TUGAS DARI UAS MATA KULIAH BIOFOTONIKA
1. Pada Pada dasarmya dasarmya OCT OCT menggun menggunan an !n"er#er !n"er#er$me $me"er "er.. a. Pen%e Pen%e&a &asan san 'em(e 'em(en"u n"uan an )!"ra )!"ra *D (er (erda dasar saran an 'ada 'ada !n"er !n"er#er #er$m $me"e e"err dengan menggunan SLD + Su'er&um!nes)en" D!$de,
Figure 1. An in-fibre interferemeter equipped with all three sacnners for time doamain optical coherence tomography. tomograph y. SLD, super-luminescent diode, D directional coupler, 1, ! microscope ob"ecti#es, $, mirror, S%&, S%&, gal#anometer scanning mirror head, $%, $&, scanners mirross , L1, L!, lenses, 'D, photo detector, AS( AS( analogue storage oscilloscope, )%, )&, triangle wa#eform generators
*ntu+ mendapat+an informasi D tentang suatu ob"e+ , sistem pencitraan dileng dileng+api +api dengan dengan dua peminda pemindaian ian.. Arti Artinya, nya, satu satu untu+ untu+ memind memindai ai ob"e+ ob"e+ secara secara mendalam dan satu lagi untu+ memindai ob"e+ trans#ersally. iasanya terdiri dari dua scanner orthogonal. )ergantung pada urutan scan ini dioperasi+an dan pada arah pemindaian ter+ait dengan garis ditampil+an dalam raster gambar a+hir yang disa disamp mpai ai+an +an.. 'esaw 'esawat at pemin pemindai daian an yang yang berb berbeda eda yang yang mung mung+i +in. n. Sist Sistem em () () menggu mengguna+a na+an n +amera +amera D atau atau array array sensor sensor array array atau atau emitte emitterr menghil menghilang ang+an +an
+ebutuhan pemindaian. 'emindaian terminologi yang ini digambar+an pada gambar !.
Figure !. elati#e orientation of the a/ial scan 0A-scan, en face scan 0)scan, longitudinal slice 0-scan and en face or trans#erse slice 0-scan (. Se(u"aan a'a sa%a eun"ungan 'enggunaan "en! 'en)!"raan "!ga d!mens! !n! dan (and!ngan dengan 'en)!"raan s"andar. 2t show an entire side-#iew 0hang, Sherif, $ao 3 Fleuraru, !445 esult of profile measurement and uses a broadband and low coherence light
source 0&asuno et al., !444 Gam(aran -u(ungan !n! un"u 'ene"ras! s res$&us!nya 2n terms of the product of depth of resolution and penetration depth, () fills the gap between confocal microscopy and ultrasound imaging. )his product is appro/imately 4,1 mm 6744 mm in confocal microscopy 8119, 1 mm 644 mm in () and 74 mm 67444 mm in high frequency ultrasound. () operates with ballitic photons , 2 . e. photons which ha#e been scattered only once. )herefore, in highly scattering tissue, () e/hibits a short penetration depth. )he depth of light penetration into highly scattering tissue can
be mpro#ed by the application of biocompatible and osmotically acti#e chemical agents. )he higher the resolution , the lower penetration, this according to the theorem on the s+in depth of electromagnetic wa#e propagation. A high frequency has a wea+ energy le#el and can only penetrate the thin depth. )he main characteristic of the (), the depth resolution, deri#es from the manipulation of wa#etrains of finite length emitted by a low coherence light source. )he principle of operation is different from that of the other medical imaging technologies. () employs optical and infrared wa#es and therefore is dominated by diffraction which precludes algorithms for image reconstruction used %-ray or $2. Sometimes analogies are made of () cross section images with scan ultrasound images. :owe#er, ultrasound beams are longitudinal wa#es, whereas the wa#es in () are trans#erse. 2t is true that similarity does e/ist between the time ta+en for the ultrasound to propagate bac+ and forth to the probe head 0gi#ing distance for a +nown ultrasound #elocity in tissue and the time ta+en by the optical wa#es in () to tra#el o#er a certain path length. :owe#er, whereas ultrasound imaging is a time of flight technique, where time gating is used to display ordered time #ents, in () the gating procces operates in space, based on interferometry, as e/plained below. ). Penanganan med!) a'a sa%a yang da'a" menggunan OCT 'ada d!agn$s"!) n$n/!nas!e.
Apli+asi () dalam berbagai apli+asi pencitraan biomedis; •
(ftalmologi ; pencitraan yang sangat bai+ dari retina dengan +emampuan untu+ mengidentifi+asi beberapa penya+it mata mung+in
dengan (). Sebagian besar produ+ comersial tersedia saat ini adalah •
untu+ penggunaan ophthalmologic. Dermatologi ; untu+ bawah permu+aan gambar dan informasi aliran
•
darah
•
mem#isualisasi+an ba+teri dalam +onser dengan gigi dan a+a r.
• •
melalui probe endos+opi. 2ntra - #as+ular ; pla+ gambar di dalam pembuluh darah. Diagnosis +an+er ; beberapa mode di () pencitraan dapat membeda+an antara "aringan ganas dan normal memung+in+an diagnosis +an+er melalui prosedur bai+ non - in#asif atau in#asif
•
minimal. (perasi intra untu+ margining tumor ; memung+in+an dis+riminasi antara "aringan ganas ganas dan non untu+ menentu+an daerah "aringan yang a+an dihapus selama operasi.
0. Pada dasarnya 'r!ns!' er%a 'en)!"raan OCT ana&$g! dengan 'en)!"raan u&"ras$n!). a. e&asan 'r!ns!' er%a OCT (erdasaran 'ada !n"er#er$me"er dan gam(aran. )he $ichelson interferometer, as used in the famous $ichelson = $orley test
of special relati#ity, is the simplest form of interferemeter. 2t in#ol#es splitting the output of a light source into two, usually perpendicular, beams. )his is done using a beam splitter, which can be a simples as a thin glass plate, although half-sil#ered mirrors are more often used in free space system to control the amount of light in each beam. A scematic diagram of this is shown in figure . Figure . Scematic diagram of a $ichelson interferometer. )he distance from the beamsplitter 0labeled S to the sample and reference mirrors are dS dan d respecti#ely
After the beams are split, they are each incident on a mirror, labeled sample and reference. After reflection from their respecti#e mirrors, the beams are recombined at the beamsplitter, producing an interference pattern that tra#els to the detector. )he distances from the beamsplitter to the sample and reference mirrors are dS and d, respecti#ely. (. Gam(aran )$-eren)e ga"!ng dar! OCT dan (er!an 'en%e&asan. *. Pada dasarnya $'"!)a& )$-eren)e "$m$gra'-y +OCT, menggunaan sum(er $-eren. a. Gam(aran dan %e&asan )a-aya (er 2!n"er#eren)e m$n$)-r$ma"!)3 (. Ber!an syara" sua"u sum(er )a-aya $-eren dan rumusan ). Se(u"an dua %en!s $-eren dan rumusan. e&asan dengan d!&enga'! gam(ar.
