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PubMed1985

Differential effects of Nd-YAG laser on collagen and elastin production by chick embryo aortae in vitro. Relevance to laser angioplasty for removal of atherosclerotic plaques.

Aortae from 17-day old chick embryos were subjected to irradiation with a Nd:YAG laser at energy densities varying from 1.2 - 4.7 X 10(3) J/cm2. The aortae were pulse-labeled in vitro with [3H]proline or [14C]valine, and the synthesis of collagenous polypeptides and soluble elastin was examined by SDS-polyacrylamide gel electrophoresis, followed by fluorography and quantitative scanning densitometry. Irradiation of the aortae with Nd:YAG laser resulted in inhibition of the synthesis of the extracellular matrix proteins. The production of collagen was inhibited to a considerably larger degree than the production of elastin. Thus, the biosynthetic pathway for collagen production appears to be more susceptible to laser inhibition than the corresponding pathway for elastin production. These observations may have relevance to laser angioplasty which has been proposed to be applicable for removal of atherosclerotic plaques in human vessels. Specifically, the results suggest that inhibition of the extracellular matrix production may result in weakening of the vessel wall with subsequent aneurysm formation and rupture.

Animals↗

PubMed1989

Comparative study of neuroma formation in the rat sciatic nerve after CO2 laser and scalpel neurectomy in combination with milliwatt CO2 laser "sealing".

Nerve transections of rat sciatic nerves were performed to compare scalpel neurectomy to CO2 laser neurectomy. Additionally, the effect of milliwatt CO2 laser application to the proximal nerve ending was studied. Animals were sacrificed at 1 to 9 weeks, and the neuromas were examined histologically and measured. Scalpel transections produced typical neuromas. Laser transections produced neuromas characterized by multinucleated giant cells and carbonaceous debris. There was no difference in the size of the neuromas produced by either method of transection. Milliwatt CO2 laser application to the proximal stump did not affect the size or histology of resultant neuroma formation regardless of the method of transection.

Animals↗

PubMed1990

Laser-induced damage to transparent polymers: chemical effect of short-pulsed (Q-switched) Nd:YAG laser radiation on ophthalmic acrylic biomaterials. I. A review.

The use of short-pulsed lasers in ophthalmic surgery inspired and called for research on the damage inflicted by the laser radiation upon the acrylic polymers from which artificial intraocular lenses are made. The possible release of toxic monomers by laser-induced depolymerization is of great concern but past investigations of this phenomenon have been very limited. The present knowledge of various types of laser-induced damage to transparent polymers is reviewed with particular emphasis on the acrylic materials and intraocular lenses.

Lasers↗

PubMed1988

Photosensitization of leukemic cells and normal bone marrow cells by 514 nm laser light and effects of laser light on migration inhibition and lymphokine response.

In a model for ex-vivo purging of bone marrow grafts, leukemic cells and normal bone marrow cells were treated with merocyanine 540 and exposed to 514 nm laser light. With this treatment, 99.9999% of leukemic cells were killed while 55% of the normal bone marrow cells survived. The deleterious effects of laser light alone in the absence of photosensitizer were not observed as determined by cell viability, cell migration, and response of target cells to human migration inhibition factor. These results indicate that laser light induced photodynamic therapy can be useful for ex-vivo autologous bone marrow purging without regard to the deleterious effects of laser light alone.

Bone Marrow↗

PubMed1994

Coronary perforation after excimer laser coronary angioplasty: the Excimer Laser Coronary Angioplasty Registry experience.

OBJECTIVES: This study assessed the frequency of perforation with excimer coronary angioplasty. BACKGROUND: Coronary artery perforation after conventional percutaneous transluminal coronary angioplasty is extremely rare. Because laser coronary angioplasty involves actual tissue ablation, it has an increased potential for perforation. METHODS: All patients in the Excimer Laser Coronary Angioplasty Registry were included in this prospective study. Those who had a perforation related to the procedure were compared with those who did not have this complication. RESULTS: Of 2,759 consecutive patients in the Excimer Laser Coronary Angioplasty Registry, 36 (1.3%) had perforation. In these patients, the left anterior descending coronary artery was the most frequently treated vessel (53%). There were no differences in fiber sizes between patients with and those without perforation. Among the patients with perforation, 36.1% required coronary artery bypass surgery, 16.7% experienced an infarction and 5.6% had a fatal outcome. Among the patients without perforation, the rates were 3.1%, 3.8% and 0.6%, respectively. However, 41.7% of the patients with documented coronary artery perforation did not need coronary artery bypass surgery or experience myocardial infarction or death. No angiographic characteristics distinguished lesions with from those without perforation. The frequency of coronary artery perforation declined over time with increasing operator experience, from 1.6% in the first 1,888 patients to only 0.4% in the last 1,000 patients (p = 0.002). CONCLUSIONS: With increasing operator experience, the rate of perforation with excimer laser coronary angioplasty has decreased. When perforation occurs, subsequent event rates increase.

Angioplasty, Balloon, Coronary↗

PubMed2005

A prospective randomized clinical trial of laser in situ keratomileusis with two different lasers.

PURPOSE: To compare optical quality, visual function, corneal shape, ocular wavefront aberrations, and patient-reported symptoms and satisfaction after laser in situ keratomileusis (LASIK) with two different excimer lasers. DESIGN: Prospective randomized clinical trial. METHODS: In an institutional practice setting, 60 eyes of 30 patients with low to moderate myopia were randomized to receive LASIK in one eye with the Technolas 217A; the other eye was treated with the VISX S3. Patients were followed for 6 months after surgery. The primary outcome measure was best spectacle-corrected visual acuity. RESULTS: At 6 months, the mean best-spectacle corrected high contrast visual acuity was similar between the two treatment groups: mean difference (95% confidence interval) was -0.01 logarithm of minimal angle of resolution (logMAR) (-0.03 to +0.01 logMAR). Uncorrected visual acuity differences were also not significant. The difference in residual spherical equivalent subjective refractive error between treatment groups was -0.15 diopter (-0.34 to +0.05 diopter). Spherical aberration increased in both groups after treatment, and the change in root mean square (RMS) ocular wavefront error was greater in the VISX group by +0.07 microm (+0.03 to +0.11 microm). After LASIK, corneal curvature was steeper in the midperipheral region among VISX-treated eyes by +1.39 diopters (+2.06 to +0.72 diopters). There were no patient-reported differences in satisfaction between eyes. CONCLUSIONS: There were no significant differences in visual acuity or refractive outcomes attributed to either laser under any of the conditions measured. There was also no significant difference in patient-reported symptoms, satisfaction with treatment, or eye preference associated with either laser. Additional study is needed to establish the importance of differences in higher-order optical aberrations and corneal shape that we observed in these two treatment groups.

Adult↗

PubMed2006

Transient light-sensitivity syndrome after laser in situ keratomileusis with the femtosecond laser Incidence and prevention.

PURPOSE: To describe the incidence of transient light-sensitivity syndrome (TLSS) after laser in situ keratomileusis (LASIK) with the femtosecond laser and to identify preventive strategies. SETTING: Hospital NISA Virgen del Consuelo, Valencia, Spain. METHODS: The first 765 eyes operated on with the 15 KHz femtosecond laser were prospectively analyzed for subjective complaints and clinical findings compatible with TLSS. Intraoperative settings, postoperative treatment, and development of complications were analyzed. RESULTS: Overall, TLSS developed in 10 eyes (incidence 1.3%). However, the incidence decreased from 2.8% to 0.4% when aggressive topical steroids were used during the first 3 postoperative days. Postoperative interface inflammation and postoperative use of a low-dose topical steroid regimen were associated with a higher incidence of TLSS. CONCLUSIONS: Transient light-sensitivity syndrome is a relatively uncommon complication related to the use of the femtosecond laser. Postoperative interface inflammation may increase the probability of developing TLSS, whereas an aggressive postoperative steroid regimen seemed to provide protection against it.

Adult↗

PubMed2006

Is surgery for multiple lung metastases reasonable? A total of 328 consecutive patients with multiple-laser metastasectomies with a new 1318-nm Nd:YAG laser.

OBJECTIVE: Our objective was to define the role of a new 1318-nm Nd:YAG laser for lobe- and parenchyma-saving resection of multiple lung metastases. PATIENTS AND METHODS: From January 1996 to December 2003, a total of 3267 nodules (10/patient) were removed from 328 patients (164 men/164 women, mean age 61 years). Criteria for eligibility were expanded to any primary tumors with no upper limit of metastases given. All parenchymal resections were performed with a new 1318-nm Nd:YAG laser whose effect on lung tissue differs significantly from that of the 1064-nm wavelength owing to a 10-fold higher absorption in water and one-third extinction in blood. In 93%, precision laser resection was achieved. The lobectomy rate was only 7%. RESULTS: Pathologic examination revealed 2546 metastases (8/patient) and lymph node disease in 19%. Complete resections (R0) were achieved in 93% of 177 patients undergoing unilateral procedures with a mean of 3 metastases (range 1%-29%) and 75% of 151 patients having bilateral operations with a mean of 13 metastases (range 2-124). The 5-year survival after R0 was 55% for solitary nodules, 41% for all patients, 28% for 10 metastases, and 26% for 20 or more metastases resected. Outcome was significantly poorer after incomplete resection (7%). No 30-day mortality was observed. Major postoperative complications included prolonged air leaks (n = 2), intrapleural bleeding (n = 2), and late pneumothorax (n = 2); all were treated successfully with a chest tube. CONCLUSION: This new 1318-nm Nd:YAG laser facilitates complete resection of multiple bilateral centrally located metastases and thus is lobe sparing. Resection of 20 or more metastases is reasonable because long-term survival was significantly better than that observed with incomplete resection.

Adult↗

PubMed2003

How do we selectively activate skin nociceptors with a high power infrared laser? Physiology and biophysics of laser stimulation.

This review presents and discusses the leading arguments justifying the use of high power laser stimulators to explore the nociceptive system. To grasp the particularity of such stimulators, fundamentals concerning the interaction of low-energy radiation with the skin will be recalled and focused on the optimal match between the wavelength of the emitting source and the thermophysical properties of the skin. This knowledge shall allow us to discuss critical characteristics of laser stimulators. Study of the cutaneous spectrum of receptors showed that laser stimulators allow the selective activation of A(delta) and C-fiber nociceptors. We will present different methods, which increase the selectivity of the laser stimulation, restricting the activation to isolated C-fiber nociceptors. These methods open new perspectives in the study of the cerebral processing of signals ascending through A(delta) and/or C nociceptors and should contribute to a better understanding of their central interaction and integration in normal and pathological states.

Biophysical Phenomena↗

PubMed1994

Outcome of cataract operations performed to permit diagnosis, to determine eligibility for laser therapy, or to perform laser therapy of retinal disorders.

Cataract operations may be recommended when retinal disease is suspected but cannot be adequately diagnosed or treated because of lens opacity. We evaluated the outcome of cataract operations performed under those circumstances. We reviewed the records of 119 patients who were examined at the Wilmer Retinal Vascular Center and within three months underwent a cataract operation. We identified 17 patients (20 eyes) who underwent a cataract operation at the recommendation of a retinal specialist, to permit diagnosis, to determine eligibility for laser therapy, or to perform laser therapy. After the cataract operation, eight (40%) of the 20 eyes were found to have a retinal disease for which laser therapy was recommended, and six (30%) of the 20 eyes underwent laser therapy that, before the cataract operation, had been impossible. These results indicate that a cataract operation may be useful when lenticular opacity prevents diagnosis or treatment in a patient with a suspected retinal disorder.

Adult↗

PubMed1997

Transmyocardial laser revascularization: results of a multicenter trial with transmyocardial laser revascularization used as sole therapy for end-stage coronary artery disease.

BACKGROUND: Transmyocardial laser revascularization was used as the sole therapy for patients with ischemic heart disease not amenable to percutaneous transluminal coronary angioplasty or coronary artery bypass grafting. This technique uses a carbon dioxide laser to create transmyocardial channels for direct perfusion of the ischemic heart. METHODS: Since 1992, 200 patients, at eight hospitals in the United States, have undergone transmyocardial laser revascularization. The patients have a combined 1560 months of follow-up for an average of 10 +/- 3 months per patient. Their age was 63 +/- 10 years and their ejection fraction was 47% +/- 12%. Eighty-two percent had at least one previous bypass graft operation and 38% had a prior angioplasty. Preoperatively, the patients underwent nuclear single photon emission computed tomography perfusion scans to identify the extent and severity of their ischemia. These scans were repeated at 3, 6, and 12 months. Angina class, admissions for angina, and medications were recorded. RESULTS: The perioperative mortality was 9%. Angina class decreased significantly from before treatment to 3, 6, and 12 months (p < 0.001). Likewise, there was a significant decrease in the number of perfusion defects in the treated left ventricular free wall. Concomitantly, there was a significant decrease in the number of admissions for angina in the year after the procedure when compared with the year before treatment (2.5 vs 0.5 admissions per patient-year). CONCLUSION: These combined results indicate that transmyocardial laser revascularization provides angina relief, decreases hospital admissions, and improves perfusion in patients with severe coronary artery disease.

Adult↗

PubMedDate not supplied

Peripheral laser angioplasty with pulsed dye laser and ball-tipped optical fibres.

Laser angioplasty with the pulsed dye laser and integral ball-tipped optical fibres was used for primary treatment of occlusive femoropopliteal vascular disease in 26 limbs of 24 patients, all of whom warranted operative intervention. 19 had "critical ischaemia", 8 had pedal ulceration, and 4 had distal gangrene. The delivery device consisted of the laser fibre loaded retrogradely into a standard 6 mm balloon angioplasty catheter, and was introduced through a common femoral artery cutdown in an attempt to recanalise femoropopliteal occlusions of a mean length of 21 cm (range 3-49). Angiographic recanalisation was achieved with a mean energy of 250 J (range 38-727 J) in 23 of the 26 limbs; in each case the channel created by the laser fibre was augmented by balloon angioplasty. Technical failure occurred in 3 patients, due to wall dissection, persistent side-branch entry, and incomplete lesion penetration, respectively. Acute occlusion within 48 h occurred in 2 diabetic patients with very poor run-off and distal gangrene, and early failure occurred in another patient due to inadequate balloon dilatation. 1 patient with segmental tibial disease below a technically successful recanalisation did not show clinical improvement. Several patients had coexisting coronary artery disease, 3 of whom died of myocardial infarction--all with patent femoropopliteal vessels. In the 21 survivors, 14 vessels remained patent at a median of 7 months' follow-up.

Aged↗

PubMed2001

Comparison of the morphologic changes after selective laser trabeculoplasty and argon laser trabeculoplasty in human eye bank eyes.

OBJECTIVE: To compare the histopathologic changes in the human trabecular meshwork (TM) after argon laser trabeculoplasty (ALT) and selective laser trabeculoplasty (SLT) with a Q-switched, frequency-doubled, neodymium:yttrium-aluminum-garnet laser. DESIGN: Human "in vitro" experimental study. TISSUE AND CONTROLS: Eight human autopsy eyes were obtained within 18 hours of death from persons aged 71 to 78 years. METHODS: The anterior segment of autopsy eyes was isolated, and one half of each trabecular meshwork underwent SLT and the other half ALT. Specimens were evaluated with scanning and transmission electron microscopy. MAIN OUTCOME MEASURES: Structural changes in the TM were detected by scanning electron microscopy, and cellular or intracellular changes were seen with transmission electron microscopy. RESULTS: Evaluation of the TM after ALT revealed crater formation in the uveal meshwork at the junction of the pigmented and nonpigmented TM. Coagulative damage was evident at the base and along the edge of craters, with disruption of the collagen beams, fibrinous exudate, lysis of endothelial cells, and nuclear and cytoplasmic debris. Evaluation of the TM after SLT revealed no evidence of coagulative damage or disruption of the corneoscleral or uveal trabecular beam structure. Minimal evidence of mechanical damage was present after SLT, and the only ultrastructural evidence of laser tissue interaction was cracking of intracytoplasmic pigment granules and disruption of trabecular endothelial cells. CONCLUSIONS: SLT applied "in vitro" to the TM of human eye bank eyes seemed to cause no coagulative damage and less structural damage to the human TM when compared with ALT and, therefore, may be a safer and more repeatable procedure.

Aged↗

PubMed2002

Tracker-assisted laser in situ keratomileusis for myopia using the autonomous scanning and tracking laser: 12-month results.

OBJECTIVE: To determine the safety, efficacy, and predictability of the Autonomous scanning and tracking laser for the correction of myopia and myopic astigmatism with laser in situ keratomileusis (LASIK) procedure. DESIGN: Retrospective, noncomparative case series. PARTICIPANTS: The first 129 consecutive eyes with up to -13.00 diopters (D) of myopia and -5.00 D of astigmatism. INTERVENTION: Myopic tracker-assisted LASIK (T-LASIK) using the Autonomous Laser (Alcon Summit Autonomous, Waltham, MA) and Hansatome microkeratome (Bausch & Lomb Surgical, Bracknell, England). MAIN OUTCOME MEASURES: Uncorrected visual acuity (UCVA), manifest spherical equivalent (MSE), best spectacle-corrected visual acuity (BSCVA), and complications were studied. RESULTS: At 12 months, the mean MSE was -0.02 +/- 1.01 D, with 79.1% of eyes within 0.5 D and 89.9% of eyes within 1 D of the intended correction. UCVA was 20/20 or better in 71.4%, 20/25 or better in 78.5%, and 20/40 or better in 92.8% of eyes. Two eyes (1.6%) lost 2 lines and five eyes (3.8%) gained 2 lines of BSCVA. Sixteen eyes (12.4%) required retreatment to correct residual myopia or astigmatism. After retreatment, 14 of 16 eyes were within 0.5 D of emmetropia. Nine eyes (6.9%) had minor flap complications; two eyes (1.6%) had grade 2 diffuse lamellar keratitis, of which one eye had associated peripheral flap melt. One eye showed slight decentration; this eye was rolling throughout the procedure. All eyes had some dryness, with 10% severe enough to require temporary punctual occlusion with plugs. CONCLUSIONS: T-LASIK for myopic astigmatism with the Autonomous Laser is relatively safe, effective, and predictable. The tracker seems to be effective, and the complications are relatively few. Retreatment rates are acceptable and can be performed safely and effectively to improve visual outcome. The outcomes are comparable with other published data.

Adult↗

PubMed2003

Assessment of nociceptive trigeminal pathways by laser-evoked potentials and laser silent periods in patients with painful temporomandibular disorders.

We assessed the trigeminal nociceptive pathways in patients with painful temporomandibular disorders (TMD) and control subjects using a CO(2)-laser stimulator which provides a predominant activation of the nociceptive system. Fifteen patients with unilateral pain were examined in accordance with the Research Diagnostic Criteria for TMD and 30 gender- and age-matched individuals were included as a control group. Laser-evoked potentials (LEPs) and laser silent periods (LSPs) after stimulation of the perioral region (V2/V3) on the painful and non-painful sides were recorded in all subjects. LEPs were evoked by low-intensity pulses (1.5 x perception threshold (PTh)) and recorded from scalp electrodes at the vertex. LSPs were evoked by high-intensity pulses (4 x PTh) and recorded bilaterally from masseter muscles with surface electromyogram (EMG) electrodes. Subjects also assessed the stimulus intensity on a 0-10 rating scale. LEPs had normal latency but smaller amplitude in TMD patients compared to the control group (P<0.001). Side-to-side comparison within patients showed that LEP amplitude was even more reduced after stimulation on the painful than the non-painful side (P<0.001). TMD patients showed a significant side-asymmetry of the pre-stimulus EMG activity, with a smaller value in the muscle on the painful side (P<0.001). LSPs were completely absent bilaterally in 12 TMD patients and unilaterally in two patients; only one patient had normal and bilateral LSPs. TMD patients perceived the laser stimulus less intense on the painful than the non-painful side (P<0.05). We found suppression of cortical responses and brainstem reflexes elicited by a predominantly nociceptive input in TMD patients. These findings are consistent with recent experimental pain studies and suggest that chronic craniofacial pain in TMD patients may be associated with a dysfunction of the trigeminal nociceptive system.

Adult↗

PubMed2001

Laser in situ keratomileusis with a scanning excimer laser for the correction of low to moderate myopia with and without astigmatism.

PURPOSE: To evaluate the safety and effectiveness of and patient satisfaction with laser in situ keratomileusis (LASIK) performed with a scanning excimer laser by experienced surgeons to correct low and moderate levels of myopia and astigmatism. SETTING: Clinique Laservue, Montreal, Quebec, Canada. METHODS: A consecutive series of 125 patients (236 eyes) with myopia of -0.5 to -7.0 diopters (D) and cylinder less than 2.5 D were enrolled in this single-center prospective clinical trial. The patients were treated with LASIK and followed for 6 months. The System-ALK Automated Corneal Shaper microkeratome (Bausch & Lomb Surgical) with a 180 microm thickness plate and the Technolas 217 excimer laser (Bausch & Lomb Surgical) with PlanoScan software for the stromal ablation were used in all procedures. Since this version of PlanoScan tended to undercorrect, a mean of 14.7% was added to the standard nomogram. Patient satisfaction was assessed by questionnaires administered preoperatively and 1 and 6 months postoperatively. Retreatments for enhancement were not performed during the 6-month follow-up. RESULTS: Six months after LASIK (86.4% follow-up), the mean postoperative manifest spherical equivalent was +0.02 D +/- 0.64 (SD) compared with a preoperative mean of -4.01 +/- 1.59 D. The uncorrected visual acuity was 20/40 or better in 94.6% of eyes and 20/20 or better in 81.9%. A total of 91.2% were within +/-1.0 D of emmetropia and 73.0% were within +/-0.5 D. Only 2 eyes were overcorrected by >1.0 D. Of the eyes with astigmatic myopia, 86.8% were within +/-1.0 D of the intended cylinder correction (by vector analysis) and 73.0% were within +/-0.5 D. The refractions were generally stable after 1 month, and the change in refraction between postoperative examinations was within +/-0.5 D in 88.0% of eyes. A 1-line decrease in best spectacle-corrected visual acuity was seen in 11.3% of eyes, and no eye lost more than 1 line. An increase of 1 or 2 lines was seen in 45.1%. No intraoperative problems occurred, and the interface was clear in all eyes. At 6 months, most symptoms present significantly more frequently than preoperatively were "mild"; none were "marked" or "severe." A total of 90.5% of eyes were reported with marked to extreme improvement in the overall quality of vision, and 99.0% of patients said they would choose LASIK surgery again. CONCLUSIONS: Mild to moderate myopia, with and without astigmatism, was corrected safely, effectively, and predictably with a high degree of patient satisfaction using LASIK with a scanning excimer laser and the System-ALK Automated Corneal Shaper.

Adult↗

PubMed1994

Percutaneous laser recanalisation of femoropopliteal occlusions using continuous wave Nd-YAG laser and sapphire contact probe delivery system.

A conventional continuous wave Nd-YAG medical laser system delivered by transparent sapphire tipped optical fibres was used for percutaneous recanalisation of 32 chronic femoropopliteal occlusions in 27 patients (19 men, eight women; median age 68 years, range 46-83 years). Twenty-four patients had severe intermittent claudication and three had critical ischaemia. The median occlusion length was 8 cm (range 3-35 cm) and lesions were not negotiable by guidewire. Laser energy was delivered at powers of 10-15 Watts using intermittent 1 second emissions (mean total energy 315 Joules, range 30-1015]). The sapphire tips used were 1.8 to 3.0 mm diameter. After laser recanalisation adjunctive balloon dilatation was necessary to widen the resulting lumen. All patients received anti-platelet therapy. Initial clinical success was achieved in 22 limbs (69%) with symptomatic relief and increase in mean (+/- S.D.) ankle-brachial pressure ratio from 0.52 (+/- 0.25) to 0.80 (+/- 0.21) [Mann-Whitney U, p < 0.001]. Recanalisation was unsuccessful in all calcified lesions (four cases). There was a high incidence of vessel perforation (28%) and wall dissection (25%). Emergency surgery was not required after failed procedures. The median follow-up was 12 months (range 6-20 months). By 6 months, 15 of 22 successfully recanalised lesions (68%) had reoccluded. The cumulative primary patency at 1 year was only 12%. These disappointing results do not support routine use of this system. Clearly, modifications of the laser/delivery system or the technique, or both, are required. The aim should be to achieve sole laser recanalisation without concomitant balloon dilatation.

Aged↗

PubMed2003

Laser-induced fluorescence of formaldehyde in combustion using third harmonic Nd:YAG laser excitation.

Formaldehyde (CH2O) is an important intermediate species in combustion processes and it can through laser-induced fluorescence measurements be used for instantaneous flame front detection. The present study has focussed on the use of the third harmonic of a Nd:YAG laser at 355 nm as excitation wavelength for formaldehyde, and different dimethyl ether (C2H6O) flames were used as sources of formaldehyde in the experiments. The investigations included studies of the overlap between the laser profile and the absorption lines of formaldehyde, saturation effects and the potential occurrence of laser-induced photochemistry. The technique was applied for detection of formaldehyde in an internal combustion engine operated both as a spark ignition engine and as a homogenous charge compression ignition engine.

Fluorescence↗