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Raman spectroscopy probe detects bladder cancer in vivo high, so likely it will be necessary to use Early detection and complete removal of showed significant spectral differences, and the bladder cancer stages had distin- it in combination with other diagnostic bladder cancer is important to prevent it guishable characteristics such as a gradu- technologies such as fluorescence imagfrom recurring or progressing, but spotally increasing intensity of specific amino ing; however, this is quite feasible, as ting all the tumors can be difficult. Rademonstrated by this work.” acid peaks. man spectroscopy can help reveal canIn theory, Raman spectroscopy might Twenty one patients also underwent cerous tissue by providing information also be combined with other techniques fluorescence cystoscopy, which uses on its molecular composition. In AC such as optical coherence tomography (DOI 10.1021/ac100448p), researchers photosensitizers and blue light to high(OCT), which creates cross-sectional, light additional bladder tumors during led by Ruud Bosch at University Meditomographic images of tissues by meacystoscopy. The technique can produce cal Center Utrecht and Christiaan van suring backscattered infrared light. OCT a great deal of false fluorescence, but Swol at the St. Antonius Hospital Nieucan determine the invasion depth of Raman spectroscopy could be used to wegein (both in The Netherlands) dembladder cancer and could identify superevaluate the suspicious lesions fluoresonstrate in vivo diagnosis and staging of ficial bladder cancer, carcinoma in situ, cence identifies. The study showed that bladder cancer with a Raman spectrosand inflammation, Draga says, but it the photosensitizers most likely do not copy probe. can’t determine the tumor grade. “The interfere with Raman spectroscopy. The tumor’s invasion depth is an imcombination of OCT and Raportant factor in the treatment man could lead to accurate didecision. “The only way to agnosis of both tumor grade determine the invasion depth and stage.” by Raman spectroscopy is to Nicholas Stone of Gloucesevaluate the Raman signals tershire Hospitals NHS Founfrom deeper tissue layers,” says dation Trust (U.K.) says that Ronald O.P. Draga at UniverRaman spectroscopy has great sity Medical Center Utrecht, potential for detection of bladone of the authors of the paResearchers used Raman spectroscopy to diagnose and stage bladder cancers. “The use of this per. Thus the researchers used der cancer in vivo. A schematic of the clinical system they used, technique coupled to fluoresa commercially available highincluding the fiber-optic probe (left), is shown. cence cystoscopy has been a volume Raman spectroscopy surprising development to the probe that collected signals Whether or not it is used with fluofield,” he says. “By coupling the two from up to 2 mm into tissue. rescence cystoscopy, Draga thinks that techniques, there is an incredible potenThe 2.1-mm diameter probe is easily Raman spectroscopy can aid fast and tial to survey large areas with the fluoinserted with an endoscope. Seven colaccurate diagnosis. “Raman optical birescence imaging and then provide acculection fibers surround the probe’s cenopsies used in the framework of a seerate molecular specific information using tral excitation optical fiber, and the fiand-treat strategy may result in an imRaman on areas classed as abnormal usbers incorporate micro-scale filters that mediate start of therapy and could ing the fluorescence.” eliminate Raman scattering from the improve the patient’s outcome.” Stone points out that an optimized excitation light in the delivery fiber and Brian C. Wilson at the University of probe would allow better specificity to block laser light backscattered by the Toronto/Ontario Cancer Institute subtle disease changes. Draga and his tissue. (Canada) comments, “Raman spectroscolleagues are working on a probe that The researchers collected Raman copy could find its way into the urology combines confocal Raman spectroscospectra during transurethral resection of clinic if these findings are confirmed in pyOideally, collecting signals from tumors from 38 patients with suspected multicenter randomized trials and if the ⬍100 m deepOwith high-volume or recurrent bladder cancer. They coltechnology can be made cost-effective. lected in the 400⫺1800 nm range and spectroscopy. The combined techniques The risks of this procedure are very low, acquired control spectra from normalwould allow measurement of a tumor’s so it could have high patient and doctor appearing bladder tissue. grade and aggressive potential and proacceptance. Raman spectroscopy was able to disvide the molecular composition of the Wilson says that Raman spectroscopy tinguish bladder cancer from normal bladder layers so that the cancer’s invahas a high specificity compared to other bladder tissue with a sensitivity of 85% sion depth could be determined. —Nancy D. Lamontagne optical spectroscopy or imaging techand a specificity of 79%. The bladder niques, but that “the sensitivity is not so cancer and normal bladder tissue 6320
ANALYTICAL CHEMISTRY /
AUGUST 1, 2010
10.1021/AC101520N 2010 AMERICAN CHEMICAL SOCIETY
Published on Web 06/21/2010
