101
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Metcalfe P. Commentary to 'Ureteral obstruction following injection of dextranomer/hyaluronic acid copolymer: an infrequent but relevant complication'. J Pediatr Urol 2012; 8:520. [PMID: 22056308 DOI: 10.1016/j.jpurol.2011.10.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/13/2011] [Accepted: 10/14/2011] [Indexed: 10/15/2022]
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102
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Metcalfe P, Rigsby P, Pearson H, Lucas G. An International reference reagent for the detection of anti-human neutrophil antigen-1a. Vox Sang 2012; 104:153-8. [PMID: 22998424 DOI: 10.1111/j.1423-0410.2012.01647.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
BACKGROUND AND OBJECTIVES Testing for neutrophil antibodies has become more common as awareness of transfusion-related acute lung injury (TRALI) has increased. However, unlike other areas of blood cell antibody testing, there are no certified reference reagents available with which laboratories can determine the sensitivity of detection of their assays. This report describes the production and evaluation of a freeze-dried preparation of human plasma, code 09/284, containing anti-human neutrophil antigen-1a (anti-HNA-1a) for use as a minimum sensitivity reagent. MATERIALS AND METHODS One-millilitre of aliquots of plasma containing anti-HNA-1a were freeze-dried in glass ampoules. To characterize the material, 24 laboratories took part in an international collaborative study. The participants evaluated doubling dilutions of the material using their in-house routine assays and recorded the highest dilution in which the antibody could be detected. RESULTS When diluted 1 in 4, most laboratories were able to detect the anti-HNA-1a in the material, and the participants agreed that this was an appropriate level to set as the minimum sensitivity required. CONCLUSIONS In October 2011, the WHO Expert Committee on Biological Standardization approved the material 09/284 as an International Reference Reagent for the detection of anti-HNA-1a.
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Boyle J, Thorpe SJ, Hawkins JR, Lockie C, Fox B, Matejtschuk P, Halls C, Metcalfe P, Rigsby P, Armstrong-Fisher S, Varzi AM, Urbaniak S, Daniels G. International reference reagents to standardise blood group genotyping: evaluation of candidate preparations in an international collaborative study. Vox Sang 2012; 104:144-52. [DOI: 10.1111/j.1423-0410.2012.01641.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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104
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Quinn A, Holloway L, Koh ES, Delaney G, Arumugam S, Goozee G, Metcalfe P. Radiation dose and contralateral breast cancer risk associated with megavoltage cone-beam computed tomographic image verification in breast radiation therapy. Pract Radiat Oncol 2012; 3:93-100. [PMID: 24674311 DOI: 10.1016/j.prro.2012.05.003] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2012] [Revised: 05/06/2012] [Accepted: 05/08/2012] [Indexed: 11/19/2022]
Abstract
PURPOSE To measure and compare organ doses from a standard tangential breast radiation therapy treatment (50 Gy delivered in 25 fractions) and a megavoltage cone-beam computed tomography (MV-CBCT), taken for weekly image verification, and assess the risk of radiation-induced contralateral breast cancer. METHODS AND MATERIALS Organ doses were measured with thermoluminescent dosimeters placed strategically within a female anthropomorphic phantom. The risk of radiation-induced secondary cancer of the contralateral breast was estimated from these values using excess absolute risk and excess relative risk models. RESULTS The effective dose from a MV-CBCT (8-monitor units) was 35.9 ± 0.2 mSv. Weekly MV-CBCT imaging verification contributes 0.5% and 17% to the total ipsilateral and contralateral breast dose, respectively. For a woman irradiated at age 50 years, the 10-year postirradiation excess relative risk was estimated to be 0.8 and 0.9 for treatment alone and treatment plus weekly MV-CBCT imaging, respectively. The 10-year postirradiation excess absolute risk was estimated to be 4.7 and 5.6 per 10,000 women-years. CONCLUSIONS The increased dose and consequent radiation-induced second cancer risk as calculated by this study introduced by the imaging verification protocols utilizing MV-CBCT in breast radiation therapy must be weighed against the benefits of more accurate treatment. As additional image verification becomes more common, it is important that data be collected in regard to long-term malignancy risk.
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105
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Oborn BM, Metcalfe P, Crozier S, Bailey M, Keall P. TU-A-BRA-06: EPID Operation in a Bi-Directional MRI-Linac System: A Monte Carlo Study. Med Phys 2012. [DOI: 10.1118/1.4735874] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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106
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Dowdell S, Clasie B, Depauw N, Metcalfe P, Rosenfeld A, Kooy H, Flanz J, Paganetti H. MO-F-213AB-03: Potential Reduction in Out-Of-Field Dose in Pencil Beam Scanning Proton Therapy Through Use of a Patient-Specific Aperture. Med Phys 2012; 39:3872. [DOI: 10.1118/1.4735808] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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107
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Jameson M, Leon JD, Windsor A, Cloak K, Holloway L, Vial P, Sidhom M, Metcalfe P. TH-C-BRA-04: Endorectal Balloons in Post-Prostatectomy: Do Gains in Stability Lead to More Predictable Dosimetry? Med Phys 2012. [DOI: 10.1118/1.4736320] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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108
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Oborn BM, Metcalfe P, Butson M, Crozier S, Keall P. SU-E-T-20: Removal of Electron Contamination in Longitudinal Field MRI-Linac Systems: A Monte Carlo Study. Med Phys 2012; 39:3706. [PMID: 28519017 DOI: 10.1118/1.4735074] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
PURPOSE The prototype inline MRI-linac system has some advantages over perpendicular models including avoiding the electron return effect. One of the disadvantages of the inline approach is the increased skin dose, estimated to be 400-1000% of the dmax dose. The purpose of this work was to design a feasible method to reduce this skin dose to acceptable levels. METHODS Magnetic modeling of proposed MRI-linac designs have been simulated with the inclusion of an optimized permanent magnet system to purge/deflect the electron contamination. The region of air above the phantom was also replaced with a helium bag (region of helium gas) and a beam scrapper below the deflector was added to collect deflected off-axis contamination. Monte Carlo simulations were then performed including the accurate 3D magnetic field maps. Surface dosimetry was recorded to verify the changes to the skin doses. RESULTS Magnetic modelling showed that an optimized NdFeB permanent magnet system located outside the MRI coils (below the MLC's) can provide a strong enough region to purge/deflect a significant portion of the electron contamination from the x-ray beam. The impact on the MRI uniformity is around 100 ppm and hence is correctable via active/passive shimming of the MRI. The helium region also significantly limits the production of contamination traveling towards the phantom surface. Entry doses near CAX are predicted to be similar to the 0 T case. CONCLUSIONS Magnetic and Monte Carlo modeling were performed to estimate the effect that a permanent magnet purging system, beam scrapper, and helium bag would have on lowering the skin doses in an inline MRI-Linac system. MRI non-uniformities introduced by the deflector could be corrected, contamination is mostly purged or blocked, and the helium bag minimizes air-generated contamination. As a result skin doses are comparable to having zero magnetic field.
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109
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Dowdell SJ, Clasie B, Depauw N, Metcalfe P, Rosenfeld AB, Kooy HM, Flanz JB, Paganetti H. Monte Carlo study of the potential reduction in out-of-field dose using a patient-specific aperture in pencil beam scanning proton therapy. Phys Med Biol 2012; 57:2829-42. [PMID: 22513726 DOI: 10.1088/0031-9155/57/10/2829] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
This study is aimed at identifying the potential benefits of using a patient-specific aperture in proton beam scanning. For this purpose, an accurate Monte Carlo model of the pencil beam scanning (PBS) proton therapy (PT) treatment head at Massachusetts General Hospital (MGH) was developed based on an existing model of the passive double-scattering (DS) system. The Monte Carlo code specifies the treatment head at MGH with sub-millimeter accuracy. The code was configured based on the results of experimental measurements performed at MGH. This model was then used to compare out-of-field doses in simulated DS treatments and PBS treatments. For the conditions explored, the penumbra in PBS is wider than in DS, leading to higher absorbed doses and equivalent doses adjacent to the primary field edge. For lateral distances greater than 10 cm from the field edge, the doses in PBS appear to be lower than those observed for DS. We found that placing a patient-specific aperture at nozzle exit during PBS treatments can potentially reduce doses lateral to the primary radiation field by over an order of magnitude. In conclusion, using a patient-specific aperture has the potential to further improve the normal tissue sparing capabilities of PBS.
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110
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Wong JHD, Fuduli I, Carolan M, Petasecca M, Lerch MLF, Perevertaylo VL, Metcalfe P, Rosenfeld AB. Characterization of a novel two dimensional diode array the “magic plate” as a radiation detector for radiation therapy treatment. Med Phys 2012; 39:2544-58. [DOI: 10.1118/1.3700234] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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111
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Wong J, Cutajar D, Lerch M, Petasecca M, Knittel T, Carolan M, Perevertaylo V, Metcalfe P, Rosenfeld A. From HEP to medical radiation dosimetry – The silicon strip detector dose magnifying glass. RADIAT MEAS 2011. [DOI: 10.1016/j.radmeas.2011.06.031] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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112
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Quinn A, Holloway L, Cutajar D, Hardcastle N, Rosenfeld A, Metcalfe P. Megavoltage cone beam CT near surface dose measurements: potential implications for breast radiotherapy. Med Phys 2011; 38:6222-7. [DOI: 10.1118/1.3641867] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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113
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Metcalfe P, Rigsby P, Tait E, Urbaniak S. An international reference reagent for the detection of RHD and SRY DNA in plasma. Vox Sang 2011; 102:243-9. [DOI: 10.1111/j.1423-0410.2011.01543.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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114
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Seymour EL, Downes SJ, Fogarty GB, Izard MA, Metcalfe P. In vivo
real-time dosimetric verification in high dose rate prostate brachytherapy. Med Phys 2011; 38:4785-94. [DOI: 10.1118/1.3615161] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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115
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Wong JHD, Hardcastle N, Tomé WA, Bayliss A, Tolakanahalli R, Lerch MLF, Petasecca M, Carolan M, Metcalfe P, Rosenfeld AB. Independent quality assurance of a helical tomotherapy machine using the dose magnifying glass. Med Phys 2011; 38:2256-64. [PMID: 21626960 DOI: 10.1118/1.3566067] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
PURPOSE Helical tomotherapy is a complex delivery technique, integrating CT image guidance and intensity modulated radiotherapy in a single system. The integration of the CT detector ring on the gantry not only allows patient position verification but is also often used to perform various QA procedures. This convenience lacks the rigor of a machine-independent QA process. METHODS In this article, a Si strip detector, known as the Dose Magnifying Glass (DMG), was used to perform machine-independent QA measurements of the multileaf collimator alignment, leaf open time threshold, and leaf fluence output factor (LFOF). RESULTS The DMG measurements showed good agreements with EDR2 film for the MLC alignment test while the CT detector agrees well with DMG measurements for leaf open time threshold and LFOF measurements. The leaf open time threshold was found to be approximately 20 ms. The LFOF measured with the DMG agreed within error with the CT detector measured LFOF. CONCLUSIONS The DMG with its 0.2 mm spatial resolution coupled to TERA ASIC allowed real-time high temporal resolution measurements of the tomotherapy leaf movement. In conclusion, DMG was shown to be a suitable tool for machine-independent QA of a tomotherapy unit.
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116
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Oborn B, Metcalfe P, Keall P. SU-E-T-682: Skin Dose Changes in Transverse Field MRIGRT: The ERE or the LFP? Med Phys 2011. [DOI: 10.1118/1.3612644] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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117
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Metcalfe P, Gray D, Kiddoo D. Management of the Urinary Tract in Spina Bifida Cases Varies With Lesion Level and Shunt Presence. J Urol 2011; 185:2547-51. [DOI: 10.1016/j.juro.2011.01.025] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2010] [Indexed: 10/18/2022]
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118
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Oborn B, Metcalfe P, Butson M, Keall P, Rosenfeld A. SU-E-T-679: Electron Contamination Modeling in Longitudinal Field MRI-Linac Systems. Med Phys 2011. [DOI: 10.1118/1.3612641] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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119
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Deshpande S, Vial P, Holloway L, Metcalfe P. SU-E-T-226: Image Acquisition and Processing Characteristics of a Siemens EPID: Potential Problems for EPID Dosimetry. Med Phys 2011. [DOI: 10.1118/1.3612176] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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120
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Wong JHD, Knittel T, Downes S, Carolan M, Lerch MLF, Petasecca M, Perevertaylo VL, Metcalfe P, Jackson M, Rosenfeld AB. The use of a silicon strip detector dose magnifying glass in stereotactic radiotherapy QA and dosimetry. Med Phys 2011; 38:1226-38. [DOI: 10.1118/1.3549759] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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121
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Kelly A, Hardcastle N, Metcalfe P, Cutajar D, Quinn A, Foo K, Cardoso M, Barlin S, Rosenfeld A. Surface dosimetry for breast radiotherapy in the presence of immobilization cast material. Phys Med Biol 2011; 56:1001-13. [DOI: 10.1088/0031-9155/56/4/008] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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122
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Williams M, Metcalfe P, Rosenfeld A, Kron T, d’Errico F, Moscovitch M. Radiochromic Film Dosimetry and its Applications in Radiotherapy. ACTA ACUST UNITED AC 2011. [DOI: 10.1063/1.3576160] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
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123
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Metcalfe P, Kelly A, Hardcastle N, Foo K, Rosenfeld A. Surface Dosimetry for Breast Radiotherapy using MOSkins to Measure the Influence of Immobilization Cast Material. Int J Radiat Oncol Biol Phys 2010. [DOI: 10.1016/j.ijrobp.2010.07.1765] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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124
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Hardcastle N, Tomé WA, Foo K, Miller A, Carolan M, Metcalfe P. Comparison of prostate IMRT and VMAT biologically optimised treatment plans. Med Dosim 2010; 36:292-8. [PMID: 20801014 PMCID: PMC2995847 DOI: 10.1016/j.meddos.2010.06.001] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2009] [Revised: 05/13/2010] [Accepted: 06/10/2010] [Indexed: 11/18/2022]
Abstract
Recently, a new radiotherapy delivery technique has become clinically available--volumetric modulated arc therapy (VMAT). VMAT is the delivery of IMRT while the gantry is in motion using dynamic leaf motion. The perceived benefit of VMAT over IMRT is a reduction in delivery time. In this study, VMAT was compared directly with IMRT for a series of prostate cases. For 10 patients, a biologically optimized seven-field IMRT plan was compared with a biologically optimized VMAT plan using the same planning objectives. The Pinnacle RTPS was used. The resultant target and organ-at-risk dose-volume histograms (DVHs) were compared. The normal tissue complication probability (NTCP) for the IMRT and VMAT plans was calculated for 3 model parameter sets. The delivery efficiency and time for the IMRT and VMAT plans was compared. The VMAT plans resulted in a statistically significant reduction in the rectal V25Gy parameter of 8.2% on average over the IMRT plans. For one of the NTCP parameter sets, the VMAT plans had a statistically significant lower rectal NTCP. These reductions in rectal dose were achieved using 18.6% fewer monitor units and a delivery time reduction of up to 69%. VMAT plans resulted in reductions in rectal doses for all 10 patients in the study. This was achieved with significant reductions in delivery time and monitor units. Given the target coverage was equivalent, the VMAT plans were superior.
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125
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Rowe C, Goldring CEP, Kitteringham NR, Jenkins RE, Lane BS, Sanderson C, Elliott V, Platt V, Metcalfe P, Park BK. Network analysis of primary hepatocyte dedifferentiation using a shotgun proteomics approach. J Proteome Res 2010; 9:2658-68. [PMID: 20373825 DOI: 10.1021/pr1001687] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The liver is the major site of xenobiotic metabolism and detoxification. Primary cultures of hepatocytes are a vital tool in the development of new therapeutic agents but their utility is hindered by the rapid loss of phenotype. Hepatocytes cultured in a sandwich of extracellular matrix protein maintain better hepatic function compared with cells cultured as a monolayer but a wide-ranging proteomics study of the differences in cultures has never been performed. We characterize the changing phenotype of rat hepatocytes in primary culture using iTRAQ proteomics and systems biology network analysis of the identified, significantly regulated, proteins. A total of 754 unique proteins were identified from 4 independent experiments. Of these, 413 proteins were common to at least 3 experiments and 328 proteins were identified in all experiments. Both culture systems displayed altered expression of many common proteins. Network analysis showed that the primary functions of these proteins were in metabolic pathways, immune responses and cytoskeleton remodelling. Monolayer cultures uniquely regulate proteins mapping to pathways of oxidative stress and cell migration, whereas sandwich culture affected translation regulation and apoptosis pathways. These experiments provide a detailed proteomics data set to direct further work into maintaining hepatic phenotype using cultured primary hepatocytes and stem cell derived hepatocyte-like cells.
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