Acceleratorer för medicinsk bruk Michael Ljungberg Michael Ljungberg/Medical Radiation Physics/Clinical Sciences Lund/Lund University/Sweden 1 Första lyckade strålbehandlingen Första lyckade strålbehandlingen genomfördes i Sverige 1899. 49-årig kvinna med basalcellscancer på nästippen 100 behandlingar under några månader Patienten mådde bra 30 år senare Michael Ljungberg/Medical Radiation Physics/Clinical Sciences Lund/Lund University/Sweden 2 1
Strålbehandling Linjäraccelerator med inbyggd röntgen Brachyterapi 4-18 MV röntgenstrålning Bromsstrålning Joniserande Icke joniserande Michael Ljungberg/Medical Radiation Physics/Clinical Sciences Lund/Lund University/Sweden 3 Djupdos i vävnad Michael Ljungberg/Medical Radiation Physics/Clinical Sciences Lund/Lund University/Sweden 4 2
Djupdos i vävnad Michael Ljungberg/Medical Radiation Physics/Clinical Sciences Lund/Lund University/Sweden 5 Linjäraccelerator Elekta Synergy Michael Ljungberg/Medical Radiation Physics/Clinical Sciences Lund/Lund University/Sweden 6 3
Linjäracceleratorn 90 80 70 60 50 40 30 Multibladskollimator (MLC) 4-18 MV röntgenstrålning Michael Ljungberg/Medical Radiation Physics/Clinical Sciences Lund/Lund University/Sweden 7 Linear accelerator (LINAC) Source of particles l 1 l 2 l 3 l 4 l 5 l 6 l 7 Metallic drift tubes ~ RF generator with fixed frequency Particles exit from the source and are accelerated by the potential of the first drift tube While the particles travel through the drift tube, the sign of the potential reverses The particles exit from the first drift tube and are accelerated by the potential of the second drift tube As the speed of the particles increases, the distance between two tubes increases Michael Ljungberg/Medical Radiation Physics/Clinical Sciences Lund/Lund University/Sweden 8 4
Block diagram SL75/10 Linjäraccelerator Water cooling Steering Accelerator head Michael Ljungberg/Medical Radiation Physics/Clinical Sciences Lund/Lund University/Sweden 9 Siemens Oncor Linjäraccelerator Michael Ljungberg/Medical Radiation Physics/Clinical Sciences Lund/Lund University/Sweden 10 5
External Radiation Therapy Specialized types of external beam radiation therapy Three-dimensional conformal radiation therapy (3D-CRT) Uses CT or MRI scans to create a 3 D picture of the tumor. Beams are precisely directed to avoid radiating normal tissue. Intensity modulated radiation therapy (IMRT) A specialized form of 3D CRT. Radiation is broken into many beamlets and the intensity of each can be adjusted individually. Michael Ljungberg/Medical Radiation Physics/Clinical Sciences Lund/Lund University/Sweden 11 MLC Michael Ljungberg/Medical Radiation Physics/Clinical Sciences Lund/Lund University/Sweden 12 6
Image guided radiotherapy (IGRT) Bilder av mjukvävnadsstrukturer i samband med strålbehandlingen för att korrigera för organ- (tumör-) rörelser mellan fraktionerna Kräver någon form av röntgenbildkälla i behandlingsrummet i. CT ii. fast monterad röntgenutrustning i behandlingsrummet iii. röntgenrör/bildplatta monterad på gantryt eller iv. helt annan typ av accelerator med inbyggd CT (t.ex. tomoterapi) Michael Ljungberg/Medical Radiation Physics/Clinical Sciences Lund/Lund University/Sweden 13 Bildstyrd radioterapi (IGRT) Detektor Röntgenrör Michael Ljungberg/Medical Radiation Physics/Clinical Sciences Lund/Lund University/Sweden 14 7
Tomotherapy Michael Ljungberg/Medical Radiation Physics/Clinical Sciences Lund/Lund University/Sweden 15 Tomoterapi en ny typ av strålbehandlingsmaskin 16 Michael Ljungberg/Medical Radiation Physics/Clinical Sciences Lund/Lund University/Sweden 16 8
Radionuklidproduktion vid cyklotronenheten i Lund Bilder av Gustav Brolin gustav.brolin@med.lu.se Michael Ljungberg/Medical Radiation Physics/Clinical Sciences Lund/Lund University/Sweden 17 PET Michael Ljungberg/Medical Radiation Physics/Clinical Sciences Lund/Lund University/Sweden 18 9
18 F-FDG 18 F-FDG or FDG, is used in the imaging modality PET. (Poistron Emission Tomography FDG, as a glucose analog, is taken up by high-glucoseusing cells such as brain, kidney, and cancer cells, where phosphorylation prevents the glucose from being released again from the cell, once it has been absorbed. As a result, the distribution of 18 F-FDG is a good reflection of the distribution of glucose uptake and phosphorylation by cells in the body. Michael Ljungberg/Medical Radiation Physics/Clinical Sciences Lund/Lund University/Sweden 19 PET- Positronemissionstomografi Före behandling 3 veckor efter behandling 6 veckor efter behandling Michael Ljungberg/Medical Radiation Physics/Clinical Sciences Lund/Lund University/Sweden 20 10
FDG-syntes Michael Ljungberg/Medical Radiation Physics/Clinical Sciences Lund/Lund University/Sweden 21 Rutinmässig radionuklidproduktion i Lund Används kliniskt: [ 18 F] FDG: 18 O(p,n) 18 F Lund 20 GBq/dag Malmö 15 GBq/dag Göteborg 30 GBq/dag Växjö 35 GBq/varannan vecka [ 18 F] Choline Lund 5 GBq/vecka Malmö 5 GBq/vecka [ 18 F] Fluorid Lund (sporadiskt) I uppstartsfas: [ 13 N] NH 3 : 16 0(p, ) 13 N T 1/2 = 10 min [ 11 C] CO 2 : Forskning: [ 89 Zr] : 14 N(p, ) 11 C T 1/2 = 20 min 89 Y(p,n) 89 Zr T 1/2 = 78,4 h Michael Ljungberg/Medical Radiation Physics/Clinical Sciences Lund/Lund University/Sweden 22 11
Cyklotronverksamheten i Lund Scanditronix MC 17 (Karolinska 1982 2000, Lund 2003 ) 17 MeV protoner 1 extraktionskanal, 2 targets Strålström 45µA GE PETtrace (2011 ) 16,5 MeV protoner 6 extraktionskanaler, 5 targets Strålström 130 µa (2*65) Michael Ljungberg/Medical Radiation Physics/Clinical Sciences Lund/Lund University/Sweden 23 Mycket förenklad princip av cyklotron X + + Michael Ljungberg/Medical Radiation Physics/Clinical Sciences Lund/Lund University/Sweden 24 12
Mycket förenklad princip X + + Michael Ljungberg/Medical Radiation Physics/Clinical Sciences Lund/Lund University/Sweden 25 Michael Ljungberg/Medical Radiation Physics/Clinical Sciences Lund/Lund University/Sweden 26 13
(Mycket) förenklad bild + Michael Ljungberg/Medical Radiation Physics/Clinical Sciences Lund/Lund University/Sweden 27 (Mycket) förenklad bild Period (varvtid) T för en proton ska vara lika med perioden med vilken polariteten växlar. 1 2 Resonansfrekvens + B=1.7 T, q=1.602*10 19 C, m=1.6726*10 27 kg 26 MHz Michael Ljungberg/Medical Radiation Physics/Clinical Sciences Lund/Lund University/Sweden 28 14
Circular accelerator: cyclotron The time for a turn is constant, therefore the frequency of the electric field for the acceleration is constant. Michael Ljungberg/Medical Radiation Physics/Clinical Sciences Lund/Lund University/Sweden 29 Cyklotronen -komponenter Jonkälla Elektromagnet Dees (acc.strukturer) RF (acc.spänning) Vakuumsystem (10-10 ) Kylsystem Target(s) Michael Ljungberg/Medical Radiation Physics/Clinical Sciences Lund/Lund University/Sweden 30 15
Verklig bild Targets Magnet Vakuumpump Jonkälla Dees Stripperfolier Michael Ljungberg/Medical Radiation Physics/Clinical Sciences Lund/Lund University/Sweden 31 Targetdesign Al(dummy) 14 N(p,α) 11 C 16 O(p,α) 13 N 18 O(p,n) 18 F Att tänka på Protonräckvidd Effektdeponering (kylning) Aktivering av targetkomponenter Michael Ljungberg/Medical Radiation Physics/Clinical Sciences Lund/Lund University/Sweden 32 16
Effekt Energideponering i targetvolymen per tidsenhet: 17 MV 45 μ 765 W Targetvolym ~4 ml ~4 g Absorberad dosrat: 200 / 18 O(p,n) 18 F T 1/2 = 109.8 min, β + = 96.7% Targetvolymen fylls med ca 4 ml H 2 18 O anrikat till 95 % Bestrålning i 1 h med 45 µa ger ca 100 GBq 18 F Michael Ljungberg/Medical Radiation Physics/Clinical Sciences Lund/Lund University/Sweden 33 Protonaccelerator för strålbehandling Michael Ljungberg/Medical Radiation Physics/Clinical Sciences Lund/Lund University/Sweden 34 17
Why Protons? Protons stop X rays keep going Michael Ljungberg/Medical Radiation Physics/Clinical Sciences Lund/Lund University/Sweden 35 Control /Complication Complication Control Complication Michael Ljungberg/Medical Radiation Physics/Clinical Sciences Lund/Lund University/Sweden 36 18
Characteristics of Proton Therapy maximize Tumor Dose minimize Normal Tissue Dose photons protons P Nilsson, MSF, Lund Michael Ljungberg/Medical Radiation Physics/Clinical Sciences Lund/Lund University/Sweden 37 Passiv spridningsteknik monoenergetic beam range modulated beam range compensator / bolus %dose target %dose depth depth depth P Nilsson, MSF, Lund Michael Ljungberg/Medical Radiation Physics/Clinical Sciences Lund/Lund University/Sweden 38 19
Aktiv scanning Spot scanning P Nilsson, MSF, Lund Michael Ljungberg/Medical Radiation Physics/Clinical Sciences Lund/Lund University/Sweden 39 Cyklotron för protonstrålbeh. E max 230 MeV Diameter 4.3 m Vikt 220 ton E max 250 MeV Diameter ca 3 m Vikt ca 100 ton Michael Ljungberg/Medical Radiation Physics/Clinical Sciences Lund/Lund University/Sweden 40 20
Utrustning Cyklotron Stråltransport Gantryn P Nilsson, MSF, Lund Michael Ljungberg/Medical Radiation Physics/Clinical Sciences Lund/Lund University/Sweden Illustration 41 från IBA Beam line P Nilsson, MSF, Lund PN/2009 42 Michael Ljungberg/Medical Radiation Physics/Clinical Sciences Lund/Lund University/Sweden 42 21
Gantry Diameter ca 10 m, weight ca 120 tons Michael Ljungberg/Medical Radiation Physics/Clinical Sciences Lund/Lund University/Sweden 43 Gantry och behandlingsbord Bord med 6 frihetsgrader P Nilsson, MSF, Lund Michael Ljungberg/Medical Radiation Physics/Clinical Sciences Lund/Lund University/Sweden 44 22
Behandlingsrum Michael Ljungberg/Medical Radiation Physics/Clinical Sciences Lund/Lund University/Sweden 45 IMPT P Nilsson, MSF, Lund Michael Ljungberg/Medical Radiation Physics/Clinical Sciences Lund/Lund University/Sweden 46 23
Medulloblastom X ray (3DCRT) X ray (IMXT) Protons (IMPT) P Nilsson, MSF, Lund Michael Ljungberg/Medical Radiation Physics/Clinical Sciences Lund/Lund University/Sweden 47 Strålbehandlingsprocessen CT inför dosplanering Fixation Inritning av tumör och riskorgan Dosplanering/dosberäkning Verifikation Behandling Michael Ljungberg/Medical Radiation Physics/Clinical Sciences Lund/Lund University/Sweden 48 24