ICRU Recommendations
96
0
0
Full text
(2) Backkground kground. Tumour cells T ll contained t i d in i the th red volume throughout the treatment course.
(3) Backkground kground. Tumour cells T ll contained t i d in i the th red volume throughout the treatment course. 95% or more of the prescribed ib d dose d given i to t everything inside green area.
(4) Backkground kground. Tumour cells T ll contained t i d in i the th red volume throughout the treatment course. 95% or more of the prescribed ib d dose d given i to t everything inside green area. How do we ensure that this picture reflects the reality of the treatment?.
(5) Backg ground Problem: We need the same definition ns of: - volume that has been treated - dose given to this volume - dose received by organs at risk. How to prescribe, record an nd report.
(6) Backg ground. ICRU Report No No.78 78 (2 2007).
(7) Backg ground. Solution: ICRU reports - International recommendations for definittions of dose and volume in RT.
(8) Backg ground ICRU Report No.29 (1978) Dose specification for reportiing external beam therapy with “Dose photons and electrons” ICRU Report No No.50 50 (1993) “Prescribing, recording and re eporting photon beam therapy” (Superseded ICRU Repo ort No.29) ICRU Report No.62 (1999) “Supplement Supplement to ICRU Report No.50 N 50” No (Updated the ICRU Repo ort No.50 with some new concepts. p ICRU 50 still valid.) v ).
(9) Backg ground ICRU Report No.71 (2004) “Prescribing, recording and reportin ng electron beam therapy” (Extends concepts and recommenda ations from ICRU 50 and 62 from photons to electrons) ICRU Report No.78 (2007) “Prescribing, recording and reportin ng proton-beam therapy” ICRU Report No.83 (2010) “Prescribing, Recording and Reportiing intensity-modulated photon-beam therapy (IMRT)” (IMRT).
(10) Volumes in IC CRU29 - 1978 “The Target Volume” The target volume consists of the tumours (if present) and any other tissue with presume ed tumour • expected movements of tissues containin ng the target volume • variations in shape and size of the target volume • variations in treatment set-up. + Organs at risk whose presence influence treatment planning.
(11) Volumes Volumes 1978 ICRU29. “The Targett Volume”. Organs at risk.
(12) Volumes Why all these e updates? Improvements in staging and a imaging procedures Improvements in the delivery and a precision of radiotherapy more detailed and accurate set of defin nitions to maximize the benefit of the develop pment..
(13) Volumes in IC CRU29 - 1978 Example p Target volume Primary + Boost “Treatment fields defined from anatomical land marks in 2D”.
(14) Computerised Tom mography (X Ray) Possible to define and delineate Outline of patient body Tumour Sensitive organs. Possible to Optimize how to irradiate.
(15) Volumes 1978 ICRU29. 1993 ICRU50. “The Targett Volume”. Organs at risk. … a realization th hat better tools were needed ….
(16) Volumes in IC CRU50 - 1993 Gross Tumour Volume (GTV) The GTV is the gross demonstrable extent and location of the malignant growth. GTV consists of: primary tumour metastatic t t ti lymphnodes l h d other metastases. The demonstrated tumour.
(17) Volumes in IC CRU50 - 1993 Clinical Target Volume (CTV) The CTV is a tissue volume that contains a demonstrable GTV and/or subclinical, microscopical malignant disease. Suspected lymph nodes Suspected disease around GTV CTV = GTV (if there) + subclinical disease Cannott b C be d detected t t d - “subclinical”. “ b li i l” Based on clinical experience.. CTV I - GTV with margin margin, and CTV II – lymph nodes.
(18) Volumes in IC CRU50 - 1993 Planning Target Volume (PTV) The PTV is a geometrical concept Movements of tissues containing CTV Movements of patient Variations in size and shape Variations in beam geometry characteristic cs PTV = CTV + margin for geometrical variatiions Aid for treatment p planning; g; dose to PTV representing dose to CTV. CTV with margin forming the PTV.
(19) Volumes in IC CRU50 - 1993 CRU50.
(20) Volumes in IC CRU50 - 1993 Organs at risk The Organs at Risk are normal tissues who ose radiation sensitivity may significantly influence treatment planning and/or prescribed dose “Any Any possible movement of the organ at as s well as uncertainties in the set up must be considered”.
(21) Volumes in IC CRU50 - 1993 Treated Volume The Treated Volume is the volume which w receives at least the dose specified as being appropriate to ac chieve the purpose of the treatment..
(22) Volumes in IC CRU50 - 1993 Irradiated Volume The Irradiated Volume is the volume e which receives a dose that is considered significant in relation to o normal tissue tolerance. tolerance.
(23) Volumes 1978 ICRU29. 1993 ICRU50. “The Targett Volume”. GTV. CTV. PTV. Organs at risk. Organs at risk.
(24) Volumes 1978 ICRU29. “The Targett Volume”. CTV. PTV. Organs at risk. Organs at risk. 1993 ICRU50. GTV. 1999 ICRU62. … a lot of focus on o g geometrical variations in this time period… ….
(25) PROB BLEM. Structures within a body are not static.
(26) Positional variations CT before treatment. e.g. Physological processes Variations in filling of bladder and rectum.
(27) Positional variations CBCT first fraction. e.g. Physological processes Variations in filling of bladder and rectum.
(28) Positional variations Dose calculation CBCT. Concequenses Concequenses, underdosage of target or overdosage of OAR..
(29) Positional variations. Organs and O d tumours t in i the th pelvis l i region i moves m mainly i l due d to t changes h in i the th digestive system and filling of bladder and rectum from day-to-day. Example: prostate, bladder, rectum, cervix. Mainly inter-fraction positional variation Typical values (1 SD) are 3 - 5 mm mm..
(30) Breathing posit positional ional variations.
(31) Breathing positional variations. Breathing cycle (3-5 s) – during treatment (intra ( fraction variation) Movement of organs and tumours in the ab bdomen region. region Examples: lung tumours, kidneys, liver, breasts. Example: Diaphragm moves 1 - 4 cm underr normal free-breathing conditions conditions. For deep-breathing, the corresponding figure can c be 10 cm! Necessary to quantify organ motion individ dually for “curative” curative lung cancer patients.
(32) Breathing positional variations. Ekberg et al. Radiother Oncol 48: 71 71--77, 1998: 20 nsclc patients – organ motion measured with fluorroscopy Mean CTV movement with quiet re espiration: • 2.4 mm (med(med-lat lat)) • 2.4 mm (ant(ant-post) • 3.9 mm (sup(sup-inf inf)) Range (sup(sup-inf inf): ): 0 – 12 mm.
(33) Volumes in IC CRU62 - 1999 Internal Target Volume (ITV) CTV with margin added to compensate for expected e physiologic movements and variations in size shape and position of CTV V in relation to Internal Reference Point. ITV = CTV + IM (Internal Margin). Internal reference point.
(34) New conceptts replacing ITV. Wolthaus et al al. Int. Int J J. Radiation Oncolo ogy Biol Biol. Phys 70 (4): 12291229-1238, 1238 2008.
(35) Mid ventilation (Time e averaged position). Time avg avg.. Geometric avg.. Wolthaus et al. Int. J. Radiation Oncology Biol. Phys 64 (5): 15601560-1571, 2006. 35.
(36) Summary o of problem. Extent of geometric variations: • abdomen target – mm to cm (iintra-fx amplitude) • pelvis target – a few mm (1 SD D inter-fx) inter fx). Strategies g for dealing g with geom g metric variations in practice: p • breathing control • real-time tumour tracking • reproducible d ibl filling filli off bl bladder dd and d rectum t • Adaptive treatment. + internal margin g (IM) ( ).
(37) Example brea athing control Expiration. Deep inspiration.
(38) Example a adaptation. Example H&N patient with tumour shrinkage/weight loss. Call for adaption?.
(39) PROB BLEM. Setting up the patient and the irradiation fields can not be done identically from day-to-day.
(40) High/Low dose area is moving when set-up of patient p is varying.
(41) Set-up variations. Vrt Lat Long Pitch Roll Rot.
(42) Set-up variations 30. Numb ber of settups. VRT LNG LAT 20. 10. -0.5. 0. Shift / [cm] [ ]. 0.5. NSCLC setup W. Ottosson, M. Baker, M. Hedman, C.F Behren ns, D Sjöström “Evaluation of setup accuracy for NSCLC studying the impact of different types off cone-beam CT matches on whole thorax, columna vertibralis, and GTV” Acta Oncol. 2010 0; 49: 1184–1191.
(43) Set-up variations Population Setup Errors 1. Long.. 2. Long.. Systematic. Vert.. Vert.. Standard Deviation. . Pop p. 3. Long.. 4. V t Vert.. Long.. Random. V t Vert.. Standard Deviation. . Pop. M (CTV PTV ) 2 .5 Pop 0 .7 Pop.
(44) Set-up Set up variations CTV to PTV margin m recipe. ICRU Report No.83 (2010).
(45) Set-up variations σ Σ 0 • We need to know the magnittude of these “set-up variations” (Σset-up variations set up and σset-up set up).. • Σset-upp and σset-upp should be minimised. m • Remaining Σset-up and σset-up should s be taken into account. t.
(46) Volumes in IC CRU62 - 1999 Planning Target Volume (PTV) ITV with margin added to compensate fo or external geometric uncertainties in relation to External Reference Point. PTV = ITV + SM (Set-up Margin). Internal reference point. External reference point.
(47) Summary o of problem. Extent of geometric variations: • often a few mm (1 SD inter-fx). Strategies for dealing with geom metric variations in practice: • fixation • off-line portal imaging with de ecision rule protocols • on-line portal imaging • IGRT. + set-up margin (SM).
(48) E ample IGRT Example. Ottosson et al. “Evaluation of setup accuracy forr NSCLC studying the impact of different types of cone-beam CT matches on whole thorax, columna vertibralis, and GTV” Acta Oncol. 2010; 49: 1184–1191.
(49) Volumes in IC CRU62 - 1999 Organ at Risk (OR) Organs g at Risk are normal tissues whose w radiation sensitivity y may y significantly influence treatment pla anning and/or prescribed dose..
(50) Volumes in IC CRU62 - 1999 Organ at Risk (OR) Organs g at Risk are normal tissues whose w radiation sensitivity y may y significantly influence treatment pla anning and/or prescribed dose.. Planning Organ at Risk Volume (PRV) The PRV is the OR with an integrate ed geometric margin added added, in analogue with the CTV-to-PTV expa ansion..
(51) Volumes in ICRU62 - 1999 Conformity index Conformity index (CI) defined as the e quotient of the treated volume (TV) and the volume of PTV (CI = VTV 1). T /VPTV ≥ 1).. < Treated Volume. > Irradiated d Volume.
(52) Volumes 1978 ICRU29. “The Targett Volume”. 1993 ICRU50. GTV. CTV. 1999 ICRU62. GTV. CTV. Organs at risk. Organs at risk. PTV. ITV. PTV. OR. PRV.
(53) Volumes 1978 ICRU29. “The Targett Volume”. 1993 ICRU50. GTV. CTV. 1999 ICRU62. GTV. CTV. 2004 ICRU71. Organs at risk. Organs at risk. PTV. ITV. PTV. OR. PRV.
(54) Volumes in IC CRU71 - 2004 Gross Tumour Volume (GTV) The GTV is the gross demonstrable extent and a location of the malignant growth. primary tumour – (GTV-T) metastatic regional node – (GTV (GTV-N) N) distant metastasis – (GTV-M). 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-T, CTV N CTV CTV-M) M). Planning Target Volume (PTV) As above: PTV-T, PTV-N, PTV-M. Comparison between macroscopic and microscopic section of malign and benign breast tumor. ICRU Report No No.83 83 (2010).
(55) Volumes 1978 ICRU29. “The Targett Volume”. Organs at risk. Organs at risk. 1993 ICRU50. GTV. CTV. PTV. 1999 ICRU62. GTV. CTV. ITV. PTV. OR. CTVCTV-T CTV--N CTV CTV CTV--M. (ITV). 2004 ICRU71. GTV-T GTVGTV--N GTV GTV--M GTV. PTVPTV-T PTV--N PTV PTV--M PTV. OAR. PRV. PRV.
(56) Volumes 1978 ICRU29. “The Targett Volume”. Organs at risk. Organs at risk. 1993 ICRU50. GTV. CTV. 1999 ICRU62. GTV. CTV. ITV. PTV. OR. CTVCTV-T CTV--N CTV CTV CTV--M. (ITV). 2004 ICRU71. GTV-T GTVGTV--N GTV GTV--M GTV. PTVPTV-T PTV--N PTV PTV--M PTV. OAR. …ICRU…. PTV. … variations i ti in i de delineation li ti … … a lot of work on n imaging … … “dose sculpting” is more readily done … … the “dose“dose-bath h” might be a problem …. PRV. PRV.
(57) PROB BLEM. Target-location might sh hift, depending on who is delinea ating it.
(58) Target-locatio on might shift, depending on wh ho is delineating it. Stenbakkers et al. Int J Ra adiat Oncol Biol Phys y 2005.
(59) Target-locatio on might shift, depending on wh ho is delineating it. KC Chao et al. Int J Radiat Oncol Biol Phys 68(5):2007.
(60) PROB BLEM Target-locatio T tl tion might i ht shift, hift depending on im maging modality.
(61) Target-location might sh hift, depending on who is delineating it and imaging modality. Stenbakkers et al. Int J Ra adiat Oncol Biol Phys y 2005.
(62) Target-locatio on might shift, depending on im maging modality. CT.
(63) Target-locatio on might shift, depending on im maging modality. MRI.
(64) Target-locatio on might shift, depending on im maging modality. CT.
(65) Target-locatio on might shift, depending on im maging modality. MRI.
(66) Target-locatio on might shift, depending on im maging modality. Charnley y et al. Britis sh J Radiology gy 2005.
(67) Summary o of problem. Extent of geometric variations: • Delineation variation the largest geometrrical variation in radiotherapy – often cm. Strategies for dealing with geom metric variations in practice:. • radiologists input in GTV delineation • use optimal imaging modalities • e.g. contrast • workshops/audits • Autocontouring (?). ICRU: “The uncertainty in the delineation ((of GTV and CTV)) should be included in margin considerations”.
(68) Volumes in ICRU U78 and ICRU83. Definition of volumes depends on the imaging modality. ICRU: “A clear annotation has to t be used” e.g.. GTV-T (CT, 0 Gy). GTV-T (MRI T2, fat sat, 0 Gy). ICRU Report No.8 83 (2010). GTV-T (FDG-PET, 0 Gy).
(69) Volumes in ICRU U78 and ICRU83. Definition of volumes depends on when imaging is done. ICRU: “… recommended to indiicate the dose and/or the time when the GTV has been evaluatted/measured… ted/measured ”. GTV-T (CT, 20 Gy). GTV-T (MRI T2,, fat sat, 20 Gy). ICRU Report No.8 83 (2010). GTV-T (FDG-PET, 20 Gy):.
(70)
(71) Volumes in ICRU U78 and ICRU83 Overlapping Volumes.
(72) Volumes in ICRU U78 and ICRU83 Overlapping Volumes and a buildup regions. ICRU Report No.83 N (2010).
(73) Volumes in ICRU U78 and ICRU83. The PTV might overlap an adjac cent PRV or there might be other reasons to subdivide the PTV ICRU: “… the delineation of the PTV margins should not be compromised” “… subdivision of the PTV into regions with different ff prescribed doses (so-called PTV sub-volumes, PTVSV) may be used”. ICRU Report No.83 (2010).
(74) Volumes in ICRU U78 and ICRU83 PTV extending outsid de body contour. ICRU Reporrt No.83 (2010).
(75) Volumes in ICRU U78 and ICRU83. With new techniques, q , carcinogenesis g need ds to be monitored;; there might g also be unsuspected regions of high dose within the t patient. ICRU: “… The volume within the patient ex xcluding any delineated OAR and the CTV(s) should be identified as the “remain ning volume at risk” (RVR)”.
(76) Volumes 1978 ICRU29. “The Targett Volume”. Organs at risk. Organs at risk. 1993 ICRU50. GTV. CTV V. 1999 ICRU62. GTV. CTV V. ITV. PTV. OR. PRV. CTVCTV-T CTV--N CTV CTV--M CTV. (ITV). 2004 ICRU71. GTV-T GTVGTV--N GTV GTV--M GTV. PTV PTV--T PTV--N PTV PTV--M PTV. OAR. PRV. 2007 ICRU78 2010 ICRU83. e.g e e.g. g. GTV--T (MR, 0 Gy GTV Gy)) GTV--T (CT, 0 Gy GTV Gy)) GTV--T (PET, 16 Gy GTV Gy)) GTV--TN (PET, 16 Gy) GTV GTV--N (MR, 16 Gy) GTV GTV--N (CT, 0 Gy) GTV. PTV. OAR PRV RVR MR, 0 Gy Gy)) (ITV) CTV-T (M CTVCTV--T (CT, 0 Gy) CTV Gy) CTV CTV--T (PET, 16 Gy Gy)) CTV CTV--TN (PET, 16 Gy) MR, 16 Gy) CTV CTV--N (M CTV CTV--N (C CT, 0 Gy). PTV PTV--T (MR, 0 Gy Gy)) PTV--T (CT, 0 Gy PTV Gy)) PTVPTV-T (PET, 16 Gy Gy)) PTVPTV-TN (PET, 16 Gy) PTV PTV--N (MR, 16 Gy) PTVPTV-N (CT, 0 Gy).
(77) Volumes – Do oes it matter?. Dirk Verelllen et al Nature Reviews Cancer 7, 949-960 9 (December 2007).
(78) ICRU recommen ndations on Dose.
(79) Dose in ICRU5 50 and ICRU62 ICRU Referrence Point - The dose at the point should be clinically relevant - The point should be easy to define in a clea ar and unambiguous way - The point should be selected so that the dosse can be accurately determined - The point should be in a region where there e is no steep dose gradient In central part of PTV at intersection of beam axes!.
(80) Dose in ICRU5 50 and ICRU62 Level 1. Minimum lev vel of reporting p g dose - The dose at the ICRU Reference Poin nt - Maximum dose to the PTV (Dmax) - Minimum dose to the PTV (Dmin) - Maximum M i d dose tto th the OR/PRV OR/PRV:s.
(81) Dose in ICRU83 Level 1. Why is it not adequate today? t -The absorbed dose distribution for IMR RT can be less homogeneous then in CRT -Each beam can produce absorbed dosse with large dose gradients - Large dose gradients (10%/mm) in the e PTV boundary i.e. small shifts in delivery can affect the reliability of using a single e point to report the dose - Because modern TPS have evaluation n tools that makes it possible.. - Monte Carlo calculations have statisticcal fluctuation in the results for small volumes which makes it difficult and uncertain to determine an absorbed dose to a point..
(82) Dose in ICRU83. Level of reporting for IMRT. Leval 2. Minimum level of reporrting dose in IMRT PTV and CTV -Report the DV, where “V” refers to a percentage p of volume covered by the specified dose, for each PTV and CTV V: -D95% (dose that covers 95% of the vo olume) -D50% (median dose) -Dmean (mean dose) -Dose near max: D2% -Dose near min: D98% OAR and PRV -Dmean (parallell organs) -D2% (serial organs) -V VD (Volume receiving more than e.g. 2 20 Gy). …AND… -State State the treatment planning system a and algorithm used for planning and delivery system.
(83) Dose in ICRU83 Leval 2. Minimum level of reportting dose in IMRT PTV and CTV %. D2% ”close to max” replaces Dmax. 100. D50% = Dmedian Dmean. OAR and PRV. Volume V. D98% ”close to min” replaces Dmin. VD (e.g volume receiving more than 50 Gy). 75. 50. 25. V50Gy (parallel organs) Dmean (parallel organs). 25. 50. Dose D. 75. 100. Gy. D2% (serial organs). …AND… -State the treatment planning syste em and algorithm used for planning and delivery system used for treatm ment.
(84) Dose in ICRU83 Reporting of absorbed a dose Why not D100% and D0%(the earrlier definition of min and max 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 rep port an absorbed dose that is not reliant on a single computation point..
(85) Dose in ICRU83 Reporting of absorbed a dose. Median ed a abso absorbed bed dose ((D50) is s likely e y to be a g good measure easu e of o a typ typical ca abso absorbed bed dose in a relatively homogeneo ously irradiated tumor. ICRU Report No.83 (2010).
(86) Dose in ICRU83 Reporting of absorbed dose Why D50 50% %?. Deviation between prescribed and planned absorbed a doses for 803 patients. The median absorbed dose (D50) is th he most accurate quantity ICRU Report No.83 (2010).
(87) Dose in ICRU83 Reporting of absorbed dose. Example p of two different approach pp es to p prescribe the dose ((assuming g that D50 corresponds to the ICRU refere ence point). ICRU Report No.83 (2010).
(88) Dose in ICRU83 Level of reporting for IMRT Leval 3. 3 Techniques and concep pts that are under development -Dose Homogeneity characterizes h t i th the uniformity if it off the th absorbed ab b d d dose di distribution t ib ti within ithi th the target -Dose D C Conformity f it characterizes the degree to which the t high dose region conforms to the target volume -Clinical and Biological evaluation (e.g.. TCP, NTCP, EUD) -Confidence C f interval (e.g. ( including sysstematic and random uncertainties)).
(89) Dose in ICRU83 Dose Homogeneity y and Dose Conformity. Homogeneity Index. ICRU Report No. 83 (2010).
(90) Dose in ICRU83 Dose Homogeneity y and Dose Conformity. Loic Feuvret et al. Int. J. Radiation Oncology Biol. Phys., 64 (2) 2006. Conformity index = 1.
(91) Dose in ICRU83 Dose Homogeneity y and Dose Conformity. Loic Feuvret et al al. Int. J. Radiation Oncology Biol. Phys., 64 (2) 2006.
(92) Dose in ICRU83 Quality assurance for IMRT treatment plans Previous 5% point dose accuracy specification. Replaced by volumetric dose ac ccuracy specification for IMRT Not limited to single point High gradient (≥20%/cm):85% of points p within 5 mm (1 SD of 3.5 mm)) Low gradient (<20%/cm): 85% of points within 5% of predicted dose normalized to the prescribed dose e.
(93) Dose in ICRU83 Example – Quality Ass surance measurement.
(94) Dose in ICRU83 Example – Quality Assurrance Independent calculation.
(95) Dose in ICRU83 Example – Quality Assurrance Independent calculation.
(96) Thank y you forr your y attention!. Ques stions?.
(97)
Related documents
PATRICK ADMINSTRATION AND CONGRESSMAN KENNEDY ANNOUNCE $292,000 IN FUNDING TO PROMOTE STEM EDUCATION
announced $292,000 in funding to promote and advance student interest, engagement and educator effectiveness in Science, Technology, Engineering and Math (STEM) education through
This paper intends to examine the relationship between residents’ neighbourhood satisfaction and their quality of urban life in a middle- income housing area in Kuala
Where case workers exhibit these skills in their one-to-one work with offenders, they surely enhance the potential effectiveness of any programme, just as a programme may complement
(AKA, DFG, FAS, MICINN, NSF, NWO, SNF) The project aims to set up a comprehensive research programme on citizens’ attitudes towards welfare policies across European countries3.
Na primjeru Bitcoina kao prve digitalne valute koja koristi hash funkcije i blockchain vidimo kako je postignut način sigurnih transakcija bez središnjeg autoriteta.. Napomenimo
The paper found that fiscal position measured by structural balance to GDP was rising during the period after transition to floating exchange rate system despite rising
Third, comparing actual ECB interest rate policy with projections based on the European data and estimated Bundesbank reaction functions, we find the following: Using
The main contributions of this research reside in presenting a mathematical model to deal with the random utilization of resources in the context of revenue management,
