what is tomotherapy and why is it different? is tomotherapy and why is it different? tomotherapy is...

WhatisTomoTherapyandwhyisitdifferent?TomoTherapyisa6MVlinearacceleratorcombinedwithahelical CT scanner. Before every treatment the patientundergoes a brief CT scan. This scan is then used toprecisely align thepatienton theTomoTherapy couchatthetimeoftreatmenttothepatient’soriginalpositionatthe time of the planning CT (the CT used to plan theradiation therapy). This ensures every treatment is givenwithsubmillimeteraccuracy.Thelinearacceleratorrotatesinacircleasthepatientmovesthroughthemachine.Athinsliceoftumoristreatedwitheveryrotation.Multipleleafcollimators (thin strips of tungsten) move constantly toshape the beam of radiation and alter its intensity. Thisallowsprotectionofthenormaltissues!TomoTherapywasdesignedattheUniversityofWisconsin–Madison.ThefirstpatientstreatedwiththistechnologyweredogsfromtheVeterinaryMedicalTeachingHospital.These client-owned dogs contributed to this technologybecomingwidespreadinhumanradiationoncology.Giventhe spectacular results seen in these dogs and thecontribution they made to medicine, the VeterinaryMedical TeachingHospital andUniversity raised funds tohaveaTomoTherapyUnitandnewRadiationandPhysicalTherapyCenterbuilthereintheTeachingHospital.TheUniversity ofWisconsinVeterinaryMedical TeachingHospital was the first veterinary facility to utilizeTomoTherapyandisoneofonlytwoveterinaryfacilitiesintheworldwiththistechnology.We are also extremely fortunate to have a medicalphysicist as part of our radiation therapy team. Ourphysicist brings extensive experience and a wealth ofknowledgeandproblemsolvingabilities fromthehuman

UpperleftgreyimageisaCTscanobtainedwiththeTomoTherapymachine.Thelowerleftimageis a diagnostic CT used to plan the radiationtreatment. The image on the right shows theTomoTherapyCT(aqua)overlyingthediagnosticCT. Adjustments are made to ensure precisepositioning.

TheUWVCTomoTherapyMachine

radiationtherapyfieldthatwecanapplytoourveterinarypatients.TheroleofthephysicististoensureallradiationtreatmentsaredeliveredasplannedandtoensuretheTomoTherapyunitperformsexactlyasexpected.Additionally,ourmedicalphysicistperformsqualityassurance(QA)onallplans.QAmeasureswheretheradiationdoseisdeliveredina“Phantom”(tissueequivalentmaterial)beforethetreatmentisgiven.Justanothermeasurewhichensuresthattheradiationtherapyisgivenexactlywhereneeded.