Name: photoacoustic cystography
Uploaded: 2013-06-11T12:00:00
Description: Watch this Scientific Journal Video about Photoacoustic Cystography at JoVE.com

This work was supported in part by a grant from the pilot studies program of the University at Buffalo Clinical and Translational Research Center and the Buffalo Translational Consortium, a grant from Roswell Park Alliance Foundation, startup funds from the University at Buffalo, IT Consilience Creative Program of MKE, and NIPA (C1515-1121-0003) and NRF grant of MEST (2012-0009249).

1. Deep Reflection Mode Photoacoustic Cystography (PAC) System
<ol>
	<li>System configuration17, 18
	<ol>
		<li>A Q-switched Nd:YAG laser (SLII-10; Continuum; 532 nm) pumps a wavelength-tunable laser (Surelite OPO PLUS; Continuum; wavelength tuning range: 680 to 2,500 nm).</li>
		<li>The pulse duration of each laser shot is ~5 nsec, and the laser repetition rate is 10 Hz.</li>
		<li>The wavelength depends on the optical absorption peak of the used contrast agent. If methylene blue serves as the contrast agen...

<ol>
	<li>Riccabona, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cystography+in+infants+and+children:+a+critical+appraisal+of+the+many+forms+with+special+regard+to+voiding+cystourethrography.">Cystography in infants and children: a critical appraisal of the many forms with special regard to voiding cystourethrography.</a> Eur. Radiol. 12 (12), 2910-2918 (2002).</li><li>Khattar, N., Dorairajan, L. N., Kumar, S., Pal, B. C., Elangovan, S., Nayak, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Giant+obstructive+megaureter+causing+contralateral+ureteral+obstruction+and+hydronephrosis:+a+first-time+report.">Giant obstructive megaureter causing contralateral ureteral obstruction and hydronephrosis: a first-time report.</a> Urology. 74 (6), 1306-1308 (2009).</li><li>Lim, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Vesicoureteral+reflux+and+urinary+tract+infection:+evolving+practices+and+current+controversies+in+pediatric+imaging.">Vesicoureteral reflux and urinary tract infection: evolving practices and current controversies in pediatric imaging.</a> AJR Am. J. Roentgenol. 192 (5), 1197-1208 (2009).</li><li>Scardapane, A., Pagliarulo, V., Ianora, A. A., Pagliarulo, A., Angelelli, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Contrast-enhanced+multislice+pneumo-CT-cystography+in+the+evaluation+of+urinary+bladder+neoplasms.">Contrast-enhanced multislice pneumo-CT-cystography in the evaluation of urinary bladder neoplasms.</a> Eur. J. Radiol. 66 (2), 246-252 (2008).</li><li>Verpoorten, C., Buyse, G. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+neurogenic+bladder:+medical+treatment.">The neurogenic bladder: medical treatment.</a> Pediatr. Nephrol. 23 (5), 717-725 (2008).</li><li>Ron, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Let's+not+relive+the+past:+a+review+of+cancer+risk+after+diagnostic+or+therapeutic+irradiation.">Let's not relive the past: a review of cancer risk after diagnostic or therapeutic irradiation.</a> Pediatr. Radiol. 32 (10), 739-744 (2002).</li><li>Berrington De Gonzalez, A., Darby, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Risk+of+cancer+from+diagnostic+X-rays:+estimates+for+the+UK+and+14+other+countries.">Risk of cancer from diagnostic X-rays: estimates for the UK and 14 other countries.</a> Lancet. 363 (9406), 345-351 (2004).</li><li>Kim, C., Favazza, C., Wang, L. V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=In+vivo+photoacoustic+tomography+of+chemicals:+high-resolution+functional+and+molecular+optical+imaging+at+new+depths.">In vivo photoacoustic tomography of chemicals: high-resolution functional and molecular optical imaging at new depths.</a> Chem. Rev. 110 (5), 2756-2782 (2010).</li><li>Ke, H., Erpelding, T. N., Jankovic, L., Liu, C., Wang, L. V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Performance+characterization+of+an+integrated+ultrasound,+photoacoustic,+and+thermoacoustic+imaging+system.">Performance characterization of an integrated ultrasound, photoacoustic, and thermoacoustic imaging system.</a> J. Biomed. Opt. 17 (5), 056010 (2012).</li><li>Akers, W. J., Kim, C., Berezin, , et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Noninvasive+Photoacoustic+and+Fluorescence+Sentinel+Lymph+Node+Identification+using+Dye-Loaded+Perfluorocarbon+Nanoparticles.">Noninvasive Photoacoustic and Fluorescence Sentinel Lymph Node Identification using Dye-Loaded Perfluorocarbon Nanoparticles.</a> Acs Nano. 5 (1), 173-182 (2011).</li><li>Jiao, S. L., Jiang, M. S., Hu, J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Photoacoustic+ophthalmoscopy+for+in+vivo+retinal+imaging.">Photoacoustic ophthalmoscopy for in vivo retinal imaging.</a> Opt. Express. 18 (4), 3967-3972 (2010).</li><li>Kim, C., Cho, E. C., Chen, J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=In+vivo+molecular+photoacoustic+tomography+of+melanomas+targeted+by+bioconjugated+gold+nanocages.">In vivo molecular photoacoustic tomography of melanomas targeted by bioconjugated gold nanocages.</a> Acs Nano. 4 (8), 4559-4564 (2010).</li><li>Kim, C., Song, H. M., Cai, X., Yao, J., Wei, A., Wang, L. V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=In+vivo+photoacoustic+mapping+of+lymphatic+systems+with+plasmon-resonant+nanostars.">In vivo photoacoustic mapping of lymphatic systems with plasmon-resonant nanostars.</a> J. Mater. Chem. 21 (9), 2841-2844 (2011).</li><li>Wang, X., Pang, Y., Ku, G., Xie, X., Stoica, G., Wang, L. V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Noninvasive+laser-induced+photoacoustic+tomography+for+structural+and+functional+in+vivo+imaging+of+the+brain.">Noninvasive laser-induced photoacoustic tomography for structural and functional in vivo imaging of the brain.</a> Nat. Biotechnol. 21 (7), 803-806 (2003).</li><li>Xie, Z., Roberts, W., Carson, P., Liu, X., Tao, C., Wang, X. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Evaluation+of+bladder+microvasculature+with+high-resolution+photoacoustic+imaging.">Evaluation of bladder microvasculature with high-resolution photoacoustic imaging.</a> Opt. Lett. 36 (24), 4815-4817 (2011).</li><li>Zhang, H. F., Maslov, K., Stoica, G., Wang, L. V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Functional+photoacoustic+microscopy+for+high-resolution+and+noninvasive+in+vivo+imaging.">Functional photoacoustic microscopy for high-resolution and noninvasive in vivo imaging.</a> Nat. Biotechnol. 24 (7), 848-851 (2006).</li><li>Kim, C., Jeon, M., Wang, L. V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Nonionizing+photoacoustic+cystography+in+vivo.">Nonionizing photoacoustic cystography in vivo.</a> Opt. Lett. 36 (18), 3599-3601 (2011).</li><li>Homan, K., Kim, S., Chen, Y. S., Wang, B., Mallidi, S., Emelianov, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Prospects+of+molecular+photoacoustic+imaging+at+1064+nm+wavelength.">Prospects of molecular photoacoustic imaging at 1064 nm wavelength.</a> Opt. Lett. 35 (15), 2663-2665 (2010).</li><li>Chang, S. L., Shortliffe, L. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Pediatric+urinary+tract+infections.">Pediatric urinary tract infections.</a> Pediatr. Clin. N. Am. 53 (3), 379 (2006).</li><li>Stratton, K. L., Pope, J. C., Adams, M. C., Brock, J. W., Thomas, J. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Implications of Ionizing Radiation in the Pediatric Urology. 183 (6), 2137-2142 (2010).</li><li>Ermilov, S. A., Khamapirad, T., Conjusteau, A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Laser+optoacoustic+imaging+system+for+detection+of+breast+cancer.">Laser optoacoustic imaging system for detection of breast cancer.</a> J. Biomed. Opt. 14 (2), 024007 (2009).</li><li>Erpelding, T. N., Kim, C., Pramanik, M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Sentinel+lymph+nodes+in+the+rat:+noninvasive+photoacoustic+and+US+imaging+with+a+clinical+US+system.">Sentinel lymph nodes in the rat: noninvasive photoacoustic and US imaging with a clinical US system.</a> Radiology. 256 (1), 102-110 (2010).</li><li>Kim, C., Erpelding, T. N., Jankovic, L., Wang, L. V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Performance+benchmarks+of+an+array-based+hand-held+photoacoustic+probe+adapted+from+a+clinical+ultrasound+system+for+non-invasive+sentinel+lymph+node+imaging.">Performance benchmarks of an array-based hand-held photoacoustic probe adapted from a clinical ultrasound system for non-invasive sentinel lymph node imaging.</a> Philos. Transact. A. Math Phys. Eng. Sci. 369 (1955), 4644-4650 (1955).</li><li>Kim, C., Song, K. H., Gao, F., Wang, L. V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Sentinel+lymph+nodes+and+lymphatic+vessels:+noninvasive+dual-modality+in+vivo+mapping+by+using+indocyanine+green+in+rats--volumetric+spectroscopic+photoacoustic+imaging+and+planar+fluorescence+imaging.">Sentinel lymph nodes and lymphatic vessels: noninvasive dual-modality in vivo mapping by using indocyanine green in rats--volumetric spectroscopic photoacoustic imaging and planar fluorescence imaging.</a> Radiology. 255 (2), 442-450 (2010).</li><li>Kruger, R. A., Kiser, W. L., Reinecke, D. R., Kruger, G. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Thermoacoustic+computed+tomography+using+a+conventional+linear+transducer+array.">Thermoacoustic computed tomography using a conventional linear transducer array.</a> Medical Physics. 30 (5), 856-860 (2003).</li><li>Kruger, R. A., Lam, R. B., Reinecke, D. R., Del Rio, S. P., Doyle, R. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Photoacoustic+angiography+of+the+breast.">Photoacoustic angiography of the breast.</a> Med. Phys. 37 (11), 6096-6100 (2010).</li><li>Manohar, S., Kharine, A., Van Hespen, J. C., Steenbergen, W., Van Leeuwen, T. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+Twente+Photoacoustic+Mammoscope:+system+overview+and+performance.">The Twente Photoacoustic Mammoscope: system overview and performance.</a> Phys. Med. Biol. 50 (11), 2543-2557 (2005).</li></ol>

In conclusion, we have shown the possibility of nonionizing PAC using nontoxic optical absorbers in a rat model in vivo. We have successfully imaged a rat bladder filled with optical absorbents using our nonionizing and noninvasive PAC system. Two critical safety issues have been resolved in our approach: (1) the use of nonionizing radiation for cystographic applications and (2) no accumulation of contrast agents in the body.
Our clinical interest includes monitoring vesicoureteral re...

X-ray cystography1 is an imaging process to identify bladder-related diseases such as bladder cancer, vesicoureteral reflux, blockage of ureters, neurogenic bladder, etc.2-5 Typically, urines are voided and a radio-opaque agent is injected through a catheter. Then, fluoroscopic X-ray images are acquired to delineate urinary bladders. However, the key safety issue is that harmful ionizing radiation is used in this procedure. The percentage of cumulative cancer risk to age 75 years owing to diagnostic X-rays ranges from 0.6 to 1.8%.6 In addition, the carcinogenic threat is significant in pediatric patients. A UK study showed that among 9 major internal organs, the average annual radiation dose from diagnostic X-rays was highest in the bladders in female children less than 4 and second highest in male children less than 4.7 This indicates that the bladder cancer risk is most significant in pediatric patients. Although pediatric radiologists endeavor to reduce the radiation exposure rate as low as reasonably achievable, ionizing radiation cannot be completely excluded. Therefore, the limitation creates a need for a completely radiation-free, sensitive, cost-effective, and high-resolution imaging modality with nonradioactive contrast agents in cystography.
Recently, photoacoustic tomography (PAT) has become a premier biomedical imaging modality because PAT can provide strong optical absorption contrasts and a high ultrasonic spatial resolution in biological tissues.8 The principle of PAT is that ultrasonic waves are induced due to thermoelastic expansion of a target followed by light absorption. By detecting time-resolved acoustic waves travelling via a medium, two- or three-dimensional photoacoustic (PA) images are formed. Because ultrasound (US) is much less scattered in tissues compared to light (typically two or three orders of magnitude), the imaging depth of PAT can reach up to ~8 cm in tissues, while the spatial resolution is maintained to 1/200 of the imaging depth.9 The key advantages of PAT for the cystographic application include: (1) PAT is completely free from ionizing radiation. (2) ClinicalUSimaging systems can be easily adapted to supply dual-modal PA and US imaging capabilities. Thus, the dual-modal PA/US imaging system can be relatively portable, cost-effective, and fast, which are key criteria for fast clinical translation. Using both endogenous and exogenous contrasts, PAT has provided high-resolution morphological, functional, and molecular imaging of tissues to study tumor physiopathology, brain hemodynamics, internal organs, ophthalmology, angiography, and etc. 10-16
In this article, we demonstrate the experimental protocols of nonionizing photoacoustic cystography (PAC) using near-infrared (NIR) optical absorbents (i.e. methylene blue, gold nanocages, or single walled carbon nanotubes) as nontoxic optical-turbid tracers. Rat bladders filled with the contrast agents were photoacoustically and spectroscopically delineated in vivo. No agents persistently accumulated in the bladders and kidneys of the rats. Thus, long-term toxicity which may be caused by agent accumulation can be excluded. This result implies that PAC with combination of the optical absorbers can potentially be a truly harmless cystographic modality for pediatric patients. The system configuration, system alignment, and in vivo / ex vivo imaging procedures are discussed in this article.

<table border="1">
	<tbody>
		<tr>
			<td>Name of Reagent/Material</td>
			<td>Company</td>
			<td>Catalog Number</td>
			<td>Comments</td>
		</tr>
		<tr>
			<td>Q-switched Nd:YAG laser</td>
			<td>Continuum</td>
			<td>SLII-10</td>
			<td>pump laser</td>
		</tr>
		<tr>
			<td>OPO laser</td>
			<td>Continuum</td>
			<td>Surelite OPO PLUS</td>
			<td>tunable laser</td>
		</tr>
		<tr>
			<td>Prisms</td>
			<td>Thorlabs</td>
			<td>PS908</td>
			<td>light deliver</td>
		</tr>
		<tr>
			<td>Ultrasound transducer</td>
			<td>Olympus NDT</td>
			<td>V308</td>
			<td>5 MHz</td>
		</tr>
		<tr>
			<td>Ultraoundpulser/receiver</td>
			<td>Olympus NDT</td>
			<td>5072PR</td>
			<td>amplifier</td>
		</tr>
		<tr>
			<td>Oscilloscope</td>
			<td>Tektronix</td>
			<td>TDS5054</td>
			<td>data acquisition</td>
		</tr>
		<tr>
			<td>Scanning stage</td>
			<td>Danaher Dover</td>
			<td>XY6060</td>
			<td>raster scanning</td>
		</tr>
		<tr>
			<td>Methylene blue</td>
			<td>Sigma-Aldrich</td>
			<td>M9140-25G</td>
			<td>contrast agent</td>
		</tr>
		<tr>
			<td>Rats</td>
			<td>Harlan</td>
			<td>Spague-Dawley</td>
			<td>animal subject</td>
		</tr>
		<tr>
			<td>Isoflourane vaporizer</td>
			<td>Euthanex</td>
			<td>EZ-155</td>
			<td>anesthesia</td>
		</tr>
		<tr>
			<td>Ultrasound gel</td>
			<td>Sonotech</td>
			<td>Clear Image singles</td>
			<td>acoustic coupling</td>
		</tr>
	</tbody>
</table>

photoacoustic cystography

Conventional pediatric cystography, which is based on diagnostic X-ray using a radio-opaque dye, suffers from the use of harmful ionizing radiation. The risk of bladder cancers in children due to radiation exposure is more significant than many other cancers. Here we demonstrate the feasibility of nonionizing and noninvasive photoacoustic (PA) imaging of urinary bladders, referred to as photoacoustic cystography (PAC), using near-infrared (NIR) optical absorbents (i.e. methylene blue, plasmonic gold nanostructures, or single walled carbon nanotubes) as an optical-turbid tracer. We have successfully imaged a rat bladder filled with the optical absorbing agents using a dark-field confocal PAC system. After transurethral injection of the contrast agents, the rat's bladders were photoacoustically visualized by achieving significant PA signal enhancement. The accumulation was validated by spectroscopic PA imaging. Further, by using only a laser pulse energy of less than 1 mJ/cm2 (1/20 of the safety limit), our current imaging system could map the methylene-blue-filled-rat-bladder at the depth of beyond 1 cm in biological tissues in vivo. Both in vivo and ex vivo PA imaging results validate that the contrast agents were naturally excreted via urination. Thus, there is no concern regarding long-term toxic agent accumulation, which will facilitate clinical translation.

Figure 1 shows the In vivo nonionizing and noninvasive PAC using optically turbid methylene blue (MB). The control PA image was obtained at 667 nm, at the peak optical absorption for MB (Figure 1A). Although the blood vessels in the FOV are clearly visualized, the bladder is invisible because it is optically transparent at this wavelength. As shown in Figure 1B, the bladder is clearly revealed in the PA image acquired at 0.2 hr post-injection of MB. To confirm t...

Watch this Scientific Journal Video about Photoacoustic Cystography at JoVE.com

Photoacoustic Cystography

Photoacoustic cystography (PAC) has a great potential to map urinary bladders, a radiation sensitive internal organ in pediatric patients, without using any ionizing radiation or toxic contrast agent. Here we demonstrate the use of PAC for mapping urinary bladders with an injection of optical-opaque tracers in rats in vivo.

Conventional pediatric cystography, which is based on diagnostic X-ray using a radio-opaque dye, suffers from the use of harmful ionizing radiation. The ...

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