Lecture 5 - Other Imaging Modalities - Imaging in Radiation Therapy PDF

Imaging in Radiation Therapy MRS257H1 RTIM 240 Lecture 5 Other Imaging Modalities Usual Second Slide Next week Term Test I Because of scheduling conflicts with rooms, invigilators, etc., our term test I has been slotted in to the 8-9am ti...

Imaging in Radiation Therapy MRS257H1 RTIM 240 Lecture 5 Other Imaging Modalities Usual Second Slide Next week Term Test I Because of scheduling conflicts with rooms, invigilators, etc., our term test I has been slotted in to the 8-9am time slot in rooms 1341 and 1325 I will post a document outlining which room will have which students One hour MCQ exam Covers material from weeks 1-4 (not this week) Questions? – please email me Conventional Simulation Blast from the Past!! x-ray unit with geometry to mimic treatment unit Incl lasers heavy reliance on external bony landmarks and internal bony structures (40-120KV) since itsonly x ray wantedto nope.tgatnut.ee image intensifier for fluoroscopy Pomandmark record amovie 2D projection images same geometry as linac 100SADor80 miniex machine  head wiresinthe Conventional Simulation iefirew bigthe tiesnihetornted machine Fordefined byColl of no muchof Anatomy can 404 iiiEi Ifitian Afls Therapist Mladroom Ferrobend So…. We can set up a patient in the same position they will be for treatment, and place the isocentre of the conventional sim in a good place, take pictures from all angles we will treat, and then tattoo the patient to tie treatment delivery to treatment simulation We can move the bed and the beam parameters from outside the room, and we can symmetrize the field Tattoos Can tattoo lots of different things Beam CAXs We can see them in the Beam corners light field from the simulator! Beam centres Lateral levelling tattoos Using the lasers in the room Straightening tattoos Etc. How it worked Position patient with treatment accessories Surface anatomy for location offend Fluoro to set iso Movien taking a Adjust beams under fluoro for anatomy Symmetrize Send films to RO and tattoo/setup note Digitize field into mosaiq Manual calc That’s about it for conventional sim Another Modality - PET PET positronemission Tomography 1. Intro to PET 2. Process of image production i 3. Factors effecting image quality 4. Radiotracers & applications - imaging tissue types, treatment planning, monitoring response Introduction PET = positron emission tomography CT, MRI, - dead or alive Advanced form of Nuclear Medicine to image in-vivo biochemistry = Molecular Imaging pthave to be alive 3D images of distribution of radioactive tracer at a specific time point in the patient PET history 1975: First commercial PET scanner 1976: FDG first used 1980’s: research - Neurology 1983: First dopamine scan in humans at McMaster why stemptIdypapio.essheTailtive 1994: FDA approved FDG use for Epilepsy 2000: FDA approved FDG tumour glucose metabolism 2001: First commercial PET-CT scanner 2011: First commercial PET-MR scanner Positron Decay decomposition metepstein  travels position adistance through meet an to e and lead 511 hev annihilation why 1.022MeV 511 511 ete of sloweddown hood so likely interaction of  PET is same of 150 as iso Ct PET/CT scanner anatomy of scan one o overlay of that istame9th Taken Apart CT ring PET ring Comparison of Different imaging 4thgeneration rowofdetector thatdon'tmove IEEfoni theannihilati i natppening w in the pt interaction Einstein valeted urine Through B. Sattler et al. / Radiotherapy and Oncology 96 (2010) 288–297 Detectors 6.5cm  detectionphotodiode determine whichwillthe PET: photodetection how large is photon pulse height current depends on analyser incident energy energy converted to photomultiplier electric current and tube amplified by PMT electrons elevated to scintillation excited state; lose crystal energy by scintillation courtesy of S. Breen  fuzier Satestion Tomography - PET PET: Coincidence detection we wanta detection coincidence a part tomakesureis identified detectors of astheme interaction paintitation Coincidence ? Line Of t1-t2 1000 for research in different biochemical systems Oncology, Neurology, Cardiology PET radioisotopes T 1/2 Use [ min ] 11C 20 Organic molecules 13N 10 13NH 3 15O 2 H215O 18F 110 18F-FDG 64Cu 762 Cu-ATSM 68Ga 68 [ Ga68 ]-EDTA 82Rb 1.2 Cardiac perfusion PET radioisotopes T 1/2 Use [ min ] 11C 20 Organic molecules 13N 10 13NH 3 15O 2 H215O O 18F 110 18F-FDG 64Cu 762 Cu-ATSM 68Ga 68 [ Ga68 ]-EDTA 82Rb 1.2 Cardiac perfusion 18 F production Cyclotron Whereitsmade Radiochemistry Facility The Various Imaging Modalities better atsensitivity detection betterat ppashtion courtesy of H. Keller Functional Imaging (Brain) function cellular activity neurons fire (+/-) requires energy blood flow glucose metabolism  FDG - Uptake mechanism transported into cells directly proportional to glucose in cells phosphorylation via hexokinase to FDG-6-PO4, metabolically trapped taken offGlucose and replaced it Torine reflects the glucose metabolic activity inside the cell directlyproportional to its use FDGbutnotresponding uptaking more so ittakesup localised in areas tracesgets metabolism of high  dontmorize FDG - Uptake mechanism Glycogen 18F-FDG-1-P Hexokinase  k1 k3 18F-FDG 18F-FDG 18F-FDG-6P k2 k4 Glucose-6- Glucose Transporters 18F-fru-6-P Phosphatase  GLUT 1 – GLUT 7 Glycolysis Tumour Cell Tumour: GLUT-1, GLUT-3  Blood  FDG PET in Oncology requires quantification for objective comparison tyiitp mp is pre-Tx pre-Tx 0 0 post-Tx post-RT 1 month quantification of FDG uptake can be absolute (kBq/mL) or semi-quantitative (SUV) methods Standardized uptake value simple, no blood samples, static scan place ROI over area of interest ROI activity normalized for injected dose & patient weight howmanydisinterigations tracer in tissue (Bq / ml ) SUV  inj. dose (Bq) / weight (g ) distribution inthe person Applications ii. Radiation Oncology: A. Staging B. Treatment planning / tumour targeting C. Monitoring treatment response  Oncology - roles of PET Diagnostics Ca?/no Ca? Increasingly quantitative Med. Imaging Staging NF PWTEasi.es High?/low? Radiation Oncology Treatment High?/low? Planning Where? How high? top Perthes how low? Monitoring lessor get Where? Treatment Emanate Response  PET-CT in Radiation Oncology A. Staging Depending on tumour type, PET can have higher sensitivity, specificity & accuracy than CT or MR structuralimage modality atsize onlylooking  PET-CT in Radiation Oncology B. Treatment planning / tumour targeting which targetthepart w̅ the is lit up beams Thresholding challenge 31.5 cm3 47.3 cm3 64.9 cm3 portion lit size is of Sowherewe diff up setup is diff  PET-CT in Radiation Oncology Treatment planning / tumour targeting - Tumour delineation: PET may help in reducing interobserver variation incontouring PTV - Planning target volume: depending on tumour type PET can alter target volume (Lung- NSCLC) - Research: Hypoxia imaging to define areas of tumour to boost the RT dose Old Paper Showing Value of PET Contours? Contours! I still wonder about this one Contours – better but not perfect Note improvement in inter-observer variability with PET imphansofieist.es PET has the ability to alter 25-50% of treatment volumes  No PET under pts over ortxed Contours - Implications Red thought this was tumour…what did the others think? What would have happened without PET?  18F-FAZA (18F-Fluoroazomycin arabinoside) goinregionsof hypoxia HO OH go inandget stuck NO2 will rachtracer and localise 18 F Fleegideandwe getoursignal N N O Research: Hypoxia imaging  18F-FAZA has regions of repetition Cervix hypoxia oxygenenhancement tipptat PestoTeathset9 effeap.ie aynEnewe  andsince 18F-FAZA Pancreas Hitchedits9ft  PET-CT in Radiation Oncology C. Response monitoring / re-staging Tx: chemo and/or radiation Assessment of response Structural: changes Functional: changes in size CT, MR in metabolism PET Response European Evaluation Organization for Criteria EORTC - PET criteria Research & In WHO: RECIST Treatment of PERCIST (2009) Solid Cancer I Tumors Positron Emission Response Criteria In Solid Tumors lookingforchanges in metabolism after tx  PET-CT in Radiation Oncology C. Response monitoring / re-staging CT May 23 pre- Jul 25 during- Aug 26 post- RT  PET-CT in Radiation Oncology C. Response monitoring / re-staging CT PET May 23/07 pre- Jul 25/07 during- Aug 26/07 post- RT  PET-CT in Radiation Oncology C. Response monitoring / re-staging CT PET Fused May 23/07 pre- Jul 25/07 during- or couldbehealing needn'ttumor Aug 26/07 post- RT Imaging for treatment response Diagnosis Therapy A Outcome Goal 1: Goal 2: Goal 3: Prognosis Response Surveillance Is it working? Tumor type Image-based features/ Is the tumour back? Histology Late effects? “Imaging biomarkers” Stage (Node involvement) PET uptake RECIST traces uptake in diff can useeach the txvolume one Tumour Volume tracers for PET tracer uptake EORTC metabolic response: Complete Response (CR) - complete resolution of FDG uptake within tumour volume Partial Response (PR) - reduction of a minimum of 15-25% in tumour SUV standarduptakevalue Stable Disease (SD) - increase in SUV less than 25% or a decrease of less than 15% Progressive Disease (PD) - increase of SUV more than 25%, or new (metastatic) lesions EORTC metabolic response: PD morethan 25 100 SD 15 25 nochange % FDG in tumour PR lessthan 15 CR SUV Treatment  PET monitoring response 18F-FLT (18F-Fluorothymidine) 8F FLT cells lightupcycling it ifYouhaveifmany notthen will light as much won't lightup study for new drug chemoTx FLT-PET-CT scans pre- and post-drug Tx quantitation of uptake reflects proliferation rate PET monitoring response 18F-FLT Scan post-chemoTx high (60 min post inj) Bynthesis met SCC tongue goingon courtesy of D. Hussey  PET monitoring response Techniques: FDG PET-CT scans during radiation treatment Studies: i. Lung Ca ii. Non-Hodgkin Lymphoma (NHL)  Clinical research Monitoring Radiotherapy (RT) response with FDG PET: RT can cause inflammatory reaction (hypermetabolism) when? will this accumulate FDG? cangetpneumonitis recommended FDG PET not performed for 2-3 months after RT, however, not much data to support this…. Lung FDG PET utility in radiotherapy treatment planning & assessment in all stages & histological types of cancer Patients: 25 (20 NSCLC & 5 SCLC) Scans (3): pre-RT, last week during-RT and 8 weeks post-RT Rationale minimal data on FDG PET during RT as a predictive parameter Purpose acquire data which might assess tumour metabolic response during RT, to possibly allow adaptation of Tx before completion do changes in tumour FDG activity during RT correlate with response after completion of Tx Acquisition protocol: I. Pre-RT a. Lung (RT planning position) scout 4D CT (respiratory gating) CTAC & PET 2 axial field of view (AFOV) b. Whole body scout Attenuferction CTAC & PET 7 AFOV II. During-RT a. Lung (same as pre-RT) III. Post-RT repeat of Pre-RT  Fused PET-CT scans pre- during- post-RT O  Pre-Tx (AM) Fused PET-CT MIP MIP = maximum intensity projection Intentness aint fate We’ve heard this before: “a visualization method for 3D data that projects in the visualization plane the voxels with maximum intensity that fall in the way of parallel rays traced from the viewpoint to the plane of projection.”  Tumour metabolic response Pre-Tx Tx Post-Tx SUV max 13.9 3.0 2.4 (-83% from pre) reduction inSUV Partial Response  Pre-Tx (WM) Pre-Tx Tx Post-Tx PR SUV 14.8 12.9 3.9 (-74% from pre) Lymphoma Pilot study - Spatio-temporal response of NHL to RT measuring FDG uptake with PET-CT Patients: 10 Scans (7): pre-RT, every week during-RT(4), then 2 post-RT (1 & 3 months)  Lymphoma Spatial-temporal data analysis Keller H, Goda JS, Vines DC, Lockwood G, and Tsang R. Quantification of local tumor response to fractionated radiation therapy for non-Hodgkin Lymphoma using weekly 18F-FDG PET/CT imaging. Int J Radiat Oncol Biol Phys 76(3): 850-858, 2010. no artifacts of Rad Tx seen on FDG PET scans during RT  PT T1 T2 MIP SUV max = 15 Radiation Pneumonitis lateeffect can monitor disease T3 T4 F1 F2 orogression of monitor sideeffects  P12 SUV Axillary large 30.5 node lymphoma 7 days 21.6  rdrum pushing eardruminletthfthe.net gttmaediminehtndane.to'teration  object sound time flight an beofused to eterminehowfar away the surface a reflected off detectthatsmth caused an echo  will the freq if object is moving the perceived of sound US  currentsto waves waves comingback Init electricagnals in  p Matingaffesamespeed causing Artifacts  the sound wave of  Fence practitien p Forte so we don't get air tissue interface onthe surface See the boundary it but sound willgothrough  neuraligntight fictionoff the theskin of returnecho is attenuation or AC all Effected whitedot mypherechoic  Liver Mets grayarea  thingis returning nodifferences inthe echo  depending on whether in shows partsrefdblordbaille or away from goingtoward transducer  Esoutisand offcausey tx so havetogo reposition prostatemight Eseedplacement pthasfullbladder downandScanning can be used inimageguidance 2 pushing the head goingtowards tragetlttkhphgt.ttthe untidangettopof a perineumand scan through Monitoring angle itonce bladder ontopof tngor the yfggfngmopysfea.mn Timingunderneath repospitton or plan ps prostateclearly attachmenton wand in ee i small size tn situ breast scopserving  local recurrence LR increase survival Radffer textbookvalue VBH  4 1 3 2 Example 2 – We’ll be doing this totheotherbreast backand PROS morestable come CONS breastmotion w̅arm up thebreastgoes andmedial up matterfield The End Have a good week