Selective photothermal interaction using an 805-nm diode laser and indocyanine green in gel phantom and chicken breast tissue

. Laser immunotherapy, a novel therapy for breast cancer, utilises selective photothermal interaction to raise the temperature of tumour tissue above the cell damage threshold. Photothermal interaction is achieved with intratumoral injection of a laser-absorbing dye followed by non-invasive laser irradiation. When tumour heating is used in combination with immunoadjuvant to stimulate an immune response, antitumour immunity can be achieved. In this study, the selective photothermal effect was investigated using gel phantom and chicken breast tissue. An 805-nm diode laser and indocyanine green (ICG) were used. An ICG-containing gelatin phantom was constructed to simulate targeted tumour tissue. The target gel was buried inside chicken breast tissue and the tissue–gel construct was irradiated by the laser. Temperatures at different locations in the construct were measured during the laser irradiation. For comparison, the thermal effect of an Nd:YAG laser on the tissue–gel construct was also investigated. Selective heating of target gel containing 0.27% ICG and buried 1 cm below the chicken tissue surface was achieved with the 805-nm diode laser using a power of 0.85 W and beam radius of 1 cm. The target gel experienced a temperature increase of more then 6°C whereas the surrounding chicken breast tissue experienced only a minor temperature increase. The feasibility of this experimental set-up has been shown. It will be used in the future to optimise treatment parameters such as laser power, laser beam radius, and dye concentration. Paper received 17 April 2002; accepted 3 May 2002. Correspondence to: W.R. Chen, Biomedical Engineering Program, Department of Physics and Engineering, University of Central Oklahoma, Edmond, OK 73034, USA. Tel.: (405) 974-5198; Fax: (405) 974-3812; e-mail: wchen@ucok.edu     

Potentiation of laser-tissue interactions of the 805 nm laser with indocyanine green

A high power 805 nm diode laser with advantages of compact size, portability and ease of installation and use has recently been introduced. This unit has comparable laser-tissue interactions to the Nd-YAG in contact mode, however the maximum power output of 25 W has limited its clinical applications. We have compared 805 nm with 1064 nm laser energy in noncontact mode before and after the addition of a chromophore (intravenous indocyanine green). There is equivalency of laser-tissue interactions of 805 and 1064 nm in non-contact mode up to a maximum power output of 20 W. Laser-tissue interactions of the 805 nm laser are significantly potentiated by indocyanine green, as shown by a significant increase in diameter of tissue thermal injury. The 805 nm diode may therefore provide an alternative to the 1064 nm laser in non-contact as well as contact mode.     

Canine colonic anastomoses reinforced with dye-enhanced fibrinogen and a diode laser

Summary Leakage from colonic anastomoses is a common cause of morbidity in patients recovering from bowel surgery. We evaluated a technique of laser-fibrinogen reinforcement to strengthen colonic anastomoses in a canine model. After creation of eight single-layer interrupted suture anastomoses in six dogs, indocyanine green-dye-enhanced fibrinogen was topically applied to the serosal surface and exposed to 808 mm diode laser energy. Immediately following colonic anastomosis, the mean leakage pressure was 137±22 mm Hg in the group (n=8) using sutures alone and 326±67 mm Hg (P<0.001) in the group (n=8) after the sutured anastomosis was reinforced with lasered-fibrinogen. On histological examination, no evidence of thermal injury to the tissue edges was noted and a layer of fibrinogen bridged the anastomotic gap. Laser dye-enhanced fibrinogen reinforcement significantly enhances the strength of sutured colonic anastomoses without causing appreciable thermal injury to the host tissues.     

Atomic force microscopy and transmission electron microscopy analyses of low-temperature laser welding of the cornea

Low-temperature laser welding of the cornea is a technique used to facilitate the closure of corneal cuts. The procedure consists of staining the wound with a chromophore (indocyanine green), followed by continuous wave irradiation with an 810 nm diode laser operated at low power densities (12–16 W/cm²), which induces local heating in the 55–65 °C range. In this study, we aimed to investigate the ultrastructural modifications in the extracellular matrix following laser welding of corneal wounds by means of atomic force microscopy and transmission electron microscopy. The results evidenced marked disorganization of the normal fibrillar assembly, although collagen appeared not to be denatured under the operating conditions we employed. The mechanism of low-temperature laser welding may be related to some structural modifications of the nonfibrillar extracellular components of the corneal stroma.     

Thermal damage of blood vessels in a rat skin-flap window chamber using indocyanine green and a pulsed alexandrite laser: A feasibility study

The design criteria and feasibility of specifically targeting blood vessels for thermal damage by using a pulsed alexandrite infra-red laser to heat an intravascularly injected infra-redabsorbing dye, namely indocyanine green (ICG), is demonstrated. Theoretical calculations map the distribution of light and heat in and around the subcutaneous blood vessels in a rat skin-flap window chamber as functions of dye concentration, vessel size, and vessel depth. Theoretical calculations showed that an injected dose of 6–24 mgkg⁻¹ of ICG and a 120-μs, 1-J cm⁻² alexandrite laser pulse at a wavelength of 785 nm would be sufficient to achieve selective vascular damage to a depth of at least 0.15 cm. Feasibility experiments were performed which illustrated that an irradiation of 1.27 J cm⁻² of skin flaps in uninjected control rats showed no evidence of vascular damage while vascular damage was seen in skin flaps using an experimental protocol of 12 mg kg⁻¹ i.v. of ICG and an energy fluence of 0.76 J cm⁻². This procedure could conceivably prove useful in the treatment of vascular lesions or cancer.     

肝硬化程度与吲哚氰绿排泄试验的相关性评价

目的 研究肝硬化程度与吲哚氰绿排泄试验的相关性。方法 分别测定了３８例肝硬化患者和１４例正常个体的吲哚氰绿排泄试验消失率（ＫＩＣＧ）、总胆汁酸盐（ＴＢＡ）、单胺氧化酶（ＭＡＯ）、白蛋白（ＡＬＢ）,并用相关分析的方法分析了诸因素与肝硬化程度的相关关系。结果 ＫＩＣＧ与肝硬化程度高度相关,其次分别为ＴＢＡ,ＭＡＯ、ＡＬＢ。结论 ＫＩＣＧ能准确反映肝硬化程度,对指导治疗有较高的辅助诊断价值。     

吲哚菁绿分子荧光成像技术在腹腔镜肝切除中的应用

目的探讨吲哚菁绿(indocyanine green,ICG)分子荧光成像技术引导腹腔镜肝切除术治疗肝细胞癌的安全性和有效性,以及对远期预后的影响。方法回顾性分析2016年8月至2019年9月期间229例接受单纯腹腔镜肝切除的肝细胞癌病人及69例接受ICG引导下腹腔镜肝切除的肝细胞癌病人的临床资料。采用倾向性评分匹配方法,比较两组病人的手术情况和术后并发症,采用Log-Rank检验分析两组病人的无病生存期和总生存期。结果 298例腹腔镜肝癌切除病人中,单纯腹腔镜肝切除组229例,ICG荧光引导腹腔镜肝切除术组69例,1∶1匹配后两组均有65例病人纳入分析。配对前、后,ICG荧光引导腹腔镜肝切除术组手术时间均短于单纯腹腔镜肝切除组(均P<0.05);术中出血量、术中输血量、术后并发症、无病生存期和总生存期两组间差异均无统计学意义(均P>0.05)。结论 ICG分子荧光成像技术可作为腹腔镜肝切除中有效的实时导航手段,可明显缩短手术时间,且并未增加术后并发症,同时可获得与单纯腹腔镜肝切除相当的远期预后。     

Preliminary study of laser welding for aortic dissection in a porcine model using a diode laser with indocyanine green

BACKGROUND AND OBJECTIVES: The objective of this study was to determine whether a dissected aorta could be welded by a diode laser with a solder using an in vitro porcine aortic dissection model. STUDY DESIGN/MATERIALS AND METHODS: Porcine aortic strips were dissected into two flaps and the dissected faces were immersed in a solution of indocyanine green. The two flaps were pressed at 0.2 kg/cm2 with contact between the two immersed faces. The pressed flaps were irradiated with a diode laser (810 nm) at intensities of 170-425 W/cm2 for 8 seconds. The welded flaps were studied by light microscopy and the adhesive strengths were measured. RESULTS: The irradiated flaps were successfully welded. The breaking stress, the maximum stress recorded in a stress-strain curve, increased with increase in irradiation intensity up to 396 W/cm2 (2.7 x 10(2) mmHg) and decreased when the intensity reached 425 W/cm2. In the specimen irradiated at 396 W/cm2, the welded faces showed continuous fusion of elastin layers, while some voids were seen between the welded faces in the specimen irradiated at 425 W/cm2. CONCLUSIONS: The dissected porcine aortas were successfully welded using a laser with solder. The results suggest that the welded aorta can bear physiological blood pressure.     

吲哚菁绿荧光显影技术在腹腔镜胆囊手术中的应用

目的探讨吲哚菁绿(indocyanine green,ICG)荧光显影技术在腹腔镜胆囊手术中的临床应用价值。方法前瞻性选取术前诊断为胆囊结石合并急性胆囊炎、慢性萎缩性胆囊炎或残余胆囊的56例病人,其中48例于气腹建立后经外周静脉注射ICG,按剂量不同分为0.5 mg组、1 mg组、5 mg组和10 mg组四组(每组各12例);另外8例于术中根据目标胆道容积经胆道注射浓度为0.025 mg/ml ICG,观察术中目标胆管荧光显影的时间、荧光强度及对手术的指导作用。结果 48例经外周静脉注射ICG的病人,均成功实施腹腔镜胆囊切除术,除0.5 mg组2例病人显影失败外,余均显影成功。0.5 mg组、1 mg组、5 mg组、10 mg组显影时间分别为(53.60±13.73)min、(42.83±7.80)min、(24.92±6.95)min、(23.17±8.11)min。显影时间显示:0.5 mg组长于1 mg组(P=0.01),1 mg组长于5 mg组(P<0.001),差异均具有统计学意义;5 mg组与10 mg组比较差异无统计学意义(P=0.647)。0.5 mg组、1mg组...     

Transmission of laser energy and assessment of target temperature in an experimental model of laser balloon angioplasty

The potential application of laser balloon angioplasty (LBA) is limited because of difficulties in temperature control and dosimetry during trans-balloon laser irradiation. An experimental model of LBA was designed to help understand the polymer membrane effects of two materials on tissue temperature. The durability of two types of polymer films with different optical properties, polyethylene terephthalate (PET), a low scattering polymer and polyetheretherketone (PEEK), a high scattering polymer, were examined as potential balloon material. The PEEK film (thickness: 50 μm) was melted and perforated by light from a diode laser (wavelength: 808±10 nm, irradiance: 1469 W cm⁻², mean exposure time: 30±7 s). On the other hand, the PET film with the same thickness was completely intact after 1 min exposure at the same irradiance. Diode laser irradiation was applied to indocyanine green stained human aortic media in three different exposure methods; directly, through the free PET and through the pressed PET film. Temperatures of laser-irradiated specimens were measured using an infra-red thermal camera with an 8–12 μm bandwidth, and corrected for the emissivity of the tissue and the PET film. Results demonstrated underestimation of surface temperature because of low transmittance of radiated intensity through the free PET film and a significant (p<0.001) increase of corrected temperature (δT=169±32°C) through the pressed-PET exposure compared with the direct exposure (ΔT=81±7°C), even though the same laser irradiance (18.6W cm⁻²) was applied for 5s. That is, the tightly PET-covered tissue develops a significantly higher temperature during diode laser irradiation, and this increased thermal effect can be advantageous for laser welding with less power in laser balloon angioplasty.     

吲哚菁绿在肝胆外科领域的应用现状及展望

近年来,外科医师对肿瘤病人进行术前评估的检查方法日臻丰富,但是辅助术者对肿瘤进行术中实时评价的工具仍处于探索阶段。而吲哚菁绿作为一种安全有效的近红外示踪剂在术中肿瘤边缘的界定、切除平面和范围的判定、前哨淋巴结的示踪等方面均展现出了极大的优势。尽管吲哚菁绿的在临床应用过程中仍存在一定的局限性,但吲哚菁绿分子生物学的研究已经取得了阶段性进展,有望进一步提高其在肿瘤示踪方面的敏感性和特异性。     

Solitary angiokeratoma of the tongue treated with diode laser

Angiokeratoma is a muco-cutaneous disorder that is usually associated with a number of metabolic disorders. Involvement of the tongue with solitary angiokeratoma, without a systemic or metabolic disease, is very rare. To the best of our knowledge, we report the second case of solitary angiokeratoma of the tongue arising in a 16-year-old woman who was treated with diode laser (810 nm) in our department. This case was partially presented as poster presentation at the 12th Congress of the BaSS, 12–14 April 2007, Istanbul, under the auspices of the Balkan Stomatological Society. An erratum to this article can be found at     

Bile leak test by indocyanine green fluorescence images after hepatectomy

Bile leak remains a serious complication after hepatectomy. The conventional leak test by intrabiliary injection of normal saline solution is not sensitive. The authors present a new bile leak test using indocyanine green (ICG) fluorescence. After hepatic transection, ICG solution (.05 mg/mL) was intrabiliarily injected through a transcystic tube under distal common bile duct clamping, and fluorescent images were visualized using an infrared camera system. The ICG leak test was performed in 27 patients undergoing hepatectomy without biliary reconstruction. Bile leaks were intraoperatively found in 8 patients and fixed, resulting in no postoperative leaks. There was no adverse reaction to ICG. In contrast, postoperative bile leaks occurred in 2 of 32 patients who received the conventional leak test with normal saline solution between April 2007 and March 2008. The new bile leak test by ICG fluorography is useful to prevent postoperative bile leak.     

Thoracoscopic resection of pulmonary sequestration with carbon dioxide insufflation and indocyanine green

We encountered a rare case of pulmonary sequestration supplied from the right renal artery, which was resected by video-assisted thoracic surgery with carbon dioxide insufflation and indocyanine green-guided technique. A 41-year-old woman with intralobar pulmonary sequestration supplied from the right renal artery was referred to our department. At the time of surgery, we used carbon dioxide insufflation to improve the manoeuvrable workspace for shutting off aberrant arteries and indocyanine green fluorescence guidance to differentiate the boundary of the sequestered lung from the normal lung. These procedures helped in the efficient resection of the lesion.     

Colonic tattooing using fluorescence imaging with light-emitting diode-activated indocyanine green: A feasibility study

Purpose  We investigated the feasibility of a fluorescence imaging technique using light-emitting diode (LED)-activated indocyanine green (ICG) fluorescence. Methods  Indocyanine green injections were given to patients undergoing preoperative colonoscopy for early colon cancer or colon adenoma. During subsequent laparotomy, the colon was first observed with the naked eye, and then using a prototype machine with a charge-coupled device (CCD) video camera equipped with a cutoff filter and a LED at a wavelength of 760 nm as the light source. Results  LED-induced fluorescence showed tumor localization clearly and accurately in all ten patients (100%) enrolled in this study, whereas it was seen with the naked eye as a green spot in only two patients (20%) (P = 0.0077; Wilcoxon’s signed-rank test). There were no complications of LED-induced fluorescence and no inflammatory signs were noted on the hematoxylin-eosin-stained slides for the identified injection sites in the resected specimens. Conclusions  Colonic tattooing using this fluorescence imaging technique of LED-activated ICG fluorescence is a new concept of colonic marking based on the characteristics that ICG is a near infrared fluorescent dye, and is useful, without any adverse effects, to identify perioperatively the tumor localization.     

机器人荧光显影深部浸润型子宫内膜异位症手术一例并文献回顾

目的探讨吲哚菁绿荧光显影技术在机器人深部浸润型子宫内膜异位症手术中指导手术范围的可行性。 方法选取解放军总医院第一医学中心妇产科的深部浸润型子宫内膜异位患者1例,术前完善检查,无手术禁忌,拟行机器人全子宫双附件切除＋子宫内膜异位病灶切除术。术中利用吲哚菁绿荧光显影技术指示子宫内膜异位病灶进而对病灶进行切除。 结果病变定位准确,患者术后顺利出院。 结论机器人荧光显影技术能够清晰识别子宫内膜异位病灶。这项技术简单、快速,且能够在术中实现实时定位,指导手术范围。     

吲哚菁绿在机器人肝脏FNH切除术中的应用

目的总结应用吲哚菁绿(indocyanine green,ICG)在机器人肝脏局灶性结节性增生(focal nodular hyperplasia,FNH)切除术中荧光显影定位导航的方法。方法回顾性分析解放军总医院肝胆胰外科医学部2018年5月至2020年10月行ICG荧光显影术中导航机器人肝脏FNH切除患者的临床病理资料。根据肿瘤大小将患者分为肿瘤<5 cm组和肿瘤≥5 cm组。术前48 h,患者经肘正中静脉注射ICG,剂量0.25 mg/kg。术中在机器人荧光模式下实时定位肿瘤边界并联合应用术中超声完成FNH切除术。结果36例患者中,男17例、女19例,平均年龄28.7岁。35例完成机器人肿瘤切除术、1例中转开腹。肿瘤平均直径(5.9±4.4)cm,13例患者肿瘤<5 cm、23例患者肿瘤≥5 cm。机器人手术患者的中位手术时间120 min,中位术中出血量50 ml,术后平均住院时间3.9 d。两组的手术时间、术中出血量和术后平均住院时间比较,差异有统计学意义(P<0.05)。结论ICG荧光显影术中可实时显示肝脏FNH肿瘤边界,引导外科医师机器人下完整切除肿瘤。