157 results on '"G. Luxton"'
Search Results
2. Image-Guided Radiosurgery for the Spine and Pancreas
- Author
-
M J, Murphy, J R, Adler, M, Bodduluri, J, Dooley, K, Forster, J, Hai, Q, Le, G, Luxton, D, Martin, and J, Poen
- Subjects
Spinal Neoplasms ,Phantoms, Imaging ,Movement ,Respiration ,Adenocarcinoma ,Radiosurgery ,Spine ,Computer Science Applications ,Arteriovenous Malformations ,Pancreatic Neoplasms ,Feasibility Studies ,Humans ,Surgery ,Family Practice ,Pancreas ,Neurilemmoma - Abstract
A robotic image-guided radiosurgical system has been modified to treat extra-cranial sites using implanted fiducials and skeletal landmarks to locate the treatment targets. The system has been used to treat an artero-venous malformation in the cervical spine, a recurrent schwannoma of the thoracic spine, a metastatic adenocarcinoma of the lumbar spine, and three pancreatic cancers. During each treatment, the image guidance system monitored the position of the target site and relayed the target coordinates to the beam-pointing system at discrete intervals. The pointing system then dynamically aligned the therapy beam with the lesion, automatically compensating for shifts in target position. Breathing-related motion of the pancreas lesions was managed by coordinating beam gating with breath-holding by the patient. The system maintained alignment with the spine lesions to within +/- 0.2 mm on average, and to within +/- 1 mm for the pancreatic tumors. This experience has demonstrated the feasibility of using image-guided robotic radiosurgery outside the cranium.
- Published
- 2000
- Full Text
- View/download PDF
3. Under-achievement and pedagogy. Experimental reforms in the teaching of mathematics using Continental approaches in schools in the London Borough of Barking and Dagenham
- Author
-
R. G. Luxton
- Subjects
Borough ,General Mathematics ,Teaching method ,Pedagogy ,Primary education ,Mathematics education ,Mathematics instruction ,Education - Published
- 1998
- Full Text
- View/download PDF
4. Acute thyroiditis following parathyroidectomy for secondary hyperparathyroidism in a chronic renal failure patient
- Author
-
G. Luxton, B. Hutchison, and Wai H. Lim
- Subjects
Parathyroidectomy ,medicine.medical_specialty ,medicine.diagnostic_test ,business.industry ,medicine.medical_treatment ,Treatment outcome ,medicine.disease ,Gastroenterology ,Thyroid function tests ,Thyroiditis ,Sepsis ,Internal medicine ,Internal Medicine ,medicine ,Chronic renal failure ,Secondary hyperparathyroidism ,Differential diagnosis ,business - Published
- 2003
- Full Text
- View/download PDF
5. Thrombotic microangiopathy from Australian brown snake (Pseudonaja) envenoming
- Author
-
Sarah Brown, J. Kennedy, Geoffrey K. Isbister, G. Cull, C. Trethewy, Ferenc Szabo, Bart J. Currie, Mark Little, G. Luxton, D. McCoubrie, and Paul D. Lawton
- Subjects
Adult ,Male ,medicine.medical_specialty ,Anemia, Hemolytic ,Thrombotic microangiopathy ,medicine.medical_treatment ,Antivenom ,Thrombotic thrombocytopenic purpura ,Snake Bites ,complex mixtures ,Internal medicine ,Internal Medicine ,Medicine ,Animals ,Humans ,Elapidae ,Pseudonaja ,Disseminated intravascular coagulation ,Aged, 80 and over ,biology ,business.industry ,Australia ,Acute Kidney Injury ,Disseminated Intravascular Coagulation ,medicine.disease ,biology.organism_classification ,Thrombocytopenia ,Snake bites ,Surgery ,Brown snake ,Plasmapheresis ,business - Abstract
Background: Australian brown snake (genus Pseudonaja) envenoming causes a venom-induced consumptive coagulopathy (VICC). A proportion of cases go on to develop thrombotic microangiopathy characterized by thrombocytopenia, microangiopathic haemolytic anaemia (MAHA) and acute renal failure (ARF). Aim: The aim of the study was to define better the natural history and empirical treatments for thrombotic microangiopathy in brown snake envenoming. Methods: A review of brown snake bites recruited to the Australian Snakebite Project (ASP), a national multicentre study of snake envenoming was undertaken. Serial data are recorded on clinical effects and laboratory results, including measurement of venom concentrations. We describe cases of thrombotic microangiopathy and compare these to cases without thrombotic microangiopathy. Results: From 32 cases of brown snake envenoming with severe VICC, four (13%) developed thrombotic microangiopathy, we also included two cases of thrombotic microangiopathy from prior to ASP. All six developed severe thrombocytopenia (
- Published
- 2007
6. A quality assurance program for the On-Board Imager®
- Author
-
Sua Yoo, G. Kim, R. Hammoud, E. Elder, T. Pawlicki, H. Guan, T. Fox, G. Luxton, F. Yin, and P. Munro
- Published
- 2007
- Full Text
- View/download PDF
7. Responsive microtubule dynamics promote cell invasion by Trypanosoma cruzi
- Author
-
Kevin M, Tyler, George W G, Luxton, Derek A, Applewhite, Sean C, Murphy, and David M, Engman
- Subjects
Tubulin ,Recombinant Fusion Proteins ,Trypanosoma cruzi ,Green Fluorescent Proteins ,Animals ,Lysosomes ,Microtubules ,Cells, Cultured ,Myoblasts, Cardiac ,Host-Parasite Interactions - Abstract
The American trypanosome, Trypanosoma cruzi, can invade non-phagocytic cell types by a G-protein-mediated, calcium-dependent mechanism, in which the cell's natural puncture repair mechanism is usurped in order to recruit lysosomes to the parasite/host cell junction or 'parasite synapse.' The fusion of lysosomes necessary for construction of the nascent parasitophorous vacuole is achieved by directed trafficking along microtubules. We demonstrate altered host cell microtubule dynamics during the initial stages of the entry process involving de novo microtubule polymerization from the cytoplasmic face of the parasite synapse which appears to serve as a secondary microtubule organizing centre. The net result of these dynamic changes to the host cell's microtubule cytoskeleton is the development of the necessary infrastructure for transport of lysosomes to the parasite synapse.
- Published
- 2005
8. Monitor unit calculation for intensity modulated photon field
- Author
-
null Lei Xing, null Yan Chen, G. Luxton, J.G. Li, and A.L. Boyer
- Published
- 2002
- Full Text
- View/download PDF
9. Prealbumin measurement as a screening tool for protein calorie malnutrition in emergency hospital admissions: a pilot study
- Author
-
M A, Potter and G, Luxton
- Subjects
Adult ,Aged, 80 and over ,Emergency Medical Services ,Adolescent ,Nutritional Support ,Pilot Projects ,Length of Stay ,Middle Aged ,Protein-Energy Malnutrition ,Child, Preschool ,Costs and Cost Analysis ,Humans ,Prealbumin ,Prospective Studies ,Child ,Energy Intake ,Biomarkers ,Serum Albumin ,Aged - Abstract
To examine the effectiveness of prealbumin measurement as a routine diagnostic test for protein calorie malnutrition (PCM) in emergency admissions.Cohort study.Canadian tertiary care hospital.A total of 147 consecutive patients admitted through the emergency department, excluding psychiatric admissions, for whom a serum sample was sent to the chemistry laboratory.(1) Albumin and prealbumin levels to diagnose PCM; (2) length of stay (LOS), in-hospital mortality, and nutritional supplementation in patients with PCM; and (3) cost analysis of using prealbumin level as an admission screening test for PCM.Twenty-four per cent of the patients had at least mild PCM (prealbumin level160 mg/L). Albumin level (35 g/L) had a sensitivity of 50% and specificity of 95% in identifying PCM. The mean LOS in the patients with PCM was 16 (standard deviation 18) days, compared with 8 (SD 12) days in the patients without PCM (p0.0002). The in-hospital mortality rate was 17% in patients with PCM compared with 4% in patients without PCM (p0.02). Only 42% of patients with PCM received nutritional supplementation. Cost analysis of screening with prealbumin level projected a saving of $414 per patient screened.PCM is underdiagnosed in current clinical practice and is associated with an increased LOS and mortality rate. Prealbumin is a biochemical marker that could be used as a cost-effective screening test to identify patients with PCM who may benefit from nutritional supplementation.
- Published
- 1999
10. Conformal Radiotherapy for Carcinoma of the Prostate
- Author
-
G. Luxton
- Subjects
Oncology ,medicine.medical_specialty ,business.industry ,medicine.medical_treatment ,Rectum ,Conformal radiotherapy ,medicine.disease ,Clinical trial ,Radiation therapy ,Prostate cancer ,medicine.anatomical_structure ,Prostate ,Internal medicine ,medicine ,Carcinoma ,Radiology ,Stage (cooking) ,business - Abstract
Although the optimum role for radiotherapy in the treatment of prostate cancer (CaP) remains controversial (e.g., Stamey et al. 1993; Kaplan et al. 1993; Bagshaw et al. 1994), there is general agreement as to what the goal of radiotherapy should be when it is used. For both primary and postsurgical treatment of localized CaP a clinical target should ideally be defined three-dimensionally. This target should be treated to a therapeutic, sufficiently high radiation dose while keeping the maximum doses to the bladder, rectum, bowel, and femoral heads as low as possible. The clinical target should consist of at least the prostate gland in the case of a patient with an intact prostate or the preoperative margins of the gland in the case of a postsurgical treatment. Beyond this, the question of exactly what should be included in the clinical target and the question of what is the appropriate dose to the target for a given stage of clinical disease are issues for clinical trials.
- Published
- 1996
- Full Text
- View/download PDF
11. Surgery with adjuvant irradiation in patients with pathologic stage C adenocarcinoma of the prostate
- Author
-
Z, Petrovich, G, Lieskovsky, J, Freeman, G, Luxton, S, Groshen, S, Formenti, L, Baert, S C, Chen, and D G, Skinner
- Subjects
Male ,Prostatectomy ,Prostatic Neoplasms ,Adenocarcinoma ,Middle Aged ,Combined Modality Therapy ,Disease-Free Survival ,Humans ,Radiotherapy, Adjuvant ,Neoplasm Metastasis ,Neoplasm Recurrence, Local ,Aged ,Follow-Up Studies ,Neoplasm Staging - Abstract
In recent years, the routine use of prostate-specific antigen (PSA) to detect cancer of the prostate (CaP) early has renewed the controversy regarding radiotherapy versus radical prostatectomy as the superior definitive treatment. Radiotherapy alone has been reported to result in a high incidence of local recurrence, whereas on the other hand surgical treatment has resulted in a high incidence of microscopic residual tumor. The purpose of this study was to review our treatment results with radical prostatectomy followed by planned courses of postoperative irradiation in patients with pathologic Stage (PS) C disease.From 1972 to 1989, 95 patients with CaP with PS C tumors were treated with radical prostatectomy and bilateral pelvic lymphadenectomy. Pathologic stage distribution was: C1 in 26 (27%), C2 in 37 (39%), and C3 in 32 (34%) patients. The median follow-up was 6 years. All 95 study patients received postoperative pelvic irradiation as the only adjuvant treatment. Radiotherapy treated volume included the prostatic fossa and its immediate vicinity. The RT dose ranged from 33 Gy to 61.8 Gy (median, 45 Gy).The overall 5- and 10-year actuarial survival rates were 94% and 73%, respectively, with the 5 and 10 year disease specific survival of 98% and 91%, respectively. Clinical and/or prostate specific antigen recurrence was 31% at 5 years and 44% at 10 years. Prostate specific antigen elevation without clinical evidence of recurrent disease was recorded in 26 (27%) patients. Seminal vesicle involvement (C3) and high Gleason's score (8-10) were the most important factors predicting recurrence. Of the 95 patients treated, 2 had pelvic recurrence alone and 1 had local and distant metastatic disease. Radiotherapy was well tolerated with no clinically important morbidity.Based on this experience, moderate dose adjuvant radiotherapy after radical prostatectomy in patients with PS C CaP is recommended.
- Published
- 1995
12. Follow-up imaging studies in patients treated with radiosurgery for metastatic melanoma
- Author
-
L. Petrus, M. J. Apuzzo, Chi-Shing Zee, Z. Petrivich, and G. Luxton
- Subjects
medicine.medical_specialty ,Stable Disease ,Metastatic melanoma ,business.industry ,medicine.medical_treatment ,Complete remission ,Medicine ,Primary treatment ,In patient ,Radiology ,Previously treated ,business ,Radiosurgery - Abstract
Our aim was to evaluate the efficacy of stereotactic radiosurgery for treatment of intracranial metastatic melanomas. A total of 13 patients with 35 intracranial metastatic melanoma lesions were treated with stereotactic radiosurgery. On imaging studies, complete remission was found in 5 of 35, partial remission in 20 of 35, stable disease in 8 of 35, and progression in 2 of 35. In addition, relapse was later seen in 3 of the 28 lesions that initially showed partial remission or stable disease. Stereotactic radiosurgery is an effective and safe therapy for brain metastatic melanomas. It can be applied as primary treatment or for a relapse in a patient previously treated by whole-brain irradiation.
- Published
- 1995
- Full Text
- View/download PDF
13. SP-0194 CLOSING THE LOOP OF RADIATION THERAPY: DOSE RECONSTRUCTION USING DYNAMIC LOG FILES AND CBCT
- Author
-
Lei Xing, T.S. Suh, W. Cho, J. Qian, G. Luxton, and L. Lee
- Subjects
Physics ,Loop (topology) ,Radiation therapy ,Oncology ,Control theory ,business.industry ,medicine.medical_treatment ,medicine ,Radiology, Nuclear Medicine and imaging ,Hematology ,Nuclear medicine ,business ,Closing (morphology) - Published
- 2012
- Full Text
- View/download PDF
14. SU-E-T-540: Verification of Dosimetric Accuracy on the TrueBeam STx: Rounded Leaf Effect of the High Definition MLC
- Author
-
K Kielar, E Mok, L Wang, G Luxton, P Maxim, A Hsu, and L Xing
- Subjects
General Medicine - Published
- 2011
- Full Text
- View/download PDF
15. Radionecrosis secondary to interstitial brachytherapy: correlation of magnetic resonance imaging and histopathology
- Author
-
J H, Oppenheimer, M L, Levy, U, Sinha, H, el-Kadi, M L, Apuzzo, G, Luxton, Z, Petrovich, C S, Zee, and C A, Miller
- Subjects
Adult ,Male ,Brain Neoplasms ,Brachytherapy ,Radiotherapy Dosage ,Astrocytoma ,Combined Modality Therapy ,Magnetic Resonance Imaging ,Frontal Lobe ,Necrosis ,Humans ,Cranial Irradiation ,Radiation Injuries ,Tomography, X-Ray Computed - Abstract
Radiation-induced tissue damage in the central nervous system is a well-known complication of interstitial brachytherapy for brain tumors, yet imaging correlates have historically been based upon computed tomographic scans. We now present magnetic resonance imaging (MRI) to correlate radiation changes after interstitial brachytherapy with the histopathology. The central nervous system of a 38-year-old man with a left frontal cerebral glioma diagnosed by stereotactic biopsy was treated with interstitial brachytherapy (iridium-192, 47 Gy), followed by limited-field irradiation (45 Gy). With progressive deterioration, a second biopsy demonstrated radiation changes. Despite aggressive medical management, the patient died 9 months after completion of radiation therapy. Postmortem evaluation compared MRI scans of the intact, fixed brain with the histopathology. Axial sections (10 mm) obtained by MRI scan and autopsy brain slices were cut in the identical plane. Neuroimaging and histopathological findings of the lesion correlated within 2 to 3 mm resolution. In the peripheral white matter, MRI scan did not indicate the extent of radiation effect histologically. We suggest that MRI has limited utility in assessing the extent of impact of radiation on surrounding brain.
- Published
- 1992
16. Algorithm for dosimetry of multiarc linear-accelerator stereotactic radiosurgery
- Author
-
G, Luxton, G, Jozsef, and M A, Astrahan
- Subjects
Models, Structural ,Humans ,Radiotherapy Dosage ,Thermoluminescent Dosimetry ,Particle Accelerators ,Radiometry ,Radiosurgery ,Algorithms - Abstract
Treatment planning for multiarc radiosurgery is an inherently complex three-dimensional dosimetry problem. Characteristics of small-field x-ray beams suggest that major simplification of the dose computation algorithm is possible without significant loss of accuracy compared to calculations based on large-field algorithms. The simplification makes it practical to efficiently implement accurate multiplanar dosimetry calculations on a desktop computer. An algorithm is described that is based on data from fixed-beam tissue-maximum-ratio (TMR) and profile measurements at isocenter. The profile for each fixed beam is scaled geometrically according to distance from the x-ray source. Beam broadening due to scatter is taken into account by a simple formula that interpolates the full width at half maximum (FWHM) between profiles at isocenter at different depths in phantom. TMR and profile data for two representative small-field collimators (10- and 25-mm projected diameter) were obtained by TLD and film measurements in a phantom. The accuracy of the calculational method and the associated computer program were verified by TLD and film measurements of noncoplanar multiarc irradiations from these collimators on a 4-MV linear accelerator. Comparison of film measurements in two orthogonal planes showed close agreement with calculations in the shape of the dose distribution. Maximal separation of measured and calculated 90%, 80%, and 50% isodose curves was less than or equal to 0.5 mm for all planes and collimators. All TLD and film measurements of dose to isocenter agreed with calculations to within 2%.
- Published
- 1991
17. Subject Index Vol. 72, Suppl. 1, 1999
- Author
-
G.K. Kim, O. Kubo, F. Li, G.H. Barnett, T. Sasaki, M.S. Kim, T. Ochiai, R. Young, R.M. Macklis, Y. Kwon, J.W. Chang, J. Régis, K. Sasaki, K.A. Leber, W. Leem, J.T. Park, P.A. Barrett, M. Komiyama, S.S. Chung, T. Morikawa, D.M.C. Forster, J.H. Sim, J. Ishihara, M.L.J. Apuzzo, J. Vymazal, T.R. Willoughby, M. Hayashi, J.H. Suh, G. Pendl, Y. Iwai, Y.J. Lim, S.K. Khang, M. Yamamoto, Y.G. Park, R.L. Crownover, T.S. Kim, J. Markert, Y. Régis, J. Novotný, K. Yamanaka, B.D. Kwun, M. Nishikawa, J. Simbrunner, A. Kemeny, M. Hirato, T. Hori, H. Nakajima, S. Atsuchi, R. Huh, S.H. Kim, T. Yasui, S.I. Lee, S. Nakamura, S. Klein, R. Meier, D.W. Miller, G. Luxton, H. Sato, C. Ohye, J. Raisis, T. Shibazaki, R. Liščagrave, S. Ramschak-Schwarzer, H. Hiyama, M. Mokry, Z. Petrovich, O. Shrö, L. Janoušková, R. Liščàk, C. Palmer, H.K. Inoue, B.A. Rhee, J.G. Walsh, D.W. Roberts, S. Eustacchio, C.J. Kim, M. Izawa, E. Kohler, M.S. Weinhous, B. Guthrie, S.H. Sim, C. Yu, J.K. Lee, Y. Andou, Y. Kida, K Nakaya, J.C. Ganz, F. Bartolomei, R. Jennelle, H. Kohga, V. Vladyka, C. Gladson, K. Takakura, H. Kishi, T. Ochial, S. Vermeulen, T. Kobayashi, and D.J. Lee
- Subjects
medicine.medical_specialty ,Index (economics) ,business.industry ,Physical therapy ,Medicine ,Surgery ,Subject (documents) ,Neurology (clinical) ,business - Published
- 1999
- Full Text
- View/download PDF
18. TRANSPLANT PATIENT FITNESS ASSESSMENT: SUBJECTIVE & QUANTITATIVE CRITERIA ANALYSIS
- Author
-
Mab, Thomas, primary, G, Luxton, additional, Hr, Moody, additional, Aj, Woodroffe, additional, and W, Lim, additional
- Published
- 2002
- Full Text
- View/download PDF
19. Subject Index Vol. 66, 1996
- Author
-
Jeff Campbell, Brian Butler, Thomas C. Chen, Gérard Mohr, Bruce A. Kall, Zhong-Ping Chen, Lucia Zamorano, Michael Lamba, Vojtech Jankovič, John C. Breneman, M. Sean Grady, Victor Onufrey, E. Arm, Judith Figura, G. Luxton, Pushpa Patel, Thomas C. Witt, Bruce Lulu, Daniel Pavord, Michael Knauth, Ben Nyman, Ole Jörgen Kirkeby, Gene H. Barnett, Stephan J. Goerss, Z. Petrovich, Chi-Shing Zee, Douglas Kondziolka, R.I. Evans, Laura D. Brynildson, David J. Bissonette, Lynne Gosset, Charles P. Steiner, Joseph Weisenberger, Gary Luxton, Kjell Tveraa, L. Dade Lunsford, Friedrich K. Albert, J. Szumoski, Eugen Ružický, P.D. Doshi, Ralph G. Dacey, J. Zhao, Christian Rainer Wirtz, Walter H. Grant, Ronald F. Young, V. Zelman, Dudley H. Davis, T.L. Hardy, D. LeMay, Jeffrey Green, H. Visarius, Mario M. Bonsanto, Robert G. Grossman, D.G.T. Thomas, Douglas C. Noll, A.C. Colchester, Vladimir Zelman, Stefan Kunze, Michael Sanders, Lutz Nolte, Ronald E. Warnick, William C. Broaddus, Michael L.J. Apuzzo, Stefan Hassfeld, Harris S. Targovnik, M.L.J. Apuzzo, Rogers C. Ritter, J.G. Gray, Allan J. Hamilton, Scott O. Stiving, Steven L. Small, Tung T. Nguyen, Peggy Eddy, N. Maitland, Calvin R. Maurer, Mark Carol, Sören Bakke, C.-S. Zee, Michael Fitzpatrick, U. Berlerman, A.J. Strong, O. Schwarzenbach, Bernard D. Coombs, Miron Šramka, Jonathan E. Hodes, Roy A. Patchell, D.J. Hawkes, Zbigniew Petrovich, Volker M. Tronnier, Matthew A. Howard, Henry Hirschberg, S.Y. Woo, Helen Fosmire, C. Yu, Stephen B. Baumann, Chandrasiri Samaratunga, Zaowei Jiang, Patrick J. Kelly, George T. Gillies, Jamal M. Taha, D.L.C. Hill, Srikanth Gadamsetty, Robert Selkar, Kim J. Burchiel, Daniel R. LeMay, Robert J. Maciunas, and D.J. Machovec
- Subjects
medicine.medical_specialty ,Index (economics) ,business.industry ,Medicine ,Surgery ,Subject (documents) ,Medical physics ,Neurology (clinical) ,business - Published
- 1996
- Full Text
- View/download PDF
20. Comparison of the procedures for measuring HbA1c
- Author
-
M Vacovsky, G Luxton, L Fu, and J Lafferty
- Subjects
Clinical Biochemistry ,General Medicine - Published
- 2000
- Full Text
- View/download PDF
21. Evaluation of the performance of biorad variant II for HbA1c, HbF and HbA2
- Author
-
J Lafferty, L Fu, G Luxton, and M Vacovsky
- Subjects
Clinical Biochemistry ,General Medicine - Published
- 2000
- Full Text
- View/download PDF
22. Automated quality assurance process for MLC-based IMRT using CT virtual simulation
- Author
-
A.L. Boyer, Y. Chen, G. Luxton, Lei Xing, and J.L. Li
- Subjects
Cancer Research ,Engineering drawing ,Radiation ,Oncology ,business.industry ,Process (computing) ,Medicine ,Radiology, Nuclear Medicine and imaging ,business ,Quality assurance - Published
- 2000
- Full Text
- View/download PDF
23. Delayed diagnosis of adrenal hypoplasia congenita in two adult brothers
- Author
-
S. Hill, G. Luxton, J.D. Booth, E. Dunn, and V. Chetty
- Subjects
Pathology ,medicine.medical_specialty ,business.industry ,X-linked adrenal hypoplasia congenita ,Clinical Biochemistry ,Medicine ,General Medicine ,business ,medicine.disease ,Delayed diagnosis - Published
- 1995
- Full Text
- View/download PDF
24. 31 Early experience and applications of HDR afterloading with the omnitron 2000
- Author
-
N.T. Glover, G. Joszef, T. Hsu, O.E. Streeter, P. Shrivastava, and G. Luxton
- Subjects
Oncology ,Radiology, Nuclear Medicine and imaging ,Hematology - Published
- 1994
- Full Text
- View/download PDF
25. Occult blood testing in a large teaching hospital
- Author
-
M. Ali, P. Kostka, and G. Luxton
- Subjects
medicine.medical_specialty ,business.industry ,Clinical Biochemistry ,Emergency medicine ,medicine ,General Medicine ,Blood testing ,business ,Occult ,Teaching hospital - Published
- 1993
- Full Text
- View/download PDF
26. Some Features ofn-pCharge-Exchange Scattering between 60 and 300 GeV/c
- Author
-
H. R. Barton, N. W. Reay, K. Reibel, M. Shaevitz, N. R. Stanton, M. A. Abolins, P. Brindza, J. A. J. Matthews, R. Sidwell, K. W. Edwards, G. Luxton, and P. Kitching
- Subjects
Physics ,Nuclear physics ,Cross section (physics) ,Momentum (technical analysis) ,Scattering ,General Physics and Astronomy ,Atomic physics ,Charge exchange - Abstract
The dependence of the n-p charge exchange cross section on the four-momentum transfer squared and on the incident momentum is examined, and some comparisons with data from lower energies are given. Implications for the difference between n-p and p-p total cross sections are presented.
- Published
- 1976
- Full Text
- View/download PDF
27. Initial Performance of the Stanford Medical Pion Generator
- Author
-
R. Taber, Malcolm A. Bagshaw, Peter Fessenden, G. Luxton, David A. Pistenma, and Douglas P. Boyd
- Subjects
Physics ,Cylindrical geometry ,Particle physics ,Radiotherapy ,Meson ,Nuclear Theory ,Radiotherapy Dosage ,Elementary particle ,Cold Temperature ,Momentum ,Generator (circuit theory) ,Nuclear physics ,Pion beam ,Pion ,Nuclear Reactors ,High Energy Physics::Experiment ,Radiology, Nuclear Medicine and imaging ,Elementary Particles - Abstract
A novel, cylindrical geometry, superconducting pion channel has been constructed at Stanford. It can simultaneously deliver up to 60 radially converging pion beams of the same mean momentum but with individually variable momentum spread (0.0-4.3%). Virtually no tuning of the pion beam is required Preliminary tests have demonstrated many of the performance characteristics which facilitate the treatment of selected human tumors.
- Published
- 1977
- Full Text
- View/download PDF
28. Interstitial radiotherapy combined with interstitial hyperthermia in the management of recurrent tumors
- Author
-
Z, Petrovich, K, Lam, M, Astrahan, G, Luxton, and B, Langholz
- Subjects
Evaluation Studies as Topic ,Brachytherapy ,Palliative Care ,Humans ,Hyperthermia, Induced ,Neoplasm Recurrence, Local ,Combined Modality Therapy - Abstract
During a 2-year period 31 sites in 27 patients with recurrent, previously treated tumors received a combination of interstitial 192Ir radiation (RT) with microwave hyperthermia (HT). Head and neck sites were treated most frequently (48%), with breast and vagina each representing about 20% of sites. Complete response (CR) with no local recurrence was obtained in 61%, partial response (PR) in 11 (36%), and one (3%) had less than 50% tumor regression. Of these patients, nine had no evidence of tumor following HT-RT therapy, 8/18 in the CR group and 1/11 in the PR group. Significant factors influencing CR were: radiation dose, tumor volume and duration of tumor control following the initial therapy (p less than 0.02). Treated site, histology and thermal dose were not significant factors influencing tumor regression. Complications of significance developed in one patient who had local skin necrosis. Interstitial HT-RT combination provides an effective palliative therapy for recurrent and/or persistent tumors. Randomized trials are necessary to assess the effectiveness of this combination as a component part of primary management of selected tumors.
- Published
- 1988
29. A 500-kHz localized current field hyperthermia system for use with ophthalmic plaque radiotherapy
- Author
-
M, Astrahan, P, Liggett, Z, Petrovich, and G, Luxton
- Subjects
Models, Structural ,Brachytherapy ,Animals ,Cattle ,Hyperthermia, Induced ,Prostheses and Implants ,Rabbits ,Eye ,Combined Modality Therapy ,Electrodes - Published
- 1988
30. Surgical therapy and radiotherapy for carcinoma of the esophagus. Treatment results in 195 patients
- Author
-
Z, Petrovich, K, Lam, B, Langholz, S, Formenti, G, Luxton, and T, Tildon
- Subjects
Adult ,Aged, 80 and over ,Male ,Survival Rate ,Postoperative Complications ,Esophageal Neoplasms ,Radiotherapy ,Humans ,Female ,Middle Aged ,Combined Modality Therapy ,Aged - Abstract
Between 1963 and 1986, 195 patients with carcinoma of the esophagus were seen in the Department of Radiation Oncology at the University of Southern California School of Medicine. Of these 195 patients, 137 had unresectable or inoperable tumors and received radiotherapy. A combination of radiotherapy and surgical therapy was used in 46 patients, 9 patients were treated with surgery alone, and three with chemotherapy alone. Among the nonsurgical patients, 13 scored less than 50 on the Karnofsky scale, 25 had distant metastases, and 69 lost more than 10% of their body weight. The majority (94%) had squamous cell carcinoma and a few (6%) had adenocarcinoma. Fifty percent had middle esophageal lesions, 30% had lower lesions, and 20% had upper esophageal lesions. Stage I was diagnosed in 13%, II in 27%, III in 29%, and IV in 27%; the disease was not staged in 5%. The 5-year actuarial survival rate for all patients was 4% (median 32 weeks). The 5-year survival rate of the 46 patients with combination therapy was 18%, and it was 2% for the remaining 149 patients (p less than 0.001). These figures are independent of stage of disease. The 2-year survival rate by stage was as follows: I, 25%; II, 21%; III, 5%; and IV, 0% (p less than 0.001). Complete response was obtained in 18% and partial response in 41%. Complete response was dependent on the tumor stage. It was 40% for stage I disease, 23% for stage II, 11% for stage III, and 6% for stage IV disease. Similarly, a larger percentage (39%) of the 46 patients with combination surgical/radiation therapy had a complete response than of patients treated by either radiotherapy alone (n = 137, 12%) or surgery alone (n = 9, 11%). Complete response and initial performance status were important factors influencing survival (p less than 0.001). Surgery with adjuvant irradiation offered a better survival rate than radiotherapy or surgery used as single modalities. Treatment results for patients with advanced carcinoma of the esophagus remain poor.
- Published
- 1989
31. Regional hyperthermia with BSD-1000 annular phased array in the management of recurrent deep seated malignant tumors
- Author
-
Z, Petrovich, B, Emami, M, Astrahan, B, Langholz, and G, Luxton
- Subjects
Adult ,Aged, 80 and over ,Male ,Abdominal Neoplasms ,Humans ,Female ,Hyperthermia, Induced ,Middle Aged ,Neoplasm Recurrence, Local ,Combined Modality Therapy ,Aged ,Pelvic Neoplasms - Published
- 1987
32. Characteristics of the high-energy photon beam of a 25-MeV accelerator
- Author
-
G, Luxton and M A, Astrahan
- Subjects
Radiotherapy, High-Energy ,Humans ,Electrons ,Particle Accelerators - Abstract
The CGR Saturne 25 is an isocentrically mounted standing wave medical linear accelerator that produces dual-energy photon beams and a scanned electron beam with six selectable energies between 4 and 25 MeV. The highest energy photon beam is nominally referred to as 23 MV. For this beam the mean energy of the accelerated electron beam on the 1.3 radiation length (4 mm) tungsten x-ray target is found to be approximately 21 MeV, with the energy acceptance stated to be +/- 5%. The electron beam traverses a 270 degrees bending magnet upstream of the x-ray production target. The resulting bremsstrahlung beam passes through a combination steel and lead flattening filter, 4-cm maximum thickness. Dosimetric data for the 23-MV beam are presented with respect to rectangular field output factor, depth of maximum dose as a function of field size, surface and buildup dose, central axis percent depth dose, tissue-phantom ratios, beam profile, applicability of inverse square, and block transmission. Some data are also presented on the effect of different flattening filter designs on apparent beam energy.
- Published
- 1988
33. Output factor constituents of a high-energy photon beam
- Author
-
G, Luxton and M A, Astrahan
- Subjects
Radiotherapy, High-Energy ,Humans ,Particle Accelerators - Abstract
Measurements designed to separate primary and various scatter components of central axis dose of the highest energy photon beam of the CGR Saturne 25 linear accelerator are described. This beam has an unusually large output variation with field size. The measurements are performed both in air and in a water phantom, with and without an aperture external to the collimator system. Results are presented in the form of relative output factors for different field sizes due to (i) flattening filter scatter, (ii) water phantom scatter, (iii) collimator backscatter into the monitor chamber, and (iv) collimator forward scatter onto the central axis. It is found that the flattening filter is the single largest scatter component, but that each of the other factors is significant in determining the output dose per monitor unit as a function of field size.
- Published
- 1988
34. Design of a Tagged Photon - Electron Beam Facility for NAL
- Author
-
C. Halliwell, P. Biggs, W. Busza, M. Chen, T. Nash, Fred Murphy, G. Luxton, and J. Prentice
- Published
- 1972
- Full Text
- View/download PDF
35. An Ice Automobile
- Author
-
G. Luxton
- Subjects
Multidisciplinary - Published
- 1906
- Full Text
- View/download PDF
36. Kinematics of Production Processes at High Energy and the Regge Pole Hypothesis
- Author
-
G. Luxton
- Published
- 1971
- Full Text
- View/download PDF
37. SU‐FF‐T‐200: Image‐Guided IMRT Dose Verification with a Plastic Photosensitive Dosimeter.
- Author
-
T Pawlicki, G Luxton, P Maxim, V Mistry, P Bourland, and A Boyer
- Published
- 2005
38. The impact of coronavirus-19 vaccination on anti-nuclear cytoplasmic antibody vasculitis hospitalisations in a Sydney health network.
- Author
-
Turner D, Luxton G, Yong K, and Sammel A
- Subjects
- Humans, Retrospective Studies, COVID-19 Vaccines, Antibodies, Antineutrophil Cytoplasmic, Granulomatosis with Polyangiitis, Microscopic Polyangiitis, Anti-Neutrophil Cytoplasmic Antibody-Associated Vasculitis, Coronavirus
- Abstract
There have been reports of COVID-19 vaccination triggering anti-nuclear cytoplasmic antibody (ANCA)-associated vasculitis (AAV), but no robust studies have examined the link. This retrospective cohort study assessed the impact of COVID vaccination on the rate of denovo and relapsed AAV in a Sydney Local Health District from 2018 to 2022. Despite more than 95% of the population receiving vaccination, the case rate of AAV was stable. These findings do not support a relationship between COVID vaccination and AAV., (© 2024 The Authors. Internal Medicine Journal published by John Wiley & Sons Australia, Ltd on behalf of Royal Australasian College of Physicians.)
- Published
- 2024
- Full Text
- View/download PDF
39. Kidney transplantation in people living with human immunodeficiency virus: An overview of the Australian experience.
- Author
-
McMullen L, Drak D, Basu G, Coates PT, Goodman DJ, Graver A, Isbel N, Lim WH, Luxton G, Sciberras F, Toussaint ND, Wong G, and Gracey DM
- Subjects
- Humans, Male, Female, Adolescent, Adult, Middle Aged, Immunosuppressive Agents adverse effects, HIV, Retrospective Studies, Graft Rejection prevention & control, Renal Dialysis, Australia epidemiology, Graft Survival, Kidney Transplantation adverse effects, HIV Infections complications, HIV Infections diagnosis, HIV Infections drug therapy
- Abstract
Kidney transplantation in people living with HIV (PLWHIV) is occurring with increasing frequency. Limited international data suggest comparable patient and graft survival in kidney transplant recipients with and without HIV. All PLWHIV aged ≥18 years who received a kidney transplant between 2000 and 2020 were identified by retrospective data initially extracted from Australia and New Zealand Dialysis and Transplant Registry (ANZDATA), with additional HIV-specific clinical data extracted from linked local health-care records. Twenty-five PLWHIV and kidney failure received their first kidney transplant in Australia between January 2000 and December 2020. Majority were male (85%), with median age 54 years (interquartile range, IQR 43-57). Focal segmental glomerulosclerosis was the most common primary kidney disease (20%), followed by polycystic kidney disease (16%). 80% of patients underwent induction with basiliximab and none with anti-thymocyte globulin (ATG). Participants were followed for median time of 3.5 years (IQR 2.0-6.5). Acute rejection occurred in 24% of patients. Two patients lost their allografts and three died. Virological escape occurred in 28% of patients, with a maximum viral load of 190 copies/mL. In conclusion, kidney transplantation in PLWHIV in Australia is occurring with increasing frequency. Acute rejection is more common than in Australia's general transplant population, but this does not appear to be associated with higher rates of graft failure or mortality out to four years., (© 2023 The Authors. Nephrology published by John Wiley & Sons Australia, Ltd on behalf of Asian Pacific Society of Nephrology.)
- Published
- 2024
- Full Text
- View/download PDF
40. The first Australian uterus transplantation procedure: A result of a long-term Australian-Swedish research collaboration.
- Author
-
Deans R, Pittman J, Gerstl B, Haghighi K, Pleass H, KÄhler PD, Kvarnström N, Hseuh W, Keung K, Luxton G, Yong K, Caldas R, Byun L, Loo C, Tippett J, Caponas G, Moses D, Wan KM, Arulpragasam K, Kiely N, Brännström M, and Abbott J
- Subjects
- Female, Humans, Sweden, Australia, Uterus transplantation, Living Donors, Infertility, Female surgery
- Abstract
Aims: The aim is to report the results of Australia's first uterus transplantation (UTx)., Methods: Following long-standing collaboration between the Swedish and Australian teams, Human Research Ethics approval was obtained to perform six UTx procedures in a collaborative multi-site research study (Western Sydney Local District Health 2019/ETH13038), including Royal Hospital for Women, Prince of Wales Hospital, and Westmead Hospital in New Souh Wales. Surgeries were approved in both the live donor (LD) and deceased donor models in collaboration with the inaugural Swedish UTx team., Results: This is the first UTx procedure to occur in Australia, involving a mother donating her uterus to her daughter. The total operative time for the donor was 9 h 54 min. Concurrently, recipient surgery was synchronised to minimise graft ischaemic time, and the total operative time for the recipient was 6 h 12 min. Surgery was by laparotomy in the LD and recipient. The total warm ischaemic time of the graft was 1 h 53 min, and the cold ischaemic time was 2 h 17 min (total ischaemic time 4 h 10 min). The patient's first menstruation occurred 33 days after the UTx procedure., Conclusion: Twenty-five years of Swedish and Australian collaboration has led to Australia's first successfully performed UTx surgery at The Royal Hospital for Women, Sydney, Australia., (© 2023 The Authors. Australian and New Zealand Journal of Obstetrics and Gynaecology published by John Wiley & Sons Australia, Ltd on behalf of Royal Australian and New Zealand College of Obstetricians and Gynaecologists.)
- Published
- 2023
- Full Text
- View/download PDF
41. Cystatin C kidney functional reserve: a simple method to predict outcome in chronic kidney disease.
- Author
-
Christiadi D, Simpson C, O'brien K, Taylor K, Luxton G, Rossleigh M, Erlich J, and Endre ZH
- Subjects
- Adult, Biomarkers, Cohort Studies, Creatinine, Glomerular Filtration Rate, Humans, Kidney diagnostic imaging, Pentetic Acid, Renal Dialysis, Cystatin C, Renal Insufficiency, Chronic
- Abstract
Background: Kidney functional reserve (KFR), the only clinical kidney stress test, is not routinely measured because the complexity of measurement has limited clinical application. We investigated the utility of plasma cystatin C (CysC) after oral protein loading (PL) to determine KFR in Stages 3 and 4 chronic kidney disease (CKD)., Methods: Following a 24-h low-protein diet, KFR was measured after oral protein by hourly plasma CysC and compared with simultaneous creatinine clearance (CrCl) and radionuclide 99technetium diethylenetriaminepentaacetatic acid (Tc-99m-DTPA) measured glomerular filtration rate (mGFR) measurement in an observational, single-centre cohort study of adults with CKD Stages 3 and 4. Subjects were followed for 3 years for fast (F) or slow (S) CKD progression, dialysis requirement or death or a combination of major adverse kidney events (MAKEs)., Result: CysC, CrCl and Tc-99m-DTPA mGFR measurements of KFR in 19 CKD Stage 3 and 21 CKD Stage 4 patients yielded good agreement. KFR was not correlated with baseline kidney function. Eight CKD Stage 3 (42%) and 11 CKD Stage 4 (52%) subjects reached their lowest serum CysC concentration 4 h after PL. CysC KFR and baseline serum creatinine (sCr) predicted death or dialysis or MAKE-F with a respective area under the curve (AUC) of 0.73 [95% confidence interval (CI) 0.48-0.89] and 0.71 (95% CI 0.51-0.84). Including CysC KFR, age, baseline sCr and nadir CysC predicted a decrease in sCr-estimated GFR >1.2 mL/min/year (MAKE-S) with an AUC of 0.89., Conclusions: Serial CysC avoided timed urine collection and radionuclide exposure and yielded equivalent estimates of KFR. Serial CysC may facilitate monitoring of KFR in clinical practice., (© The Author(s) 2021. Published by Oxford University Press on behalf of ERA-EDTA.)
- Published
- 2022
- Full Text
- View/download PDF
42. Living kidney donor and recipient perspectives on their relationship: longitudinal semi-structured interviews.
- Author
-
Ralph AF, Butow P, Craig JC, Wong G, Chadban SJ, Luxton G, Gutman T, Hanson CS, Ju A, and Tong A
- Subjects
- Adult, Aged, Female, Humans, Interviews as Topic, Longitudinal Studies, Male, Middle Aged, Young Adult, Attitude, Interpersonal Relations, Kidney Transplantation psychology, Living Donors psychology
- Abstract
Background and Objectives: Many donors and recipients report an improved bond posttransplantation; however, unexpected conflicts and tension may also occur. Insights into the lived experiences of the donor-recipient relationship can inform strategies for interventions and support. We aimed to describe donor and recipient expectations and experiences of their relationship before and after living kidney donor transplantation., Design, Setting and Participants: Semistructured interviews were conducted with 16 donor-recipient pairs before the transplant and 11-14 months post-transplant. Transcripts were analysed thematically., Results: We identified seven themes (with respective subthemes): donation as enacting familial responsibility for care; analytical decision making to mitigate regret (avoiding anticipated regret and maintaining control, removing emotional impulsivity); strengthened interpersonal ties (gaining a deeper appreciation among family members, stronger empathy for each other, improving social participation); instability of relational impacts (anger and aggression threatening dynamics, unanticipated stress and emotional lability, triggering familial tension); renegotiating social roles (unexpected continuation of caregiving responsibilities, inability to relinquish the caregiving role, disappointment with unfulfilled renewal of intimacy, dissatisfaction over discrepant energy levels); guilt over unmet expectations and inevitability of the gift relationship (vague and transient indebtedness, expectation of reciprocity, transferring kidney ownership)., Conclusions: Donor-recipient relationships may be improved through increased empathy, appreciation, and ability to participate in life together; however, unfulfilled expectations and behavioural and emotional changes in recipients (a side effect related to immunosuppression) remain unresolved consequences of living kidney donor transplantation. Education and counselling to help donors and recipients adjust to potential changes in relationship dynamics may help protect and foster relational stability postdonation., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2019. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)
- Published
- 2019
- Full Text
- View/download PDF
43. Long-term outcomes of kidney transplant recipients with end-stage kidney disease attributed to presumed/advanced glomerulonephritis or unknown cause.
- Author
-
Lim WH, Wong G, McDonald SP, Chakera A, Luxton G, Isbel NM, Pilmore HL, Barbour T, Hughes P, and Chadban SJ
- Subjects
- Adult, Australia epidemiology, Female, Graft Rejection epidemiology, Graft Rejection etiology, Humans, Incidence, Kaplan-Meier Estimate, Kidney Failure, Chronic complications, Kidney Failure, Chronic epidemiology, Kidney Transplantation adverse effects, Male, Middle Aged, New Zealand epidemiology, Risk Factors, Glomerulonephritis complications, Graft Rejection diagnosis, Kidney Failure, Chronic therapy, Kidney Transplantation methods, Transplant Recipients statistics & numerical data
- Abstract
People with biopsy-proven glomerulonephritis (GN) as their cause of end-stage kidney disease (ESKD) who undergo kidney transplantation incur significant risk of recurrent GN-related graft failure, but the risk in recipients with ESKD where GN was suspected but not biopsy proven (presumed/advanced GN) and when the cause of ESKD is unknown remains uncertain. Using the Australia and New Zealand Dialysis and Transplant registry, we examined the associations between primary kidney transplant recipients whose ESKD was attributed to: 1) commonly-recurring GN (i.e. IgA nephropathy, membranoproliferative GN, focal segmental glomerulosclerosis and membranous GN), 2) presumed/advanced GN, and 3) cause of ESKD unknown (uESKD) and GN-related graft failure using adjusted competing risk models. Of 5258 recipients followed for a median of 8 years, 3539 (67.3%) had commonly-recurring GN, 1195 (22.7%) presumed/advanced GN, and 524 (10.0%) uESKD. Compared to recipients with commonly-recurring GN, recipients with presumed/advanced GN or uESKD experienced a low incidence of GN-related graft failure (<1%) and a lower hazard of GN-related graft failure (adjusted sub-distribution hazard ratio [HR] 0.28 [95%CI 0.15-0.54,p < 0.001] and 0.20 [95%CI 0.06-0.64,p = 0.007], respectively). People with ESKD attributed to either presumed/advanced GN or unknown cause face a very low risk of graft failure secondary to GN recurrence after transplantation.
- Published
- 2018
- Full Text
- View/download PDF
44. Donor and Recipient Views on Their Relationship in Living Kidney Donation: Thematic Synthesis of Qualitative Studies.
- Author
-
Ralph AF, Butow P, Hanson CS, Chadban SJ, Chapman JR, Craig JC, Kanellis J, Luxton G, and Tong A
- Subjects
- Humans, Qualitative Research, Attitude, Interpersonal Relations, Kidney Transplantation, Living Donors, Transplant Recipients
- Abstract
Background: Many donors and recipients report an improved relationship after transplantation; however, tension, neglect, guilt, and proprietorial concern over the recipient can impede donor and recipient well-being and outcomes. We aimed to describe donor and recipient expectations and experiences of their relationship in the context of living kidney donation., Study Design: Thematic synthesis of qualitative studies., Setting & Population: Living kidney donors and recipients., Search Strategy & Sources: Electronic databases were searched to October 2015., Analytical Approach: Thematic synthesis., Results: From 40 studies involving 1,440 participants (889 donors and 551 recipients) from 13 countries, we identified 6 themes. "Burden of obligation" described the recipient's perpetual sense of duty to demonstrate gratitude to the donor. "Earning acceptance" was the expectation that donation would restore relationships. "Developing a unique connection" reflected the inexplicable bond that donor-recipient dyads developed postdonation. "Desiring attention" was expressed by donors who wanted recognition for the act of donation and were envious and resentful of the attention the recipient received. "Retaining kidney ownership" reflected the donor's inclination to ensure that the recipient protected "their" kidney. "Enhancing social participation" encompassed relieving both the caregiver from the constraints of dialysis and the recipient from increased involvement and contribution in family life., Limitations: Non-English articles were excluded., Conclusions: Living kidney donation can strengthen donor-recipient relationships but may trigger or exacerbate unresolved angst, tension, jealousy, and resentment. Facilitating access to pre- and posttransplantation psychological support that addresses potential relationship changes may help donors and recipients better adjust to changes in the relationship dynamics, which in turn may contribute to improved psychosocial and transplantation outcomes following living kidney donation., (Copyright © 2016 National Kidney Foundation, Inc. Published by Elsevier Inc. All rights reserved.)
- Published
- 2017
- Full Text
- View/download PDF
45. Life-threatening hypocalcaemia associated with denosumab in advanced chronic kidney disease.
- Author
-
Killen JP, Yong K, Luxton G, and Endre Z
- Subjects
- Bone Density Conservation Agents administration & dosage, Calcium blood, Denosumab administration & dosage, Female, Humans, Middle Aged, Bone Density Conservation Agents adverse effects, Denosumab adverse effects, Hypocalcemia chemically induced, Osteoporosis drug therapy, Renal Insufficiency, Chronic complications
- Published
- 2016
- Full Text
- View/download PDF
46. Estimated Risk Level of Unified Stereotactic Body Radiation Therapy Dose Tolerance Limits for Spinal Cord.
- Author
-
Grimm J, Sahgal A, Soltys SG, Luxton G, Patel A, Herbert S, Xue J, Ma L, Yorke E, Adler JR, and Gibbs IC
- Subjects
- Humans, Radiation Injuries prevention & control, Radiotherapy Dosage, Risk, Radiation Tolerance, Radiosurgery methods, Spinal Cord radiation effects
- Abstract
A literature review of more than 200 stereotactic body radiation therapy spine articles from the past 20 years found only a single article that provided dose-volume data and outcomes for each spinal cord of a clinical dataset: the Gibbs 2007 article (Gibbs et al, 2007(1)), which essentially contains the first 100 stereotactic body radiation therapy (SBRT) spine treatments from Stanford University Medical Center. The dataset is modeled and compared in detail to the rest of the literature review, which found 59 dose tolerance limits for the spinal cord in 1-5 fractions. We partitioned these limits into a unified format of high-risk and low-risk dose tolerance limits. To estimate the corresponding risk level of each limit we used the Gibbs 2007 clinical spinal cord dose-volume data for 102 spinal metastases in 74 patients treated by spinal radiosurgery. In all, 50 of the patients were previously irradiated to a median dose of 40Gy in 2-3Gy fractions and 3 patients developed treatment-related myelopathy. These dose-volume data were digitized into the dose-volume histogram (DVH) Evaluator software tool where parameters of the probit dose-response model were fitted using the maximum likelihood approach (Jackson et al, 1995(3)). Based on this limited dataset, for de novo cases the unified low-risk dose tolerance limits yielded an estimated risk of spinal cord injury of ≤1% in 1-5 fractions, and the high-risk limits yielded an estimated risk of ≤3%. The QUANTEC Dmax limits of 13Gy in a single fraction and 20Gy in 3 fractions had less than 1% risk estimated from this dataset, so we consider these among the low-risk limits. In the previously irradiated cohort, the estimated risk levels for 10 and 14Gy maximum cord dose limits in 5 fractions are 0.4% and 0.6%, respectively. Longer follow-up and more patients are required to improve the risk estimates and provide more complete validation., Competing Interests: Conflict of Interests Notification: None of the authors has received any funding for this research. Dr. Grimm developed and holds intellectual property rights to the DVH Evaluator software tool which is an FDA-cleared product in commercial use, which has been used for this analysis., (Copyright © 2016 Elsevier Inc. All rights reserved.)
- Published
- 2016
- Full Text
- View/download PDF
47. The Effect of Different Glycaemic States on Renal Transplant Outcomes.
- Author
-
Sheu A, Depczynski B, O'Sullivan AJ, Luxton G, and Mangos G
- Subjects
- Adult, Cardiovascular Diseases complications, Female, Graft Rejection, Graft Survival, Hospitalization, Humans, Hyperglycemia complications, Male, Middle Aged, Perioperative Period, Renal Insufficiency complications, Retrospective Studies, Risk, Treatment Outcome, Blood Glucose analysis, Kidney Transplantation, Renal Insufficiency surgery
- Abstract
Background . Optimal glycaemic targets following transplantation are unknown. Understanding the impact of DM and posttransplant diabetes mellitus (PTDM) may improve patient and graft survival in transplant recipients. Aim . To determine the perioperative and one-year outcomes after renal transplantation and whether these outcomes are affected by preexisting DM, PTDM, or glycaemia during transplant admission. Method . Adult recipients of renal transplants from a single centre over 5.5 years were retrospectively reviewed. Measured outcomes during transplant admission included glycaemia and complications (infective complications, acute rejection, and return to dialysis) and, at 12 months, glycaemic control and complications (cardiovascular complication, graft failure). Results . Of 148 patients analysed, 29 (19.6%) had DM and 27 (18.2%) developed PTDM. Following transplantation, glucose levels were higher in patients with DM and PTDM. DM patients had a longer hospital stay, had more infections, and were more likely return to dialysis. PTDM patients had increased rates of acute rejection and return to dialysis. At 1 year after transplant, there were more cardiovascular complications in DM patients compared to those without DM. Conclusions . Compared to patients without DM, patients with DM or PTDM are more likely to suffer from complications perioperatively and at 12 months. Perioperative glycaemia is associated with graft function and may be a modifiable risk., Competing Interests: The authors have no conflict of interests to declare.
- Published
- 2016
- Full Text
- View/download PDF
48. Predictors of toxicity associated with stereotactic body radiation therapy to the central hepatobiliary tract.
- Author
-
Osmundson EC, Wu Y, Luxton G, Bazan JG, Koong AC, and Chang DT
- Subjects
- Adult, Aged, Aged, 80 and over, Carcinoma, Hepatocellular secondary, Dose Fractionation, Radiation, Dose-Response Relationship, Radiation, Female, Follow-Up Studies, Humans, Linear Models, Liver Neoplasms secondary, Male, Middle Aged, Radiosurgery methods, Relative Biological Effectiveness, Retrospective Studies, Stents, Bile Duct Neoplasms surgery, Bile Ducts, Intrahepatic radiation effects, Carcinoma, Hepatocellular surgery, Cholangiocarcinoma surgery, Liver radiation effects, Liver Neoplasms surgery, Radiation Injuries pathology, Radiosurgery adverse effects
- Abstract
Purpose: To identify dosimetric predictors of hepatobiliary (HB) toxicity associated with stereotactic body radiation therapy (SBRT) for liver tumors., Methods and Materials: We retrospectively reviewed 96 patients treated with SBRT for primary (53%) or metastatic (47%) liver tumors between March 2006 and November 2013. The central HB tract (cHBT) was defined by a 15-mm expansion of the portal vein from the splenic confluence to the first bifurcation of left and right portal veins. Patients were censored for toxicity upon local progression or additional liver-directed therapy. HB toxicities were graded according to Common Terminology Criteria for Adverse Events version 4.0. To compare different SBRT fractionations, doses were converted to biologically effective doses (BED) by using the standard linear quadratic model α/β = 10 (BED10)., Results: Median follow-up was 12.7 months after SBRT. Median BED10 was 85.5 Gy (range: 37.5-151.2). The median number of fractions was 5 (range: 1-5), with 51 patients (53.1%) receiving 5 fractions and 29 patients (30.2%) receiving 3 fractions. In total, there were 23 (24.0%) grade 2+ and 18 (18.8%) grade 3+ HB toxicities. Nondosimetric factors predictive of grade 3+ HB toxicity included cholangiocarcinoma (CCA) histology (P<.0001), primary liver tumor (P=.0087), and biliary stent (P<.0001). Dosimetric parameters most predictive of grade 3+ HB toxicity were volume receiving above BED10 of 72 Gy (VBED1072) ≥ 21 cm(3) (relative risk [RR]: 11.6, P<.0001), VBED1066 ≥ 24 cm(3) (RR: 10.5, P<.0001), and mean BED10 (DmeanBED10) cHBT ≥14 Gy (RR: 9.2, P<.0001), with VBED1072 and VBED1066 corresponding to V40 and V37.7 for 5 fractions and V33.8 and V32.0 for 3 fractions, respectively. VBED1072 ≥ 21 cm(3), VBED1066 ≥ 24 cm(3), and DmeanBED10 cHBT ≥14 Gy were consistently predictive of grade 3+ toxicity on multivariate analysis., Conclusions: VBED1072, VBED1066, and DmeanBED10 to cHBT are associated with HB toxicity. We suggest VBED1072 < 21 cm(3) (5-fraction: V40 < 21 cm(3); 3-fraction: V33.8 < 21 cm(3)), VBED1066 < 24 cm(3) (5-fraction: V37.7 < 24 cm(3); 3-fraction: V32 < 24 cm(3)) as potential dose constraints for the cHBT when clinically indicated., (Copyright © 2015 Elsevier Inc. All rights reserved.)
- Published
- 2015
- Full Text
- View/download PDF
49. Association between GFR estimated by multiple methods at dialysis commencement and patient survival.
- Author
-
Wong MG, Pollock CA, Cooper BA, Branley P, Collins JF, Craig JC, Kesselhut J, Luxton G, Pilmore A, Harris DC, and Johnson DW
- Subjects
- Australia epidemiology, Humans, Kaplan-Meier Estimate, Kidney Diseases mortality, Kidney Diseases physiopathology, Multivariate Analysis, Predictive Value of Tests, Proportional Hazards Models, Risk Factors, Time Factors, Treatment Outcome, Glomerular Filtration Rate, Kidney physiopathology, Kidney Diseases diagnosis, Kidney Diseases therapy, Models, Biological, Renal Dialysis adverse effects, Renal Dialysis mortality
- Abstract
Background and Objectives: The Initiating Dialysis Early and Late study showed that planned early or late initiation of dialysis, based on the Cockcroft and Gault estimation of GFR, was associated with identical clinical outcomes. This study examined the association of all-cause mortality with estimated GFR at dialysis commencement, which was determined using multiple formulas., Design, Setting, Participants, & Measurements: Initiating Dialysis Early and Late trial participants were stratified into tertiles according to the estimated GFR measured by Cockcroft and Gault, Modification of Diet in Renal Disease, or Chronic Kidney Disease-Epidemiology Collaboration formula at dialysis commencement. Patient survival was determined using multivariable Cox proportional hazards model regression., Results: Only Initiating Dialysis Early and Late trial participants who commenced on dialysis were included in this study (n=768). A total of 275 patients died during the study. After adjustment for age, sex, racial origin, body mass index, diabetes, and cardiovascular disease, no significant differences in survival were observed between estimated GFR tertiles determined by Cockcroft and Gault (lowest tertile adjusted hazard ratio, 1.11; 95% confidence interval, 0.82 to 1.49; middle tertile hazard ratio, 1.29; 95% confidence interval, 0.96 to 1.74; highest tertile reference), Modification of Diet in Renal Disease (lowest tertile hazard ratio, 0.88; 95% confidence interval, 0.63 to 1.24; middle tertile hazard ratio, 1.20; 95% confidence interval, 0.90 to 1.61; highest tertile reference), and Chronic Kidney Disease-Epidemiology Collaboration equations (lowest tertile hazard ratio, 0.93; 95% confidence interval, 0.67 to 1.27; middle tertile hazard ratio, 1.15; 95% confidence interval, 0.86 to 1.54; highest tertile reference)., Conclusion: Estimated GFR at dialysis commencement was not significantly associated with patient survival, regardless of the formula used. However, a clinically important association cannot be excluded, because observed confidence intervals were wide.
- Published
- 2014
- Full Text
- View/download PDF
50. Impact of chemotherapy on normal tissue complication probability models of acute hematologic toxicity in patients receiving pelvic intensity modulated radiation therapy.
- Author
-
Bazan JG, Luxton G, Kozak MM, Anderson EM, Hancock SL, Kapp DS, Kidd EA, Koong AC, and Chang DT
- Subjects
- Aged, Antineoplastic Agents administration & dosage, Anus Neoplasms therapy, Bone Marrow radiation effects, Chemoradiotherapy methods, Cisplatin administration & dosage, Cisplatin adverse effects, Drug Administration Schedule, Female, Fluorouracil administration & dosage, Fluorouracil adverse effects, Genital Neoplasms, Female therapy, Humans, Ilium radiation effects, Leukopenia etiology, Logistic Models, Lumbosacral Region radiation effects, Lymphatic Irradiation adverse effects, Lymphatic Irradiation methods, Male, Middle Aged, Mitomycin administration & dosage, Mitomycin adverse effects, Neutropenia etiology, Pelvic Bones diagnostic imaging, Pelvic Bones radiation effects, Pelvis, Probability, Prostatic Neoplasms therapy, Radiography, Radiotherapy Dosage, Radiotherapy, Intensity-Modulated methods, Rectal Neoplasms therapy, Regression Analysis, Retrospective Studies, Thrombocytopenia etiology, Antineoplastic Agents adverse effects, Bone Marrow drug effects, Chemoradiotherapy adverse effects, Radiation Tolerance drug effects, Radiotherapy, Intensity-Modulated adverse effects
- Abstract
Purpose: To determine how chemotherapy agents affect radiation dose parameters that correlate with acute hematologic toxicity (HT) in patients treated with pelvic intensity modulated radiation therapy (P-IMRT) and concurrent chemotherapy., Methods and Materials: We assessed HT in 141 patients who received P-IMRT for anal, gynecologic, rectal, or prostate cancers, 95 of whom received concurrent chemotherapy. Patients were separated into 4 groups: mitomycin (MMC) + 5-fluorouracil (5FU, 37 of 141), platinum ± 5FU (Cis, 32 of 141), 5FU (26 of 141), and P-IMRT alone (46 of 141). The pelvic bone was contoured as a surrogate for pelvic bone marrow (PBM) and divided into subsites: ilium, lower pelvis, and lumbosacral spine (LSS). The volumes of each region receiving 5-40 Gy were calculated. The endpoint for HT was grade ≥3 (HT3+) leukopenia, neutropenia or thrombocytopenia. Normal tissue complication probability was calculated using the Lyman-Kutcher-Burman model. Logistic regression was used to analyze association between HT3+ and dosimetric parameters., Results: Twenty-six patients experienced HT3+: 10 of 37 (27%) MMC, 14 of 32 (44%) Cis, 2 of 26 (8%) 5FU, and 0 of 46 P-IMRT. PBM dosimetric parameters were correlated with HT3+ in the MMC group but not in the Cis group. LSS dosimetric parameters were well correlated with HT3+ in both the MMC and Cis groups. Constrained optimization (0
- Published
- 2013
- Full Text
- View/download PDF
Catalog
Discovery Service for Jio Institute Digital Library
For full access to our library's resources, please sign in.