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Review
Medical
physics
in
radiotherapy:
The
importance
of
preserving
clinical
responsibilities
and
expanding
the
profession’s
role
in
research,
education,
and
quality
control
Julian
Malicki
a,b,c,∗aUniversityofMedicalSciences,ElectroradiologyDepartment,Garbary15,61-866Poznan,Poland
bGreaterPolandCancerCentre,MedicalPhysicsDepartment,Garbary15,61-866Poznan,Poland
cAdamMickiewiczUniversity,MedicalPhysicsDepartment,Umultowska85,61-614Poznan,Poland
a
r
t
i
c
l
e
i
n
f
o
Articlehistory:
Received10February2014 Receivedinrevisedform 12November2014 Accepted8January2015
Keywords:
Medicalphysics Profession Education
Professionaltraining
a
b
s
t
r
a
c
t
Medicalphysicistshavelonghadanintegralroleinradiotherapy.Inrecentdecades,medical physicistshaveslowlybutsurelysteppedbackfromdirectclinicalresponsibilitiesin plan-ningradiotherapytreatmentswhilemedicaldosimetristshaveassumedmoreresponsibility. Inthisarticle,Iargueagainstthisgradualwithdrawalfromroutinetherapyplanning.Itis essentialthatphysicistsbeinvolved,atleasttosomeextent,intreatmentplanningand clin-icaldosimetryforeachandeverypatient;otherwise,physicistscannolongerbeconsidered clinicalspecialists.Moreimportantly,thiswithdrawalcouldnegativelyimpacttreatment qualityandpatientsafety.Medicalphysicistsmusthaveasoundunderstandingofhuman anatomyandphysiologyinordertobecompetentpartnerstoradiationoncologists.In addi-tion,theymustpossessathoroughknowledgeofthephysicsofradiationasitinteractswith bodytissues,andalsounderstandthelimitationsofthealgorithmsusedinradiotherapy. Medicalphysicistsshouldalsotaketheleadinevaluatingemergingchallengesinquality andsafetyofradiotherapy.Inthissense,theinputofphysicistsinclinicalauditsandrisk assessmentiscrucial.Thewayforwardistoproactivelytakethenecessarystepstomaintain andadvanceourimportantroleinclinicalmedicine.
©2015GreaterPolandCancerCentre.PublishedbyElsevierSp.zo.o.Allrightsreserved.
1.
Introduction
In recent decades, medical physicists have slowly become furtherremovedfromdirectclinicalresponsibilitiesin plan-ning radiotherapy treatments. This change hasbeen more
∗ Correspondenceto:UniversityofMedicalSciences,ElectroradiologyDepartment,Garbary15,61-866Poznan,Poland.Tel.:+48618850700.
E-mailaddress:julian.malicki@wco.pl
prominent in countries in Western and Northern Europe, somewhatlessevidentinSouthernEurope,andonlymarginal inEasternEurope.
Previously,physicistshandledallaspectsofthetreatment planningfromstarttofinish.Overtime,however,thismodel has steadily given wayto a new structure inwhich other
http://dx.doi.org/10.1016/j.rpor.2015.01.001
specialists and technicians (primarily medicaldosimetrists andtechnologists)haveassumedmanyofthese responsibili-ties.Whilethereasonsforthistransformationaremanyand varied,medicalphysiciststhemselvesareundoubtedlyatleast partlyresponsible.
Noteveryoneagreeswiththenotionthatmedical physi-cistshavebecometoodistancedfromclinicalwork.Bortfeld and Jeraj1 argue that the real problem in medical physics
isnotinsufficient clinicalinvolvement, but ratherthat the researchandacademicaspectsoftheprofessionare weaken-ing.Despitethesearguments,Icontendthattherehasindeed beenashiftintheresponsibilitiesofmedicalphysicists.
One of the primary reasons that medical physics has become ever more distanced from its original, clinical role—in which the physicist was closely involved in treat-ingpatients—istheemergenceofadvancedtechnologiesand thechallengesthatthesetechnologiespresent.Theworkof medicalphysicistsintheclinicalsettinghasbecome increas-inglylessclinical.Thisisparticularlyevidentinradiotherapy, wherephysicistswereonceresponsiblefordeveloping treat-mentplansforallpatients,butnowhaveamoresupervisory roleintreatmentplanning.Thischangehasalteredhow physi-cistsareperceivedbyothermembersoftheclinicalstaff,and itmightevenhaveanegativeimpactonthejobpositioningof physicistsinthehospital,wherethemostimportant responsi-bilitiesareconsideredthosethatdirectlyrelatetopatientcare andtreatment.
Inthepresentarticle,Idescribehowandwhythisshiftin responsibilitieshasoccurred,andIexplainhowithasaffected theprofessionofmedicalphysics.Iarguethatitisessential thatmedicalphysicists maintaintheirclinical involvement because the specialized knowledge that physicists possess cannotbeeasilyreplacedbytechniciansorradiation oncolo-gists,norbyspecializedsoftwarerunonadvancedcomputers. Inthelongrun,ifmedicalphysicistsdonottakestepsnowto altercurrenttrends,weruntheriskofirreparablyharmingthe profession.
2.
Historical
background
The discipline ofradiation oncology has changed tremen-douslysincethediscoveryofthetherapeuticvalueofX-rays aroundtheturnofthe20thcentury.Whilecontributionstothe advanceofradiotherapyhavecomefromexpertsfroma vari-etyoffields—includingcliniciansandbiologists—itseemssafe tosaythattheinnovationsofphysicistshavebeenessential.2,3
From the very beginning, physics has had an impor-tant role in radiotherapy.4 The early discoveries of the
valueofionizing radiationinthetreatmentofcancerwere madebyeminentphysicistssuchasWilhelmRoentgen,and Marie andPierre Curie.Asaresult, physicistswere closely involvedin developing radiotherapytreatments and proto-cols. The typical job titles of these early physicists—e.g., radiationphysicist,clinicalphysicist,andmedicalphysicist inradiotherapy—underscoretheirimportance.Thephysicist wasakeymemberofthetreatmentteamand,more impor-tantly,wasinvolvedineverycasewithoutexception.
Until the advent of computerized treatment planning and the sophisticated imaging methods made possible by
computers, theseearly physicists performed mostof their planning tasksmanually.Consequently,developingan indi-vidualizedtreatmentplanwasnotonlytime-consuming(early sources,suchaskilo-voltageX-rayunits,werenotautomated andrequiredthatthephysicistperformfrequentdosimetry andoutputdosechecks),butalsohighlychallenging.Inorder tocreateaneffectivetreatmentplan,itwasnecessaryforthe physicisttohaveanadequateunderstandingofbothbiology and anatomy, inadditiontothe abilitytovisualizepatient anatomyinthreedimensions.Moreover,technological limi-tationsmeantthatphysicistshadtoconfigurethebeamsand calculatethedosesusingonlythetopographicmeasurements ofthe outer contoursofthepatient’s body and orthogonal X-rayimages.Inthispre-computerera,thedosecalculation algorithmswere quitesimple,so muchso thatdose distri-butions could becalculated manually or with the aid ofa calculatororcalculatingmachine.
Despite the evident limitations of these now outdated methods, theyhad onevery importantadvantagethathas sincebeenlost:becausephysicistswereobligedtoperform dosecalculationsmanually,theydevelopedastrong under-standing ofthe limitationsofthealgorithms andformulas used to calculate the dose. Through experience, medical physicistsknewinstinctivelythatanytypeofbodyslopeor inhomogeneityhadtobecorrectedfor.Ofcourse,thisisnot tosaythatweshouldlamentthepassingoftheoldmethods, northatweshouldreturntousingthem;rather,thisexample showsthatweneedtothinkaboutwhetherandwhatkinds ofhands-on computationalapproaches should beincluded intrainingphysicists,assuchmethodsstillhaveeducational value.
Theinteractionbetweenionizingradiationandthehuman bodyiscomplex,inlargepartbecauseavarietyofdifferent phenomenacan affect thedose. Inthe past, it waswidely understoodthatthepersonwho performedthedose calcu-lationsandbeamconfigurationsneededtopossessextensive knowledgeofthephysicalinteractionbetweenradiationand matter.Moreover,theseearlyphysicistshadtobeableto mea-surethedelivereddosestocalibratethetherapeuticsources and toassure that the correct dose was delivered in vivo. Giventhecomplexitiesinvolved,thisworkcouldonlybe per-formedbyhighly-trainedindividualswhohadstudiedphysics atthemaster’sorPh.D.level.3,5Thismeansthat,in
radiothe-rapyhospitals,theroleandpositionofthemedicalphysicists wascloselyassociatedwiththedailyclinicalactivityof treat-mentplanning,althoughtheprofessionofmedicalphysicsin radiotherapywasnotformallyrecognizedinsomecountries. However,asweshallsee,thatscenariohaschanged.
3.
Medical
physics
in
the
21st
century
As technological developments continue to revolutionize radiation oncology, the role of medicalphysicists hasalso evolved.1,3However,somebelievethatsomeofthesechanges
emphasisisplacedon improvingphysicists’technical abil-ity rather than their overall knowledgeand skill. To some degree,thissupportstheconclusionsofBortfeldandJeray,1
whoarguethatthegreaterconcernisresearchactivity. How-ever,asIargueinthispaper,withdrawalfromroutineclinical obligationsmightalsobeaseriousdrawbackofthesechanges. Recently,TheLancet6 publishedaseriesofpapersabout
thecontributionsofphysicstohumanhealth.AsKnight7state
intheircontributiontotheLancetseries,medicalphysicists havelongbeeninvolvedintransferringlaboratorydiscoveries intovaluabletoolsthathavehelpedtoimprovehealthcare. Examplesofsuchtechnologiesincludecomputedtomography, positronemissiontomography,andlinearaccelerators.Those same authors also pointout the needto supportresearch inphysics,particularlywithregardtomedicalapplications. Overtime, radiotherapydeliverymachines(linear accelera-tors,etc.)andimagingunits(CT,MRI,etc.)havebecomeever moresophisticated,ashavethecomputerizedtreatment plan-ning systems neededto operate these technologies.These advanceshave undoubtedly changedthe role ofphysicists inthetreatmentplanningprocess.Forinstance,innerbody structuresarenowscannedbyCTandthedataistransferred directlytotheplanningsystem,thuseliminatingtheneedfor whatiscommonlycalled“manualdosecalculation”.Similarly, the complexity ofdose distribution algorithms(due tothe manycross-sections)requirestheuseofhigh-speedcomputer calculations,andthusmanualdosecalculationisnolonger feasible. Similarly,the algorithms usedin these computer-izedplanningsystemshavebecomeincreasinglyaccurate,but witha corresponding increasein complexity.Daily routine treatmentplanningisperformedonacomputer,anditisthe computerwhichperformsthecomplexdosecalculationsand optimizationsbasedonaphysicist’spre-designedbeam set-up.Asaresult,thisgivestheperceptionthatalessqualified personisperfectlyabletoperformroutinetreatment plan-ning.Infact,inmanydepartments,thisjobisperformedby dosimetrists.
Anotherdownsideofthehighlysophisticatedalgorithms usedtocalculateandoptimizetreatmentplan calculations isthat theyare less easily understood bythe people who designthe treatmentplan, regardlessofwhether theseare medicalphysicists or other professionals. Overtime, algo-rithmdevelopmenthasbecomeahighlyspecializeddomain ofasub-groupofmedicalphysicists,whoreadandpublishin scientificjournalsandattendconferencesonthissubject.As aresult,thepersonwhopreparesindividualtreatmentplans andwhoseresponsibilitiesareprimarilyclinicalhaslessneed topossessacomprehensiveunderstandingofthemore theo-reticalaspectsofthesealgorithms.Consideringthatin-depth knowledgeofthealgorithmsandtheirlimitationsisnolonger necessaryfordailyplanning,andthatphysicistsaresubject toinevitabletime demandsand constraints,dowedare to claimthatspecificexpertiseinphysicsisnolongerneededfor treatmentplanpreparation?Orperhapsthatplanningcanbe splitbetweenthepersonwhopreparestheplan(nota physi-cist) and the person (aphysicist) who verifies and accepts theplan?Neithersolutionseemssatisfactory becauseeven thoughacceptingatreatmentplanimpliesacertain respon-sibility,this doesnotallowthepersontodevelopsufficient expertisegiventhatcreatingaplanandacceptingaplanare
twoverydifferenttasks.Asaresult,overtime,thepersonwho preparestheplanislikelytobecomemoreexpertthanthe per-sonwhoseonlyroleistocheckandacceptorrejecttheplan.In short,medicalphysicistsshoulddesigntreatmentplans,not merelycheckthem.
Undoubtedly, an important reason behind the decrease in actual clinical work (i.e., dosimetry and treatment plan design) for medical physicists has been the development and introduction of new equipment and procedures such as intensity-modulated radiotherapy (IMRT) and image-guidedRT(IGRT).Thesetechnologiesandtechniquesrequire extraordinary amounts of time for quality assurance and dosimetry.8–12 The routine duties of physicists in quality
control, commissioning of equipment, and performing of acceptancetestsbecamemuchmorecomplicatedtaskswhen organ motion and size variability became important. This newtaskpresentedachallengetomedicalphysicistswhile routinetreatmentplanning,bycontrast,begantolook com-paratively simple. Thequestion that aroseisthis: towhat extent should routineclinical treatmentplanning be dele-gatedtodosimetrists?Thesenewertechniquesnowoccupy alargeportionofphysicists’time,totheexclusionofother tasks.Thischangehasopenedthedoorfordosimetristsand technologists toreplace medicalphysicistsinroutine plan-ning.Ofcourse,wecannotoverlookarelatedargument:that itistooexpensivetotrainaqualifiedmedicalphysicist(which requiresaMaster’sdegreeinphysicsplusapostgraduate res-idencyprogrammeintheclinic)ifhis/herprimaryroleisto preparestandardizedtreatmentplans.
Abiggerthreattotheprofessionmaybethelargechanges thatcanbeseenonthefarhorizon.Whatwereonce clearly-definedboundariesbetweenthevariousmedicaldisciplines arebecomingincreasinglyblurred,andthisistruefor diag-nosis,treatment,andmanagement.Numeroustherapiesare nowavailable(orsoonwillbe)toallowspecialistsfromfields other than oncology to treat cancer patients. The use of radioactiveparticlestotreattumoursusingcatheters, high-intensityfocusedultrasound,electromagneticwaveablation, andphotodynamictherapyandnanoparticles13arejustsome
challengestotheexistingparadigm.
Theuncertainty andturf battleswillonlybecomemore intense,andmedicalphysicistswillnotbespared.Thisraises animportantquestion:howdomedicalphysicistsfitintothis rapidlychangingscenario?Inadditiontothenew technolo-giesalreadymentioned,wemustalsoconsiderthemolecular revolutionthatisunderway.Arewepreparedtoexplorethe newer technologies such asnanotechnology?And are uni-versitycurriculabeingadaptedquicklyenoughtorespondto changingneeds?Thefollowingsectionsofthispaperaddress suchquestions indetail.Iexplorenumerousissues associ-atedwithvariousaspectsoftheprofessionalprofileofmedical physiciststoday.Finally,Idescribethedangersthatthreaten todiminishtheimportantroleandstatusofmedicalphysics.
4.
Clinical
obligation—the
evolving
roles
in
radiotherapy
planning
responsibilitiesfromphysiciststomedicaldosimetrists.Inthe earlydaysofradiotherapy,theroleoftechnicians(ornurses) was toposition patients in the treatment unit, set up the parametersaccordingtothetreatment plan,and todeliver theradiotherapy.Originally,thestaffmembersthatperformed thesedutieswerecalledelectroradiologists,radiographers,or radiotherapy technicians.Training wastypically a2–3 year courseatprofessionalschools(i.e.,notuniversitylevel)after graduationfromhighschool.Someofthesetechniciansbegan toassistmedicalphysicistsintreatmentplanning,and,over time, ultimately came to specialize in treatment planning underthesupervisionofmedicalphysicists.Thesenew tech-niciansspecializingindosimetryhavecometobeknownas medicaldosimetristsandinmanycountriestheynowperform mostoftheday-to-daytreatmentplanningforpatients.This processhasacceleratedinrecentyearsasmanyuniversities havelaunchedbachelor’sandevenmaster’sdegreecourses dedicatedtotrainingradiationtechnicians(technologists)to meetnewdemands.14,15However,giventhemanydifferences
betweencountriesandregions,itisdifficulttodrawa gen-eralpictureofthesituationregardingwhoperformstreatment planningandthedegreeofinvolvementofradiation oncolo-gists,medicalphysicists,anddosimetrist/technologists.
Theemergenceofthisnewfigurehaschangedtheroleof medicalphysicistsintreatmentplanning,whose responsibil-itiesarenowofamoresupervisorynature.Physicistsspend lesstimedevelopingtreatmentplansforindividualpatients andmoretime performingother tasks.Infact, inmuchof WesternEurope,medicalphysicistsnolongercarryoutsimple radiotherapyplanning,asthisisperformedbydosimetrists or assistants. In contrast, physicists in Eastern European countries continue to design routine treatment plans.16,17
In some centres, for example, designing treatment plans is almost exclusively performed by dosimetrists, with the plancheckedbytheradiationoncologist(withonlyminimal involvementofthephysicists).Giventhattheinteractionof ionizingradiationwithabodyisacomplexprocessrequiring astrongunderstandingofphysics—knowledgewhichcanonly be obtained through university-level physics courses—the completeexclusionofphysicistsfromtreatmentplanningis wholly inappropriate and ismost definitely nota positive change,asIdiscussintheparagraphsthatfollow.
Thegradualeliminationofmedicalphysicistsfrom treat-ment planning might also affect the quality and safety of routineprocedures.Inallmedicalspecialities,safetyisalways prioritizedovercost.Thereisnodoubtthathavinga physi-cist perform treatment planning for each patient is more expensive; however, just as the important role of highly-qualifiednurseshasnoteliminatedtheneedforphysicians todirectlycareforindividual patients,sotoowithmedical physicists. If computerized planning systems allow physi-cists to withdraw from routine planning, does that imply thatsomemoreadvancedcomputersystem—suchasartificial intelligence—willeventuallyreplacemedicaldoctors,sothat alessqualified person couldperformroutinepatientvisits whiletheroleofthedoctorismerelysupervisory?
As inmany other specialties, the driving forces behind thesechanges are financialand political pressuresto opti-mizelimitedresourcesinhealthcare.Curiously,ifweconsider theoverallcostofcancertreatment—whichincludessurgery,
radiotherapyandchemotherapy—thecostofphysics exper-tiseaccountsforonlyasmallfractionoftheexpense.This implies that efforts to reducecosts should focus on other areas,astreatmentcanstillbecost-effectiveevenwhen physi-cistsplayanimportantroleinperformingoraccepting the individualtreatmentplan.
Anotherimportantconcernisthattheincreasinglylimited clinicalroleforphysicistscouldimpairtheabilityofthenext generation of medical physicists to respond to new tech-nologies.However,weneedbeconcernednotonlywiththe research aspectsofthe profession,but alsowithproviding career opportunities in the clinic. If the opportunities for physicists become increasingly narrow, university students willhavelessinterestinpursuingradiotherapyphysicsafter graduatingfromtheuniversity.
5.
Education
Inthenot-too-distantpast,medicalphysicistswererecruited fromgraduateswhoattendeduniversitydegreeprogrammes (inmostcases,5-yeardegrees)inphysics.Dependingonthe country,thesephysicscoursesmayhaveprovidedsome train-ingintheapplicationofphysicsinmedicine,andsomemay haveevenincludedafocusonradiationaspects.Thus,upon graduation(masterdegree),thegraduatespossessed exten-siveknowledgeinphysicsandjoinedamedicalphysicsteam wheretheywouldbetrainedinmedicalphysics.18,19However,
timeshavechangedand,inmanycountries,universitieshave increasingautonomyindefiningthecurricularcontent,and thusthebackgroundtraininginphysicsmaybestrongeror weakerdependingonthe universityandcountry.Forsome jobs,especiallyclinicalones,publicsafetyrequiresthatthe staffinvolvedhaveclearlydefinedcompetencesandskills.
AnotherimportantpointisrelatedtotherecentBologna Agreement.20,21Underthechangesimplementedthroughthe
BolognaAgreement,alldegreeprogrammes(withthe excep-tionofmedicineandfewotherspecialities)aretobesplitinto Bachelor’sandMaster’sdegrees.Theoretically,then,astudent couldobtainaBachelor’sdegreeinonefield(e.g.,engineering orevenafieldfurtherremovedfromphysics)butthengoonto doanM.S.degreeinPhysics.Thisimpliesthatstudentsfrom fields otherthanphysicsmaygraduatefrom theseMaster’s programmes,andwillthusnotbeaswellpreparedinphysics aspreviousgenerationswhohadcompletedatraditional, 5-yearundergraduatecourseinphysics.
This new situation accentuates the need for intensive, high-qualitypost-graduatetraininginthefield.However,in a number of countries, the requirements to work in clini-calradiotherapyortoenteraresidencyprogrammearenot clearlydefinedandtheyvaryfromcountrytocountry.22Asa
result,thereissomedoubtastowhetheraBachelor’sdegree inphysicsissufficientorwhetheraMaster’sisrequired,or whetherthecombinationofaBachelor’sdegreeinarelated field (e.g., engineering) combined with an M.S. in physics is sufficient. Atthe moment,theseare questionsopen for debate.
FederationofOrganizationsforMedicalPhysics(EFOMP) pol-icystatementno.12.23Thisstatementsupportsthepositive
resultsoftheBolognaprocess,whosefirststep(bachelorlevel) equipsthephysicistwithbasicknowledgeinphysics, math-ematicsandotherrelevanttopicsinnaturalscience.Inthe secondstep,medicalphysicsrelatedtopicsshouldideallybe taughtinmastercourses,whiletheusualpostgraduate train-ing ofatleast 2years should be undertaken ina hospital setting.EFOMPrecommendationssuggestthatonly comple-tionofthesethreestepswouldallowastudenttogainthe appropriateknowledgeand competencies,and this should beconfirmedbyinclusioninaNationalRegister.Thatpolicy statement isvery clearand practical. Itaccepts the exist-ing reality that, in some countries, medical physicists are recruitedfromgraduatesofengineeringorrelatedfields,but itstressesthe necessitythat allstudentsobtain amaster’s degreeinmedicalphysics.However,wemustremaincautious giventhattheBolognaprocessinitiatedderegulationinhigher education.Traininginmedicalphysicsisnotregulated,and thismeansthat,inmanycountries,thecontentofbachelor’s andmaster’scurriculaisnotregulatedbyanynationalbodies. Asaconsequence,universitiesarefreetochoosethecontent theyofferandallowthemarkettodecidewhichmodelismost appealing.Thisapproachisstandsinstarkcontrasttomedical studies,inwhichthecurricularcontentisregulatedbyvarious professionalandstatebodies.
Animportantdocumenthasbeenrecentlypublishedbythe ECinwhichkeycompetenciesandqualificationsofthe Medi-calPhysicsExpert(MPE)aredefined.24Althoughthisworkhas
beencarriedoutundertheumbrellaofRadiationProtection Section,itscontentgoesbeyondsafetyissuesandhighlights theimportanceofafoundationinphysicsinundergraduate educationand postgraduatetraining inaclinicalsetting.It quotesaterm “orequivalent”foreacheducational compo-nent,andextensivelydefinestheparticularmeaningsofeach “equivalent”.Although thiseffort reflects existing diversity ineducationalbackground,itsomehowconfirmsthedoubts raisedhereregardingwhethercurrentspecificationsof educa-tionalstandardsformedicalphysicistaretoolooseandvague. ThenewCouncilDirective2013/59/Euratomof5December 2013layingdownbasicsafetystandardsforprotectionagainst thedangersarisingfromexposuretoionizingradiation (EC BSS)laysoutingreatdetailtheresponsibilitiesand compe-tenciesofMPEsastheyrelatetoradiationprotectionandthe significant role ofdosimetry as setout inarticle 83,while treatmentplanningreceivesmuchlessattention.25
Both of the aforementioned EC documents stress the importance of medical physicists in the clinical setting, althoughtheemphasisisplacedonsafety-relatedaspectsin radiotherapy.Safetyisnodoubtimportant,butmoreemphasis needstobeplacedontheclinicalcompetenciesand profes-sionaltrainingofMPEs.
6.
Postgraduate
residency
Inmanycountries, residencyprogrammes(similartothose inmedicalspecialities)havebeenintroducedtoassurethat medicalphysicistspossesstherequisiteknowledgeand com-petenciestocarryoutworkinclinicalphysicsforradiotherapy.
Thus,inmany(thoughnotall)countries,physicistsmust com-pletea2–3yearresidencyprogrammeunderthesupervision ofanexperiencedandcertifiedtutor,followedbya compre-hensiveexam,inordertobecomecertifiedinmedicalphysics. Insomecountries theseprogrammes aremanaged by gov-ernmentalagencies.Forinstance, inPoland,this processis regulatedbytheMedicalCentreofPostgraduateEducation(in Polish,theCentrumMedyczneKsztalceniaPodyplomowego;CMKP) andthediplomaisawardedbythestate.5,19Inothercountries,
private entities—including professional bodies or societies (e.g.,theSocietyofMedicalPhysicists)—awardcertificatesand evaluatecoursesdevelopedbydifferenthospitals.22,26
These residency programmes highlight the need for a strong understanding of physics, particularly as it relates to medicine and biology—in other words, medical physics.3,22,26,27Despitetheimportanceofmedicineand
biol-ogyinthefieldofmedicalphysics,itisworthnotingthatthe focusofsuchtrainingprogrammesis,properly,onphysicsand notmedicine.Thisisanimportantpoint,aswearenot train-ingmedicaldoctorsbutrathermedicalphysicists.Themedical physicistmustfirstandforemostthoroughlyunderstandall aspectsinvolvingtheinteractionbetweenionizingradiation andmatter,andthen,morespecifically,howradiation inter-actswithhumantissuesand thebody.Asthejob involves notonlydosecalculationsbutalsomeasurements,medical physicistsmusthaveathoroughunderstandingofdosimetric methodsandthelimitationsthereof.
The rapid technological advances of recent years have broughtuseffectiveyethighlycomplexofdosedelivery meth-ods(e.g.,IGRT,IMRT,VMAT, Tomotherapy,etc.)that require athoroughunderstandingoftheprinciplesunderlyingthese technologies. While radiation oncologists do not need to possesssuchastrongtheoreticalunderstandingofthese tech-nologies,physicistsdo.Thisisakeydifferencebetweenthese twoprofessions,especiallybecausethisknowledgeis essen-tialtoevaluatingthelimitationsofthevariousdosedelivery methods.9,12,28
Fornon-specialists,itiseasytosupposethattheroleofthe medicalphysicistissimplytousethecomputer(i.e.,the treat-mentplanningsystem)toshapetheisodosecurvestoprovide maximum tumourcoveragewhilecomplyingwiththe con-straintstohealthytissues.Certainly,thisispartofthejob, butthistaskisonlyvaluable(andsafe)whentheperson per-formingitpossessesacomprehensiveunderstandingofthe processes the various body tissuesand organs undergo as radiationpassesthroughandinteractswiththetissues.This complexinteractionbetweenradiationandhumancellsand organismswillinvariablycause bothdesiredandundesired effects,justasoccurswithmanymedications.
training(i.e.,theresidencyperiod)andexperience.Ofcourse, itisclearthatmodernsoftwarehasmadetheprocessof fit-tingthedosetothetumourmucheasiernowadays,withfar fewerdifficultiesthaninthepast.Theuseoftemplatesmake thistaskeasierandthisiswhythedosimetristsand technol-ogists,whodonottypicallypossessastrongbackgroundin physics, are abletoperform this taskinroutinecases.14,22
Nevertheless,toassure patientsafety and treatment effec-tiveness, it is essential that physicists regularly check the simpletreatmentplanspreparedbydosimetrists.For more sophisticatedplans,suchasthose thatuseIMRT and IGRT techniques,thephysicistshouldactuallyperformthe calcu-lations. However,thereappearstobeagrowing beliefthat dosimetristscanalsoperformcalculationsforsophisticated plans,withthephysicistlimitedtoprovidingfinalapproval oftheplan.Inmyview,verificationandapprovalisfarless valuable—intermsofreliability—thanactuallyperformingthe primarycalculationandforthisreasonIstronglybelievethat physicists shouldcontinueperforming this highlycomplex task.
7.
Collaboration
and
overlap
between
specialists
Tothispoint, Ihaveargued thatmedicalphysicistsshould beclosely involvedindeveloping and implementing radio-therapytreatments.However,wemustrecognizethatthere is,inevitably,acertain amountofoverlap inthework per-formedbythevariousspecialists(technicians,dosimetrists, radiation oncologists,andmedical physicists)who work in radiotherapy.11,14,16Indeed,treatmentplanningcanbedone
by any of these figures, and in high-resource European countries, technicians/dosimetrists and physicists perform treatment planning in equal shares (42.8%). In contrast, the bulk (85%) of treatment planning in medium and low-resource countries is performed by medical physi-cists. A similar contrast is seen in quality assurance, in which low and medium-resource European countries rely on physicists to perform this task in 90% of cases, whereas this percentage drops to 67% in high-resource countries.29,30
Notwithstandingthissituation,Ibelievethatitisimportant toclearlydefinetheroleofallspecialistsinordertominimize overlap,andtoavoidencroachment.Certainly,changescan bemadeasappropriate,asrolescanbeexpanded,reduced,or simplyaltered.However,itisbettertodosowithforethought ratherthanafterthefact.
8.
Involvement
in
academics
Academicworkusuallyreferstobothteachingandresearch. Atsomeuniversities,academicpositionsincludeboth com-ponents and both are mandatory for staff faculty. Other universities,incontrast,allowtheir academicstaff to con-centrateprimarilyoneitherresearchorteaching,avariation ontraditionalprofessorialobligations,whichtypicallyinvolve bothareas.
Academicwork(teachingorresearch)usedtobe consid-eredessentialonlyinacademicinstitutionsoratuniversity
radiotherapy clinics. Medical physicists who work in com-munity hospitalsmay notwantto beinvolvedin teaching or research and may prefer to focus mostly on the clini-cal aspectsoftheirwork. Whileclinical medicalphysicists areoftennotinvolvedinteachinguniversitystudents,their worktypicallyincludessupervisingtrainees.Physicistsmust superviseandtrainnotonlynewmedicalphysicists,butalso dosimetristsandradiotherapytechnologists.Inaddition, dur-ingresidency,mostradiationoncologistswillspendatleast sometimeobservingtheworkofphysicists.
Depending on the speciality, students or trainees may require varying levels of supervision. For instance, under-graduate physicscoursesmay includematerialonmedical radiationphysics,andthusanypracticalcomponentsofsuch courseswillrequiregreaterstaffinvolvement—inotherwords, a greater time commitment. These supervisoryand train-ingaspectsaretime-consumingandthismustbeaccounted forwhendeterminingappropriatestaffinglevels.Inaddition, thetrainingprocessshouldincludeelementsofself-training (more or less formalized continuingmedical education) in orderforthephysiciststolearntousenewtechnologiesand techniques.
Althoughmanyphysicistsarenotinvolvedinconventional research, itisimportanttoemphasizethe factthatclinical physicistshavelongplayedanimportantroleindeveloping newtreatmentmethods—bothinthepastandpresent—and sucheffortscouldcertainlybecalled“research”.Today,given thattheroleofphysicistsinroutinetreatmentplanninghas been reduced,involvementin researchand teaching activ-ities might improve the job profile and should, therefore, be valued highly. However, this is not always the case. If teachingandresearchactivitiesareincludedinthejob pro-file, thenthe institutionneedstohavea policyinplaceto governtheworkofstaffinvolvedintheseactivities,andto provide suitable financialcompensationfortheir work.16,29
Typically,teachingformspartofthephysicist’sclinicalduties and thus, clearly,physicists with teaching obligations can-notperformthesameamountofworkasthosewithoutsuch obligations.
Researchinmedicalphysicsisextremelyimportant com-ponent in fostering development ofnew technologies and elevatingthejobprofile.1,3,31Forthisreason,inmost
9.
Quality
control
and
quality
assurance
Qualitycontrol(QC)andassurance(QA)isbecomingevermore importantinlight ofthe increasing complexity ofmodern radiotherapydeliveryandthehighdoses.Patientsafetyisa high priority,and amongthe best waystoassure safety is toimplement strong,consistentprotocols. Inrecent years, theEuropeanUnionhasimplementedmeasureswhoseaim isto harmonise medical procedures and training through-outitsmembercountries.25Theideaisnotonlytoincrease
qualityandsafety,buttoassuresimilarqualitylevelsfor radio-therapytreatmentsthroughoutEurope.Theseinitiativesare leading,inevitably,toastandardizationinradiotherapy plan-ning and delivery.QA & QCare theimportant dutyofthe medicalphysicsdepartment.Inmostlargehospitals,onestaff memberisdesignatedasthequalityofficer.Thequality offi-cercouldbeaphysicistoroncologist,orevenaspecialistsuch aspublichealth.Similar,thequalityofficermaybeamember ofthedepartment,orsimplyworkasanoutsideconsultant. Nowadays,“quality”hasamuchwidermeaningthanitdidin thepast.However,themainaimofqualityremainsthesame asalways:toofferthebestmedicalcare.31,32
Oneaspectofqualitythatisoftenoverlookedistherole ofnurses.Nurseshaveanimportantfunctioninoptimizing patientcareandimprovingtherapeuticoutcomes.However, asdescribedpreviously,therolesofthevariousstaffmembers mustbepreciselydefinedtoavoidoverlap.
Finally,inmanycountries,particularlyinEasternand Cen-tral Europe, radiation oncologists and physicists are often askedtoperformmuchoftheroutineclericalwork associ-atedwiththeirotherduties.However,thistakestimefrom theirmoreimportantclinicalworkandcanthushavea neg-ativeimpactonquality.Forthisreason,appropriateclerical staffingisanimportantrequirement.
AnemergingareaofQAisriskassessment,reportingand analysisofnearmissesandadverseerror-events.33This
con-cept,which iswell-known inindustry, involvesQA ofnew radiotherapy tools,and this islargely the domain of med-icalphysicists. Moreover,this area isnow the focus ofEC recommendations.34 Implementation of suchanalyses and
activities,whichwillshortlybemandatedinallradiotherapy departmentswillcreatejobopportunitiesformedical physi-cists.
10.
Clinical
audits
Clinicalauditsareconsideredmoreeffectivethanquality con-trolaudits(ISO9000)inharmonizingradiotherapydelivery.35
Clinicalauditsdiffergreatlyfromtheformalcontrolscarried outbyradiationprotectionorothergovernmentinstitutions. Medicalstaffmembersaremorereceptivetoclinicalaudits, mostlybecausetheauditingteamiscomprisedofpeers(e.g., radiationoncologists,physicists,and radiation technicians) ratherthan administrative personnel.In addition, properly performedclinicalauditsevaluateclinicalactivity(howthe workisconducted)ingreaterdepththanisdoneinquality controlaudits(whichusuallyfocusonlyonrecord verifica-tion). Professionals with clinical expertise are essential to
the clinical auditprocess because onlythese professionals reallyknowhowtheprocedureshouldbeperformed.Given theirhands-onknowledgeoftheradiotherapyprocess, clin-ical physicists are ideal candidates to take part in clinical audits—andthiscouldbeakeyareaofinterestinthefuture. Togetherwiththeradiationoncologistsandthetechnicians who actuallyrun themachines, physicists are best ableto judgethemanyproceduresinvolvedinradiotherapyplanning anddelivery.Moreover,giventhatadosimetryauditshould alsobeperformedaspartoftheclinicalaudit,itisobviousthat theroleofthephysicistispredominant(althoughdosimetrists canalsoprovidevaluableinput).
Whileclinicalauditsarestillrelativelyuncommoninsome EU countries, the International Atomic Energy Association (IAEA)hasbeenperformingclinicalauditsformanyyearsnow undertheacronymQUATRO.36Infact,theEUrecently(2009)
publishedclinicalauditguidelinesthatshouldbeincorporated intothelawsofallindividualEUcountries.35
11.
Radiation
protection
of
patients
Medicalphysicistsalsohaveanotherobligation:radiation pro-tection forpatients.Althoughpolicies havelong existedto protectstaff,patientprotectiontoavoidaccidentaland unin-tendedexposureisalsoextremelyimportant.Radiotherapy isgenerallyasafeprocedure,butconsideringpublicconcerns abouttheeffectsofradiation,evensmallaccidentswithminor injuriesreceivemuchattentioninthepress.Forthisreason, the EU hasconsolidated the existing legal framework and passeda newBasic SafetyStandards directivethat obliges allEUmembercountriestoimplementregulationstoprevent unintendedpatientexposureandtoevaluaterisks.25Thenew
BSSdirectlyaddressestheroleofmedicalphysicistsinthese standards, specificallycallingfortheactiveparticipationof these specialistsin theprocess, and physicists are consid-eredindispensibleforpreventingandrectifyingsituationsthat mightputeitherthestafforpatientsatrisk.Interestingly,in somecountries,regulationdonotrequirethattheradiation protectionofficer(RPO)beamedicalphysicist,oreventhat theRPOhaveauniversitydegree.
12.
Conclusions
Medicalphysicshasalongandstoriedtraditionin radiothe-rapy,anditisimportantthattheclinicalteamnotlosesight ofthatfact.Sophisticatedtreatmentplanningsystemsmake iteasytoforgetthatthepeoplewhodesignedthealgorithms andtrulyunderstandthesesystemsaremainlymedical physi-cists.Itisessentialthatphysicistscontinuetobeinvolvedin performingtreatmentplanningandclinicaldosimetry.Such anapproachisnotintendedtoexcluderadiotherapy techni-cians, especiallythosewithadvanced training(i.e.,anM.S. degree).Itisclearthattechnicianshaveanimportantroleto play.However,itisimperativethatcertainclinicalkey respon-sibilitiesbeperformedbytheprofessionofmedicalphysics.
oncologists. However, unlike our physician colleagues, we mustalsohaveacomprehensiveknowledgeofthephysicsof radiationasitinteractswithbodytissuesandunderstandthe limitationsofthe algorithmsusedinradiotherapy.Without suchknowledge,wecannothopetobetreatedasequalsand tofully participateinclinicaltreatmentplanning.Wemust beconfidentinourknowledge,competence,andskillsandbe abletodefendandsustainouropinionswhendiscussingthe besttechnologicalapproachtoeachparticularclinical situa-tion.
Medicalphysicists shouldalso takethe leadin evaluat-ingemergingchallengesassociatedwithradiotherapyquality and safety. They must be involved in clinical audits and risk assessment. Education has a crucial role in medical physics. Physicists need proper and consistent education beforejoiningamedicalphysicsdepartment,andthereafter bothpostgraduateeducationandlife-longcontinuous educa-tionareessentialaswell.
Thewayforwardistobeproactiveinourapproachtothe profession,tocarefullyconsiderourownrole,andtotakethe necessarystepstopromoteourprofessiontoitsrightfulplace inclinicalmedicine.
I thank Bradley Londres for his assistance in editing and improvingtheEnglishlanguageinthispaper.
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