The Effect of Light Fluence Rate in Photodynamic Therapy of Normal Rat Brain Author(s): Q. Chen, M. Chopp, M. O. Dereski, B. C. Wilson, M. S. Patterson, A. Schreiber and F. W. Hetzel Source: Radiation Research, Vol. 132, No. 1 (Oct., 1992), pp. 120-123 Published by: Radiation Research Society Stable URL: http://www.jstor.org/stable/3578343 . Accessed: 21/06/2014 11:49 Your use of the JSTOR archive indicates your acceptance of the Terms & Conditions of Use, available at . http://www.jstor.org/page/info/about/policies/terms.jsp

. JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range of content in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new forms of scholarship. For more information about JSTOR, please contact [email protected].

.

Radiation Research Society is collaborating with JSTOR to digitize, preserve and extend access to Radiation Research.

http://www.jstor.org

This content downloaded from 185.44.78.31 on Sat, 21 Jun 2014 11:49:39 AM All use subject to JSTOR Terms and Conditions

RADIATION RESEARCH 132,120-123(1992)

SHORT COMMUNICATION The Effect ofLightFluenceRateinPhotodynamic RatBrain ofNormal Therapy Q. CHEN,*'t M. CHOPP,*'t M. O. DERESKI,*B. C. WILSON,f M. S. PATTERSON,4A. SCHREIBER,*AND F. W. HETZEL*'t Cancer Hamilton Ford andNeurology, Detroit, 48202; Physics, Regional Hospital, Michigan tMedical Henry Oncology ofRadiation *Department 48309 Oakland andtDepartment Rochester, andMcMaster Hamilton, Ontario, University, Michigan Canada; Center, ofPhysics, University, ofwhitelight.Survivalwas irradiances exposedto varying from5.5 to 0.28 wasdecreased enhancedas theirradiance mWcm-2.Similareffects etal. (3), wereseenbyMatthews Rat whoexposedhumanlungcarcinoma ofNormal RateinPhotodynamic ofLightFluence Therapy of cellstoirradiances Brain.Radiat.Res.132,120-123(1992). 2 h incu0.038to0.3 mWcm-2of630-nmlightfollowing survivalat a lower rateon bationwithPhotofrin ofincident theeffect Thispaperreports II. The greater lightfluence lesionsareproduced thedepthtowhichnecrotic to cellularrepairmechanisms. ratewasattributed byphotody-fluence Fisherrats.The namictherapy (PDT) inthebrainsofnormal in vivostudiesof thefluencerateare even Systematic withPhotofrin ratswereinjected (12.5 mg morescarce.Gomeretal. (1) evaluated intraperitoneally of theskinresponse fluence of35 J kg-')48 h priorto PDT witha fixedincident of 270 J a total mice whose received hind exposure cm-2 leg at10,50,100,and200mW wasperformed Thetreatment cm-2. of 5, 25, or 125 mW cm-2.The micewere at irradiances manner cm-2andalsoina periodic (30s "on"at100mWcm-2, with 7.5 (ip)24 h mgkg-'ofHPD intraperitoneally wasdeter- injected occurred 30 s "off").Thedepthto whichnecrosis were No differences seenin to treatment. oftis- prior significant examination treatment mined24 h after bymicroscopic of evaluated or course the skin time the inthedepthtowhich werefound No differences suesections. response severity schedules.subjectively. wasproduced In a recentpaper,however, Gibsonand conecrosis byanyofthefiveirradiation doseofother inthecontext isdiscussed Thisfinding published workers (4) reported longergrowth delayoftransplanted rateexperiments.@ 1992AcademicPress,Inc. PDT withPhotofrin tumorsin micereceiving mammary on thetumor (24 h after5 mgkg-' ip) as theirradiance surface wasreducedfrom200to50 mWcm-2(totalfluence INTRODUCTION 180-360Jcm-2).Evengreater delaywasobserved growth ina periodic et when the was delivered Foster al. light (5) bothinvi- by tophotodynamic therapy response Biological a "on" 100mW of 30-s phase(irradiance consisting concentra-pattern on thephotosensitizer troandinvivodepends The a 30-s interval. authors "off' sugWhilemanypapershave cm-2)followedby tionandthetotallightfluence. local dose-rate effects are due to that these oxygen gested these two theinfluence of whichexamine beenpublished This processitself. inwhich depletioncausedbythephotodynamic havebeenreported fewexperiments parameters, a and would be more severe at fluence rates, depletion high withother treatoffluence ratealonewasstudied theeffect scheme at the correct would irradiance periodic frequency no Gomeretal. (1) observed controlled. mentparameters duringthedarkphasesofthecycle. hamster ofChinese ovary(CHO)' allowreoxygenation changein thesurvival Farrell et al. didnotobservea changein the however, (6), whenthecells fluence ofthetotallight cellsas a function to which necrosis was causedbyPDT withA1SPCin derivativedepth for1 h in hematoporphyrin wereincubated normal rat liver when periodicas opposedto continuous with630-nm in vitro irradiated (HPD) andsubsequently was used. of0.5 to 60 mWcm-2.On theother irradiation lightat irradiance In photodynamic ofbraintumors, in differences Ben-Hur et typicallight therapy al. hand, significant (2) reported for90minwith fluenceratesof4 to 70 mWcm-2havebeenusedin recent ofCHO cellsincubated curves thesurvival tumor irradiation ofresected cholorosulfonated aluminum (AISPC)and clinicaltrialsofintracavitary phthalocyanine bed (7). As discussedby Staret al. (8), thetotalincident irradiances wouldhavebeen severaltimeshigherdue to Abbreviations used:AISPC,aluminum chlorosulfonated phthalocyanof lightfromthetissueback intothe diffuse reflectance derivative; ip, ine;CHO, Chinesehamster ovary;HPD, hematoporphyrin The is to thatspanned comparable PDT, photodynamic cavity. range therefore therapy. intraperitoneally;

CHEN, Q., CHOPP, M., DERESKI, M. O., WILSON,B. C., PATTERSON,M. S., SCHREIBER,A., ANDHETZEL, F. W. TheEffect

$5.00 0033-7587/92

120

Copyright@ 1992 by Academic Press,Inc. All rightsof reproductionin any formreserved.

This content downloaded from 185.44.78.31 on Sat, 21 Jun 2014 11:49:39 AM All use subject to JSTOR Terms and Conditions

121

SHORTCOMMUNICATION

a separate oftemperature to the groupofanimalsshowedno elevation of at level the delivered rate fluence levels hyperthermia (unpublished laser Argondye timescorresponding to 10,50, 100,and 200 mW data).The irradiation Thecraniotomy sitewaskept cm-2were59,12,6,and3 min,respectively. with saline After moist irradiation. the was treatment, during craniotomy Neutral filter density hemostat coveredwithsurgical absorbable andJohnson, New (Johnson closed.Theanimalwasthenallowed Brunswick, NJ)andthescalpsutured The incident ratewascontrolled to recover. fluence Opticalaperture bya neutral density Craniotomy Craniotomy filter Theoutputpowerofthemicrolens fiber Griot, Irvine, (Melles CA). Craniotomy was measuredwitha powermeter(Photodyne, WestlakeVillage,CA, Model88XL). In addition tothegroups laserirradiation, continuous wealso receiving irradiated a groupofanimalsusingperiodic Onesideofthe light delivery. brainwastreated withcontinuous of100mWcm-2as lightat irradiance described abovefor6 min,whiletheothersidewasirradiated with100 Brain mWcm-2during 30-s"on" periods with30s ofnoirradiation, alternating Skull fora totaltreatment timeof12min(also 35 Jcm-2). Allratsweresacrificed 24 hafter treatment theleft byperfusion through ratbrain.Crani- cardiacventricle ofnormal forirradiation FIG. 1. Experimental design of250 ml4% neutral buffered following formaldehyde byshading. otomysitesareindicated with250 mlheparinized vascular washout saline.Thebrainsweresubseremoved andslicedinto3-mm-thick coronalsections. Brainsecquently theareadirectly theirradiated tionsfrom beneath surfaces wereplacedin and a 6-Amsectionwas cutand collectedevery0.5 mm.The ofGibsonet al. (4). paraffin experiments by thein vivodose-rate sections werethenstainedwithhematoxylin and eosinforlight paraffin as a function ofdepthwithin microscopic ratealsodecreases Thefluence examination. lesiondepthwas As described thetissueso that,at themarginofthenecrotic byDereskiet al. (9, 10) PDT-induced regionloin from measured each section the brain surface tothepoint paraffin pial the fluence catedattwoorthreeopticalpenetration depths, wereevident. CoronalsectionsizewasnorFor whereno cellularalterations ratewouldbe onlyabout5-10%ofthatat thesurface. malizedto freshtissuemeasurements, due to eliminating anyartifacts the fluencerate at tissuepreparation some clinicaltreatments, therefore, wascarried outforthePDT lesions size.Thisprocedure effectsinbothhemispheres to thosewheredose-rate foreachanimal.A pairedStudent's ttestwasusedto depthmaybe comparable between thelesiondepths from different thatthe testfordifferences invitro. Itispossible, havebeenobserved optiresulting therefore, clini- cal fluencerates. be important ratemight oflightfluence effects during

inrelation toeither theanti-tumor cal PDT ofbraintumors ordamagetothenormalbrain.In previous experiefficacy RESULTS ofnormalratbrainto mentswe havestudiedtheresponse as occurred thedepthtowhichnecrosis PDT bymeasuring 2 showsa typicalpatternofdamageto normal suchas injectedphoto- Figure oftreatment a function parameters between thenecrotic tissueand brain.A sharpdemarcation doseandincident sensitizer (9, 10).Thispaper normaltissuewas foundat all treatment lightfluence dose rates.No theefofthosestudiesto investigate theextension reports withinthisnecrotic viablecellsweredetected zone,while rate. fluence fectofincident light or no little damageof boundary, beyondthedemarcation neuronaltissuewasobserved. MATERIALSAND METHODS wasobserved Figure3 showsthedepthtowhichnecrosis fluenceratesand schedules.The lesion forthedifferent Male Fisherrats(n = 45, 220-280g,CharlesRiver,NewYork)were at 100 mW treatment bythecontinuous Van- depthgenerated used in all experiments. Photofrin (QuadraLogicTechnologies, cm-2 in each group was consistent among all groups.No hours after the (12.5 mgkg-',ip). Forty-eight couver)wasadministered the lesion detected between differences were with anesthetized Ketamine was the animal (44 mg administration, significant drug of 10,50,and fromcontinuous irradiances kg-')and Xylazine(13 mgkg-').A 2-cmmidlineincisionwasmadeto depthresulting on each wasperformed craniotomy exposetheskull.A 5-mm-diameter to thecoronalsutureand 3 mm 3 mmposterior centered hemisphere, Thebody themidline suture lateralfrom (Fig.1).Thedurawasleftintact. was monitored usinga rectalprobeand keptwithin36 ?+ temperature 0.50C usinga heating pad. Palo Theirradiation sourcewasan argon-pumped dyelaser(Coherent, Alto,CA,ModelANOVA-70andCR599)tunedto633? 2 nm.Thelight a witha distalmicrolens wascoupledintoa 400-Mm giving opticalfiber field.Eachcraniotomy sitewasirrairradiation uniform 5-mm-diameter of35 Jcm-2.One sideofthe fluence to an incident diatedsequentially rateof 100mWcm-2,whilethe at a fluence brainwasalwaysirradiated othersidereceived 10,50,or200mWcm-2.The 100mWcm-2sideand in studies Ourpreliminary werechosenrandomly. theorderofirradiation

200 mW cm-2 or periodic irradiationat 100 mW cm-2 compared withthat fromthe continuous 100 mW cm-2 treatment(P > 0.5). There werealso no detectabledifferences (P > 0.5) amongthePDT lesiondepthsat all treated dose-ratelevelsin all groups(10-200 mW cm-2). DISCUSSION difference In theseexperimentswe foundno significant

innormal inthedepthtowhichPDT lesionswereproduced

This content downloaded from 185.44.78.31 on Sat, 21 Jun 2014 11:49:39 AM All use subject to JSTOR Terms and Conditions

SHORT COMMUNICATION

122

Ad M 1''INSIR

r

""M

:: ~x

:

..

thePDT treatment, a lesionarea(volumeyin eachhemisphere. Thelesionswere FIG. 2. A representative brainmicrograph at 24 h after showing thelesionandthenormalintactbraintissue. Thearrows inducedby100mWcm-2(left)and 10mWcm-2(right). pointtothedemarcation separating

~~2i

no changein theresponse One ofthosestudiesreported ratbrainwhentheirradiance rangedfrom10 to 200 mW in normal whereas of mouse theothera fluence-rateThe cm-2orwhenthelightwasadministered skin, periodically. in tumor and dose dependentchange growthdelaywas observed. (12.5mgkg-1) injection-irradiation injecteddrug on in Since different different tissuetypeswereused,it two other in to those were similar assays reported delay(48 h) to comparetheseresultsdirectly withours. fluence(35 Jcm-2) is impossible vivostudies(1, 4). The totaldelivered in some than that used either of are raised which lower Nonetheless, questions was,however, interesting considerably in futureresearch. could be considered The observation theotherexperiments. inthetwonormaltissues thatfluence ratewasunimportant studiedmaybe consistent withthehypothesis ofFosteret that is for the rate-deal. (5) oxygendepletion responsible 4.0 seenintumors, as tumors have S: Single dose treatment pendentresponse generally a less The brain a adequate represents speoxygensupply. F: Fractionated dose treatment the because is confined case cial photosensitizer likely 3.0 mainlyto vascularelementsby the blood-brainbarrier wouldprobably be theprimary I(11). Sincethevasculature PDT target, and becauseendothelial cellswouldbe wellw 2.0 withblood-borne itwouldnotbeexpected supplied oxygen, 0 thatoxygen duetolimited wouldinfludiffusion, depletion, .. encethefluence ratedependence oftissuedamage. 1.0o On theotherhand,failure to observean effect offluence ratein eithernormalbrainor skinmightbe attributed to 0.0 theassaysused.Thegrowth ofGibsonetal. (4) delay assay 8100-810 S100-S50 S100-S200 S100-F100 PDT byvirwoulddetectsmallnestsofcellswhichsurvive TREATMENT GROUP (mW cm') tue of theirdistancefromcapillariesand thenmultiply, PDT lesion ofthemaximum deviation FIG. 3. Meanand standard Thegrossmeasurement tumorregrowth. ofnecrotothe100 causing Thelesiondepths corresponding depthsinalltreatment groups. whichwe usedin thisstudyor thesubjective assis depth in each groupare indicatedby theshadedbars. mW cm-2 treatments sessment of skin et Gomer al. response (1) employed by in ofanimals eachgroupwere14,10,9, theleft, thenumbers Readingfrom wouldpresumably notdetectsucheffects. Itwouldbeinterand 12.

This content downloaded from 185.44.78.31 on Sat, 21 Jun 2014 11:49:39 AM All use subject to JSTOR Terms and Conditions

SHORT COMMUNICATION

evidenceofsuchsurviving estingtosearchformicroscopic cellsin thetumormodelwhereFosteretal. andGibsonet fluence-rate effects. al. observed of Iftumorcellsandtissuesaremoresubjecttotheeffects couldbe exratethannormalcells,thisdifference fluence thefluence rate,as longas theresulting ploitedbyreducing this To someextent, remained practical. longertreatment in PDT, as thenormaltiseffect mayalreadybe operative is at themarginofthetumorwhere interface sue/tumor Exrateis alreadyreducedduetolightattenuation. fluence shouldbe done in a modelwhere plorationofthiseffect ofthehost totheresponse canbe compared tumorresponse tissue. ACKNOWLEDGMENTS Thisworkwas supported by NIH GrantPO1-CA43892and theNaofCanada.Theauthors alsothankMs.LaraMaditionalCancerInstitute ofthe Ruffin forthepreparation andMs.Patricia support ganfortechnical manuscript. 9, 1992;ACCEPTED: May22, 1992 January RECEIVED:

REFERENCES In vitro N. J.Razum,andA. L. Murphree, 1. C. J.Gomer,N. Rucker, derivatohematoporphyrin related doserateeffects andinvivolight CancerRes.45, 1973-1977(1985). tivephotodynamic therapy. of Effect R. Kol,E. Riklis,R. Marko,andI. Rosenthal, 2. E. Ben-Hur, cellsphotosensitization rateon mammalian bychlorolightfluence aluminum Int.J.Radiat.Biol.51, tetrasulphonate, phthalocyanine 467-476(1987).

123

R. R. Perry, S. Evans,andH. I. J.Cook,J.B. Mitchell, 3. W.Matthews, ofhumanlungcancer:InvestiPass,In vitro photodynamic therapy effects. CancerRes.49, 1718-1721(1989). gationofdose-rates R. S. Murant, R. F. Baubertas, and 4. S. L. Gibson,K. R. VanDerMeid, ofvariousphotoradiation ontheantitumor R. Hilf,Effect regimens forR3230ACmammary carciof photodynamic therapy efficacy nomas.CancerRes.50,7236-7241(1990). R. G. Bryant, R. S. Murant, 5. T. H. Foster, R. S. Knox,S. L. Gibson, in photodyanddiffusion effects and R. Hilf,Oxygen consumption namictherapy. Radiat.Res. 126,296-303(1991). andR. Chow,ThedepenB. C. Wilson, M. S. Patterson, 6. T. J.Farrell, in denceofphotodynamic threshold doseon treatment parameters normalratliverin vivo.In OpticalMethods forTumorTreatment andEarlyDiagnosis:Mechanisms andTechniques (T. J.Dougherty, 1991. Ed.),pp. 146-155.SPIE,Bellingham, 7. P. J.MullerandB. C. Wilson,Photodynamic ofmalignant therapy braintumors. Can.J.Neurol.Sci. 17, 193-198(1990). and 8. W. M. Star,B. C. Wilson,and M. S. Patterson, Lightdelivery In Phoofsolidtumors. inphotodynamic opticaldosimetry therapy andClinical BasicPrinciples (T. J. Applications todynamic Therapy: New andB. W. Henderson, Eds.),pp. 333-367.Dekker, Dougherty York,1992. M. Chopp,Q. Chen,andF. W. Hetzel,Normalbrain 9. M. O. Dereski, tophotodynamic vascular tissueresponse permetherapy: Histology, Photochem. Photobiol.50, 653-657 abilityand specificgravity. (1989). 10. M. O. Dereski,M. Chopp,J.H. Garcia,and F. W. Hetzel,Depth of photodycharacterization and histopathological measurements as a function ofincinamictherapy normalbrainnecrosis generated dentopticalenergy dose.Photochem. Photobiol. 54,109-112(1991). Labora11. A. H. KayeandJ.S. Hill,Photoradiation ofbraintumours: InPhototherapy and ofCancer(G. Morstyn toryandclinicalstudies. NewYork,1990. A. H. Kaye,Eds.),pp. 101-118.Harwood,

This content downloaded from 185.44.78.31 on Sat, 21 Jun 2014 11:49:39 AM All use subject to JSTOR Terms and Conditions