Safety Of Nd Research Articles

Effect of Nd:YAG laser capsulotomy on graft endothelium after penetrating keratoplasty

BackgroundTo investigate the safety of Nd:YAG laser capsulotomy in eyes with Penetrating Keratoplasty (PK) and its impact on corneal endothelium as well as graft survival. MethodsThirty patients who underwent Nd: YAG laser capsulotomy after PK and 30 pseudophakic control eyes were included in this prospective study. Endothelial cell density (ECD), hexagonality (HEX), coefficient of variation (CV), central corneal thickness (CCT), and the change of these values during follow-up measured at the 1st hour, first week, and first month after the laser and the data were compared between groups. ResultsThe mean time passed between the PK procedure and the subsequent YAG laser procedure was i.e. of YAG laser after PK was 30.5 ± 15.2 months (range 6 to 57 months). Baseline ECD was 1648.2 ± 669.77 cells/mm² in the PK group and 2008.27 ± 347.42 cells/mm² in the control group. In the first month, ECD was 1545.2 ± 639.35 cells/mm² in the PK group and 1979 ± 350.95 in the control group. The loss was significantly higher in PK group (-103 ± 153.67 cells/mm²) (6.25%) compare to the control group (-28.73 ± 82.31 cells/mm²) (1.44%) (p = 0.024). A significant increase in CV was observed in the PK group, and not in the control group (p = 0.008, p = 0.255, respectively). There were no significant changes in HEX and CCT values in either group. ConclusionNd:YAG laser provides a significant increase in visual acuity in first month in patients with PK with no significant harmful effect on graft transparency. Endothelial cell density measurements during follow-up will be beneficial.

Nd:YAG laser ablation of internal limiting membrane to treat myopic macular retinoschisis: Case series.

Purpose; To evaluate the efficacy and safety of Nd:YAG laser ablation of the internal limiting membrane (ILM) to treat myopic macular retinoschisis (MRS).Methods; Four patients with myopic MRS that extended out of the macular area were studied. All patients underwent YAG laser ablation of the detached ILM in the paramacular area, and the eyes were examined by ultra-widefield OCT at the baseline and 6 months after the treatment. The measured outcomes were the foveal retinal thickness and the best-corrected visual acuity (BCVA).Results; Nd:YAG laser was applied to the paramacular ILM in all 4 eyes. In each eye, the procedure failed to disrupt the ILM, and no significant changes were observed in foveal retinal thickness or BCVA subsequently. No serious adverse event occurred in all eyes. A transient intraretinal hemorrhage developed at the site of the application in 2 eyes but resolved within a week after the treatment.Conclusion; Nd:YAG laser was applied to ILM in the peripheral macula in eyes with myopic MRS. However, the lack of a reduction of the foveal thickness and improvement of the BCVA indicate that accurate focusing system is needed to treat eyes with myopic MRS.

On studying the mechanisms and assessing the safety of Nd:YAG laser irradiation of the posterior lens capsule (experimental and clinical study)

To study the mechanisms of laser destruction in exposing the posterior lens capsule (PLC) tissue to Nd:YAG laser irradiation, and to evaluate its side effects on the cornea. The experiment involved 6 autopsy samples of human posterior lens capsule with different optical and mechanical properties, which were exposed to laser irradiation. We used the Nd:YAG ophthalmic laser LPULSA SYL-9000 Premio manufactured by «LightMed» (Taiwan/USA) and an experimental Nd:YAG laser system (1.064 μm). The following parameters were compared: the power of the incident radiation and radiation transmitted through the PLC, the mechanical stresses in the PLC tissue, the kinetic energy of the laser ablation products, and the pressure of gas bubbles during laser exposure in capsule samples of different densities. In the clinical part of the work, the negative effects of Nd:YAG laser on the cornea at different PLC densities were assessed using the endothelial microscope SP 3000P («Topcon», Japan). The experiment showed that in hard samples of PLC there are star-shaped point perforations with a diameter of 50±20 μm with partial rarefaction around the point defects. Damage to soft PLC samples in the form of large complete perforations was up to 200 µm in size. The temperature of laser irradiation necessary to achieve breakdown in soft PLC samples was 90 °C, in hard samples - 120 °C. The results of the experiment indicate that the final outcome - destruction of the PLC tissue - is safer to achieve not by increasing the energy, but by increasing the number of laser pulses. Clinical study results confirm a significant effect of the density of PLC on the values of laser energy and on the state of the cornea after laser intervention. The experimental data on the mechanisms of laser destruction of the lens capsule should contribute to the development of new and improvement of already known technologies aimed at reducing the risks associated with laser surgeries.

Nd:YAG Laser in the Treatment of Nail Psoriasis: Clinical and Dermoscopic Assessment.

The Nd:YAG laser has emerged as a promising modality for the management of nail psoriasis owing to its ability for deep penetration of the skin surface, which has the advantage of destroying deep vessels. To assess the efficacy and safety of Nd:YAG laser in treating nail psoriasis. The present study was a randomized controlled study, conducted on 20 patients of both sexes (age older than 12 years) with mild to moderate psoriasis with nail involvement. We utilized facial telangiectasia parameters of Nd:YAG laser and beam diameter of 2.5 mm. Laser energy started with 110 J/cm2 in the first session and 130 J/cm2 in the rest of the sessions. Sessions were performed once monthly for up to 6 sessions. We found no statistically significant difference in total Nail Psoriasis Severity Index (NAPSI) and nail bed scores before and after treatment among the treated group. However, there was statistically significant improvement in nail matrix score after treatment. On the other hand, the control group did not show any statistically significant changes for all scores throughout the study, except for the nail matrix score mean difference (0.35 ± 1.23 vs -1.00 ± 1.86 in the treated group). The degree of dermoscopic improvement was evident in the treated group (45% vs 25% in the control group). However, it was not statistically significant because of small sample size. The patients' satisfaction and the external investigator's assessment showed statistically significant negative correlation with total NAPSI mean difference in the treated group. The role of Nd:YAG laser in nail psoriasis is still controversial.

Efficacy and safety of Nd:YAG laser vitreolysis for symptomatic vitreous floaters: A randomized controlled trial.

Vitreous floaters are a common and inconvenient phenomena. This study aims to examine the efficacy and safety in treating vitreous floaters using Nd:YAG laser vitreolysis. In this prospective double-blinded randomized clinical trial 24 eyes of twenty-four patients were randomized into intervention with YAG laser vitreolysis and control groups. Primary outcomes were visual disturbance on a 10-point scale, qualitative changes in a 4-level scale, contrast sensitivity measured with the Pelli-Robson table and the National Eye Institute Visual Functioning Questionnaire 25 (NEI VFQ-25). Secondary results included objective change in vitreous opacities, best-corrected visual acuity (BCVA), variation in intraocular pressure (IOP) and other adverse events. Twenty-one patients (21 eyes; 5 male, 16 female) were enrolled in this study (mean age 62 ± 7.9 years), three were lost during follow-up. In the YAG laser group, the 10-point visual disturbance score improved a mean of 4.7 points (p < 0.001) compared to the control group that improved 2.1 (p = 0.09). The YAG laser group reported greater subjectively symptomatic improvement (77%) than controls (25%). NEI VFQ-25 revealed improved general vision (75.8 versus 59.2; p = 0.037) and in mental health at 6 months (84.3 versus 70.3; p = 0.048). There was no significant difference in contrast sensitivity (p = 0.848) and in IOP (p = 0.505). No differences in adverse events between groups were identified. Vitreolysis with Nd:YAG laser improves visual results in patients with symptomatic vitreous floaters, without adverse events considered clinically relevant. Other trials with a larger number of participants are required to corroborate these results.

Efficacy and safety of 1440-nm Nd:YAG laser on lower face and neck rejuvenation.

Reviewing the literatures, we did not found-to our knowledge-any study using the Nd:YAG laser with wavelength 1440nm in assisted liposuction and rejuvenation of the head and neck region although of the higher absorption rate for fat and water. Evidence-based practice supports the benefits of laser-assisted liposuction over conventional liposuction with skin tightening in selected areas specifically the submental area and the neck. The aim of the work is to evaluate the efficacy and safety of Nd:YAG laser wavelength (WL) 1440nm on lipolysis of submental area and skin tightening of the lower face and neck area. Fifty-seven patients with submental localized fat deposits and mild to moderate skin laxity were subjected to laser liposuction using Nd:YAG laser with WL 1440nm (SmartLipo Triplex)® device. The efficacy of skin laxity improvement was assessed together with the whole satisfaction rate for each patient. Overall satisfaction rate was 97% of the patients. One sample test regarding skin laxity showed significant improvement (34.6%) after 6months follow-up (0.268 SD p < 0.05) (Table 4). Complications included edema, soreness, weakness in the lower lip, and ecchymosis that resolved conservatively except one case that complained of seroma which needed aspiration and healed without infection. In conclusions, Nd:YAG laser with WL 1440nm can be used safely and effectively for submental-assisted liposuction and lower face and neck rejuvenation. Less laser energy was needed for lipolysis and skin tightening as the fat and water have a higher absorption rate at wavelength 1440nm.

Efficacy and safety of Nd:YAG laser alone compared with combined Nd:YAG laser with intralesional steroid or botulinum toxin A in the treatment of hypertrophic scars.

The aim of this study is to evaluate the efficacy and safety of Nd:YAG laser alone or in combination with intralesional injection of botulinum toxin type A or intralesional injection of steroid in treatment of hypertrophic scars. This study included 45 patients with hypertrophic scars who were randomly divided into three equal groups. All participants received 4 sessions of Nd:YAG laser at 4-week intervals. Immediately after the laser treatment, patients in group II were assigned to intralesional triamcinolone acetonide, and those in group III were assigned to intralesional botulinum toxin type A. All patients were followed up monthly for 3months after the last session for any recurrence, or side effects. Clinical evaluation of the cases was done by Vancouver Scar Scale. Hypertrophic scars in the three groups showed a significant improvement (p < 0.001) compared with before treatment in all variables (except for pigmentation) and also a significant improvement in pruritus, pain, and patient relief. The highest percentage of improvements was seen in patients treated with Nd:YAG laser combined with intralesional steroid in all variables according to Vancouver Scar Scale. The degree of improvement was negatively correlated with the patients' age. The three treatment modalities were effective, safe with minimal side effects. Nd:YAG laser followed by intralesional injection of Triamcinolone acetonide had the highest percentage of Vancouver Scar Scale reduction. Combination therapy of Nd:YAG laser with intralesional injection of either Triamcinolone acetonide or Botox revealed better results than using Nd:YAG as a single therapeutic modality for HTS.

Efficacy and safety of ND:YAG 1064nm lasers for photoepilation: a systematic review.

Using light sources in phototherapy has presented promising results regarding several types of facial and body skin affections for centuries. The neodymium-doped yttrium aluminum garnet (ND:YAG) 1064nm laser has become a standard treatment in dermatology for dermatological disturbances related to the pilous follicle and the structures surrounding it. Despite the reports of its clinical benefits, few scientific studies show its actual safety and efficacy. To substantiate the effects, benefits, and safety of applying an ND:YAG 1064 laser in the epilation process during esthetic treatment, a systematic review was carried out between October 2018 and January 2019, on studies published in the last 20years. Randomized clinical trials in humans were considered that evaluated the efficacy, safety, and benefits of ND:YAG laser application at 1064nm wavelengths for hair removal. A total of 198 articles were identified; 58 articles remained after their titles and abstracts were read; and 21 articles were selected after the removal of duplicates. After the integral reading, 13 of these articles were included in the systematic review (734 patients). The ND:YAG 1064nm laser presents safety and promising, beneficial effects in epilation. However, further scientific studies with better methodologic quality are necessary to better standardize ND:YAG laser therapy and clarify its parameters for photoepilation.

Efficacy and Safety of Nd:YAG Laser 1064-nm in the Treatment of Onychomycosis

Efficacy and Safety of Nd:YAG Laser 1064-nm in the Treatment of Onychomycosis

Pervasion of beta-tricalcium phosphate with nanodiamond particles yields efficient and safe bone replacement material amenable for biofunctionalization and application in large-size osseous defect healing

Biofunctionalization of scaffold materials can enable the healing of large bone defects. In case of minimally invasive guided-bone regeneration (GBR), limitations are however hard-to-control side effects related to the potential release of biofactors into the systemic environment. Biofactors can be stably bound to nanodiamond particles (ND) through physisorption. We therefore tested the biological and clinical effects of refining beta-tricalcium phosphate (βTCP) with ND in vitro and in vivo. In vitro, βTCP carrying 4% ND resulted in enhanced attachment of mesenchymal stem cells. When assessing GBR after lateral augmentation of the mandible in sheep showed that ND in βTCP resulted in a consistently steady bone formation when compared to pure βTCP, demonstrating the biological inert behavior and the potential clinical safety of ND.

MTE 19.01 Laser Therapy for Airway Obstruction

MTE 19.01 Laser Therapy for Airway Obstruction

Nd:YAG laser vitreolysis versus pars plana vitrectomy for vitreous floaters.

The vitreous is the clear jelly of the eye and contains fine strands of proteins. Throughout life the composition of this vitreous changes, which causes the protein strands in it to bundle together and scatter light before it reaches the retina. Individuals perceive the shadows cast by these protein bundles as 'floaters'. Some people are so bothered by floaters that treatment is required to control their symptoms. Two major interventions for floaters include Nd:YAG laser vitreolysis and vitrectomy. Nd:YAG laser vitreolysis involves using laser energy to fragment the vitreous opacities via a non-invasive approach. Vitrectomy involves the surgical replacement of the patient's vitreous (including the symptomatic vitreous floaters) with an inert and translucent balanced salt solution, through small openings in the pars plana. To compare the effectiveness and safety of Nd:YAG laser vitreolysis to pars plana vitrectomy for symptomatic vitreous floaters. We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (which contains the Cochrane Eyes and Vision Trials Register) (2016, Issue 12), MEDLINE Ovid (1946 to 17 January 2017), Embase Ovid (1947 to 17 January 2017), LILACS (Latin American and Caribbean Health Sciences Literature Database) (1982 to 17 January 2017), the ISRCTN registry (www.isrctn.com/editAdvancedSearch); searched 17 January 2017, ClinicalTrials.gov (www.clinicaltrials.gov); searched 17 January 2017 and the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP) (www.who.int/ictrp/search/en); searched 17 January 2017. We did not use any date or language restrictions in the electronic searches for trials. We also searched conference proceedings to identify additional studies. We included only randomised controlled trials (RCTs) that compared Nd:YAG laser vitreolysis to pars plana vitrectomy for treatment of symptomatic floaters. We planned to use methods recommended by Cochrane. The primary outcome we planned to measure was change in vision-related quality of life from baseline to 12 months, as determined by a vision-related quality of life questionnaire. The secondary outcomes we planned to measure were best corrected logMAR or Snellen visual acuity at 12 months for the treated eye(s) and costs. Adverse outcomes we planned to record were the occurrence of sight-threatening complications by 12 months (asymptomatic retinal tears, symptomatic retinal tears, retinal detachment, cataract formation, and endophthalmitis). No studies met the inclusion criteria of this review. There are currently no RCTs that compare Nd:YAG laser vitreolysis with pars plana vitrectomy for the treatment of symptomatic floaters. Properly designed RCTs are needed to evaluate the treatment outcomes from the interventions described. We recommend future studies randomise participants to either a Nd:YAG laser vitreolysis group or a vitrectomy group, with participants in each group assigned to either receive treatment or a sham intervention. Future studies should follow participants at six months and 12 months after the intervention. Also they should use best corrected visual acuity (BCVA) using an Early Treatment of Diabetic Retinopathy Study (ETDRS) chart read at 4 metres, vision-related quality of life (VRQOL), and adverse outcomes as the outcome measures of the trial.

Clinical analysis of port-wine stain in 130 Chinese patients treated by long-pulsed 1064-nm Nd: YAG laser

Background: The long-pulsed 1064-nm Nd: YAG laser is effective for treating port-wine stain (PWS). This study evaluated the efficacy and safety of Nd: YAG laser in treating PWS in Chinese patients. Methods: A retrospective study of 130 PWS patients treated with long-pulsed 1064-nm Nd: YAG laser from 2009 to 2011. Results: After treatment, 2, 15, 64, and 19 percent of patients experienced < 25%, 25–49%, 50–75%, and > 75% lesion clearance, respectively. Purple lesions showed more significant improvement than pink lesions. The initial response was blistering, dark gray coloration, or light gray coloration, the best improvement occurred in 100% (27/27), 82.5% (52/63), and 72.5% (29/40), respectively. Patients older than 20 years showed the best improvement (37/38, 97.4%), followed by those 10–20 years old (20/24, 83.3%), 1–9 years old (23/29, 79.3%) and less than 1 year old (28/39, 71.8%). Patients with neck lesions had the best outcome (47/48, 97.9%), followed by those with lesions on the face (43/53, 81.2%), extremities (13/18, 72.2%), and trunk (5/11, 45.5%). The common adverse side effects were blistering and pigment changes. Conclusions: 1064-nm Nd: YAG laser is effective and safe for the treatment of PWS. The efficacy is affected by the age of the patient, the color and location of the lesions, and immediate responses to the laser.

Comments on peeling and aspiration of posterior capsular epithelial pearls

Sir, I read with interest an article by Bharghava et al.[1] It is challenging to persuade patients for such a surgical technique. Potential disadvantages of the procedure are recurrence of posterior capsular pearls (11.05%) and second surgical procedure, which patient may have to undergo. Inadequate removal of epithelial pearls and residual lens epithelial cells in the equatorial area could be the possible cause of recurrence in this study. This is substantiated by the presence of epithelial cells on the periphery of the posterior capsule at 3 months of follow up as displayed in Fig. 4 of the aforementioned article. I would like to draw attention of the authors to the interchange of aspiration probe and the anterior chamber maintainer. This will help in the removal of epithelial pearls from the posterior capsular area hiding in the subincisional area of the respective ports. In that endeavor, anterior chamber may become shallow. Viscoelastic may have to be injected to form the anterior chamber. The procedure described by the authors needs rotation of the intraocular lens IOL in the capsular bag to find a potential space between IOL optic and the continuous curvilinear capsulorhexis margin in the bag implanted IOLs. Viscoelastic comes handy in such a situation. However, viscoelastic material needs to be cleansed at the end of the procedure. Visual acuity is expected to improve after clearing the epithelial pearls from the posterior capsule. However, it may change the effective lens position leading to change in the postoperative refraction. Methodology section mentions retrospective analysis of 217 eyes with pearl form of posterior capsular opacification for age-related cataract (>45 years). However, result section states the mean age as 56.84 years (range 40-87 years), suggesting few patients in the study were less than 45 years. It is also stated that 20 patients were lost in follow up by 6 months. However, if the range of follow up is 23-40 months, how were 20 patients lost to follow up at 6 months? The authors have quoted, 186 eyes (85.71%) had final best-corrected visual acuity of 20/20 at 3 months. Twenty-nine (13.36%) eyes had a final vision between 20/30 and 20/40. Two (0.92%) eyes had a final vision of worse than 20/40. However, result section mentions the mean follow up period was 30.13 months (range 23-40 m). Three months is too short period for follow up in such type of study. What tests were used for calculating mean age and follow-up duration? Where was Chi-square test used is not clear from the results shown. Young patients undergoing such type of procedure for membranous posterior capsular opacification (PCO) after cataract surgery and getting mentioned complications could be a drawback of the procedure. Recurrence of the epithelial pearls may need similar procedure or neodymium-doped: Yttrium aluminum garnet (ND: YAG) laser posterior capsulotomy in future. Caballero et al., have demonstrated the safety of ND: YAG laser capsulotomy in membranous type of PCO and clear posterior capsule overtime in most of the cases.[2,3] Finally, there would be an issue of lost to follow up over longer period, especially in country like India.

The role of endoscopy in patients with anorectal disorders

The role of endoscopy in patients with anorectal disorders

Long-term results of Nd:YAG laser treatment for premacular subhyaloid haemorrhage owing to Valsalva retinopathy

Valsalva retinopathy produces sudden visual loss, which may be prolonged if untreated. Nd:YAG laser enables rapid diffusion of premacular subhyaloid haemorrhage. This study was performed to assess the long-term results and safety of Nd:YAG laser treatment in cases with Valsalva retinopathy. Sixteen patients had Nd:YAG laser treatment to drain premacular haemorrhage. The follow-up period was 24 months. All eyes had marked clearing of haemorrhage and immediate improvement of vision following laser treatment. In 14 eyes visual acuity improved to 20/20 level at the end of the first week and the remaining two patients achieved 20/20 level within 1 month. No patient had evidence of retinal or choroidal damage. Nd:YAG laser treatment for Valsalva retinopathy is an effective, non-invasive, and safe procedure for patients with a premacular subhyaloid haemorrhage larger than 3 disc diameter and no longer than 3 weeks of duration.

Efficacy and safety of Nd. YAG laser for the treatment of bleeding from radiation proctocolitis

Background. Bleeding due to radiation proctocolitis is a frequent and severe complication of radiotherapy in cancers of the pelvis. Aim. The aim of this study was to evaluate the efficacy and safety of endoscopic treatment with Nd:YAG laser in this condition. Patients and Methods. A series of 9 patients with radiation-induced damage in the rectum and sigma were treated with endoscopic Nd: YAG laser until significant bleeding stopped and endoscopic features of proctocolitis improved. They received a median of 3 laser treatments (range 1–10] over a maximum time period of 11 months. Results. In 4 cases, bleeding ceased and, in 4, it was reduced to occasional spotting. In the remaining patient, laser therapy led to only a transient improvement, but did not modify the requirement of blood transfusion. In the 5 patients also suffering from urgency, incontinence and/or rectal mucoid discharge, the laser therapy course also relieved these symptoms. No significant treatment-related complications were observed. Conclusions. Endoscopic Nd::YAG laser is a useful and safe treatment for patients with bleeding due to radiation proctocolitis.

7111 Efficacy and safety of nd:yag laser for treatment of bleeding from radiation proctitis.

Bleeding from radiation proctitis is a frequent and severe complication of radiotherapy for cancers of the pelvis. The aim of this study was to evaluate the efficacy and safety of endoscopic treatment with Nd:YAG laser in the healing of rectal bleeding in patients with radiation proctitis. Six patients with teleangectasias, atrophic mucosa, and oozing lesions in the rectum and distal sigmoid colon, not responding to local drug therapy, were treated with endoscopic Nd:YAG laser using shots of 0.3-1.5 seconds at 20-40 W. The time from completion of radiotherapy to onset of bleeding ranged from 0.5 to 13 months and that from bleeding to the start of laser treatment ranged from 2 to 17 months. The patients were treated until significant bleeding stopped and endoscopic features of proctitis improved. Patients received an average of 7 laser treatments (range 1-13) over a mean time period of 8 months. The energy employed per session ranged from 1400 to 12500 J. In 4 cases bleeding stopped, after the first session in 1 patient and after multiple sessions in the other 3 (5, 9 and 13, respectively). In the remaining 2 patients bleeding was reduced to occasional spotting, in 1 case after the first session, and in the other after 6. The patient who received blood transfusion (4 units per month) before treatment did not require any further transfusion after 13 laser sessions. In the 5 patients who were also suffering from diarrhea and/or mucus secretion, a laser therapy course was also able to relieve these symptoms. No treatment related complications were observed. Endoscopic Nd:YAG laser is a safe and effective treatment for patients with bleeding from radiation proctitis. Bleeding from radiation proctitis is a frequent and severe complication of radiotherapy for cancers of the pelvis. The aim of this study was to evaluate the efficacy and safety of endoscopic treatment with Nd:YAG laser in the healing of rectal bleeding in patients with radiation proctitis. Six patients with teleangectasias, atrophic mucosa, and oozing lesions in the rectum and distal sigmoid colon, not responding to local drug therapy, were treated with endoscopic Nd:YAG laser using shots of 0.3-1.5 seconds at 20-40 W. The time from completion of radiotherapy to onset of bleeding ranged from 0.5 to 13 months and that from bleeding to the start of laser treatment ranged from 2 to 17 months. The patients were treated until significant bleeding stopped and endoscopic features of proctitis improved. Patients received an average of 7 laser treatments (range 1-13) over a mean time period of 8 months. The energy employed per session ranged from 1400 to 12500 J. In 4 cases bleeding stopped, after the first session in 1 patient and after multiple sessions in the other 3 (5, 9 and 13, respectively). In the remaining 2 patients bleeding was reduced to occasional spotting, in 1 case after the first session, and in the other after 6. The patient who received blood transfusion (4 units per month) before treatment did not require any further transfusion after 13 laser sessions. In the 5 patients who were also suffering from diarrhea and/or mucus secretion, a laser therapy course was also able to relieve these symptoms. No treatment related complications were observed. Endoscopic Nd:YAG laser is a safe and effective treatment for patients with bleeding from radiation proctitis.

Thermally Controlled Laser Irradiation of the Myocardium with Intraoperative Ultrasound Monitoring

We used intraoperative ultrasonography (IOUS) to study the feasibility and safety of Nd:YAG laser irradiation of the myocardium in 26 canine left ventricular segments. During the laser irradiation process, the myocardial temperature was monitored and surface cooling was used. Afterward, intraoperative ultrasonographic scans, which enabled the evaluation of the irradiated lesions, were compared with cross sections made through the tissues. The total dose of laser energy ranged from 200 to 3,600 joules, and the estimated volume of irradiated lesions ranged from 76.8 to 2590 mm3. There were significant correlations between the laser discharge output (in joules [J]) and the irradiated lesion volume (P less than 0.001), and between the laser energy density (in J/mm2) and the depth of the lesions (P less than 0.01). Macroscopic examination of the cross sections of irradiated myocardium revealed that the lesions were well-demarcated, but not charred or perforated. Thus, we could obtain a satisfactorily large zone of laser photocoagulation without inducing tissue damage, if surface cooling was used and the myocardial temperature was monitored. IOUS was successful in visualizing and locating the irradiated lesions that were seen as hypoechoic, clearly outlined nodules. We submit that this study has established the technical feasibility and dose-response relationship of thermally controlled laser irradiation, and has demonstrated the usefulness of IOUS for the precise localization and monitoring of such laser treatment.