Journal of Medical Physics / Association of Medical Physicists of India最新文献_第2页

Respiratory gated radiotherapy-pretreatment patient specific quality assurance 呼吸门控放射治疗预处理患者特异性质量保证

Journal of Medical Physics / Association of Medical Physicists of India Pub Date : 2016-01-01 DOI: 10.4103/0971-6203.177279

R. Thiyagarajan, SujitNath Sinha, R. Ravichandran, K. Samuvel, G. Yadav, Ashokkumar Sigamani, Vikraman Subramani, Arunai Nambiraj

{"title":"Respiratory gated radiotherapy-pretreatment patient specific quality assurance","authors":"R. Thiyagarajan, SujitNath Sinha, R. Ravichandran, K. Samuvel, G. Yadav, Ashokkumar Sigamani, Vikraman Subramani, Arunai Nambiraj","doi":"10.4103/0971-6203.177279","DOIUrl":"https://doi.org/10.4103/0971-6203.177279","url":null,"abstract":"Organ motions during inter-fraction and intra-fraction radiotherapy introduce errors in dose delivery, irradiating excess of normal tissue, and missing target volume. Lung and heart involuntary motions cause above inaccuracies and gated dose delivery try to overcome above effects. Present work attempts a novel method to verify dynamic dose delivery using a four-dimensional (4D) phantom. Three patients with mobile target are coached to maintain regular and reproducible breathing pattern. Appropriate intensity projection image set generated from 4D-computed tomography (4D-CT) is used for target delineation. Intensity modulated radiotherapy plans were generated on selected phase using CT simulator (Siemens AG, Germany) in conjunction with \"Real-time position management\" (Varian, USA) to acquire 4D-CT images. Verification plans were generated for both ion chamber and Gafchromic (EBT) film image sets. Gated verification plans were delivered on the phantom moving with patient respiratory pattern. We developed a MATLAB-based software to generate maximum intensity projection, minimum intensity projections, and average intensity projections, also a program to convert patient breathing pattern to phantom compatible format. Dynamic thorax quality assurance (QA) phantom (Computerized Imaging Reference Systems type) is used to perform the patient specific QA, which holds an ion chamber and film to measure delivered radiation intensity. Exposed EBT films are analyzed and compared with treatment planning system calculated dose. The ion chamber measured dose shows good agreement with planned dose within ± 0.5% (0.203 ± 0.57%). Gamma value evaluated from EBT film shows passing rates 92–99% (96.63 ± 3.84%) for 3% dose and 3 mm distance criteria. Respiratory gated treatment delivery accuracy is found to be within clinically acceptable level.","PeriodicalId":143694,"journal":{"name":"Journal of Medical Physics / Association of Medical Physicists of India","volume":"4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127689506","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 10

Computed tomography imaging parameters for inhomogeneity correction in radiation treatment planning 放射治疗计划中不均匀性校正的计算机断层成像参数

Journal of Medical Physics / Association of Medical Physicists of India Pub Date : 2016-01-01 DOI: 10.4103/0971-6203.177277

I. Das, Chee-Wai Cheng, M. Cao, P. Johnstone

{"title":"Computed tomography imaging parameters for inhomogeneity correction in radiation treatment planning","authors":"I. Das, Chee-Wai Cheng, M. Cao, P. Johnstone","doi":"10.4103/0971-6203.177277","DOIUrl":"https://doi.org/10.4103/0971-6203.177277","url":null,"abstract":"Modern treatment planning systems provide accurate dosimetry in heterogeneous media (such as a patient' body) with the help of tissue characterization based on computed tomography (CT) number. However, CT number depends on the type of scanner, tube voltage, field of view (FOV), reconstruction algorithm including artifact reduction and processing filters. The impact of these parameters on CT to electron density (ED) conversion had been subject of investigation for treatment planning in various clinical situations. This is usually performed with a tissue characterization phantom with various density plugs acquired with different tube voltages (kilovoltage peak), FOV reconstruction and different scanners to generate CT number to ED tables. This article provides an overview of inhomogeneity correction in the context of CT scanning and a new evaluation tool, difference volume dose-volume histogram (DVH), dV-DVH. It has been concluded that scanner and CT parameters are important for tissue characterizations, but changes in ED are minimal and only pronounced for higher density materials. For lungs, changes in CT number are minimal among scanners and CT parameters. Dosimetric differences for lung and prostate cases are usually insignificant (<2%) in three-dimensional conformal radiation therapy and < 5% for intensity-modulated radiation therapy (IMRT) with CT parameters. It could be concluded that CT number variability is dependent on acquisition parameters, but its dosimetric impact is pronounced only in high-density media and possibly in IMRT. In view of such small dosimetric changes in low-density medium, the acquisition of additional CT data for financially difficult clinics and countries may not be warranted.","PeriodicalId":143694,"journal":{"name":"Journal of Medical Physics / Association of Medical Physicists of India","volume":"450 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128024181","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 34

Ten years of online publication of Journal of Medical Physics 《医学物理杂志》在线出版十年

Journal of Medical Physics / Association of Medical Physicists of India Pub Date : 2016-01-01 DOI: 10.4103/0971-6203.177276

A. Pradhan

引用次数: 1

Reply to the comments on “Setup error analysis in helical tomotherapy based image-guided radiation therapy treatments” by Slav Yartsev 回复Slav Yartsev关于“基于图像引导的螺旋断层治疗中的设置误差分析”的评论

Journal of Medical Physics / Association of Medical Physicists of India Pub Date : 2016-01-01 DOI: 10.4103/0971-6203.177282

Bhagyalakshmi Akkavil Thondykandy, J. Swamidas, J. Agarwal, T. Gupta, S. Laskar, U. Mahantshetty, S. Iyer, Indrani U. Mukherjee, S. Shrivastava, D. Deshpande

{"title":"Reply to the comments on “Setup error analysis in helical tomotherapy based image-guided radiation therapy treatments” by Slav Yartsev","authors":"Bhagyalakshmi Akkavil Thondykandy, J. Swamidas, J. Agarwal, T. Gupta, S. Laskar, U. Mahantshetty, S. Iyer, Indrani U. Mukherjee, S. Shrivastava, D. Deshpande","doi":"10.4103/0971-6203.177282","DOIUrl":"https://doi.org/10.4103/0971-6203.177282","url":null,"abstract":"Sir,The aim of our study was to assess the patient setup errors for various tumor sites based on clinical data treated with helical tomotherapy using pretreatment image guidance (IG) based on the institutional practice. In addition, we also calculated and compared the planning target volume (PTV) margins for all disease sites based on the analysis of systematic and random errors. The motivation of this study was to analyze our institution’s specific setup errors considering the fact that setup errors vary according to each immobilization system and patient which in turn influence the PTV margins. We have divided the tumor sites into various categories as brain, head and neck, thorax - abdomen, pelvis, and craniospinal irradiation. Planning computed tomography (CT) images were obtained on lightSpeed Xtra (GE Health care Pvt Limited , India.) with a slice thickness of 3 mm for all the disease sites as per the protocol. For thorax and abdominal tumors, four-dimensional CT scans were obtained, from which internal target volume was generated for planning purposes. studies which is our results. we agree fast CT studies for planning may be suboptimal for IG purposes, and untagged average studies may be used.","PeriodicalId":143694,"journal":{"name":"Journal of Medical Physics / Association of Medical Physicists of India","volume":"16 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127612683","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Comparison of computed tomography dose index in polymethyl methacrylate and nylon dosimetry phantoms 计算机断层扫描剂量指数在聚甲基丙烯酸甲酯和尼龙剂量学模型中的比较

Journal of Medical Physics / Association of Medical Physicists of India Pub Date : 2016-01-01 DOI: 10.4103/0971-6203.177287

S. Sookpeng, P. Cheebsumon, T. Pengpan, Colin J. Martin

{"title":"Comparison of computed tomography dose index in polymethyl methacrylate and nylon dosimetry phantoms","authors":"S. Sookpeng, P. Cheebsumon, T. Pengpan, Colin J. Martin","doi":"10.4103/0971-6203.177287","DOIUrl":"https://doi.org/10.4103/0971-6203.177287","url":null,"abstract":"The use of computed tomography (CT) scanning has been growing steadily. Therefore, CT dose measurement is becoming increasingly important for patient protection and optimization. A phantom is an important tool for dose measurement. This paper focuses on the evaluation of a CT dosimetry phantom made from nylon, instead of the standard polymethyl methacrylate (PMMA), which is not readily available or is too expensive in some countries. Comparison between phantoms made from the two materials is made in terms of measurements of the CT dose indices (CTDI). These were measured for four different beam widths and kVp settings at the center and periphery in head and body phantoms made from both materials and weighted CTDIs (CTDIw) were calculated. CT numbers along the z-axis of the phantom were also measured at the center and four peripheral positions of each scanned slice to check phantom homogeneity. Results showed that values for the CTDIw measured in the nylon phantoms were slightly higher than those from the PMMA while CT numbers for nylon were lower than those of PMMA. This is because the mass attenuation coefficient of the nylon is higher. Nylon could be used as a substitute material for CT dosimetry phantom to enable measurements and adjustment factors are given which could be used to estimate PMMA values for making comparisons with displayed values.","PeriodicalId":143694,"journal":{"name":"Journal of Medical Physics / Association of Medical Physicists of India","volume":"349 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122868392","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 7

Application of Chang's attenuation correction technique for single-photon emission computed tomography partial angle acquisition of Jaszczak phantom 张氏衰减校正技术在Jaszczak幻体单光子发射计算机断层局部角度采集中的应用

Journal of Medical Physics / Association of Medical Physicists of India Pub Date : 2016-01-01 DOI: 10.4103/0971-6203.177278

K. Saha, S. Hoyt, B. Murray

{"title":"Application of Chang's attenuation correction technique for single-photon emission computed tomography partial angle acquisition of Jaszczak phantom","authors":"K. Saha, S. Hoyt, B. Murray","doi":"10.4103/0971-6203.177278","DOIUrl":"https://doi.org/10.4103/0971-6203.177278","url":null,"abstract":"The acquisition and processing of the Jaszczak phantom is a recommended test by the American College of Radiology for evaluation of gamma camera system performance. To produce the reconstructed phantom image for quality evaluation, attenuation correction is applied. The attenuation of counts originating from the center of the phantom is greater than that originating from the periphery of the phantom causing an artifactual appearance of inhomogeneity in the reconstructed image and complicating phantom evaluation. Chang's mathematical formulation is a common method of attenuation correction applied on most gamma cameras that do not require an external transmission source such as computed tomography, radionuclide sources installed within the gantry of the camera or a flood source. Tomographic acquisition can be obtained in two different acquisition modes for dual-detector gamma camera; one where the two detectors are at 180° configuration and acquire projection images for a full 360°, and the other where the two detectors are positioned at a 90° configuration and acquire projections for only 180°. Though Chang's attenuation correction method has been used for 360° angle acquisition, its applicability for 180° angle acquisition remains a question with one vendor's camera software producing artifacts in the images. This work investigates whether Chang's attenuation correction technique can be applied to both acquisition modes by the development of a Chang's formulation-based algorithm that is applicable to both modes. Assessment of attenuation correction performance by phantom uniformity analysis illustrates improved uniformity with the proposed algorithm (22.6%) compared to the camera software (57.6%).","PeriodicalId":143694,"journal":{"name":"Journal of Medical Physics / Association of Medical Physicists of India","volume":"41 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128367811","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 7

Analysis of small field percent depth dose and profiles: Comparison of measurements with various detectors and effects of detector orientation with different jaw settings 小场百分比深度剂量和剖面的分析:用各种探测器测量的比较和不同颚设置下探测器方向的影响

Journal of Medical Physics / Association of Medical Physicists of India Pub Date : 2016-01-01 DOI: 10.4103/0971-6203.177284

H. Godson, M. Ravikumar, S. Sathiyan, K. Ganesh, Y. Ponmalar, C. Varatharaj

{"title":"Analysis of small field percent depth dose and profiles: Comparison of measurements with various detectors and effects of detector orientation with different jaw settings","authors":"H. Godson, M. Ravikumar, S. Sathiyan, K. Ganesh, Y. Ponmalar, C. Varatharaj","doi":"10.4103/0971-6203.177284","DOIUrl":"https://doi.org/10.4103/0971-6203.177284","url":null,"abstract":"The advent of modern technologies in radiotherapy poses an increased challenge in the determination of dosimetric parameters of small fields that exhibit a high degree of uncertainty. Percent depth dose and beam profiles were acquired using different detectors in two different orientations. The parameters such as relative surface dose (DS), depth of dose maximum (Dmax), percentage dose at 10 cm (D10), penumbral width, flatness, and symmetry were evaluated with different detectors. The dosimetric data were acquired for fields defined by jaws alone, multileaf collimator (MLC) alone, and by MLC while the jaws were positioned at 0, 0.25, 0.5, and 1.0 cm away from MLC leaf-end using a Varian linear accelerator with 6 MV photon beam. The accuracy in the measurement of dosimetric parameters with various detectors for three different field definitions was evaluated. The relative DS(38.1%) with photon field diode in parallel orientation was higher than electron field diode (EFD) (27.9%) values for 1 cm ×1 cm field. An overestimation of 5.7% and 8.6% in D10depth were observed for 1 cm ×1 cm field with RK ion chamber in parallel and perpendicular orientation, respectively, for the fields defined by MLC while jaw positioned at the edge of the field when compared to EFD values in parallel orientation. For this field definition, the in-plane penumbral widths obtained with ion chamber in parallel and perpendicular orientation were 3.9 mm, 5.6 mm for 1 cm ×1 cm field, respectively. Among all detectors used in the study, the unshielded diodes were found to be an appropriate choice of detector for the measurement of beam parameters in small fields.","PeriodicalId":143694,"journal":{"name":"Journal of Medical Physics / Association of Medical Physicists of India","volume":"17 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121993953","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 15

Analyzing the characteristics of 6 MV photon beam at low monitor unit settings 分析了低监控单元设置下6 MV光子束的特性

Journal of Medical Physics / Association of Medical Physicists of India Pub Date : 2016-01-01 DOI: 10.4103/0971-6203.177285

L. Nithya, N. Raj, S. Rathinamuthu

{"title":"Analyzing the characteristics of 6 MV photon beam at low monitor unit settings","authors":"L. Nithya, N. Raj, S. Rathinamuthu","doi":"10.4103/0971-6203.177285","DOIUrl":"https://doi.org/10.4103/0971-6203.177285","url":null,"abstract":"Analyzing the characteristics of a low monitor unit (MU) setting is essential, particularly for intensity-modulated techniques. Intensity modulation can be achieved through intensity-modulated radiotherapy (IMRT) or volumetric-modulated arc therapy (VMAT). There is possibility for low MUs in the segments of IMRT and VMAT plans. The minimum MU/segment must be set by the physicist in the treatment planning system at the time of commissioning. In this study, the characteristics such as dose linearity, stability, flatness, and symmetry of 6 MV photon beam of a Synergy linear accelerator at low MU settings were investigated for different dose rates. The measurements were performed for Synergy linear accelerator using a slab phantom with a FC65-G chamber and Profiler 2. The MU linearity was studied for 1–100 MU using a field size of 10 cm ×10 cm. The linearity error for 1 MU was 4.2%. Flatness of the beam was deteriorated in 1 MU condition. The beam stability and symmetry was well within the specification. Using this study, we conclude that the treatment delivered with <3 MU may result in uncertainty in dose delivery. To ensure the correct dose delivery with less uncertainty, it is recommended to use ≥3 MU as the minimum MU per segment in IMRT and VMAT plans.","PeriodicalId":143694,"journal":{"name":"Journal of Medical Physics / Association of Medical Physicists of India","volume":"52 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126191641","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

The modulating effect of royal jelly consumption against radiation-induced apoptosis in human peripheral blood leukocytes 食用蜂王浆对辐射诱导的人外周血白细胞凋亡的调节作用

Journal of Medical Physics / Association of Medical Physicists of India Pub Date : 2016-01-01 DOI: 10.4103/0971-6203.177281

N. Rafat, A. Monfared, M. Shahidi, T. Pourfallah

{"title":"The modulating effect of royal jelly consumption against radiation-induced apoptosis in human peripheral blood leukocytes","authors":"N. Rafat, A. Monfared, M. Shahidi, T. Pourfallah","doi":"10.4103/0971-6203.177281","DOIUrl":"https://doi.org/10.4103/0971-6203.177281","url":null,"abstract":"The present work was designed to assess the radioprotective effect of royal jelly (RJ) against radiation-induced apoptosis in human peripheral blood leukocytes. In this study, peripheral blood samples were obtained on days 0, 4, 7, and 14 of the study from six healthy male volunteers taking a 1000 mg RJ capsule orally per day for 14 consecutive days. On each sampling day, all collected whole blood samples were divided into control and irradiated groups which were then exposed to the selected dose of 4 Gy X-ray. Percentage of apoptotic cells (Ap %) was evaluated for all samples immediately after irradiation (Ap0) and also after a 24 h postirradiation incubation at 37°C in 5% CO2 (Ap24) by the use of neutral comet assay. Concerning Ap0, collected data demonstrated that the percentage of apoptotic cells in both control and irradiated groups did not significantly change during the study period. However, with respect to Ap24, the percentage of apoptotic cells in irradiated groups gradually reduced during the experiment, according to which a significant decrease was found after 14 days RJ consumption (P = 0.002). In conclusion, the present study revealed the protective role of 14 days RJ consumption against radiation-induced apoptosis in human peripheral blood leukocytes.","PeriodicalId":143694,"journal":{"name":"Journal of Medical Physics / Association of Medical Physicists of India","volume":"29 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125474411","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 10

Comparison of two programs in calculating electron output factors at extended source-surface distances 扩展源面距离时计算电子输出因子的两种程序的比较

Journal of Medical Physics / Association of Medical Physicists of India Pub Date : 2016-01-01 DOI: 10.4103/0971-6203.177283

Yunfei Hu, J. Lambert, Yang Wang

{"title":"Comparison of two programs in calculating electron output factors at extended source-surface distances","authors":"Yunfei Hu, J. Lambert, Yang Wang","doi":"10.4103/0971-6203.177283","DOIUrl":"https://doi.org/10.4103/0971-6203.177283","url":null,"abstract":"Monitor units (MUs) calculated by radiotherapy treatment planning systems need to be verified independently. At extended source-surface distances (SSDs), different output factors (OFs) can be given by different independent MU checking packages due to the calculation methods used and assumptions made within them. The accuracy of two software packages - RadCalc® (LifeLine Software Inc., Austin, USA) and eDatabook (Y. Wang, Radiation Oncology Institute, Sydney, AUS) - was determined by comparing the calculated OFs directly to measured OFs for a series of standard electron cutouts on an Elekta Synergy linear accelerator at standard and extended SSDs (100 cm and above). For the majority of the measurements made, eDatabook provided OFs closer to the measured value than RadCalc; however, in two cases, eDatabook was unable to provide a factor. RadCalc failed to calculate the OFs accurately at extended SSDs as its calculation is based on the assumption that the established effective-SSD curve can accurately predict the data where there are no measurements available. The accuracy of eDatabook is due to its use of a linear interpolation to determine the OF at an extended SSD when there are no measurement data available.","PeriodicalId":143694,"journal":{"name":"Journal of Medical Physics / Association of Medical Physicists of India","volume":"41 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129791372","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0