المؤلفون: Rahman, Mahbubur, Zhang, Rongxiao, Gladstone, David J., Williams, Benjamin B., Chen, Erli, Dexter, Chad A., Thompson, Lawrence, Bruza, Petr, Pogue, Brian W.

مصطلحات موضوعية: Physics - Medical Physics

الوصف: Background: Use of a linear accelerator in ultra-high dose rate (UHDR) mode can provide a conduit for wider access to UHDR FLASH effects, sparing normal tissue, but care needs to be taken in the use of such systems to ensure errors are minimized. Purpose: Failure Modes and Effects Analysis (FMEA) was carried out in a team that has been involved in converting a LINAC between clinical use and UHDR experimental mode for more than one year, following the proposed methods of TG100. Methods: A team of 9 professionals with extensive experience were polled to outline the process map and workflow for analysis, and developed fault trees for potential errors, as well as failure modes that would results. The team scored the categories of severity magnitude (S), occurrence likelihood (O), and detectability potential (D) in a scale of 1 to 10, so that a risk priority number (RPN=S*O*D) could be assessed for each. Results: A total of 46 potential failure modes were identified, including 5 with RPN>100. These failure modes involved 1) patient set up, 2) gating mechanisms in delivery, and 3) detector in the beam stop mechanism. Identified methods to mitigate errors included 1) use of a checklist post conversion, 2) use of robust radiation detectors, 3) automation of QA and beam consistency checks, and 4) implementation of surface guidance during beam delivery. Conclusions: The FMEA process was considered critically important in this setting of a new use of a LINAC, and the expert team developed a higher level of confidence in the ability to safely move UHDR LINAC use towards expanded research access.
Comment: 26 Pages, 6 Figures, 4 Tables

الوصول الحر: http://arxiv.org/abs/2112.10338Test

المؤلفون: Rahman, Mahbubur, Ashraf, M. Ramish, Zhang, Rongxiao, Bruza, Petr, Dexter, Chad A., Thompson, Lawrence, Cao, Xu, Williams, Benjamin B., Hoopes, P. Jack, Pogue, Brian W., Gladstone, David J.

مصطلحات موضوعية: Physics - Medical Physics

الوصف: Purpose: In this study, procedures were developed to achieve efficient reversible conversion of a clinical linear accelerator (LINAC) and deliver electron FLASH (eFLASH) or conventional beams to the treatment room isocenter. Material & Methods: The LINAC was converted to deliver eFLASH beam within 20 minutes by retracting the x-ray target from the beam's path, positioning the carousel on an empty port, and selecting 10 MV photon beam energy in the treatment console. Dose per pulse and average dose rate were measured in a solid water phantom at different depths with Gafchromic film and OSLD. A pulse controller counted the pulses via scattered radiation signal and gated the delivery for preset pulse count. A fast photomultiplier tube-based Cherenkov detector measured per pulse beam output at 2 ns sampling rate. After conversion back to clinical mode, conventional beam output, flatness, symmetry, field size and energy were measured for all clinically commissioned energies. Results: Dose per pulse of 0.86 +/- 0.01 Gy (310 +/- 7 Gy/s average dose rate) were achieved at isocenter. The dose from simultaneous irradiation of film and OSLD were within 1%. The PMT showed the LINAC required about 5 pulses before the output stabilized and its long-term stability was within 3% for measurements performed at 3 minutes intervals. The dose, flatness, symmetry, and photon energy were unchanged from baseline and within tolerance (1%, 3%, 2%, and 0.1% respectively) after reverting to conventional beams. Conclusion: 10 MeV FLASH beams were achieved at the isocenter of the treatment room. The beam output was reproducible but requires further investigation of the ramp up time in the first 5 pulses, equivalent to <100 cGy. The eFLASH beam can irradiate both small and large subjects in minimally modified clinical settings and dose rates can be further increased by reducing the source to surface distance.
Comment: Manuscript: 21 Pages, 1 Table, 8 Figures; Supplementary Material A: 2 Pages, 2 Figures; Appendix: Film Dosimetry: 2 Pages, 2 Tables

الوصول الحر: http://arxiv.org/abs/2008.06980Test

المؤلفون: Sloop, Austin, Ashraf, M Ramish, Rahman, Mahbubur, Sunnerberg, Jacob, Dexter, Chad A, Thompson, Lawrence, Gladstone, David J, Pogue, Brian W, Bruza, Petr, Zhang, Rongxiao

المصدر: Int J Radiat Oncol Biol Phys ; ISSN:1879-355X ; Volume:119 ; Issue:4

الوصف: In this study, a C-series linear accelerator was configured to enable rapid and reliable conversion between the production of conventional electron beams and an ultrahigh-dose-rate (UHDR) electron beamline to the treatment room isocenter for FLASH radiation therapy. Efforts to tune the beam resulted in a consistent, stable UHDR beamline.

العلاقة: https://doi.org/10.1016/j.ijrobp.2024.01.215Test; https://pubmed.ncbi.nlm.nih.gov/38552990Test

الإتاحة: https://doi.org/10.1016/j.ijrobp.2024.01.215Test
https://pubmed.ncbi.nlm.nih.gov/38552990Test

المؤلفون: Rahman, Mahbubur, Zhang, Rongxiao, Gladstone, David J., Williams, Benjamin B., Chen, Erli, Dexter, Chad A., Thompson, Lawrence, Bruza, Petr, Pogue, Brian W.

المصدر: Practical Radiation Oncology ; volume 13, issue 2, page 153-165 ; ISSN 1879-8500

مصطلحات موضوعية: Radiology, Nuclear Medicine and imaging, Oncology

الإتاحة: https://doi.org/10.1016/j.prro.2022.10.011Test
https://api.elsevier.com/content/article/PII:S1879850022003332?httpAccept=text/xmlTest
https://api.elsevier.com/content/article/PII:S1879850022003332?httpAccept=text/plainTest

المؤلفون: Rahman, Mahbubur, Ashraf, M. Ramish, Zhang, Rongxiao, Bruza, Petr, Dexter, Chad A., Thompson, Lawrence, Cao, Xu, Williams, Benjamin B., Hoopes, P. Jack, Pogue, Brian W., Gladstone, David J.

المساهمون: Dartmouth College, Foundation for the National Institutes of Health

المصدر: International Journal of Radiation Oncology*Biology*Physics ; volume 110, issue 3, page 872-882 ; ISSN 0360-3016

مصطلحات موضوعية: Cancer Research, Radiology, Nuclear Medicine and imaging, Oncology, Radiation

الإتاحة: https://doi.org/10.1016/j.ijrobp.2021.01.011Test
https://api.elsevier.com/content/article/PII:S0360301621000249?httpAccept=text/xmlTest
https://api.elsevier.com/content/article/PII:S0360301621000249?httpAccept=text/plainTest

المؤلفون: Rahman, Mahbubur, Ramish Ashraf, M., Zhang, Rongxiao, Bruza, Petr, Dexter, Chad A., Thompson, Lawrence, Cao, Xu, Williams, Benjamin B., Jack Hoopes, P., Pogue, Brian W., Gladstone, David J.

المساهمون: National Cancer Institute

المصدر: International Journal of Radiation Oncology*Biology*Physics ; volume 110, issue 3, page 909-910 ; ISSN 0360-3016

مصطلحات موضوعية: Cancer Research, Radiology, Nuclear Medicine and imaging, Oncology, Radiation

الإتاحة: https://doi.org/10.1016/j.ijrobp.2021.03.045Test
https://api.elsevier.com/content/article/PII:S0360301621003072?httpAccept=text/xmlTest
https://api.elsevier.com/content/article/PII:S0360301621003072?httpAccept=text/plainTest

المؤلفون: DEXTER, CHAD ALEXANDER

المصدر: Theological Research Exchange Network (TREN): Theses & Dissertations. 2012, preceding p1-134. 140p.

مصطلحات موضوعية: *CHRISTIAN life, *CHRISTIANITY, *GOVERNMENT policy

Reviews & Products: MAGNA Carta

People: ISAIAH (Biblical prophet)

مستخلص: Liberty is something which all men desire. It is cherished by those who possess it and longed for by those who do not. Myriad wars have been fought and countless men have died in pursuit of or in defense of liberty, but no man is freer than the Christian. The Christian possesses a freedom not won by the edge of a sword, but granted him by His Creator. The freedom given a Christian is a precious gift, but it is often misunderstood. Some fail to embrace their freedom and fall into the error of legalism. Others abuse their freedom and take it as a license for self-indulgence. In order to properly understand Christian freedom, we must look to the foundations of Christian liberty in the Scriptures. There is no better place to tum than to the book of Galatians, which has been described as the Magna Carta of Christian liberty. This study will examine the doctrine of Christian liberty in this great epistle of the Apostle Paul and in his other writings. The study will contain four chapters. The first chapter will examine the importance of Christ's redemption to the doctrine of Christian liberty in Galatians 3:1014. ln this chapter we will see that Christian liberty is rooted in the work of Christ on the cross and that Christian liberty is not freedom of just any kind, but freedom from the Law. The second chapter will look at the doctrine of adoption in Galatians 4:1-7 and the implications of adoption and sonship for Christian freedom. In this chapter we will see the Father's role in making Christians free and what it means to be a son of God. A third chapter will examine the Spirit's role in Christian freedom in Galatians 5: 16-25. In that chapter, we will see that Christian freedom is not absolute freedom from any authority, but rather a freedom which is found only in submission to the leading of the Spirit. A final chapter will look to the Scriptures for guidelines concerning the practical outworking of Christian freedom in the life of a believer and in the church. These principles will be gathered from selected verses in Romans 14:1-15:13 and in 1 Corinthians 8: 1-11 : I. [ABSTRACT FROM AUTHOR]