Sung Sook Lee

HO-1 and JAK-2/STAT-1 signals are involved in preferential inhibition of iNOS over COX-2 gene expression by newly synthesized tetrahydroisoquinoline alkaloid, CKD712, in cells activated with lipopolysacchride

We found that CKD712, an S enantiomer of YS49, strongly inhibited inducible nitric oxide synthase (iNOS) and NO induction but showed a weak inhibitory effect on cyclooxygenase-2 (COX-2) and PGE(2) induction in LPS-stimulated RAW 264.7 cells. We, therefore, investigated the molecular mechanism(s) responsible for this by using CKD712 in LPS-activated RAW264.7 cells. Treatment with either SP600125, a specific JNK inhibitor or TPCK, a NF-kappaB inhibitor, but neither ERK inhibitor PD98059 nor p38 inhibitor SB203580, significantly inhibited LPS-mediated iNOS and COX-2 induction. CKD712 inhibited NF-kappaB (p65) activity and translocation but failed to prevent JNK activation. However, AG490, a specific JAK-2/STAT-1 inhibitor, efficiently prevented LPS-mediated iNOS induction but not the induction of COX-2, and CKD712 completely blocked STAT-1 phosphorylation by LPS, suggesting that the NF-kappaB and JAK-2/STAT-1 pathways but not the JNK pathway are important for CKD712 action. Interestingly, CKD712 induced heme oxygenase 1 (HO-1) gene expression in LPS-treated cells. LPS-induced NF-kappaB and STAT-1 activation was partially prevented by HO-1 overexpression. Furthermore, HO-1 siRNA partly reversed not only the LPS-induced NF-kappaB activation and STAT-1 phosphorylation but also inhibition of these actions by CKD 712. Additionally, silencing HO-1 by siRNA prevented CKD712 from inhibiting iNOS expression but not COX-2. When examined plasma NO and PGE(2) levels and iNOS and COX-2 protein levels in lung tissues of mice injected with LPS (10 mg/kg), pretreatment with CKD712 greatly prevented NO and iNOS induction in a dose-dependent manner and slightly affected PGE(2) and COX-2 production as expected. Taken together, we conclude that inhibition of JAK-2/STAT-1 pathways by CKD 712 is critical for the differential inhibition of iNOS and COX-2 by LPS in vitro and in vivo where HO-1 induction also contributes to this by partially modulating JAK-2/STAT-1 pathways.

Effects of the anti-sepsis drug, (S)-1-(α-naphthylmethyl)-6,7-dihydroxy-1,2,3,4-tetrahydroisoquinoline (CKD-712), on mortality, inflammation, and organ injuries in rodent sepsis models

CKD-712 is a 1-naphthyl analog of higenamine that has been reported to have potent antiinflammatory and thus anti-sepsis effects. The purpose of this study was to investigate the potential of CKD-712 as a medicine for sepsis and to confirm its protective effects on organs in animal sepsis models. Pretreatment with CKD-712 dose-dependently increased survival rate in a lipopolysaccharide-induced sepsis model in mice. Body temperature decrease, an important pre-symptom of septic death, was also prevented by CKD-712. CKD-712 still significantly increased survival rate even when administered one and four hours after lipopolysaccharide injection. Therapeutic efficacy of CKD-712 was also confirmed against sepsis following zymosan-induced endotoxemia and in cecal ligation and puncture surgery in mice. In a disseminated intravascular coagulation model in rats, CKD-712 showed organ-protective effect by reducing serum glutamate-oxaloacetate transaminase, glutamate-pyruvate transferase, blood urea nitrogen, and creatinine levels. CKD-712 also prevented histological damage to the lung and liver. In this same model, CKD-712 showed anti-inflammatory effects through decreases in tumor necrosis factor-α and interleukin-6 in the blood and reduced translocation of nuclear factor-κB to the nuclei of lung cells. CKD-712 administration also diminished infiltration of leukocytes into the lung and liver. Taken together, these results show that CKD-712 has excellent potential as an effective medicine for sepsis.

CKD-712, (S)-1-(α-naphthylmethyl)-6,7-dihydroxy-1,2,3,4-tetrahydroisoquinoline, Inhibits the NF-κB Activation and Augments Akt Activation during TLR4 Signaling

Since CKD-712 has been developed as an anti-inflammatory agent, we examined the effect of CKD-712 during TLR4 signaling. Using HEK293 cells expressing TLR4, CKD-712 was pre-treated 1 hr before LPS stimulation. Activation of NF-κB was assessed by promoter assay. The activation of ERK, JNK, p38, IRF3 and Akt was measured by western blotting. CKD-712 inhibited the NF-κB signaling triggered by LPS. The activation of ERK, JNK, p38 or IRF3 was not inhibited by CKD-712. On the contrary the activation of these molecules was augmented slightly. The activation of Akt with stimulation of LPS was also enhanced with CKD-712 pre-treatment at lower concentration, but was inhibited at higher concentration. We suggest that during TLR4 signaling CKD-712 inhibits NF-κB activation. However, CKD-712 augmented the activation of Akt as well as Map kinases. Therefore, we suggest that CKD-712 might have a role as an immunomodulator.

SU-G-BRB-01: A Novel 3D Printed Patient-Specific Phantom for Spine SBRT Quality Assurance: Comparison of 3D Printing Techniques

PURPOSE The novel 3 dimensional (3D)-printed spine quality assurance (QA) phantoms generated by two different 3D-printing technologies, digital light processing (DLP) and Polyjet, were developed and evaluated for spine stereotactic body radiation treatment (SBRT). METHODS The developed 3D-printed spine QA phantom consisted of an acrylic body and a 3D-printed spine phantom. DLP and Polyjet 3D printers using the high-density acrylic polymer were employed to produce spine-shaped phantoms based on CT images. To verify dosimetric effects, the novel phantom was made it enable to insert films between each slabs of acrylic body phantom. Also, for measuring internal dose of spine, 3D-printed spine phantom was designed as divided laterally exactly in half. Image fusion was performed to evaluate the reproducibility of our phantom, and the Hounsfield unit (HU) was measured based on each CT image. Intensity-modulated radiotherapy plans to deliver a fraction of a 16 Gy dose to a planning target volume (PTV) based on the two 3D-printing techniques were compared for target coverage and normal organ-sparing. RESULTS Image fusion demonstrated good reproducibility of the fabricated spine QA phantom. The HU values of the DLP- and Polyjet-printed spine vertebrae differed by 54.3 on average. The PTV Dmax dose for the DLP-generated phantom was about 1.488 Gy higher than for the Polyjet-generated phantom. The organs at risk received a lower dose when the DLP technique was used than when the Polyjet technique was used. CONCLUSION This study confirmed that a novel 3D-printed phantom mimicking a high-density organ can be created based on CT images, and that a developed 3D-printed spine phantom could be utilized in patient-specific QA for SBRT. Despite using the same main material, DLP and Polyjet yielded different HU values. Therefore, the printing technique and materials must be carefully chosen in order to accurately produce a patient-specific QA phantom.

SU-E-T-647: Quality Assurance of VMAT by Gamma Analysis Dependence On Low-Dose Threshold

Purpose: The AAPM TG-119 instructed institutions to use low-dose threshold (LDT) of 10% or a ROI determined by the jaw when they collected gamma analysis QA data of planar dose distribution. Also, based on a survey by Nelms and Simon, more than 70% of institutions use a LDT between 0% and 10% for gamma analysis. However, there are no clinical data to quantitatively demonstrate the impact of the LDT on the gamma index. Therefore, we performed a gamma analysis with LDTs of 0% to 15% according to both global and local normalization and different acceptance criteria: 3%/3 mm, 2%/2 mm, and 1%/1 mm. Methods: A total of 30 treatment plans—10 head and neck, 10 brain, and 10 prostate cancer cases—were randomly selected from the Varian Eclipse TPS, retrospectively. For the gamma analysis, a predicted portal image was acquired through a portal dose calculation algorithm in the Eclipse TPS, and a measured portal image was obtained using a Varian Clinac iX and an EPID. Then, the gamma analysis was performed using the Portal Dosimetry software. Results: For the global normalization, the gamma passing rate (%GP) decreased as the LDT increased, and all cases of low-dose thresholds exhibited a %GP above 95% for both the 3%/3 mm and 2%/2 mm criteria. However, for local normalization, the %GP increased as LDT increased. The gamma passing rate with LDT of 10% increased by 6.86%, 9.22% and 6.14% compared with the 0% in the case of the head and neck, brain and prostate for 3%/3 mm criteria, respectively. Conclusion: Applying the LDT in the global normalization does not have critical impact to judge patient-specific QA results. However, LDT for the local normalization should be carefully selected because applying the LDT could affect the average of the %GP to increase rapidly.

SU-E-T-160: Evaluation of Accuracy for Target Margin Size Obtained From CBCT On Lung SBRT Based On Film Dosimetry

PURPOSE To analysis delivered dose on target using gafchromic films for evaluating accuracy of target margin size obtained from cone beam computed tomography (CBCT) during lung stereotactic body radiation therapy (SBRT) METHODS: The phantom consists of measurement part and driving part. The motor of Quasar motion phantom (Modus Medical Devices Inc, London, ON, Canada) was used for driving part and we developed measurement part which consist of cork cylindrical body and acrylic target with radiochromic film inserted into central and both ends of acrylic target. In this study lung SBRT cases through both four dimensional computed tomography (4DCT) and CBCT were selected. Target contouring including margin based on 4DCT is defined with a 1 cm margin around gross tumor volume (GTV) in all directions except for inferior direction. The moving range in inferior direction was larger than other directions thus, including 2 cm margin. In case of CBCT, the margin means blurring of target on CBCT images. This study was compared margin size determined through 4DCT and that of based on CBCT and we also evaluated dose profile and the length of margin in superior-inferior direction on CBCT compared with 4DCT. RESULTS The length of target including margin was 2.48 cm (based on CBCT) and 2.66 cm (based on 4DCT), respectively in superior-inferior direction. The difference of delivered dose on target between two margins was only within 1%. CONCLUSIONS This study has shown the feasibility of determining target margin using CBCT for delivering more accurate prescription dose to lung cancer.

SU-E-J-33: Cardiac Movement in Deep Inspiration Breath-Hold for Left-Breast Cancer Radiotherapy

PURPOSE The present study was designed to investigate the displacement of heart using Deep Inspiration Breath Hold (DIBH) CT data compared to free-breathing (FB) CT data and radiation exposure to heart. METHODS Treatment planning was performed on the computed tomography (CT) datasets of 20 patients who had received lumpectomy treatments. Heart, lung and both breasts were outlined. The prescribed dose was 50 Gy divided into 28 fractions. The dose distributions in all the plans were required to fulfill the International Commission on Radiation Units and Measurement specifications that include 100% coverage of the CTV with ≥ 95% of the prescribed dose and that the volume inside the CTV receiving > 107% of the prescribed dose should be minimized. Displacement of heart was measured by calculating the distance between center of heart and left breast. For the evaluation of radiation dose to heart, minimum, maximum and mean dose to heart were calculated. RESULTS The maximum and minimum left-right (LR) displacements of heart were 8.9 mm and 3 mm, respectively. The heart moved > 4 mm in the LR direction in 17 of the 20 patients. The distances between the heart and left breast ranged from 8.02-17.68 mm (mean, 12.23 mm) and 7.85-12.98 mm (mean, 8.97 mm) with DIBH CT and FB CT, respectively. The maximum doses to the heart were 3115 cGy and 4652 cGy for the DIBH and FB CT dataset, respectively. CONCLUSION The present study has demonstrated that the DIBH technique could help to reduce the risk of radiation dose-induced cardiac toxicity by using movement of cardiac; away from radiation field. The DIBH technique could be used in an actual treatment room for a few minutes and could effectively reduce the cardiac dose when used with a sub-device or image acquisition standard to maintain consistent respiratory motion.

SU-E-J-71: Feasibility Study On MRI-Based BANG3 Gel Dosimetry Using Dual-Source Parallel RF Transmission System

PURPOSE In this work, we present the feasibility of use of the parallel RF transmission with multiple RF source (MultiTransmit) imaging in MRI-based polymer gel dosimetry. METHODS The commercially available BANG3 gel was used for gel dosimetry. Spin-spin relaxation rate R2 was used to quantify the absorbed dose. The image quality (signal-to-noise ratio, SNR; image uniformity) and B1 field inhomogeneity between conventional single-source and MultiTransmit MR imaging were compared. Finally, the estimated R2 uncertainty σ(R2) and dosimetric performance (i.e., dose resolution) between conventional single-source and MultiTransmit MR imaging were compared. RESULTS Image quality and B1 field homogeneity within each calibration vial and large phantom was statistically better in MultiTransmit imaging than in conventional single-source RF transmission imaging (P < 0.005 for all calibration vials). In particular, σ(R2) (defined as the standard uncertainty of R2) was lower on the MultiTransmit images than on the conventional single-source images. Furthermore, the MultiTransmit measurement gives a lower than that obtained using the conventional single-source method. CONCLUSION The improved image quality and B1 homogeneity resulted in reduced dose uncertainty (i.e., σ(R2) and dose resolution) in MRI-based polymer gel dosimetry, suggesting that MultiTransmit MR imaging has potential benefits for use in clinical 3D gel dosimetry without the need for the complicated B1 field correction method.

SU-E-J-58: Dosimetric Verification of Metal Artifact Effects: Comparison of Dose Distributions Affected by Patient Teeth and Implants.

PURPOSE Implant-supported dentures seem particularly appropriate for the predicament of becoming edentulous and cancer patients are no exceptions. As the number of people having dental implants increased in different ages, critical dosimetric verification of metal artifact effects are required for the more accurate head and neck radiation therapy. The purpose of this study is to verify the theoretical analysis of the metal(streak and dark) artifact, and to evaluate dosimetric effect which cause by dental implants in CT images of patients with the patient teeth and implants inserted humanoid phantom. METHODS The phantom comprises cylinder which is shaped to simulate the anatomical structures of a human head and neck. Through applying various clinical cases, made phantom which is closely allied to human. Developed phantom can verify two classes: (i)closed mouth (ii)opened mouth. RapidArc plans of 4 cases were created in the Eclipse planning system. Total dose of 2000 cGy in 10 fractions is prescribed to the whole planning target volume (PTV) using 6MV photon beams. Acuros XB (AXB) advanced dose calculation algorithm, Analytical Anisotropic Algorithm (AAA) and progressive resolution optimizer were used in dose optimization and calculation. RESULTS In closed and opened mouth phantom, because dark artifacts formed extensively around the metal implants, dose variation was relatively higher than that of streak artifacts. As the PTV was delineated on the dark regions or large streak artifact regions, maximum 7.8% dose error and average 3.2% difference was observed. The averaged minimum dose to the PTV predicted by AAA was about 5.6% higher and OARs doses are also 5.2% higher compared to AXB. CONCLUSION The results of this study showed that AXB dose calculation involving high-density materials is more accurate than AAA calculation, and AXB was superior to AAA in dose predictions beyond dark artifact/air cavity portion when compared against the measurements.

SU‐E‐T‐296: Optimization of the Energy Selection System with Varying Magnetic Field for Laser‐Accelerated Proton Beams

PURPOSE Laser-based accelerated proton beams are unsuitable for clinical use because of their broad energy spectra. For this reason, it is essential to employ an energy selection system (ESS). The purpose of this study is to determine optimum parameters of the ESS which uses a varying magnetic field to generate Bragg-peak. METHODS We simulated an accelerated proton beams using radiation pressure acceleration mechanism with carbon-proton mixture target. The density ratio (n = 6) between the protons and the carbon ions is one of optimization parameters in determining the accelerating mechanisms. The ESS was implemented by the Geant4 Monte Carlo toolkit. In order to optimize the hole size and position of the energy selection collimator, and magnetic field at ESS, these parameters were simulated for acquiring energy and dose distributions by changing each values. RESULTS The proton energy distributions had a poly-energetic distribution after passing through the ESS. As the magnetic field was increased, the mean energy of the proton beams also was increased. Also as the hole size was increased, the energy bandwidth of proton passed through the ESS was increased. The hole size and position of the energy selection collimator were effectively optimized to 2 cm and 5 cm from the z-axis, respectively. CONCLUSIONS We simulated laser-accelerated proton beams using ESS for generation of Bragg-peak. Our results suggest that the ESS with magnetic field variation can effectively generate a Bragg-peak suitable for use in proton radiation therapy. Our ESS can be applied to pencil beam scanning proton therapy.