ICRU Recommendations

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(Superseded ICRU Repo(Superseded ICRU Repo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

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

1993 ICRU501993 ICRU50 GTVGTV CTVCTV


mes

PTVPTV Organs at riskOrgans at risk


Volu


1999 ICRU621999 ICRU62 … a lot of focus o… a lot of focus othis time period…this time period…


mes


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


CBCT first fraction

variationsvariationse.g.

Physological processes Variations in filling of bladder and rectum


Dose calculation CBCT

variationsvariationsConcequensesConcequenses, underdosage of target or overdosage of OAR.


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


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)


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




mes


ITV PTVITV PTV OR PRVOR PRV


Volu



2004 ICRU712004 ICRU712004 ICRU712004 ICRU71


mes



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



2004 ICRU712004 ICRU71GTVGTV--TT CTVCTV--GTVGTV NN CTVCTV2004 ICRU712004 ICRU71 GTVGTV--NN CTVCTV--GTVGTV--MM CTVCTV--


mes



--TT (ITV) (ITV) PTVPTV--TTNN PTVPTV NN OAR PRVOAR PRV--NN PTVPTV--NN

--MM PTVPTV--MMOAR PRVOAR PRV


Volu



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


mes



--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


MRI



CT



MRI



Charnley Charnley et al.et al. BritisBritisyy


sh J Radiology 2005sh J Radiology 2005gygy

Summary o


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”


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



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


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 (


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


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


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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