Side-firing Fiber Research Articles

Optical characteristics of laser medical instrument with side-firing fiber under complete bevel angle range

The side-firing instrument is studied under the complete bevel angle range. The fiber core and cladding are 0.6mm and 0.66mm, respectively, the fiber core refractive index is 1.457, and the fiber cladding refractive index is from 1.409 to 1.452 corresponding to the numerical aperture from 0.37 to 0.12. The bevel angle range is subdivided by ten crucial angles, whose relationship changes as the fiber cladding refractive index reaches 1.418. The beam's divergence angle and coverage increase as the bevel angle deviates from being equal and close to π/4 rad, respectively. When all rays achieve total internal reflection, with numerical aperture being 0.37, the divergence angle and coverage would increase by 28.29% and 44.74%, respectively. The required emission opening size has a minimum under the bevel angle being close to π/4 rad, whose expression is obtained. It increases sharply as the bevel angle reaches a certain value.

Continuous monitoring of endotracheal tube position with near infrared light.

Endotracheal intubation is a common approach for airway management in critically ill patients. However, the position of the endotracheal tube (ETT) may be altered during the procedure due to head movements. Accidental displacement or dislodge of the ETT may reduce the airflow, leading to moderate to severe complications, and in some cases even fatality. Therefore, timely detection of changes in ETT position in the trachea is critical to ensure immediate and intermediate interventions to maintain the ETT in the proper position. Currently, there are no widely utilized tools for real-time monitoring of ETT positions. The goal of this study is to develop a cost-effective and easy-to-use near-infrared (NIR) device, named Opt-ETT, capable of continuously monitoring the ETT position in the trachea of a patient. A side-firing fiber is attached to the side of the ETT to illuminate the trachea tissue with NIR light, and a detector board containing five phototransistors is affixed to the chest skin to measure the intensity of diffusely transmitted light. Displacement of the ETT is estimated using second-order polynomial fitting to the ratios of the phototransistor readings. Monte Carlo simulations, ex vivo experiment on porcine tissue, and in vivo experiments using a swine model have been conducted to assess the feasibility of the device. The design of the Opt-ETT device has been verified by the Monte Carlo simulations and ex vivo experiment. The estimation of displacement from in vivo experiments using the Opt-ETT exhibited a high degree of agreement with that measured by a reference sensor, with a discrepancy between to within a displacement range from to . The Opt-ETT device provides a potentially cost-effective solution for real-time and continuous monitoring of ETT position in patient during an intubation procedure.

Diffuse reflection spectroscopy at the fingertip: design and performance of a compact side-firing probe for tissue discrimination during colorectal cancer surgery.

Optical technologies are widely used for tissue sensing purposes. However, maneuvering conventional probe designs with flat-tipped fibers in narrow spaces can be challenging, for instance during pelvic colorectal cancer surgery. In this study, a compact side-firing fiber probe was developed for tissue discrimination during colorectal cancer surgery using diffuse reflectance spectroscopy. The optical behavior was compared to flat-tipped fibers using both Monte Carlo simulations and experimental phantom measurements. The tissue classification performance was examined using freshly excised colorectal cancer specimens. Using the developed probe and classification algorithm, an accuracy of 0.92 was achieved for discriminating tumor tissue from healthy tissue.

Benefits of Side-Firing Optical Fibers in Endoscopic Laser Treatment of the Larynx.

To elucidate potential tissue coverage of side-firing optical fibers in office-based endoscopic laser treatment of larynx, as well as to demonstrate their enhanced ability to address challenging anatomic areas. We performed a comparative study of four different fiber designs: a traditional forward-facing fiber, and three side-firing fibers that emit light at an angle of 45°, 70°, and 90°, respectively. The study was conducted in simulation, using eight three-dimensional models of the human larynx generated from microtomography x-ray scans. A computer program simulated the insertion of the endoscope into the larynx, and the Möller-Trumbore algorithm was used to simulate the application of laser light. Side-firing laser fibers increased potential tissue coverage by a mean of 50.2 (standard deviation [SD] 25.8), 73.8 (SD 41.3), and 84.0 (SD 47.6) percent for angles of 45°, 70°, and 90°, respectively, compared to forward-facing fibers. Angled fibers provided access to areas of the larynx considered difficult to address by traditional methods, including the infraglottis, laryngeal ventricle, and right vocal fold. Simulation results suggest that side-firing optical fibers have the potential to enhance anatomical access during in-office endoscopic laser procedures in the larynx. Further research is needed to better understand the benefits and any potential risks or contraindications of side-firing optical fibers. NA Laryngoscope, 133:1205-1210, 2023.

Reciprocating Side-Firing Fiber for Laser Sealing of Blood Vessels.

Infrared lasers may provide faster and more precise sealing of blood vessels and with lower jaw temperatures than ultrasonic and electrosurgical devices. This study explores an oscillating or reciprocating side-firing optical fiber method for transformation of a circular laser beam into a linear beam, necessary for integration into a standard 5-mm-diameter laparoscopic device, and for uniform irradiation perpendicular to the vessel length. A servo motor connected to a side-firing, 550-μm-core fiber, provided linear translation of a 2.0-mm-diameter circular beam over either 5 mm or 11 mm scan lengths for sealing small or large vessels, respectively. Laser seals were performed, ex vivo, on a total of 20 porcine renal arteries of 1-6 mm diameter (n = 10 samples for each scan length). Each vessel was compressed to a fixed 0.4-mm-thickness, matching the 1470-nm laser optical penetration depth. Vessels were irradiated with fluences ranging from 636 J/cm2 to 716 J/cm2. A standard burst pressure (BP) setup was used to evaluate vessel seal strength. The reciprocating fiber produced mean BP of 554 ± 142 and 524 ± 132 mmHg, respectively, and consistently sealing blood vessels, with all BP above hypertensive (180 mmHg) blood pressures. The reciprocating fiber provides a relatively uniform linear beam profile and aspect ratio, but will require integration of servo motor into a handpiece.

Comparison of fiber-optic linear beam shaping designs for laparoscopic laser sealing of vascular tissues.

Infrared lasers may provide faster and more precise sealing of blood vessels and with lower device jaw temperatures than ultrasonic and electrosurgical devices during surgery. Our study explores three beam shaping methods using optical fibers for transformation of a circular laser beam into a linear beam, necessary for integration into a standard 5-mm-diameter laparoscopic device, and for uniform irradiation perpendicular to the vessel length. In the first design, a servo motor connected to a side-firing, 550-μm-core fiber, provided linear translation of a 2.0-mm-diameter circular beam, back, and forth, over either 5 or 11 mm scan lengths for sealing of small or large vessels. The second design used external beam splitters to divide laser power equally into three side-firing fibers, stacked side-by-side, producing a linear beam of 4 × 2 mm. The third design used external beam splitters with three forward-firing fibers and a slanted jaw surface, to produce a linear beam of 5 × 1.5 mm. Laser seals were performed, ex vivo, on 41 porcine renal arteries of 1- to 6-mm diameter (n ≥ 10 samples for each design). Each vessel was compressed to a fixed 0.4-mm-thickness, matching the optical penetration depth at 1470 nm. Vessels were irradiated with fluences of 636 to 800 J/cm2, which, based on previous studies, is sufficient for sealing, but not cutting. A burst pressure setup was used to evaluate vessel seal strength. Reciprocating fiber and fiber bundles produced mean burst pressures of 554 ± 142, 524 ± 132, 429 ± 99, and 390 ± 140 mmHg, respectively. All designs consistently sealed blood vessels, with burst pressures above hypertensive (180 mmHg) blood pressures. The reciprocating fiber produced the most uniform linear beam profile and aspect ratio but will require integration of the servo motor into a handpiece. Fiber bundle designs produced shorter, less uniform beams, but enable optical components to be assembled outside the handpiece.

On the Merits of Using Angled Fiber Tips in Office-based Laser Surgery of the Vocal Folds.

Office-based endoscopic laser surgery is an increasingly popular option for the treatment of many benign and pre-malignant tumors of the vocal folds. While these procedures have been shown to be generally safe and effective, recent clinical studies have revealed that there are a number of challenging locations inside the larynx where laser light cannot be easily delivered due to line-of-sight limitations. In this paper, we explore whether these challenges can be overcome through the use of side-firing laser fibers. Our study is conducted in simulation, using three-dimensional models of the human larynx generated from X-ray microtomography scans. Using computer graphics techniques (ray-casting), we simulate the application of laser pulses with different types of laser fibers and compare the total anatomical coverage attained by each fiber. We consider four fiber types: a traditional "forward-looking" fiber - not unlike the ones currently used in clinical practice - and three side-firing fibers that emit light at an angle of 45, 70, and 90 degrees, respectively. Results show that side-firing fibers enable a ~70% increase in accessible anatomy compared to forward-looking fibers.

Ultrafine intravascular photoacoustic endoscope with a 0.7 mm diameter probe.

Intravascular photoacoustic (IVPA) imaging, benefiting from high optical contrast, large imaging depth and absorption specificity, is of great potential for lipid-rich plaque detection. However, the diameters of reported IVPA endoscopes are too big to intervene into the coronary artery branches. Here, by designing an ultracompact house embedded with a side-fire fiber and a miniature single-element ultrasound transducer, we developed an ultrafine IVPA endoscope with a diameter of 0.7mm aiming at coronary artery branches atherosclerotic plaque detection. The reliability and feasibility of the ultrafine IVPA endoscope was demonstrated by imaging a stent with a 1.6mm inner diameter. Furthermore, the photoacoustic imaging and ultrasound imaging of a mouse thoracic aorta with an inner diameter of 1.15mm was conducted to verify the clinical potentiality of the endoscope, and the PA images have good consistency with histological staining results. To the best of our knowledge, this is the first time we have achieved the IVPA imaging in fine vessel by the 0.7mm diameter ultrafine photoacoustic endoscope, which paved a way for the translation of the IVPA endoscope to clinical application.

Impact of different color fiber sleeves on beam hazards of 532-nm laser and vaporization efficiency.

The 532-nm laser has become increasingly popular for the treatment of urologic diseases. However, laser beam will pose significant hazards for the health of surgeons. In order to reduce beam hazards during surgery, we compared the beam hazards of laser fiber with black sleeves to the traditional fiber with transparent sleeves, and the vaporization efficiency. A total of 18 porcine kidney specimens were vaporized in normal saline at a room temperature under 532-nm laser delivered through a 760-μm core diameter side firing fiber. Two groups were divided according to the color of fiber sleeves: the transparent and the black. Each group was then divided into another three subgroups by laser power: the 80W group, the 120W group, and the 160W group. The beam hazard was evaluated by light intensity measured in a sector area at a distance of 0m, 0.5m, and 1m from the irradiation center. The vaporization efficiency was measured by the vaporization groove depth under the working power of 80W, 120W, and 160W with a working distance of 5mm and irradiation time of 10s. The light intensity measured in the black fiber sleeve group is significantly lower than that in the transparent one (P < 0.01), regardless of the measuring distance (0m, 0.5m, and 1.0m) and laser power (80W, 120W, and 160W). No statistical difference was found on the vaporization efficiency between the groups protected by fiber sleeves of different colors (transparent/black, p > 0.05). Compared to the traditional transparent fiber sleeves, more beam hazards will be reduced in the operative region with the protection of black fiber sleeves, especially those from the irradiation center. The vaporization efficiency is not affected by the color of fiber sleeves. Such findings may offer a completely new idea for the protection of surgeons in surgeries with 532-nm lasers.

Green Laser Enucleation of the Prostate “En bloc Technique”: Surgical Technique and Initial Experience

Introduction and Objectives: Green laser “en bloc” enucleation of the prostate (GreenLEP) is an alternative enucleation technique for the treatment of lower urinary tract symptoms secondary to benign prostatic hyperplasia. All endoscopic enucleation of the prostate procedures require significant endoscopic surgical skills and have a steep learning curve. The aim of this study is to demonstrate the GreenLEP surgical technique step-by-step and report our initial experience. Material and Methods: We report our single surgeon's (E.R.) initial experience with this novel technique. Thirty patients underwent GreenLEP between July 2015 and March 2016 in our institution with prostate volumes between 60 and 140 cc. All patients were evaluated preoperatively and after surgery (at 1, 3, and 6 months) by prostate-specific antigen, prostate volume, International Prostate Symptom Score, quality-of-life score, maximum flow rate, and postvoid residual urine volume, and all the complications were recorded. The surgery was performed with a 532-nm lithium triborate laser (GreenLight™ XPS 180W device; American Medical Systems, Minnetonka, MN), 2090 side-fire laser fiber at the following power settings: 80W for cutting, 25W for coagulation, and a Piranha™ morcellation system (Richard Wolf GmbH, Germany) using single-use blade. Results: The mean operative time was 64 minutes (range: 55–95 minutes) and the mean amount of retrieved prostate tissue was 70 g (range 40–120 g). There was no need for blood transfusion. Capsular perforation occurred in four cases. We did not have any case of bladder injuries related to the morcellation procedure. The postoperative catheterization time (same as hospital stay) was 48 hours, except in two cases: one of incomplete morcellation because of bleeding and required an endoscopic second look (morcellation for residual adenoma), and the other required open surgery conversion for removal of the enucleated adenoma (poor vision because of venous bleeding caused by surgical perforation of the capsule during enucleation). Transient urinary incontinence was present in three cases and was completely resolved in 2 months. Three months later, all the parameters evaluated preoperatively showed significant improvement. Conclusions: GreenLEP appears to be a safe alternative enucleation technique for the complete removal of en bloc adenomatous prostate tissue. Regardless of gland size, it is particularly advantageous for the treatment of large prostates (not recommended for small glands). Endoscopic laser enucleation of the prostate is feasible with a side-firing fiber. This technique is probably easier to learn in a progressive pathway, that is, vaporization, vapoenucleation, and finally enucleation. These promising results warrant further studies to assess long-term outcomes. No competing financial interests exist. Runtime of video: 10 mins

波長980 nm の高出力ダイオードレーザーおよびTwister&lt;sup&gt;TM&lt;/sup&gt; Large Fiber を用いた接触式前立腺蒸散術（CVP）

High power 980 nm diode laser vaporization of the prostate was introduced since 2007 to the western countries and has proven its efficiency and safety. Using TwisterTM Fiber instead of side-firing fibers, the procedure can be done in the contact manner with higher efficacy and durability. In Japan, the clinical trial for PMDA approval was performed from April 2013 and proved its safety and non-inferiority of IPSS to TURP. Since the absorption coefficients of 980 nm laser to the major chromophores of prostate (hemoglobin and water) are not so high as those of 532 nm (KTP laser or LBO laser) to hemoglobin and of 2100 nm (Ho:YAG laser) to water, the absorption depth to prostatic tissue is higher. Thus, the high efficiency of vaporization and hemostasis are assumed to be achieved when the high energy is applied. It was shown in ex vivo experiment of bovine prostate using 300W that the vaporization depth was about 3 mm and the coagulation depth was 1.2 mm after 1 sec irradiation. Clinically, the heat affected depth of prostate from urethral cavity was about 5 mm which was recognized as a low signal zone in the T2 image of MRI at two weeks after operation. Considering comparatively larger coagulation depth, on the counter side of high efficiency of vaporization and hemostasis, this modality is quite efficient and user-friendly.

V3-08 GREEN LASER ENUCLEATION OF THE PROSTATE (GREENLEP) “EN-BLOC TECHNIQUE”

You have accessJournal of UrologyMale Voiding/Sexual Dysfunction/BPH/ Incontinence/Infection/Infertility1 Apr 2016V3-08 GREEN LASER ENUCLEATION OF THE PROSTATE (GREENLEP) “EN-BLOC TECHNIQUE” Enrique Rijo, Jose Antonio Lorente, Oscar Bielsa, and Fernando Gomez-Sancha Enrique RijoEnrique Rijo More articles by this author , Jose Antonio LorenteJose Antonio Lorente More articles by this author , Oscar BielsaOscar Bielsa More articles by this author , and Fernando Gomez-SanchaFernando Gomez-Sancha More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2016.02.1528AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES Laser vaporization is an alternative to transurethral resection of the prostate (TURP) for the treatment of small to medium glands. For large prostates (>80ml.) open prostatectomy or Holmium laser enucleation of the prostate (HoLEP) remains the prefered choice of treatment. Green laser ‘en bloc’ enucleation of the prostate (GreenLEP) followed by mechanical morcellation is an alternative enucleation technique developed by Fernando Gomez-Sancha in Madrid, Spain. The aim of this video is to demonstrate the GreenLEP technique step-by-step. METHODS The surgery was performed with a 532-nm lithium triborate laser (GreenLightTM XPS 180W, American Medical Systems, Minnetonka, Minnesota, USA), 2090 side-fire laser fiber at power settings: 80W for cutting, 20W for coagulation and a PiranhaTM morcellation system (Richard Wolf GmbH, Germany) using the Vmax blade. Case Report: A 64-year-old patient presented with lower urinary tract symptoms secondary to benign prostatic obstruction with no response to alpha-blockers. The prostate volume was 92 mL, PSA of 2.4 ng/mL, peak urinary flow rate (Qmax) was 8 mL/sec, postvoid residual volumen (PVR) of 150 mL and international prostate symptom score (IPSS) of 22. It was decided to proceed with GreenLEP technique in this case. RESULTS The total operative time was 64 minutes, laser time 22 minutes, morcellation time 8 minutes, total energy employed was 52kJ and 73g. of tissue were enucleated (pathology report showed no evidence of prostate cancer). The bladder catheter was removed at 24 hours postsurgery and the patient was discharged 48 hours postoperative without complication. Three months later all the parameters showed significant improvement (PSA: 0.4 ng/mL, IPSS: 4, Qmax: 26 mL/seg and PVR: 20 mL). There was no incontinence or erectile dysfunction as a result of the procedure. CONCLUSIONS GreenLEP represents a safe alternative enucleation technique for the complete removal of en bloc adenomatous prostate tissue, regardless of gland size, it is particularly advantageous for the treatment of large prostates. Endoscopic laser enucleation of the prostate is feasible with a side-firing fiber. Gentle mechanical dissection allows for an optimal visualization and understanding of the anatomical planes. Low energy coagulation (20W) is used against the capsule providing excellent hemostasis. These promising results warrant further studies to assess longterm outcomes. © 2016FiguresReferencesRelatedDetails Volume 195Issue 4SApril 2016Page: e469 Advertisement Copyright & Permissions© 2016MetricsAuthor Information Enrique Rijo More articles by this author Jose Antonio Lorente More articles by this author Oscar Bielsa More articles by this author Fernando Gomez-Sancha More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...

Diffusing, Side-Firing, and Radial Delivery Laser Balloon Catheters for Creating Subsurface Thermal Lesions in Tissue.

Infrared lasers have been used in combination with applied cooling methods to preserve superficial skin layers during cosmetic surgery. Similarly, combined laser irradiation and tissue cooling may also allow development of minimally invasive laser therapies beyond dermatology. This study compares diffusing, side-firing, and radial delivery laser balloon catheter designs for creation of subsurface lesions in tissue, ex vivo, using a near-IR laser and applied contact cooling. An Ytterbium fiber laser with 1075 nm wavelength delivered energy through custom built 18 Fr (6-mm-OD) balloon catheters incorporating either 10-mm-long diffusing fiber tip, 90 degree side-firing fiber, or radial delivery cone mirror, through a central lumen. A chilled solution was flowed through a separate lumen into 9-mm-diameter balloon to keep probe cooled at 7°C. Porcine liver tissue samples were used as preliminary tissue model for immediate observation of thermal lesion creation. The diffusing fiber produced subsurface thermal lesions measuring 49.3 ± 10.0 mm2 and preserved 0.8 ± 0.1 mm of surface tissue. The side-firing fiber produced subsurface thermal lesions of 2.4 ± 0.9 mm2 diameter and preserved 0.5 ± 0.1 mm of surface tissue. The radial delivery probe assembly failed to produce subsurface thermal lesions, presumably due to the small effective spot diameter at the tissue surface, which limited optical penetration depth. Optimal laser power and irradiation time measured 15 W and 100 s for diffusing fiber and 1.4 W and 20 s, for side-firing fiber, respectively. Diffusing and side-firing laser balloon catheter designs provided subsurface thermal lesions in tissue. However, the divergent laser beam in both designs limited the ability to preserve a thicker layer of tissue surface. Further optimization of laser and cooling parameters may be necessary to preserve thicker surface tissue layers.

A Multicenter Study for Cellulite Treatment Using a 1440-nm Nd:YAG Wavelength Laser with Side-Firing Fiber.

Treatment of cellulite using a 1440-nm YAG wavelength laser with side-firing fiber has proven safe and effective, lasting at least 6 months. The authors evaluate the safety and efficacy of a single, subdermal procedure to treat the underlying structure of cellulite for at least 1 year. Fifty-seven patients underwent a 3-step cellulite treatment with a 1440-nm Nd:YAG laser with a side-firing fiber and temperature-sensing cannula. Efficacy was measured by the blinded evaluators to distinguish baseline photos from those taken at 12 months posttreatment, with results on a 5-point, 2-category ordinal photonumeric scale when comparing baseline photos to 12 months posttreatment. Subject and physician satisfaction was assessed based on completion of a satisfaction survey. Adverse events (AE) were recorded throughout the study. Twelve month data were analyzed and compared to 6 month data. Evaluators chose baseline photographs 97% on average from 6 (-1, +2) months and 91% from the 12 (-3, +2) months posttreatment photographs. At 6 (-1, +2) months, the average improvement score was 1.7 for dimples and 1.1 for contour irregularities. At 12 (-3, +2) months, the average improvement score was 1.4 for dimples and 1.0 for contour irregularities. The average satisfaction score for the physician was 5.6 and the patient was 5.3 on a 6-point scale. A single, 3-step, minimally invasive laser treatment using a 1440-nm Nd:YAG laser, side-firing fiber, and temperature-sensing cannula to treat the underlying structure of cellulite proved to be safe and maintained effectiveness at least 1 year post treatment. LEVEL OF EVIDENCE 2: Therapeutic.

Transurethral light delivery for prostate photoacoustic imaging.

Photoacoustic imaging has broad clinical potential to enhance prostate cancer detection and treatment, yet it is challenged by the lack of minimally invasive, deeply penetrating light delivery methods that provide sufficient visualization of targets (e.g., tumors, contrast agents, brachytherapy seeds). We constructed a side-firing fiber prototype for transurethral photoacoustic imaging of prostates with a dual-array (linear and curvilinear) transrectal ultrasound probe. A method to calculate the surface area and, thereby, estimate the laser fluence at this fiber tip was derived, validated, applied to various design parameters, and used as an input to three-dimensional Monte Carlo simulations. Brachytherapy seeds implanted in phantom, ex vivo, and in vivo canine prostates at radial distances of 5 to 30 mm from the urethra were imaged with the fiber prototype transmitting 1064 nm wavelength light with 2 to 8 mJ pulse energy. Prebeamformed images were displayed in real time at a rate of 3 to 5 frames per second to guide fiber placement and beamformed offline. A conventional delay-and-sum beamformer provided decreasing seed contrast (23 to 9 dB) with increasing urethra-to-target distance, while the short-lag spatial coherence beamformer provided improved and relatively constant seed contrast (28 to 32 dB) regardless of distance, thus improving multitarget visualization in single and combined curvilinear images acquired with the fiber rotating and the probe fixed. The proposed light delivery and beamforming methods promise to improve key prostate cancer detection and treatment strategies.

Fabrication of novel bundled fiber and performance assessment for clinical applications.

During laser vaporization of benign prostate hyperplasia (BPH), high precision of optical fiber handling is pivotal to minimize any post-operative complications. The aim of the study was to evaluate the feasible applications of a bundled fiber to treat BPH by directionally and selectively manipulating laser light onto the targeted tissue. A bundled optical fiber, consisting of four side-firing fibers, was fabricated to selectively emit laser beams in from one to four directions. Both transmission efficiency and light distribution were qualitatively and quantitatively characterized on the bundled fiber. In terms of interstitial application of the proposed fiber with 1064 nm on porcine liver tissue, the extent of thermal denaturation was estimated and compared at various laser parameterizations and for different directions of light. From the laser source to the fiber tip, the fabricated fiber device demonstrated a total light transmission of 52%. Due to internal light reflection, a secondary beam was emitted backward from the fiber tip and was responsible for 25% of the transmission loss. According to tissue testing, the extent of tissue denaturation generally increased with laser power, irradiation time, and number of light directions. The geometrical shape of thermal coagulation correlated well with the direction of light emission. Thermal damage to the glass tube occurred during excessive heat accumulation generated by continuous irradiation. The proposed fiber can be beneficial for laser vaporization of BPH by providing a selective light direction irradiation along with minimal thermal damage. Further studies will extend the applicability of the bundled fiber to treat tubular tissue structure.

Review of diverse optical fibers used in biomedical research and clinical practice.

Optical fiber technology has significantly bolstered the growth of photonics applications in basic life sciences research and in biomedical diagnosis, therapy, monitoring, and surgery. The unique operational characteristics of diverse fibers have been exploited to realize advanced biomedical functions in areas such as illumination, imaging, minimally invasive surgery, tissue ablation, biological sensing, and tissue diagnosis. This review paper provides the necessary background to understand how optical fibers function, to describe the various categories of available fibers, and to illustrate how specific fibers are used for selected biomedical photonics applications. Research articles and vendor data sheets were consulted to describe the operational characteristics of conventional and specialty multimode and single-mode solid-core fibers, double-clad fibers, hard-clad silica fibers, conventional hollow-core fibers, photonic crystal fibers, polymer optical fibers, side-emitting and side-firing fibers, middle-infrared fibers, and optical fiber bundles. Representative applications from the recent literature illustrate how various fibers can be utilized in a wide range of biomedical disciplines. In addition to helping researchers refine current experimental setups, the material in this review paper will help conceptualize and develop emerging optical fiber-based diagnostic and analysis tools.

Optical absorption and scattering properties of bulk porcine muscle phantoms from interstitial radiance measurements in 650–900 nm range

We demonstrated the application of relative radiance-based continuous wave (cw) measurements for recovering absorption and scattering properties (the effective attenuation coefficient, the diffusion coefficient, the absorption coefficient and the reduced scattering coefficient) of bulk porcine muscle phantoms in the 650–900 nm spectral range. Both the side-firing fiber (the detector) and the fiber with a spherical diffuser at the end (the source) were inserted interstitially at predetermined locations in the phantom. The porcine phantoms were prostate-shaped with ∼4 cm in diameter and ∼3 cm thickness and made from porcine loin or tenderloin muscles. The described method was previously validated using the diffusion approximation on simulated and experimental radiance data obtained for homogenous Intralipid-1% liquid phantom. The approach required performing measurements in two locations in the tissue with different distances to the source. Measurements were performed on 21 porcine phantoms. Spectral dependences of the effective attenuation and absorption coefficients for the loin phantom deviated from corresponding dependences for the tenderloin phantom for wavelengths <750 nm. The diffusion constant and the reduced scattering coefficient were very close for both phantom types. To quantify chromophore presence, the plot for the absorption coefficient was matched with a synthetic absorption spectrum constructed from deoxyhemoglobin, oxyhemoglobin and water. The closest match for the porcine loin spectrum was obtained with the following concentrations: 15.5 µM (±30% s.d.) Hb, 21 µM (±30% s.d.) HbO2 and 0.3 (±30% s.d.) fractional volume of water. The tenderloin absorption spectrum was best described by 30 µM Hb (±30% s.d), 19 µM (±30% s.d.) HbO2 and 0.3 (±30% s.d.) fractional volume of water. The higher concentration of Hb in tenderloin was consistent with a dark-red appearance of the tenderloin phantom. The method can be applied to a number of biological tissues and organs for interstitial optical interrogation.

Single Treatment of Grades II and III Cellulite Using a Minimally Invasive 1,440-nm Pulsed Nd:YAG Laser and Side-Firing Fiber: An Institutional Review Board-Approved Study with a 24-Month Follow-Up Period

Cellulite represents one of the common topographic alterations to the skin surface and one of the structural changes to the subdermal fat and septal band of the posterolateral thighs. Currently, no treatment exists to address this entity with a multifactorial genesis that produces long-term beneficial outcomes. This clinical study evaluated the safety and efficacy of the 1,440-nm laser and the duration of the clinical benefits during 2 years. Initially, 25 healthy women with thigh cellulite were enrolled in this prospective institutional review board (IRB)-approved study. For grade II cellulite, the laser fiber delivered up to 1,000 J of energy to the undersurface of the entire involved skin. For grade III cellulite, the laser fiber distributed 1,300 to 1,500 J of energy to melt the subdermal fat, subcise the taut septal bands, and heat the reticular dermis. Baseline and posttreatment analyses included standardized high-resolution photography, skin elasticity measurements, ultrasound scanning for dermal thickness, histology, investigator global assessment scores, and recording of adverse events. Of the 24 subjects who underwent treatment, only 20 were available for the 6-month follow-up assessment. Objective measurements at 2 years demonstrated an increase over the baseline mean skin elasticity (34 %) and mean dermal thickness (11 %), as well as an increase in the average percentage of dermal thickening determined by ultrasound imaging. Independent investigator global assessments were rated higher for grade II subjects than for grade III subjects throughout the 2-year follow-up period. Mild adverse events disappeared by the third month. This IRB-conducted clinical trial, as part of a multicenter study for Food and Drug Administration approval, demonstrated the safety and efficacy of a single minimally invasive treatment for grades II and III thigh cellulite during a 2-year follow-up period. This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

A Multicenter Study for a Single, Three-Step Laser Treatment for Cellulite Using a 1440-nm Nd:YAG Laser, a Novel Side-Firing Fiber, and a Temperature-Sensing Cannula

Historically, treatments for cellulite have not been able to address all of its physiological components and require multiple sessions. The authors evaluate the safety and efficacy of a single, subdermal procedure to treat the underlying structure of cellulite. Fifty-seven patients underwent a 3-step cellulite treatment with a 1440-nm Nd:YAG laser with a side-firing fiber and temperature-sensing cannula. Efficacy was measured by the ability of blinded evaluators to distinguish baseline photos from those taken at 3 and 6 months posttreatment, as well as their rating of the results on a 5-point, 2-category ordinal photonumeric scale when comparing baseline photos to those taken at 2, 3, and 6 months posttreatment. Patient and physician satisfaction was assessed based on completion of a satisfaction survey at 2, 3, and 6 months posttreatment. Adverse events (AE) were recorded throughout the study. At 6 months posttreatment, blinded evaluators rated at least a 1-point improvement in the appearance of cellulite in 96% of treated sites. Blinded evaluators were also able to correctly identify baseline versus posttreatment photos in 95% of cases. At least 90% of patients and physicians reported satisfaction with the results of treatment throughout 6 months. AE were mild in intensity and transient to treatment. A single, 3-step, minimally invasive laser treatment using a 1440-nm Nd:YAG laser, side-firing fiber, and temperature-sensing cannula to treat the underlying structure of cellulite proved to be safe and maintained effectiveness at least 6 months posttreatment. 2.