Pho­toa­coustics is a tech­ni­que, which com­bi­nes the ad­van­ta­ges of the op­ti­cal ima­ging me­thods with es­ta­blis­hed ul­tra­so­nic tech­ni­ques. With pho­toa­coustics it is pos­si­ble to con­nect the high op­ti­cal con­trast of op­ti­cal ima­ging with the good re­so­lu­ti­on abi­li­ties of ul­tra­so­nic ima­ging in high­ly dis­per­si­ve tis­sue. For this re­a­son pho­toa­coustics pres­ents an es­sen­ti­al new ima­ging me­thod for me­di­cal en­gi­nee­ring. For in­stan­ce, using ade­qua­te con­trast me­cha­nis­ms pho­toa­coustics is able to se­pa­ra­te bet­ween tu­mou­rous and healthy tis­su­es to de­tect, for ex­amp­le, tu­mours in the bre­ast pre­ma­tu­re­ly. In con­trast to the es­ta­blis­hed me­thods on the basis of x-rays pho­toa­coustics has the ad­di­tio­nal ad­van­ta­ge, that it does not use po­ten­ti­al­ly dan­ge­rous io­ni­zing ra­dia­ti­on. In the fu­ture the health risks of the cur­rent­ly used preven­ti­ve me­di­cal check-ups, like for in­stan­ce the mam­mo­gram, could be re­du­ced si­gni­fi­cant­ly by pho­toa­coustics.

The com­bi­na­ti­on of light and sound is pos­si­ble by the use of the pho­toa­coustic ef­fect: Wi­t­hin the pho­toa­coustic ef­fect an ul­tra­so­nic wave is ge­ne­ra­ted by in­ci­dent light, which can be de­tec­ted with an ul­tra­so­nic trans­du­cer. In the pro­cess the de­tec­ted pres­su­re am­pli­tu­de is pro­por­tio­nal to the op­ti­cal ab­sorp­ti­on of the me­di­um.

In co­ope­ra­ti­on with Prof. Dr.-Ing. G. Schmitz (In­sti­tu­te of Me­di­cal En­gi­nee­ring of the Ruhr-Uni­ver­si­ty of Bo­chum), Prof. Dr.-Ing. H. Er­mert (In­sti­tu­te of High Fre­quen­cy En­gi­nee­ring of the Ruhr-Uni­ver­si­ty of Bo­chum) and Prof. Dr. med. C. Bre­mer (In­sti­tu­te of Cli­ni­cal Ra­dio­lo­gy of the Uni­ver­si­ty Hos­pi­tal of Müns­ter) our work­group is de­ve­lo­ping a sys­tem, which makes the pho­toa­coustic ef­fect use­ful for me­di­cal ap­p­li­ca­ti­ons: In this case the ex­amined tis­sue will be il­lu­mi­na­ted by short laser pul­ses and the ul­tra­so­nic wave ge­ne­ra­ted in the tis­sue is me­a­su­red by the aid of a com­mer­ci­al ul­tra­so­nic sys­tem. The laser pul­ses have a pulse width of a few na­no­se­conds and high pulse en­er­gies. Be­cau­se of the light pulse the tis­sue ex­pands and contracts af­ter­wards. In this way a pres­su­re wave is ge­ne­ra­ted, which can be de­tec­ted by the ul­tra­so­nic trans­du­cer.

Since dif­fe­rent sorts of tis­su­es have dif­fe­rent op­ti­cal ab­sorp­ti­on be­ha­viours, cer­tain sorts of tis­su­es can be sys­te­ma­ti­cal­ly em­pha­si­zed on the ul­tra­so­nic scan. That way blood en­ri­ched with oxy­gen, for in­stan­ce, can be se­pa­ra­ted from not en­ri­ched on the ul­tra­so­nic scan. This can be used as a con­trast me­cha­nism for the de­tec­tion of tu­mours. To cut a long story short: By using the pho­toa­coustic ef­fect we teach an ul­tra­so­nic sys­tem to see co­lours.


  • M.P. Mi­en­ki­na, N.C. Ger­hardt, J. Wal­deck, M. Bree­de, C. Bre­mer, M. Hof­mann and G. Schmitz, Eva­lua­ti­on eines kom­mer­zi­el­len Ul­tra­schall­ge­räts für den Ein­satz im pho­to­akus­ti­schen Re­fle­xi­ons­mo­dus, Bio­me­di­zi­ni­sche Tech­nik 52, (2007) Suppl 1 - ac­cep­ted
  • M.P. Mi­en­ki­na, K. Hen­sel , T.N. Le, N.C. Ger­hardt, Ch. Han­sen, M. Hof­mann and G. Schmitz , Ex­pe­ri­men­tal Cha­rac­te­riza­t­i­on of Fe­ru­c­ar­bo­tran as a Pho­toa­coustic Con­trast Agent, Proc IEEE In­ter­na­tio­nal Ul­tra­so­nics Sym­po­si­um 0, 393 (2006)
  • M.P. Mi­en­ki­na, K. Hen­sel, T.N. Le, N.C. Ger­hardt, I. Kopf, E. Brün­der­mann, M. Ha­ve­nith, M. Hof­mann, G. Schmitz, Ex­pe­ri­men­tel­le Cha­rak­te­ri­sie­rung von Fe­ru­c­ar­bo­tran als pho­to­akus­ti­sches Kon­trast­mit­tel, Proc Ge­mein­sa­me Jah­res­ta­gung der Deut­schen, Ös­ter­rei­chi­schen und Schwei­ze­ri­schen Ge­sell­schaf­ten für Bio­me­di­zi­ni­sche Tech­nik 51, V180 (2006)


Postal Address

Ruhr-University Bochum
Faculty of Electrical Engineering
and Information Technology
Photonics and Terahertz Technology
Postbox ID 16
Universitätsstraße 150
D-44801 Bochum


Room: ID 04/327
Te­l.: (+49) (0) 234 32 - 23051
Fax: (+49) (0) 234 32 - 14167
E-Mail: ptt+office(at)
RUB campus map & travel instructions

Chair Holder

Prof. Dr.-Ing. Martin Hofmann
Building: ID 04/329
Te­l.: (+49) (0) 234 32 - 22259
Fax: (+49) (0) 234 32 - 14167
E-Mail: martin.hofmann(at)

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