Stable pulsed operation of Lissajous structured beams by Nd:YVO4/Cr4+:YAG laser in a concave-convex resonator.

A Nd:YVO4/Cr4+:YAG laser with a symmetric concave-convex cavity ensuring strong intracavity beam focusing on the absorber is designed for stable pulsed operation of Lissajous structured modes with transverse patterns as Lissajous figures. Setting the cavity length to fulfill the criterion for efficient passive Q switching (PQS), as well as to meet the accidental degenerate conditions, Lissajous pulsed beams with well-defined structures and good temporal stability are created under two-dimensional off-axis pumping. Although the multi-transverse-mode oscillation inevitably induces asynchronous pulsation and leads the short-term pulse profiles to reveal parasitic effects, the overall long-term behavior of Lissajous pulses can be kept regular with amplitude fluctuations ≤15% and pulse-to-pulse timing jitter ≤5%. With the maximum peak power exceeding 500 W at a pump power of 4.5 W, the PQS Lissajous modes are further transformed into trochoidal pulsed beams to realize high-order and high-peak power structured vortex fields.

[Attention should be paid to glaucoma following pediatric cataract surgery].

Glaucoma following cataract surgery is one of the common complications after pediatric cataract surgery, and it is the main cause of "second blindness" in children. Since this atypical disease is difficult to diagnose and evaluate, it has been gradually paid more attention by clinicians. There are still some controversies and challenges related to the characteristics of the disease, diagnostic criteria, and treatment options. This article discusses the definition, diagnostic criteria, related risk factors, treatment strategies, follow-up, and prognoses of glaucoma following cataract surgery. Establishment of a diagnosis and treatment system can better improve the visual rehabilitation of pediatric cataract children.

[Reflections on surgical treatment of congenital cataract].

Congenital cataract is the first main cause of avoidable blindness in children. The manifestations of congenital cataract are diverse and complex, often associated with other ocular structural abnormalities. The infantile eyeballs are in the growth and development stage, the structure of eyeball wall is fragile, and the blood-ocular barrier is immature. Therefore, congenital cataract surgery features relatively higher surgical technical requirements with higher postoperative complications occurrence. Congenital cataract is not a miniature version of age-related cataract, which has its own unique surgical principles. In this article, issues including the preoperative characteristics of congenital cataract, surgical timing and techniques, and follow-up treatment, were discussed based on expert clinical experiences of Zhongshan Ophthalmic Center and relevant literatures. (Chin J Ophthalmol, 2021, 57: 11-16).

[Study on the immune functions of dendritic cells regulated by histone deacetylase inhibitor Belinostat].

Objective: To explore effects of histone deacetylase inhibitor Belinostat on the immunologic function of dendritic cells (DC) and its possible mechanism. Methods: Cultured mouse bone marrow-derived DC from C57BL/6 mouse in vitro. The experiments were divided into 0, 50, 100 nmol/L Belinostat + immature DC (imDC) group, and 0, 50, 100 nmol/L Belinostat mature DC (mDC). The changes of the ultrastructure of DC were observed by transmission electron microscope (TEM). Immunophenotype and CCR7 expression rate were detected by FCM, and the migration rate was observed by chemotaxis assay. The proliferation of lymphocytes stimulated by different DC was detected by mixed lymphocyte culture reaction. The cytokines in the culture supernatant, including TNF-α, IL-12 and IL-10, were examined by ELISA. RQ-PCR was used to examine the relative expression of mRNA in RelB. Results: Successful cultured and identified the qualified imDC and mDC. Belinostat decreased the expression of CCR7 on imDC [(25.82±7.25)% vs (50.44±5.61)% and (18.71±2.00)% vs (50.44±5.61)%], meanwhile increased the rate on mDC [(71.14±1.96)% vs (64.90±1.47)%]. Chemotaxis assay showed that the migration rate of Belinostat+imDC and Belinostat+mDC group were both decreased, but the difference in imDC was not significant. T lymphocyte proliferation rate stimulated by 100 nmol/L Belinostat+imDC group was lower than imDC group in condition irritation cell∶reaction cell=1∶2 [(227.09±13.49)% vs (309.49±53.69)%]. Belinostat significantly suppressed the secretion of cytokines TNF-α, IL-12 and IL-10 (all P<0.01). The relative expression of mRNA in RelB was slightly decreased in Belinostat+imDC and Belinostat+mDC group (all P<0.05). Conclusion: Belinostat could effectly suppress DC maturation and regulate immune tolerance of DC, which may be due to the down-regulation of mRNA level of RelB in DC.

[Clinical characteristics and surgical effect observation of congenital aniridia combined with cataract].

Objective: To analyze the clinical manifestations, surgical approaches and postoperative prognosis for the cases of congenital aniridia combined with cataract. Methods: In this retrospective case series, 26 patients diagnosed with congenital aniridia combined with cataract were collected from Zhongshan Ophthalmic Center from February 2002 to August 2016. The Clinical data were collected to analyze the clinical features, surgical approaches and postoperative prognosis. T-test was used for statistical analysis. Results: Twenty-six bilateral congenital aniridia patients were included in the case series, with 50% male cases. The average age for the first visit was (8.72±8.06) years old. Hereditary patients constitutes 30.8% (8/26) of the total number. The proportions for bilateral and unilateral cataracts were 88.5% (23/26) and 11.5% (3/26) respectively, and 49 eyes suffering from both congenital aniridia and cataract were therefore included in the final analysis. The most common morphology cataract subtypes were lamellar cataract (24.5%, 12/49), posterior subcapsular cataract (22.4%, 11/49), and total cataract (18.4%,9/49). The observed ocular comorbidities included nystagmus (36.7%, 18/49), vitreous opacity (28.6%, 14/49), foveal hypoplasia (20.4%, 10/49), ametropia (12.2%, 6/49), exotropia (12.2%, 6/49), congenital glaucoma (12.2%, 6/49), esotropia (4.1%, 2/49), congenital ptosis (4.1%, 2/49), lens ectopia (4.1%, 2/49), scleral staphyloma (2.0%, 1/49) and pigmentary degeneration of retina (2.0%, 1/49). 30.6% (15/49) eyes were performed the cataract extraction surgery. The percentage of postoperative best corrected visual acuity (BCVA) for ≥0.1 and ≥0.3 were 93.3% (14/15) and 20.0% (3/15) respectively. Evaluated ocular pressure (33.3%, 5/15), severe posterior capsular opacification (PCO) (13.3%, 2/15) and choroidal hemorrhage combined with choroidal detachment (6.7%, 1/15) were detected as the postoperative complications. Followed by cataract extraction, 80.0% (12/15) eyes were sequentially performed the intraocular lens implantation, while, 20.0% (3/12) eyes remained aphakia due to ocular comorbidities. Conclusions: Congenital aniridia combined with cataract are rare diseases, calling for the precious retrospective researches. This disorder tended to affect both eyes and occurred hereditary. The clinical courses of the cases presented progressive features. Ocular comorbidities were the crucial factors to influence the surgical approaches and postoperative prognosis. (Chin J Ophthalmol, 2017, 53: 821-827).

Suppression of lentivirus-mediated transgenic dendritic cells in graft-versus-host disease after allogeneic bone marrow transplantation in mice.

We determined whether genetically engineered immature dendritic cells (imDCs) mediated by lentiviral vectors alleviate acute graft-versus-host disease (GVHD) after allogeneic bone marrow transplantation (allo-BMT) in mice. We introduced the mouse chemokine receptor 7 (Ccr7) gene into the bone marrow-derived imDCs of C57BL/6 mice to construct genetically engineered imDCs. A 1:1 mixture of bone marrow and spleen cells from the donors was injected into the recipients, which were divided into four groups: radiation, transplantation, empty vector, and transgenic imDC groups. Symptoms, clinical scores, GVHD pathological changes, and survival times and rates of recipients were recorded; secretion of IFN-γ and IL-4, and allogeneic chimerism rates were detected. The survival time of the transgenic imDC group (27.5 ± 7.55 days) was significantly longer than in the other three groups (P < 0.01). The GVHD score of the imDC group mice was significantly lower than in the transplantation and empty vector groups (P < 0.05), which meant that mice in the transgenic imDC group had the lightest pathology damage in the target organs. In the transplantation group, IFN-γ increased while IL-4 decreased. In contrast, IFN-γ decreased and IL-4 increased in both empty vector and trans-imDC groups, and the difference was significant in the latter (P < 0.01). Thirty days or more following transplantation, the allogeneic chimerism rate was still 95-100%, suggesting complete donor type implantation. Ccr7 transfection into imDCs suppressed occurrence and severity of acute GVHD after allo-BMT in mice; the mechanism might be associated with IFN-γ decrease and IL-4 increase.

Synergistic effects of glycated chitosan with high-intensity focused ultrasound on suppression of metastases in a syngeneic breast tumor model.

Stimulation of the host immune system is crucial in cancer treatment. In particular, nonspecific immunotherapies, when combined with other traditional therapies such as radiation and chemotherapy, may induce immunity against primary and metastatic tumors. In this study, we demonstrate that a novel, non-toxic immunoadjuvant, glycated chitosan (GC), decreases the motility and invasion of mammalian breast cancer cells in vitro and in vivo. Lung metastatic ratios were reduced in 4T1 tumor-bearing mice when intratumoral GC injection was combined with local high-intensity focused ultrasound (HIFU) treatment. We postulate that this treatment modality stimulates the host immune system to combat cancer cells, as macrophage accumulation in tumor lesions was detected after GC-HIFU treatment. In addition, plasma collected from GC-HIFU-treated tumor-bearing mice exhibited tumor-specific cytotoxicity. We also investigated the effect of GC on epithelial-mesenchymal transition-related markers. Our results showed that GC decreased the expression of Twist-1 and Slug, proto-oncogenes commonly implicated in metastasis. Epithelial-cadherin, which is regulated by these genes, was also upregulated. Taken together, our current data suggest that GC alone can reduce cancer cell motility and invasion, whereas GC-HIFU treatment can induce immune responses to suppress tumor metastasis in vivo.

Microwave torrefaction of rice straw and Pennisetum.

Microwave torrefaction of rice straw and pennisetum was researched in this article. Higher microwave power levels contributed to higher heating rate and reaction temperature, and thus produced the torrefied biomass with higher heating value and lower H/C and O/C ratios. Kinetic parameters were determined with good coefficients of determination, so the microwave torrefaction of biomass might be very close to first-order reaction. Only 150W microwave power levels and 10min processing time were needed to meet about 70% mass yield and 80% energy yield for torrefied biomass. The energy density of torrefied biomass was about 14% higher than that of raw biomass. The byproducts (liquid and gas) possessed about 30% mass and 20% energy of raw biomass, and they can be seen as energy sources for heat or electricity. Microwave torrefaction of biomass could be a competitive technology to employ the least energy and to retain the most bioenergy.

Potassium currents of olfactory bulb juxtaglomerular cells: characterization, simulation, and implications for plateau potential firing.

Odor identity is encoded by the activity of olfactory bulb glomeruli, which receive primary sensory input and transfer it to projection neurons. Juxtaglomerular cells (JGCs) may influence glomerular processing via firing of long lasting plateau potentials. Though inward currents have been investigated, little is known regarding potassium current contribution to JGC plateau potentials. We pursued study of these currents, with the overarching goal of creating components for a computational model of JGC plateau potential firing. In conditions minimizing calcium-activated potassium current (I(K(Ca))), we used whole cell voltage clamp and in vitro slice preparations to characterize three potassium currents in rat JGCs. The prominent component I(kt1) displayed rapid kinetics (τ(10%-90% rise), 0.6-2 ms; τ(inactivation), 5-10 ms) and was blocked by high concentration 4-aminopyridine (4-AP) (5 mM) and tetramethylammonium (TEA) (40 mM). It had half maximal activation at -10 mV (V(½)max) and little inactivation at rest. I(kt2), with slower kinetics (τ(10%-90% rise), 11-15 ms; τ(inactivation), 100-300 ms), was blocked by low concentration 4-AP (0.5 mM) and TEA (5 mM). The V(½)max was 0 mV and inactivation was also minimal at rest. Sustained current I(kt3) showed sensitivity to low concentration 4-AP and TEA, and had V(½)max of +10 mV. Further experiments, in conditions of physiologic calcium buffering, suggested that I(K(Ca)) contributed to I(kt3) with minimal effect on plateau potential evolution. We transformed these characterizations into Hodgkin-Huxley models that robustly mimicked experimental data. Further simulation demonstrated that I(kt1) would be most efficiently activated by plateau potential waveforms, predicting a critical role in shaping JGC firing. These studies demonstrated that JGCs possess a unique potassium current profile, with delayed rectifier (I(kt3)), atypical A-current (I(kt1)), and D-current (I(kt2)) in accordance with known expression patterns in olfactory bulb (OB) glomeruli. Our simulations also provide an initial framework for more integrative models of JGC plateau potential firing.

Calcium currents of olfactory bulb juxtaglomerular cells: profile and multiple conductance plateau potential simulation.

The olfactory glomerulus is the locus of information transfer between olfactory sensory neurons and output neurons of the olfactory bulb. Juxtaglomerular cells (JGCs) may influence intraglomerular processing by firing plateau potentials that support multiple spikes. It is unclear what inward currents mediate this firing pattern. In previous work, we characterized potassium currents of JGCs. We focus here on the inward currents using whole cell current clamp and voltage recording in a rat in vitro slice preparation, as well as computer simulation. We first showed that sodium current was not required to mediate plateau potentials. Voltage clamp characterization of calcium current (I(Ca)) determined that I(Ca) consisted of a slow activating, rapidly inactivating (τ(10%-90% rise) 6-8 ms, τ(inactivation) 38-77 ms) component I(cat1), similar to T-type currents, and a sustained (τ(inactivation)>>500 ms) component I(cat2), likely composed of L-type and P/Q-type currents. We used computer simulation to test their roles in plateau potential firing. We robustly modeled I(cat1) and I(cat2) to Hodgkin-Huxley schemes (m(3)h and m(2), respectively) and simulated a JGC plateau potential with six conductances: calcium currents as above, potassium currents from our prior study (A-type I(kt1), D-type I(kt2), delayed rectifier I(kt3)), and a fast sodium current (I(Na)). We demonstrated that I(cat1) was required for mediating the plateau potential, unlike I(Na) and I(cat2), and its τ(inactivation) determined plateau duration. We also found that I(kt1) dictated plateau potential shape more than I(kt2) and I(kt3). The influence of these two transient and opposing conductances suggests a unique mechanism of plateau potential physiology.

Host antitumour immune responses to HIFU ablation.

The ideal cancer therapy not only induces the death of all localized tumour cells without damage to surrounding normal tissue, but also activates a systemic antitumour immunity. High-intensity focused ultrasound (HIFU) has the potential to be such a treatment, as it can non-invasively ablate a targeted tumour below the skin surface, and may subsequently augment host antitumour immunity. In addition to thermal and cavitation effects, which act directly and locally on the tumour, there is increasing evidence linking systemic anti-tumour immune response to HIFU ablation. This may provide micro-metastatic control and long-term tumour resistance for cancer patients. The goal of this article is to review the emerging pre-clinical and clinical results suggesting that HIFU ablation may enhance host anti-tumour immunity, and to discuss its potential mechanisms. It is concluded that the systemic immune response induced by thermal ablation may play an important role in local recurrence and metastasis control after HIFU treatment.

In situ photoimmunotherapy: a tumour-directed treatment for melanoma.

We report a new immunological treatment for advanced cutaneous melanoma which combines laser stimulation with topical application of a toll-like receptor agonist. This treatment, in situ photoimmunotherapy (ISPI), provides an alternative to traditional therapies for melanoma patients with cutaneous metastases. A 6-week cycle of ISPI is carried out on cutaneous metastases located in a designated 20 x 20 cm treatment area: 2 weeks of pretreatment with twice-daily topical applications of imiquimod (5% cream under plastic occlusion), with a laser treatment session at week 2 and again at week 4. Topical imiquimod is continued for the entire 6-week cycle. Two patients with late-stage melanoma were treated with ISPI. Patient 1 had the primary tumour and local metastases on the left arm, as well as metastatic tumours in the lungs [American Joint Committee on Cancer (AJCC) stage IV]. Patient 2 had a head and neck melanoma with multiple local metastases (AJCC stage IIIC), which had failed repeated attempts at surgical resection and high-dose radiation therapy. Patient 1 is now free of all clinically detectable tumours (including the lung metastases) >20 months after the first treatment cycle. Patient 2 has been free of any clinical evidence of the tumour for over 6 months. These two cases demonstrate that ISPI can clear local tumour and trigger beneficial systemic responses, with a side-effect profile that compares favourably with other treatments for advanced melanoma.

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 degrees 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.

Observation of a re-entrant kinetic glass transition in a micellar system with temperature-dependent attractive interaction.

We detect in a tri-block co-polymer micellar system an ergodic-to-nonergodic-to-ergodic transition, as a function of temperature, in a range of concentrations, by photon correlation measurements. The shear viscosity is also shown to jump two order of magnitude at these transition temperatures. Surprisingly, the structure factor as measured by small angle neutron scattering shows a marked narrowing at the structural arrest state. Rationalization of these results with the existence of an attractive branch in the phase diagram of an attractive colloid system predicted by mode coupling theory is made.

Localization error analysis for stereo X-ray image guidance with probability method.

The mean value and standard deviation of localization error for the stereo imaging systems are derived based on probability theory. Compared with the maximum error analysis method used in our previous study, the new approach yields more informative and precise results as the guidance for X-ray imaging system design and protocol optimization. The prototype for our current study is a CCD based monoplane digital stereo X-ray imaging system. The imaging model consists of two X-ray sources and one detector plane. With perspective geometry, the least-square solution is derived to reconstruct 3-dimensional object points, such as a biopsy needle tip, from a pair of 2-dimensional digital radiographs. Under the conditions of our specific prototype, the measurement errors of interested points in the radiographs are modeled as random variables with Gaussian distribution. Such variables account for finite image system noise and positioning errors. Then, the 3D localization error, in terms of mean value and standard deviation, is formulated using measurement error, feature point location, and separation between the two X-ray sources and distance from source to detector. Both theoretical analysis and numerical simulation are performed. The mean value and standard deviation of the localization error are first evaluated using numerical simulation under practical imaging conditions. Then, the error estimates are given in simply analytic forms. Simulation and theoretical results are in excellent agreement. The results show that our prototype X-ray stereological imaging system is accurate and reliable to locate feature points in 3D for medical intervention. Imaging protocols can be effectively optimized through the 3D localization error analysis using the approximate formulas proposed in this study.

Serial changes of cardiac troponin-I in acute myoischemia induced by exercise treadmill test.

Cardiac troponin-I (cTn-I) is a sensitive and specific marker for the diagnosis of acute myocardial infarction (AMI). However, elevation of serum cTn-I has been observed in some unstable angina patients who have a worse prognosis than those with normal serum cTn-I levels. It is unknown whether serum cTn-I can elevate in stable angina patients with acute ischemic burden. Therefore, the purpose of this study was to determine a serial change of cTn-I in patients with acute ischemia induced by a treadmill exercise test. Thirty-five patients suspected of having coronary artery disease and five healthy medical students were enrolled into this study. Every patient received a treadmill exercise test. Cardiac troponin-I was measured by fluorescent immunoassay before the treadmill test and at 5 minutes, 1 hour, 3 hours, and 6 hours after the treadmill test. Patients with cTn-I levels of less than 0.5 ng/ml were considered normal, and those with cTn-I levels of greater than 2.0 ng/ml was considered to have AMI. The exercise test was positive in 19 of the 35 patients and negative in 16 of the 35 patients and 5 medical students. Among the 19 patients with positive treadmill exercise test, the cTn-I concentrations were abnormally increased in 7/19 (37%) patients (mean: 1.1 +/- 0.4 ng/ml; range: 0.5 to 2.0 ng/ml). One of the 16 patients with negative treadmill test showed an increase of serum cTn-I. Normal cTn-I levels were found in the other 15 patients and the 5 medical students. In conclusion, serum cTn-I levels were found to increase to some extent in one third of stable angina patients who have an acute ischemic episode induced by treadmill exercise test.

Antitumor immunity induced by laser immunotherapy and its adoptive transfer.

The ideal cancer treatment modality should not only cause tumor regression and eradication but also induce a systemic antitumor immunity, which is essential for control of metastatic tumors and for long-term tumor resistance. Laser immunotherapy using a laser, a laser-absorbing dye, and an immunoadjuvant has induced such long-term immunity in treatment of a mammary metastatic tumor. The successfully treated rats established total resistance to multiple subsequent tumor challenges. To further study the mechanisms of the antitumor immunity induced by this novel treatment modality, passive adoptive transfer was performed using splenocytes as immune cells. The spleen cells that were harvested from successfully treated tumor-bearing rats provided 100% immunity in the naive recipients. The passively protected first cohort rats were immune to tumor challenge with an increased tumor dose; their splenocytes also prevented the establishment of tumor in the second cohort of naive recipient rats. This immunity transfer was accomplished without the usually required T-cell suppression in recipients.

Serum antioxidant status of civil aircrew.

Objective. To study the serum antioxidant status in civil aircrew members who had more than 4000 h of cumulative flight hours, therefore exposed to a higher dose of cosmic radiation comparing to the dose received by ground residents. Method. Differences in the serum levels of total antioxidant capacity (TAOC), superoxide dismutase (SOD) and malondialdehyde (MDA) were investigated in 230 crew members, 37 local ground residents in Xinjiang, and 37 ground residents in Tianjin. Result. Significantly higher levels of all the three serum indexes were found in civil aircrew members. Serum levels of TAOC and SOD were higher in Xinjiang than in Tianjin ground residents, although no difference was found for MDA. Positive correlations were observed among the three serum indexes in this study. Conclusion. The elevated serum level of MDA in civil aircrew members deserves a proper attention by health care policy makers.

Position-dependent image characteristics of a CCD-based full-field digital mammography system.

Full-field digital mammography imaging systems have been investigated extensively. However, most investigations focus on the quality assessment of the entire image. In this article, we present the results of experimental measurements on the position-dependent image characteristics of a CCD array-based digital imaging system. Objective image quality parameters such as noise power spectrum (NPS) and signal-to-noise ratio (SNR), which are also frequency-dependent, are employed for this investigation. The image detector uses 12 CCDs arranged in a 4 × 3 array to cover a field of 18 cm × 24 cm with a single x-ray exposure. Totally 18 sub-areas were chosen as the regions-of-interest (ROIs) for each full-field image to study position-dependent characteristics. Our experimental results indicate that the image quality at different positions of the full-field image exhibit slightly variance due to the characteristic diversity of the CCDs and due to the oblique angle of the ROIs to the x-ray source. The image seams caused by the physical gaps between adjacent CCDs do not increase the noise components significantly to the composite full-field image. The x-ray energy-dependence of NPS and SNR was also studied.

Lens distortion in optically coupled digital x-ray imaging.

UNLABELLED: The objectives of this research are to analyze geometrical distortions introduced by relay lenses in optically coupled digital x-ray imaging systems and to introduce an algorithm to correct such distortions. METHODS: The radial and tangential errors introduced by a relay lens in digital x-ray imaging were experimentally measured, using a lens-coupled CCD (charge coupled device) prototype. An algorithm was introduced to correct these distortions. Based on an x-ray image of a standard calibration grid, the algorithm first identified the location of the optical axis, then corrected the radial and tangential distortions using polynomial transformation technique. RESULTS: Lens distortions were classified and both radial and tangential distortions introduced by lenses were corrected using polynomial transformation. For the specific lens-CCD prototype investigated, the mean positional error caused by the relay lens was reduced by the correction algorithm from about eight pixels (0.69 mm) to less than 1.8 pixels (0.15 mm). Our investigation also shows that the fourth order of polynomial for the correction algorithm provided the best correction result. CONCLUSIONS: Lens distortions should be considered in position-dependent, quantitative x-ray imaging and such distortions can be minimized in CCD x-ray imaging by appropriate algorithm, as demonstrated in this paper.