
, Physicist, Denmark
1
BackBackkgroundkground
T ll t i d i thTumour cells contained in thered volume throughout the treatment course
BackBackkground
T ll t i d i th
kground
Tumour cells contained in thered volume throughout the treatment course
95% or more of the ib d d i tprescribed dose given to
everything inside green area
BackBackkground
T ll t i d i th
kground
Tumour cells contained in thered volume throughout the treatment course
95% or more of the ib d d i tprescribed dose given to
everything inside green area
How do we ensure that this How do we ensure that this picture reflects the reality ofpicture reflects the reality ofpicture reflects the reality of picture reflects the reality of the treatment?the treatment?
BackgProblem:
Backg
We need the same definition- volume that has been treated- dose given to this volume- dose received by organs at ris
How to prescribe, record an
groundground
ns of:
k
nd report
BackgBackg
ICRU Report No 78 (2ICRU Report No.78 (2
groundground
2007)2007)
BackgBackg
SSolution:
ICRU reports - InternationalICRU reports International recommendations for definitof dose and volume in RT
groundground
tions
BackgBackg
ICRU Report No.29 (1978)“Dose specification for reportiDose specification for reportiphotons and electrons”
ICRU Report No 50 (1993)ICRU Report No.50 (1993)“Prescribing, recording and re
(Superseded ICRU Repo(Superseded ICRU Repo
ICRU Report No.62 (1999)ICRU Report No.62 (1999)“Supplement to ICRU Report NSupplement to ICRU Report N
(Updated the ICRU Repoconcepts. ICRU 50 still vp
groundground
ing external beam therapy withing external beam therapy with
eporting photon beam therapy”ort No.29)ort No.29)
No 50”No.50ort No.50 with some new valid.))
BackgBackg
ICRU Report No.71 (2004)“Prescribing, recording and reportin(Extends concepts and recommendaphotons to electrons)
ICRU Report No.78 (2007)“Prescribing, recording and reportin
ICRU Report No.83 (2010)“Prescribing, Recording and Reportitherapy (IMRT)”therapy (IMRT)
groundground
ng electron beam therapy”ations from ICRU 50 and 62 from
ng proton-beam therapy”
ing intensity-modulated photon-beam
Volumes in ICVolumes in IC“The Target Volume”The target volume consists of the tumourspresent) and any other tissue with presumetumour
• expected movements of tissues containinthe target volume• variations in shape and size of the target volume• variations in treatment set-up
+ Organs at risk whose presence influence treatment planning
CRU29 - 1978CRU29 1978
(if ed
ng
Volu“The Target“The Target1978 ICRU291978 ICRU29
Volumest Volume”t Volume” Organs at riskOrgans at risk
mes
VoluWhy all these
Volu
Improvements in staging a
Improvements in the delivery a
more detailed and accurate set of definmore detailed and accurate set of defindevelop
mese updates?
mes
and imaging procedures
and precision of radiotherapy
nitions to maximize the benefit of thenitions to maximize the benefit of the pment.
Volumes in ICExample
Volumes in ICp
Target volumePrimary + Boost
“Treatment fields defined from anatomical land marksfrom anatomical land marks in 2D”
CRU29 - 1978CRU29 1978
Computerised TomComputerised TomPossible to define and delineateOutline of patient body
TumourTumour
Sensitive organs
Possible to
Optimize how to irradiate
mography (X Ray)mography (X Ray)
Volu“The Target“The Target1978 ICRU291978 ICRU29
Volu
1993 ICRU501993 ICRU50 … a realization th… a realization th
mest Volume”t Volume” Organs at riskOrgans at risk
mes
hat better tools were needed …hat better tools were needed …
Volumes in ICVolumes in ICGross Tumour Volume (GTV)The GTV is the gross demonstrable extent and location of the malignant growth.
GTV consists of:GTV consists of:
primary tumour
t t ti l h dmetastatic lymphnodes
other metastases
CRU50 - 1993CRU50 1993
The demonstrated tumour
Volumes in ICVolumes in ICClinical Target Volume (CTV)The CTV is a tissue volume that contains ademonstrable GTV and/or subclinical, microscopical malignant disease.
Suspected lymph nodesSuspected disease around GTV
CTV = GTV (if there) + subclinical disease
C t b d t t d “ b li i l”Cannot be detected - “subclinical”. Based on clinical experience.
CRU50 - 1993CRU50 1993
a
CTV I GTV with margin and CTV IICTV I - GTV with margin, and CTV II –lymph nodes
Volumes in ICVolumes in ICPlanning Target Volume (PTV)The PTV is a geometrical concept
Movements of tissues containing CTVMovements of patientVariations in size and shapeVariations in beam geometry characteristic
PTV = CTV + margin for geometrical variati
Aid for treatment planning; dose to PTV p g;representing dose to CTV
CRU50 - 1993CRU50 1993
cs
ions
CTV with margin forming the PTV
Volumes in ICVolumes in ICCRU50 - 1993CRU50 1993
Volumes in ICOrgans at risk
Volumes in IC
The Organs at Risk are normal tissues whoradiation sensitivity may significantly influence treatment planning and/orinfluence treatment planning and/or prescribed dose
“Any possible movement of the organ at asAny possible movement of the organ at aswell as uncertainties in the set up must be considered”
CRU50 - 1993CRU50 1993
ose
ss
Volumes in ICVolumes in ICTreated VolumeTreated VolumeTreated VolumeTreated Volume
The Treated Volume is the volume wspecified as being appropriate to acspecified as being appropriate to actreatment.
CRU50 - 1993CRU50 1993
which receives at least the dose chieve the purpose of thechieve the purpose of the
Volumes in ICVolumes in ICIrradiated VolumeIrradiated VolumeIrradiated VolumeIrradiated Volume
The Irradiated Volume is the volumeconsidered significant in relation toconsidered significant in relation to
CRU50 - 1993CRU50 1993
e which receives a dose that is o normal tissue toleranceo normal tissue tolerance.
Volu“The Target“The Target1978 ICRU291978 ICRU29
Volu
1993 ICRU501993 ICRU50 GTVGTV CTVCTV
mest Volume”t Volume” Organs at riskOrgans at risk
mes
PTVPTV Organs at riskOrgans at risk
Volu“The Target“The Target1978 ICRU291978 ICRU29
Volu
1993 ICRU501993 ICRU50 GTVGTV CTVCTV
1999 ICRU621999 ICRU62 … a lot of focus o… a lot of focus othis time period…this time period…
mest Volume”t Volume” Organs at riskOrgans at risk
mes
PTVPTV Organs at riskOrgans at risk
on geometrical variations in on geometrical variations in gg……
PROBPROB
Structures within a
BLEMBLEM
body are not static
PositionalPositional
CT before treatment
variationse.g.
variations
Physological processes Variations in filling of bladder and rectum
PositionalPositional
CBCT first fraction
variationsvariationse.g.
Physological processes Variations in filling of bladder and rectum
PositionalPositional
Dose calculation CBCT
variationsvariationsConcequensesConcequenses, underdosage of target or overdosage of OAR.
PositionalPositional
O d t i th l i iOrgans and tumours in the pelvis region mdigestive system and filling of bladder andprostate, bladder, rectum, cervix.
Mainly inter-fraction positional variation
Typical values (1 SD) are 3 5 mmTypical values (1 SD) are 3 - 5 mm.
variationsvariations
i l d t h i thmoves mainly due to changes in the rectum from day-to-day. Example:
Breathing positBreathing positional variationsional variations
Breathing positBreathing posit
Breathing cycle (3-5 s) – during treatment (
Movement of organs and tumours in the abMovement of organs and tumours in the abtumours, kidneys, liver, breasts.
Example: Diaphragm moves 1 - 4 cm underExample: Diaphragm moves 1 - 4 cm underdeep-breathing, the corresponding figure c
Necessary to quantify organ motion individNecessary to quantify organ motion individ
ional variationsional variations
(intra fraction variation)
bdomen region Examples: lungbdomen region. Examples: lung
r normal free-breathing conditions Forr normal free-breathing conditions. For can be 10 cm!
dually for “curative” lung cancer patientsdually for curative lung cancer patients
Breathing positBreathing posit
EkbergEkberg et al.et al. RadiotherRadiother OncolOncol 48:48:Ekberg Ekberg et al.et al. RadiotherRadiother OncolOncol 48: 48: organ motion measured with fluororgan motion measured with fluorMean CTV movement with quiet reMean CTV movement with quiet re
•• 2.4 mm (med2.4 mm (med--latlat))•• 2.4 mm (ant2.4 mm (ant--post)post)•• 3.9 mm (sup3.9 mm (sup--infinf))
Range (supRange (sup--infinf): 0 ): 0 –– 12 mm12 mm
ional variationsional variations
7171--77, 1998:77, 1998: 2020 nsclcnsclc patientspatients ––7171 77, 1998: 77, 1998: 20 20 nsclcnsclc patients patients roscopyroscopyespiration:espiration:
Volumes in ICInternal Target Volume (ITV)Internal Target Volume (ITV)
Volumes in IC
CTV with margin added to compensate for evariations in size shape and position of CTV
ITV = CTV + IM (Internal Margin)
Internal reference point
CRU62 - 1999CRU62 1999
expected physiologic movements and V in relation to Internal Reference Point.
New conceptNew concept
WolthausWolthaus et alet al Int J Radiation OncoloInt J Radiation OncoloWolthaus Wolthaus et al. et al. Int. J. Radiation OncoloInt. J. Radiation Oncolo
ts replacing ITVts replacing ITV
ogy Biol Phys 70 (4): 1229ogy Biol Phys 70 (4): 1229--1238 20081238 2008ogy Biol. Phys 70 (4): 1229ogy Biol. Phys 70 (4): 1229--1238, 20081238, 2008
Mid ventilation (TimeMid ventilation (Timee averaged position)e averaged position)
Time avgTime avg.
Geometric avg.Wolthaus Wolthaus et al. et al. Int. J. Radiation OncologyInt. J. Radiation OncologyBiol. Phys 64 (5): 1560Biol. Phys 64 (5): 1560--1571, 20061571, 2006
35
Summary o
Extent of geometric variations:
Summary o
Extent of geometric variations:• abdomen target – mm to cm (i• pelvis target – a few mm (1 SDpelvis target a few mm (1 SD
Strategies for dealing with geomg g g• breathing control • real-time tumour tracking
d ibl filli f bl dd• reproducible filling of bladder • Adaptive treatment
+ internal margin (IM)g ( )
of problemof problem
intra-fx amplitude)D inter-fx)D inter fx)
metric variations in practice:p
d tand rectum
Example breaExample brea
Expiration
athing controlathing control
Deep inspiration
Example aExample a
Example H&N patient with tuCall for a
adaptationadaptation
mour shrinkage/weight loss. daption?
PROBPROB
Setting up the patient acan not be done ident
BLEMBLEM
nd the irradiation fields ically from day-to-day
High/Low dose when set-up of p
area is moving patient is varying
Set-up vSet-up v
VrtLatLongPitchRollRot
ariationsariations
Set-up vSet-up v30
20tups
ber o
f set
10
Num
b
-0.5 0Shift / [
NSCLC setupW. Ottosson, M. Baker, M. Hedman, C.F Behren
Shift / [
NSCLC studying the impact of different types ofcolumna vertibralis, and GTV” Acta Oncol. 2010
ariationsariations
VRTLNGLNGLAT
0.5[ ]
ns, D Sjöström “Evaluation of setup accuracy for
[cm]
f cone-beam CT matches on whole thorax, 0; 49: 1184–1191
Set-up vPopulation Setup Errors
Set-up v1 2Long. Long
Vert.
3 4 LongLong.
V tVert.
ariationsariations
Systematic
Standard
.
Standard Deviation
Pop
Vert.
p
Random.
Random
StandardDeviationV t Deviation
Pop
Vert.
PopPopPTVCTVM 7.05.2)(
Set-up vSet up vCTV to PTV m
ICRU Report N
ariationsariationsmargin recipe
o.83 (2010)
Set-up vSet-up vσ
Σ
σ
Σ0
• We need to know the magnitvariations” (Σset up and σset up).variations (Σset-up and σset-up).
• Σset-up and σset-up should be mp p
• Remaining Σset-up and σset-up staccount.
ariationsariations
tude of these “set-up ..
minimised.
should be taken into
Volumes in ICVolumes in ICPlanning Target Volume (PTV)Planning Target Volume (PTV)
ITV with margin added to compensate forelation to External Reference Point.
PTV = ITV + SM (Set-up Margin)
Internal reference point
CRU62 - 1999CRU62 1999
or external geometric uncertainties in
External reference point
Summary o
Extent of geometric variations:
Summary o
Extent of geometric variations:• often a few mm (1 SD inter-fx)
Strategies for dealing with geom• fixation• off-line portal imaging with de• on-line portal imaging
IGRT• IGRT
+ set-up margin (SM)+ set-up margin (SM)
of problemof problem
metric variations in practice:
ecision rule protocols
E ample IGRTExample IGRT
Ottosson et al. “Evaluation of setup accuracy forcone-beam CT matches on whole thorax, colum1184–1191
r NSCLC studying the impact of different types of na vertibralis, and GTV” Acta Oncol. 2010; 49:
Volumes in ICOrgan at Risk (OR)Organ at Risk (OR)Organs at Risk are normal tissues w
Volumes in ICg
significantly influence treatment pla
CRU62 - 1999whose radiation sensitivity may
CRU62 1999y y
anning and/or prescribed dose.
Volumes in ICOrgan at Risk (OR)Organ at Risk (OR)Organs at Risk are normal tissues w
Volumes in ICg
significantly influence treatment pla
Planning Planning Organ at Risk VoOrgan at Risk VoThe PRV is the OR with an integrateThe PRV is the OR with an integrateanalogue with the CTV-to-PTV expa
CRU62 - 1999whose radiation sensitivity may
CRU62 1999y y
anning and/or prescribed dose.
lume (PRV)lume (PRV)ed geometric margin added ined geometric margin added, in ansion.
Volumes in IConformity indexConformity indexConformity index (CI) defined as theConformity index (CI) defined as the
Volumes in IConformity index (CI) defined as theConformity index (CI) defined as the(TV) and the volume of PTV (CI = V(TV) and the volume of PTV (CI = VTT
<<Treated Treated
>>>>IrradiatedIrradiated
CRU62 - 1999e quotient of the treated volumee quotient of the treated volume
CRU62 - 1999e quotient of the treated volume e quotient of the treated volume
TVTV/V/VPTV PTV ≥ 1≥ 1). ).
<<VolumeVolume
>>>>d Volumed Volume
Volu“The Target“The Target1978 ICRU291978 ICRU29
Volu
1993 ICRU501993 ICRU50 GTVGTV CTVCTV
1999 ICRU621999 ICRU62 GTVGTV CTVCTV
mest Volume”t Volume” Organs at riskOrgans at risk
mes
PTVPTV Organs at riskOrgans at risk
ITV PTVITV PTV OR PRVOR PRV
Volu“The Target“The Target1978 ICRU291978 ICRU29
Volu
1993 ICRU501993 ICRU50 GTVGTV CTVCTV
1999 ICRU621999 ICRU62 GTVGTV CTVCTV
2004 ICRU712004 ICRU712004 ICRU712004 ICRU71
mest Volume”t Volume” Organs at riskOrgans at risk
mes
PTVPTV Organs at riskOrgans at risk
ITV PTVITV PTV OR PRVOR PRV
Volumes in ICGross Tumour Volume (GTV)Gross Tumour Volume (GTV)
Volumes in IC
The GTV is the gross demonstrable extent a
primary tumour – (GTV-T)metastatic regional node – (GTV-N)metastatic regional node (GTV N)distant metastasis – (GTV-M)
Clinical Target Volume (CTV)Clinical Target Volume (CTV)Clinical Target Volume (CTV)Clinical Target Volume (CTV)
The CTV is a tissue volume that contains a demonstrable GTV and/or subclinical, ,microscopical malignant disease, which must be eliminated. CTV = GTV (if there) + subclinical disease(CTV T CTV N CTV M)(CTV-T, CTV-N, CTV-M)
Planning Target Volume (PTV)Planning Target Volume (PTV)
As above: PTV-T, PTV-N, PTV-M
CRU71 - 2004CRU71 2004
and location of the malignant growth.
Comparison between macroscopic and
ICRU Report No 83 (2010)
Comparison between macroscopic and microscopic section of malign and benign breast tumor
ICRU Report No.83 (2010)
Volu“The Target“The Target1978 ICRU291978 ICRU29
Volu
1993 ICRU501993 ICRU50 GTVGTV CTVCTV
1999 ICRU621999 ICRU62 GTVGTV CTVCTV
2004 ICRU712004 ICRU71GTVGTV--TT CTVCTV--GTVGTV NN CTVCTV2004 ICRU712004 ICRU71 GTVGTV--NN CTVCTV--GTVGTV--MM CTVCTV--
mest Volume”t Volume” Organs at riskOrgans at risk
mes
PTVPTV Organs at riskOrgans at risk
ITV PTVITV PTV OR PRVOR PRV
--TT (ITV) (ITV) PTVPTV--TTNN PTVPTV NN OAR PRVOAR PRV--NN PTVPTV--NN
--MM PTVPTV--MMOAR PRVOAR PRV
Volu“The Target“The Target1978 ICRU291978 ICRU29
Volu
1993 ICRU501993 ICRU50 GTVGTV CTVCTV
1999 ICRU621999 ICRU62 GTVGTV CTVCTV
2004 ICRU712004 ICRU71GTVGTV--TT CTVCTV--GTVGTV NN CTVCTV2004 ICRU712004 ICRU71 GTVGTV--NN CTVCTV--GTVGTV--MM CTVCTV--
i ti i di ti i d… variations in de… variations in de… a lot of work on… a lot of work on
“dose sculptin“dose sculptin
…ICRU……ICRU…
… “dose sculptin… “dose sculptin… the “dose… the “dose--bathbath
mest Volume”t Volume” Organs at riskOrgans at risk
mes
PTVPTV Organs at riskOrgans at risk
ITV PTVITV PTV OR PRVOR PRV
--TT (ITV) (ITV) PTVPTV--TTNN PTVPTV NN OAR PRVOAR PRV--NN PTVPTV--NN
--MM PTVPTV--MM
li tili ti
OAR PRVOAR PRV
elineation …elineation …n imaging …n imaging …g” is more readily doneg” is more readily doneg” is more readily done …g” is more readily done …
h” might be a problem …h” might be a problem …
PROBPROB
Target-location might shdelinea
BLEMBLEM
hift, depending on who is ating it
Target-locatiodepending on wh
Stenbakkers Stenbakkers et al.et al. Int J RaInt J Ra
on might shift, ho is delineating it
adiat Oncol Biol Phys 2005adiat Oncol Biol Phys 2005yy
Target-locatiodepending on wh
KC ChaoKC Chao et al.et al. Int J Radiat Int J Radiat
on might shift, ho is delineating it
Oncol Biol Phys 68(5):2007Oncol Biol Phys 68(5):2007
PROBPROB
T t l tiTarget-locatiodepending on im
BLEMBLEM
i ht hifton might shift, maging modality
Target-location might shdelineating it and
Stenbakkers Stenbakkers et al.et al. Int J RaInt J Ra
hift, depending on who is imaging modality
adiat Oncol Biol Phys 2005adiat Oncol Biol Phys 2005yy
Target-locatiodepending on im
CT
on might shift, maging modality
Target-locatiodepending on im
MRI
on might shift, maging modality
Target-locatiodepending on im
CT
on might shift, maging modality
Target-locatiodepending on im
MRI
on might shift, maging modality
Target-locatiodepending on im
Charnley Charnley et al.et al. BritisBritisyy
on might shift, maging modality
sh J Radiology 2005sh J Radiology 2005gygy
Summary o
Extent of geometric variations:
Summary o
Extent of geometric variations:• Delineation variation the largest geometr
Strategies for dealing with geom• radiologists input in GTV delineation• use optimal imaging modalitiesuse optimal imaging modalities• e.g. contrast• workshops/audits• Autocontouring (?)Autocontouring (?)
ICRU: “The uncertainty in the delineation (of GTV and CTV)( )should be included in marginconsiderations”
of problemof problem
rical variation in radiotherapy – often cm
metric variations in practice:
Volumes in ICRUDefinition of volumes depends
Volumes in ICRUDefinition of volumes depends ICRU: “A clear annotation has t
GTV-T (CT, 0 Gy) GTV-T (MRI T2
ICRU Report No.8
U78 and ICRU83on the imaging modality
U78 and ICRU83on the imaging modality
to be used” e.g.
, fat sat, 0 Gy) GTV-T (FDG-PET, 0 Gy)
83 (2010)
Volumes in ICRUDefinition of volumes depends
Volumes in ICRUDefinition of volumes depends ICRU: “… recommended to indiwhen the GTV has been evaluatwhen the GTV has been evaluat
GTV-T (CT, 20 Gy) GTV-T (MRI T2,
ICRU Report No.8
U78 and ICRU83on when imaging is done
U78 and ICRU83on when imaging is doneicate the dose and/or the time ted/measured ”ted/measured…
, fat sat, 20 Gy) GTV-T (FDG-PET, 20 Gy):
83 (2010)
Volumes in ICRUVolumes in ICRUOverlapping
U78 and ICRU83U78 and ICRU83Volumes
Volumes in ICRUVolumes in ICRUOverlapping Volumes a
ICRU Report N
U78 and ICRU83U78 and ICRU83and buildup regions
No.83 (2010)
Volumes in ICRUVolumes in ICRUThe PTV might overlap an adjacThe PTV might overlap an adjacother reasons to subdivide the
ICRU: “… the delineation of the PTV margins should not be compromised” “… subdivision of the PTV into regions
ffwith different prescribed doses (so-called PTV sub-volumes, PTVSV) may be used”
U78 and ICRU83U78 and ICRU83cent PRV or there might becent PRV or there might be PTV
ICRU Report No.83 (2010)
Volumes in ICRUVolumes in ICRUPTV extending outsid
ICRU Repor
U78 and ICRU83U78 and ICRU83de body contour
rt No.83 (2010)
Volumes in ICRUWith new techniques, carcinogenesis need
Volumes in ICRUq , g
unsuspected regions of high dose within t
ICRU: “… The volume within the patient exCTV(s) should be identified as the “remain
U78 and ICRU83ds to be monitored; there might also be
U78 and ICRU83; g
the patient
xcluding any delineated OAR and the ning volume at risk” (RVR)”
Volu“The Target“The Target1978 ICRU291978 ICRU29
Volu
1993 ICRU501993 ICRU50 GTVGTV CTVCTV
1999 ICRU621999 ICRU62 GTVGTV CTVCTV
2004 ICRU712004 ICRU71GTVGTV--TT CTVCTV--GTVGTV NN CTVCTV
e ge g
2004 ICRU712004 ICRU71 GTVGTV--NN CTVCTV--GTVGTV--MM CTVCTV--
e.ge.g..GTVGTV--T (MR, 0 T (MR, 0 GyGy)) CTVCTV--T T (M(MGTVGTV--T (CT, 0 T (CT, 0 GyGy)) CTVCTV--T (CT (CGTVGTV--T (PET, 16 T (PET, 16 GyGy)) CTVCTV--T (PT (P
2007 ICRU782007 ICRU782010 ICRU832010 ICRU83
GTVGTV--TN (PET, 16 Gy)TN (PET, 16 Gy) CTVCTV--TN (TN (GTVGTV--N (MR, 16 Gy)N (MR, 16 Gy) CTVCTV--N (MN (MGTVGTV--N (CT, 0 Gy)N (CT, 0 Gy) CTVCTV--N (CN (C
mest Volume”t Volume” Organs at riskOrgans at risk
mes
VV PTVPTV Organs at riskOrgans at risk
VV ITV PTVITV PTV OR PRVOR PRV
--TT ((ITV) ITV) PTVPTV--TTNN PTVPTV NN OAROAR PRVPRV--NN PTVPTV--NN
--MM PTVPTV--MMOAR OAR PRVPRV
OAR PRV RVROAR PRV RVR
MR, 0 MR, 0 GyGy) (ITV) ) (ITV) PTVPTV--T T (MR, 0 (MR, 0 GyGy))T, 0 T, 0 GyGy)) PTVPTV--T T (CT, 0 (CT, 0 GyGy))ET, 16 ET, 16 GyGy)) PTVPTV--T T (PET, 16 (PET, 16 GyGy))PET, 16 Gy)PET, 16 Gy) PTVPTV--TN TN (PET, 16 Gy)(PET, 16 Gy)
MR, 16 Gy)MR, 16 Gy) PTVPTV--N N (MR, 16 Gy)(MR, 16 Gy)CT, 0 Gy)CT, 0 Gy) PTVPTV--N N (CT, 0 Gy)(CT, 0 Gy)
Volumes – DoVolumes Do
Dirk VerellNature Reviews Cancer 7, 9
oes it matter?oes it matter?
len et al949-960 (December 2007)
ICRU recommenndations on Dose
Dose in ICRU5ICRU ReferICRU Refer
Dose in ICRU5
- The dose at the point should be clinically re- The point should be easy to define in a cleaThe point should be easy to define in a clea- The point should be selected so that the dos- The point should be in a region where there
In central part of PTV at intersection of be
50 and ICRU62rence Pointrence Point
50 and ICRU62
levantar and unambiguous wayar and unambiguous wayse can be accurately determined
e is no steep dose gradient
am axes!
Dose in ICRU5Level 1. Minimum levLevel 1. Minimum lev
Dose in ICRU5
- The dose at the ICRU Reference Poin
- Maximum dose to the PTV (Dmax)
- Minimum dose to the PTV (Dmin)
M i d t th OR/PRV- Maximum dose to the OR/PRV:s
50 and ICRU62vel of reporting dosevel of reporting dose
50 and ICRU62p gp g
nt
Dose inLevel 1. Why is it not adequate tLevel 1. Why is it not adequate t
Dose in
-The absorbed dose distribution for IMRhomogeneous then in CRT
-Each beam can produce absorbed dosdose gradients
- Large dose gradients (10%/mm) in thecan affect the reliability of using a singlecan affect the reliability of using a single
- Because modern TPS have evaluation
- Monte Carlo calculations have statisticvolumes which makes it difficult and unvolumes which makes it difficult and unpoint.
ICRU83today?today?ICRU83
RT can be less
se with large
e PTV boundary i.e. small shifts in delivery e point to report the dosee point to report the dose
n tools that makes it possible.
cal fluctuation in the results for small certain to determine an absorbed dose to acertain to determine an absorbed dose to a
Dose inLevalLeval 2. Minimum level of repor2. Minimum level of repor
Dose inLevel of Level of reportingreporting for IMRTfor IMRT
PTV and CTVPTV and CTV-Report the DV, where “V” refers to a pspecified dose, for each PTV and CTV-D95% (dose that covers 95% of the vo-D50% (median dose)-Dmean (mean dose)-Dose near max: D2%-Dose near min: D98%
OAR and PRVOAR and PRVOAR and PRVOAR and PRV-Dmean (parallell organs)-D2% (serial organs)-VD (Volume receiving more than e.g. 2VD (Volume receiving more than e.g. 2
…AND……AND…State the treatment planning system a-State the treatment planning system a
delivery system
ICRU83rting dose in IMRTrting dose in IMRT
ICRU83
percentage of volume covered by the V: olume)
20 Gy).20 Gy).
and algorithm used for planning andand algorithm used for planning and
Dose inPTV and CTVPTV and CTVLevalLeval 2. Minimum level of report2. Minimum level of report
D2% ”close to max” replaces Dmax
D98% ”close to min” replaces Dmin
D50% = Dmedian
Dmean
OAR and PRVOAR and PRVVD (e.g volume receiving more than 50
V50Gy (parallel organs)
Dmean (parallel organs)mean
D2% (serial organs)…AND……AND…-State the treatment planning systeand delivery system used for treatm
ICRU83
%
ting dose in IMRTting dose in IMRT
V
100
%
ume
V
75
50
Vol
Gy)
50
25
Dose D100755025
Gy
Dose D
em and algorithm used for planning ment
Dose inDose inReporting of aReporting of a
Why not DWhy not D100%100% and Dand D0%0%(the ear(the earabsorbed dose)?absorbed dose)?
E.g. PTV of 0.5 litres (radius 49.2 mm).
radius changed by less than 0.2 mm => 1% change in volume
D98% and D2% serve the purpose to repan absorbed dose that is not reliant onan absorbed dose that is not reliant on single computation point.
ICRU83 ICRU83absorbed doseabsorbed dose
rlier definition of min and max rlier definition of min and max
port aa
Dose inDose inReporting of aReporting of a
Median absorbed dose (D50) is likely to be a ged a abso bed dose ( 50) s e y to be a grelatively homogeneo
ICRU Report No.83 (
ICRU83 ICRU83absorbed doseabsorbed dose
good measure of a typical absorbed dose in agood easu e o a typ ca abso bed dose aously irradiated tumor
2010)
Dose inDose inReporting of Reporting of
Why DWhy DWhy DWhy D
Deviation between prescribed and planned aabsorbed dose (D50) is th
ICRU Report N
ICRU83 ICRU83absorbed doseabsorbed dose
DD ??DD5050%%??
absorbed doses for 803 patients. The median he most accurate quantity
o.83 (2010)
Dose inDose inReporting of Reporting of
Example of two different approachp ppD50 corresponds to the ICRU refere
ICRU Report N
ICRU83 ICRU83absorbed doseabsorbed dose
es to prescribe the dose (assuming that p ( gence point).
o.83 (2010)
Dose in
LevalLeval 3 Techniques and concep3 Techniques and concep
Dose inLevel of reporting for IMRTLevel of reporting for IMRTLevalLeval 3. Techniques and concep3. Techniques and concep
-Dose Homogeneityh t i th if it f thcharacterizes the uniformity of the a
target
D C f it-Dose Conformitycharacterizes the degree to which ttarget volume
-Clinical and Biological evaluation (e.g.
C f (-Confidence interval (e.g. including sys
ICRU83
pts that are under developmentpts that are under development
ICRU83
pts that are under development pts that are under development
b b d d di t ib ti ithi thabsorbed dose distribution within the
the high dose region conforms to the
. TCP, NTCP, EUD)
)stematic and random uncertainties)
Dose inDose inDose HomogeneityDose Homogeneity
ICRU Report N
ICRU83 ICRU83y and Dose Conformityy and Dose Conformity
Homogeneity Index
o. 83 (2010)
Dose inDose HomogeneityDose Homogeneity
Dose in
Conformity index = 1
ICRU83y and Dose Conformityy and Dose Conformity
ICRU83
Loic Feuvret et al. Int. J. Radiation Oncology Biol. Phys., 64 (2) 2006
Dose inDose inDose HomogeneityDose Homogeneity
ICRU83 ICRU83y and Dose Conformityy and Dose Conformity
Loic Feuvret et alLoic Feuvret et al. Int. J. Radiation Oncology Biol. Phys., 64 (2) 2006
Dose inDose inQuality assurance for IMRT Quality assurance for IMRT PreviousPreviousPreviousPrevious
5% point dose accuracy specification
Replaced by volumetric dose acReplaced by volumetric dose acNot limited to single pointNot limited to single pointHigh gradient (≥20%/cm):85% of pmm))Low gradient (<20%/cm): 85% of normalized to the prescribed dose
ICRU83 ICRU83treatment planstreatment plans
ccuracy specification for IMRT ccuracy specification for IMRT
points within 5 mm (1 SD of 3.5
points within 5% of predicted dose e
Dose inDose inExampleExample –– QualityQuality AssAss
ICRU83 ICRU83surance surance measurementmeasurement
Dose inDose inExample Example –– Quality AssurQuality Assur
ICRU83 ICRU83rance Independent calculationrance Independent calculation
Dose inDose inExample Example –– Quality AssurQuality Assur
ICRU83 ICRU83rance Independent calculationrance Independent calculation
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stions?
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