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Tulip R, Manolopoulos S, Richmond N, Walker C. An evaluation of an energy independent CT reconstruction algorithm for use in radiotherapy treatment planning. Br J Radiol 2023; 96:20230004. [PMID: 37751165 PMCID: PMC10646643 DOI: 10.1259/bjr.20230004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2023] [Revised: 07/06/2023] [Accepted: 07/06/2023] [Indexed: 09/27/2023] Open
Abstract
OBJECTIVE Radiotherapy treatment planning relies upon density information provided by CT for accurate dose calculations. Hounsfield units (HUs) are converted to electron/physical density via an energy dependant calibration curve. Multiple curves are required to make full use of the available accelerating potentials (kVp). The curves are bi-linear with a discontinuity occurring at soft-tissue densities. The commercial algorithm, DirectDensityTM (Siemens Healthcare GmbH), constructs a single calibration curve covering all available kVp. This enables the optimisation of the CT image quality, e.g. in terms of contrast, or the reduction of the imaging dose, whilst rendering the radiotherapy treatment dose calculation robust to the energy used to acquire the CT image. We report our investigations on the clinical utilisation of the DirectDensityTM algorithm for radiotherapy treatments, by using all accelerating potentials, i.e. from 70 kVp up to 140 kVp, available at our CT treatment simulator, in contrast to previous studies that were limited to accelerating potentials spanning a subset of the available kVp. METHODS The DirectDensityTM (DD) reconstruction algorithm available on a SOMATOM go.Open Pro CT scanner (Siemens Healthineers) was evaluated using the RayStation v. 9 treatment planning system (RaySearch Laboratories, Stockholm, Sweden) and a CIRS Model 002LFC IMRT Thorax Phantom (SunNuclear, Melbourne, FL), which was imaged at all available kVp with clinical protocols corresponding to various anatomical sites. The DD images were compared to those with the standard reconstruction algorithm acquired only at 120 kVp, as per our routine clinical practice. The effect of increasing kVp on HU is investigated for relevant tissue substitutes. In addition, a dosimetric comparison is performed for a VMAT plan technique with 6 MV X-rays using retrospective patient CT data sets representing four anatomical sites (pelvis, thorax, brain and "head and neck") with five patients for each site. The original dose distributions were calculated on images acquired at 120 kVp using the standard clinical iterative reconstruction (Qr40) and compared with dose distributions recalculated on images reconstructed with the new DD (Sm40) algorithm. RESULTS The maximum difference for radiotherapy doses calculated using images of the phantom reconstructed with Qr40 (120 kVp) or DD (all available kVp) was 0.73%. The patient plans on the anatomically representative sites studied here showed a mean PTV dose difference of -0.2% (s.d. 0.7) for D99%, -0.4% (s.d. 0.4%) for D50% and -0.3% (s.d. 0.4%) for D2%. Incidentally, we found a previously unreported decrease in HU, mostly notable for bone type inserts (~34 HU (cortical bone)), at 110 kVp for the DD reconstructed images. The effect was not noted for the standard Qr40 reconstructions. CONCLUSION DD has a minimal dosimetric impact in the dose calculations for radiotherapy treatments and could be implemented with existing clinical workflows. Attention should be paid to the HU values for images acquired at 110 kVp (DD algorithm), which warrants further investigation. ADVANCES IN KNOWLEDGE This is the first paper where DD was evaluated at all available kVp, leading to the incidental discovery of abnormal HU values at 110 kVp for this algorithm.
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Affiliation(s)
- Rachael Tulip
- Northern Centre for Cancer Care – North Cumbria, Newcastle upon Tyne Hospitals NHS Foundation Trust, Newcastle upon Tyne, United Kingdom
| | - Spyros Manolopoulos
- Northern Centre for Cancer Care – North Cumbria, Newcastle upon Tyne Hospitals NHS Foundation Trust, Newcastle upon Tyne, United Kingdom
| | - Neil Richmond
- Northern Centre for Cancer Care, Newcastle upon Tyne Hospitals NHS Foundation Trust, Newcastle upon Tyne, United Kingdom
| | - Christopher Walker
- Northern Centre for Cancer Care, Newcastle upon Tyne Hospitals NHS Foundation Trust, Newcastle upon Tyne, United Kingdom
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Richmond N, Chester K, Manley S. Evaluation of the RadCalc collapsed cone dose calculation algorithm against measured data. Med Dosim 2023; 48:216-224. [PMID: 37164787 DOI: 10.1016/j.meddos.2023.04.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2022] [Revised: 03/31/2023] [Accepted: 04/11/2023] [Indexed: 05/12/2023]
Abstract
This work describes the experimental validation of the RadCalc (Lifeline software Inc, Tyler) collapsed cone dose calculation algorithm against measured data for a range of scenarios. 6 MV photon beam data were measured in a large water tank on a Varian TrueBeam linear accelerator. These were input into the RadCalc software, in conjunction with head geometry and output calibration information, then used to create a collapsed cone beam model. The model performance was assessed by comparison against measurement, using a selection of homogeneous and inhomogeneous geometries not incorporated into the original beam model. Dose calculations generated using the collapsed cone algorithm are generally in good agreement with measurement. However, the primary collimating of the linac is not accounted for in the RadCalc model and hence dose in the corners of large fields is significantly overestimated. Percentage depth doses were within 0.5% beyond a depth of 2 cm. The dose in the build-up region was underestimated by RadCalc Version 7.1.4.1, with (Distance To Agreement) discrepancies of up to 3 mm which were corrected in Version 7.2.2.0. Beam profiles for homogeneous phantom comparisons were within 2% in the central 80% of the field with out of field dose underestimated by no more than 3%. Dose comparisons in heterogeneous geometries were acceptable and generally within 3.5%. The largest observed differences were found at density interfaces and a result of the RadCalc dose resolution of 2 mm against 1 mm measured. Absolute dose comparisons demonstrated that RadCalc agreed with measurement to within 1.2% under homogeneous media irradiation geometries. For static beam IMRT deliveries agreement was within 2% or 2 mm of measured data, and for complex VMAT deliveries within 3% or 2 mm. The implementation of the (model-based) photon collapsed cone algorithm in RadCalc shows generally good agreement with measured data over a range of simple and complex scenarios considered.
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Affiliation(s)
- Neil Richmond
- Department of Radiotherapy Physics, Northern Centre for Cancer Care, Freeman Hospital, Newcastle upon Tyne, NE7 7DN, UK.
| | - Katherine Chester
- Department of Radiotherapy Physics, Northern Centre for Cancer Care, Freeman Hospital, Newcastle upon Tyne, NE7 7DN, UK
| | - Steven Manley
- Department of Medical Physics, The James Cook University Hospital, Middlesbrough, TS4 3BW, UK
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Wyatt JJ, Pearson RA, Frew J, Walker C, Richmond N, Wilkinson M, Wilkes K, Driver S, West S, Karen P, Brooks-Pearson RL, Ainslie D, Wilkins E, McCallum HM. The first patients treated with MR-CBCT soft-tissue matching in a MR-only prostate radiotherapy pathway. Radiography (Lond) 2023; 29:347-354. [PMID: 36736147 DOI: 10.1016/j.radi.2023.01.015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2022] [Revised: 01/16/2023] [Accepted: 01/19/2023] [Indexed: 02/05/2023]
Abstract
INTRODUCTION Magnetic Resonance (MR)-only radiotherapy for prostate cancer has previously been reported using fiducial markers for on-treatment verification. MR-Cone Beam Computed Tomography (CBCT) soft-tissue matching does not require invasive fiducial markers and enables MR-only treatments to other pelvic cancers. This study evaluated the first clinical implementation of MR-only prostate radiotherapy using MR-CBCT soft-tissue matching. METHODS Twenty prostate patients were treated with MR-only radiotherapy using a synthetic (s)CT-optimised plan with MR-CBCT soft-tissue matching. Two MR sequences were acquired: small Field Of View (FOV) for target delineation and large FOV for organs at risk delineation, sCT generation and on-treatment verification. Patients also received a CT for validation. The prostate was independently contoured on the small FOV MR, copied to the registered CT and modified if there were MR-CT soft-tissue alignment differences (MR-CT volume). This was compared to the MR-only volume with a paired t-test. The treatment plan was recalculated on CT and the doses compared. Independent offline CT-CBCT matches for 5/20 fractions were performed by three therapeutic radiographers using the MR-only contours and compared to the online MR-CBCT matches using two one-sided paired t-tests for equivalence within ±1 mm. RESULTS The MR-only volumes were significantly smaller than MR-CT (p = 0.003), with a volume ratio 0.92 ± 0.02 (mean ± standard error). The sCT isocentre dose difference to CT was 0.2 ± 0.1%. MR-CBCT soft-tissue matching was equivalent to CT-CBCT (p < 0.001), with differences of 0.1 ± 0.2 mm (vertical), -0.1 ± 0.2 mm (longitudinal) and 0.0 ± 0.1 mm (lateral). CONCLUSIONS MR-only radiotherapy with soft-tissue matching has been successfully clinically implemented. It produced significantly smaller target volumes with high dosimetric and on-treatment matching accuracy. IMPLICATIONS FOR PRACTICE MR-only prostate radiotherapy can be safely delivered without using invasive fiducial markers. This enables MR-only radiotherapy to be extended to other pelvic cancers where fiducial markers cannot be used.
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Affiliation(s)
- J J Wyatt
- Northern Centre for Cancer Care, Newcastle Upon Tyne Hospitals NHS Foundation Trust, Newcastle, UK; Translational and Clinical Research Institute, Newcastle University, Newcastle, UK.
| | - R A Pearson
- Northern Centre for Cancer Care, Newcastle Upon Tyne Hospitals NHS Foundation Trust, Newcastle, UK; Translational and Clinical Research Institute, Newcastle University, Newcastle, UK
| | - J Frew
- Northern Centre for Cancer Care, Newcastle Upon Tyne Hospitals NHS Foundation Trust, Newcastle, UK
| | - C Walker
- Northern Centre for Cancer Care, Newcastle Upon Tyne Hospitals NHS Foundation Trust, Newcastle, UK
| | - N Richmond
- Northern Centre for Cancer Care, Newcastle Upon Tyne Hospitals NHS Foundation Trust, Newcastle, UK
| | - M Wilkinson
- Northern Centre for Cancer Care, Newcastle Upon Tyne Hospitals NHS Foundation Trust, Newcastle, UK
| | - K Wilkes
- Northern Centre for Cancer Care, Newcastle Upon Tyne Hospitals NHS Foundation Trust, Newcastle, UK
| | - S Driver
- Northern Centre for Cancer Care, Newcastle Upon Tyne Hospitals NHS Foundation Trust, Newcastle, UK
| | - S West
- Northern Centre for Cancer Care, Newcastle Upon Tyne Hospitals NHS Foundation Trust, Newcastle, UK
| | - P Karen
- Northern Centre for Cancer Care, Newcastle Upon Tyne Hospitals NHS Foundation Trust, Newcastle, UK
| | - R L Brooks-Pearson
- Northern Centre for Cancer Care, Newcastle Upon Tyne Hospitals NHS Foundation Trust, Newcastle, UK
| | - D Ainslie
- Northern Centre for Cancer Care, Newcastle Upon Tyne Hospitals NHS Foundation Trust, Newcastle, UK
| | - E Wilkins
- Northern Centre for Cancer Care, Newcastle Upon Tyne Hospitals NHS Foundation Trust, Newcastle, UK
| | - H M McCallum
- Northern Centre for Cancer Care, Newcastle Upon Tyne Hospitals NHS Foundation Trust, Newcastle, UK; Translational and Clinical Research Institute, Newcastle University, Newcastle, UK
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Lee J, Bates M, Shepherd E, Riley S, Henshaw M, Metherall P, Daniel J, Blower A, Scoones D, Wilkinson M, Richmond N, Robinson C, Cuculich P, Hugo G, Seller N, McStay R, Child N, Thornley A, Kelland N, Atherton P, Peedell C, Hatton M. Cardiac stereotactic ablative radiotherapy for control of refractory ventricular tachycardia: initial UK multicentre experience. Open Heart 2021; 8:openhrt-2021-001770. [PMID: 34815300 PMCID: PMC8611439 DOI: 10.1136/openhrt-2021-001770] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/23/2021] [Accepted: 11/01/2021] [Indexed: 12/25/2022] Open
Abstract
Background Options for patients with ventricular tachycardia (VT) refractory to antiarrhythmic drugs and/or catheter ablation remain limited. Stereotactic radiotherapy has been described as a novel treatment option. Methods Seven patients with recurrent refractory VT, deemed high risk for either first time or redo invasive catheter ablation, were treated across three UK centres with non-invasive cardiac stereotactic ablative radiotherapy (SABR). Prior catheter ablation data and non-invasive mapping were combined with cross-sectional imaging to generate radiotherapy plans with aim to deliver a single 25 Gy treatment. Shared planning and treatment guidelines and prospective peer review were used. Results Acute suppression of VT was seen in all seven patients. For five patients with at least 6 months follow-up, overall reduction in VT burden was 85%. No high-grade radiotherapy treatment-related side effects were documented. Three deaths (two early, one late) occurred due to heart failure. Conclusions Cardiac SABR showed reasonable VT suppression in a high-risk population where conventional treatment had failed.
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Affiliation(s)
- Justin Lee
- Department of Cardiology, Sheffield Teaching Hospitals NHS Foundation Trust, Sheffield, UK
| | - Matthew Bates
- Department of Cardiology, South Tees Hospital NHS Foundation Trust, Middlesbrough, UK
| | - Ewen Shepherd
- Department of Cardiology, Newcastle Hospitals NHS Foundation Trust, Newcastle upon Tyne, UK
| | - Stephen Riley
- Weston Park Cancer Centre, Sheffield Teaching Hospitals NHS Foundation Trust, Sheffield, UK
| | - Michael Henshaw
- Weston Park Cancer Centre, Sheffield Teaching Hospitals NHS Foundation Trust, Sheffield, UK
| | - Peter Metherall
- 3D Lab, Sheffield Teaching Hospitals NHS Foundation Trust, Sheffield, UK
| | - Jim Daniel
- Department of Oncology, South Tees Hospitals NHS Foundation Trust, Middlesbrough, UK
| | - Alison Blower
- Department of Oncology, South Tees Hospitals NHS Foundation Trust, Middlesbrough, UK
| | - David Scoones
- Department of Pathology, South Tees Hospital NHS Foundation Trust, Middlesbrough, UK
| | - Michele Wilkinson
- Northern Centre for Cancer Care, Newcastle Hospitals NHS Foundation Trust, Newcastle upon Tyne, UK
| | - Neil Richmond
- Northern Centre for Cancer Care, Newcastle Hospitals NHS Foundation Trust, Newcastle upon Tyne, UK
| | - Clifford Robinson
- Center for Noninvasive Cardiac Radioablation, Washington University School of Medicine in St Louis, St Louis, Missouri, USA
| | - Phillip Cuculich
- Center for Noninvasive Cardiac Radioablation, Washington University School of Medicine in St Louis, St Louis, Missouri, USA
| | - Geoffrey Hugo
- Center for Noninvasive Cardiac Radioablation, Washington University School of Medicine in St Louis, St Louis, Missouri, USA
| | - Neil Seller
- Department of Cardiology, Newcastle Hospitals NHS Foundation Trust, Newcastle upon Tyne, UK
| | - Ruth McStay
- Department of Radiology, Newcastle NHS Hospitals Foundation Trust, Newcastle Upon Tyne, UK
| | - Nicholas Child
- Department of Cardiology, South Tees Hospital NHS Foundation Trust, Middlesbrough, UK
| | - Andrew Thornley
- Department of Cardiology, South Tees Hospital NHS Foundation Trust, Middlesbrough, UK
| | - Nicholas Kelland
- Department of Cardiology, Sheffield Teaching Hospitals NHS Foundation Trust, Sheffield, UK
| | - Philip Atherton
- Northern Centre for Cancer Care, Newcastle Hospitals NHS Foundation Trust, Newcastle upon Tyne, UK
| | - Clive Peedell
- Department of Oncology, South Tees Hospitals NHS Foundation Trust, Middlesbrough, UK
| | - Matthew Hatton
- Weston Park Cancer Centre, Sheffield Teaching Hospitals NHS Foundation Trust, Sheffield, UK
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Richmond N, Angerud A, Tamm F, Allen V. Comparison of the RayStation photon Monte Carlo dose calculation algorithm against measured data under homogeneous and heterogeneous irradiation geometries. Phys Med 2021; 82:87-99. [PMID: 33601165 DOI: 10.1016/j.ejmp.2021.02.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/15/2020] [Revised: 02/02/2021] [Accepted: 02/06/2021] [Indexed: 10/22/2022] Open
Abstract
PURPOSE This work compares Monte Carlo dose calculations performed using the RayStation treatment planning system against data measured on a Varian Truebeam linear accelerator with 6 MV and 10 MV FFF photon beams. METHODS The dosimetric performance of the RayStation Monte Carlo calculations was evaluated in a variety of irradiation geometries employing homogeneous and heterogeneous phantoms. Profile and depth dose comparisons against measurement were carried out in relative mode using the gamma index as a quantitative measure of similarity within the central high dose regions. RESULTS The results demonstrate that the treatment planning system dose calculation engine agrees with measurement to within 2%/1 mm for more than 95% of the data points in the high dose regions for all test cases. A systematic underestimation was observed at the tail of the profile penumbra and out of field, with mean differences generally <0.5 mm or 1% of curve dose maximum respectively. Out of field agreement varied between evaluated beam models. CONCLUSIONS The RayStation implementation of photon Monte Carlo dose calculations show good agreement with measured data for the range of scenarios considered in this work and is deemed sufficiently accurate for introduction into clinical use.
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Affiliation(s)
- Neil Richmond
- Department of Radiotherapy Physics, Northern Centre for Cancer Care, Freeman Hospital, Freeman Road, Newcastle upon Tyne NE7 7DN, UK.
| | | | | | - Vincent Allen
- Department of Radiotherapy Physics, Northern Centre for Cancer Care, Freeman Hospital, Freeman Road, Newcastle upon Tyne NE7 7DN, UK
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Iqbal MS, West N, Richmond N, Kovarik J, Gray I, Willis N, Morgan D, Yazici G, Cengiz M, Paleri V, Kelly C. A systematic review and practical considerations of stereotactic body radiotherapy in the treatment of head and neck cancer. Br J Radiol 2021; 94:20200332. [PMID: 32960652 PMCID: PMC7774675 DOI: 10.1259/bjr.20200332] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2020] [Revised: 08/12/2020] [Accepted: 08/20/2020] [Indexed: 12/22/2022] Open
Abstract
OBJECTIVES Stereotactic radiotherapy (SBRT) is gaining popularity although its use in head and neck cancer (HNC) is not well defined. The primary objective was to review the published evidence regarding the use of stereotactic radiotherapy in HNC. METHODS A literature search was performed by using MEDLINE and EMBASE databases for eligible studies from 2000 to 2019 and 26 relevant studies were identified. RESULTS Literature demonstrates a heterogeneous use of this technique with regards to patient population, primary or salvage treatment, dose fractionation regimens, outcomes and follow-up protocols. Carotid blow out syndrome is a risk as with other forms of reirradiation but alternative treatment regimens may reduce this risk. CONCLUSION At present there is a lack of evidence regarding SBRT as a primary treatment option for HNC and definitive answers regarding efficacy and tolerability cannot be provided but there is growing evidence that SBRT reirradiation regimens are safe and effective. In lieu of evidence from large Phase III trials, we define appropriate organ at risk constraints and prescription doses, with accurate plan summation approaches. Prospective randomised trials are warranted to validate improved treatment outcomes and acceptable treatment morbidity. ADVANCES IN KNOWLEDGE This article provides a comprehensive review of evidence of use of stereotactic radiotherapy in HNC site (either as a primary treatment or as reirradiation). We also provide an evidence-based approach to the implementation and practical consideration of stereotactic radiotherapy in HNC.
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Affiliation(s)
- Muhammad Shahid Iqbal
- Department of Clinical Oncology, Northern Centre for Cancer Care, The Newcastle upon Tyne Hospitals NHS Foundation Trust, Newcastle upon Tyne, United Kingdom
| | - Nick West
- Department of Radiotherapy Physics, Northern Centre for Cancer Care, The Newcastle upon Tyne Hospitals NHS Foundation Trust, Newcastle upon Tyne, United Kingdom
| | - Neil Richmond
- Department of Radiotherapy Physics, Northern Centre for Cancer Care, The Newcastle upon Tyne Hospitals NHS Foundation Trust, Newcastle upon Tyne, United Kingdom
| | - Josef Kovarik
- Department of Clinical Oncology, Northern Centre for Cancer Care, The Newcastle upon Tyne Hospitals NHS Foundation Trust, Newcastle upon Tyne, United Kingdom
| | - Isabel Gray
- Department of Clinical Oncology, Northern Centre for Cancer Care, The Newcastle upon Tyne Hospitals NHS Foundation Trust, Newcastle upon Tyne, United Kingdom
| | - Nick Willis
- Department of Radiotherapy Dosimetry, Northern Centre for Cancer Care, The Newcastle upon Tyne Hospitals NHS Foundation Trust, Newcastle upon Tyne, United Kingdom
| | - David Morgan
- Department of Radiotherapy Physics, Northern Centre for Cancer Care, The Newcastle upon Tyne Hospitals NHS Foundation Trust, Newcastle upon Tyne, United Kingdom
| | - Gozde Yazici
- Department of Radiation Oncology, Hacettepe University, Ankara, Turkey
| | - Mustafa Cengiz
- Department of Radiation Oncology, Hacettepe University, Ankara, Turkey
| | - Vinidh Paleri
- The Royal Marsden NHS Foundation Trust, London, United Kingdom
| | - Charles Kelly
- Department of Clinical Oncology, Northern Centre for Cancer Care, The Newcastle upon Tyne Hospitals NHS Foundation Trust, Newcastle upon Tyne, United Kingdom
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McCallum H, Wyatt J, Frew J, Walker C, Richmond N, Wilkinson M, Driver S, Pilling K, Rachel L B, West S, Pearson R. PO-1794: Real-life experiences of an MR-Only prostate radiotherapy pathway with MR-CBCT soft-tissue matching. Radiother Oncol 2020. [DOI: 10.1016/s0167-8140(21)01812-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Wyatt J, Pearson R, Frew J, Walker C, Richmond N, Wilkinson M, Wilkes K, Driver S, West S, Pilling K, Brooks R, Ainslie D, Wilkins E, McCallum H. OC-0473: Evaluation of first 20 patients treated with MR-Only prostate radiotherapy with MR-CBCT matching. Radiother Oncol 2020. [DOI: 10.1016/s0167-8140(21)00495-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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McCallum HM, Andersson S, Wyatt JJ, Richmond N, Walker CP, Svensson S. Technical Note: Efficient and accurate MRI-only based treatment planning of the prostate using bulk density assignment through atlas-based segmentation. Med Phys 2020; 47:4758-4762. [PMID: 32682337 DOI: 10.1002/mp.14406] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2020] [Revised: 06/05/2020] [Accepted: 07/02/2020] [Indexed: 01/20/2023] Open
Abstract
PURPOSE This study investigates the dosimetric accuracy as well as the robustness of a bulk density assignment approach to magnetic resonance imaging (MRI)-only based treatment planning of the prostate, with bulk density regions automatically identified using atlas-based segmentation (ABS). METHODS Twenty prostate radiotherapy patients received planning computed tomography (CT) and MRI scans and were treated with volumetric modulated arc therapy (VMAT). Two bulk densities were set, one for bone and one for soft tissue. The bone contours were created by using ABS followed by manual modification if considered necessary. A range of soft tissue and bone density pairs, between 0.95 and 1.03 g/cm3 with increments of 0.01 for soft tissue, and between 1.15 and 1.65 g/cm3 with increments of 0.05 for bone, were evaluated. Using the density pair giving the lowest dose difference compared to the CT-based dose, dose differences were calculated using both the manually modified bone contours and the bone contours from ABS. Contour overlap measurements between the ABS contours and the manually modified contours were calculated. RESULTS The dose comparison shows a very good agreement with the CT when using 0.98 g/cm3 for soft tissue and 1.20 g/cm3 for bone, with a dose difference less than 1 % in average dose in all regions of interest. The mean Dice similarity coefficient for bone was 0.94 and the Mean Distance to Agreement was <1 mm in most cases. CONCLUSIONS Using bulk density assignment on MR images with suitable densities for bone and soft tissue results in clinically acceptable dose differences compared to dose calculated on the CT, for both atlas-based and manual bone contours. This demonstrates that an integrated MRI-only pathway utilizing a bulk density assignment for two tissue types is a feasible and robust approach for patients with prostate cancer treated with VMAT.
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Affiliation(s)
- Hazel Mhairi McCallum
- Northern Centre for Cancer Care, Newcastle upon Tyne Hospitals NHS Foundation Trust, Newcastle upon Tyne, NE7 7DN, UK
| | | | - Jonathan James Wyatt
- Northern Centre for Cancer Care, Newcastle upon Tyne Hospitals NHS Foundation Trust, Newcastle upon Tyne, NE7 7DN, UK
| | - Neil Richmond
- Northern Centre for Cancer Care, Newcastle upon Tyne Hospitals NHS Foundation Trust, Newcastle upon Tyne, NE7 7DN, UK
| | - Christopher Paul Walker
- Northern Centre for Cancer Care, Newcastle upon Tyne Hospitals NHS Foundation Trust, Newcastle upon Tyne, NE7 7DN, UK
| | - Stina Svensson
- RaySearch Laboratories AB (PUBL), PO Box 3297, Stockholm, SE-103 65, Sweden
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Abstract
Objectives: The objective of this work was to undertake a non-judgemental study of prostate planning practice across the UK by inviting all departments to undertake the same case. Methods: An invitation to take part in the study was sent to the Heads of all UK radiotherapy departments and posted on the UK Medical Physics mailbase. Individuals interested in participating were able to access a single anonymised CT dataset for download with the prostate gland, seminal vesicles, bladder, rectum, bowel, femoral heads, and penile bulb outlined. A brief patient history was also supplied. Participants were asked to create planning target volumes (PTVs) according to their local clinical protocol and plan to give 60 Gy in 20 fractions to the PTV receiving the highest dose. No guidance was given for acceptable organ at risk doses. Dicom plan and dose information was loaded back into ProKnow for analysis by contributors. Results: There were 102 plan submissions made to the study representing 48 different UK radiotherapy departments. Seventeen distinct methodologies for creating the prescription PTV from the prostate and seminal vesicles were identified with the ethos of the CHHIP trial protocol for margin growing followed in nearly two-thirds of cases. Positive correlations were found when assessing the doses received by the bladder and rectum against the volume of the PTV to which 60 Gy was prescribed. Conclusions: A national planning study whereby staff from a multitude of radiotherapy departments create plans based solely on a single dataset is feasible. The cohort of data was made available to all participants following the study to enable self-assessment and benchmarking against that of their peers. Advances in knowledge: This is the first UK wide treatment planning study to investigate local clinical prostate planning practice. This has given UK departments the opportunity to evaluate their planning practices against those of their peers.
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Affiliation(s)
- Timothy Taylor
- Department of Medical Physics & Bioengineering, Royal United Hospitals Bath NHS Foundation Trust, Combe Park, Bath, BA1 3NG
| | - Neil Richmond
- Northern Centre for Cancer Care, Freeman Hospital, Freeman Road, Newcastle upon Tyne, NE7 7DN
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Pilling K, Wilkinson M, Richmond N, Walker C, McQuillan L, Brooks R, Ogilvie A, Shepherd E, McStay R, Greenhalgh D, Seller N, Atherton P. Non-invasive cardiac radioablation for ventricular Tachycardia. Radiography (Lond) 2020. [DOI: 10.1016/j.radi.2019.11.020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Pearson RA, Brooks R, Driver S, Frew JA, Pedley ID, Pilling K, Richmond N, Walker C, West S, Wilkinson M, Wyatt J, McCallum H. Magnetic Resonance-only Workflow: Implementation in a UK Centre. Clin Oncol (R Coll Radiol) 2019; 32:278. [PMID: 31786082 DOI: 10.1016/j.clon.2019.10.009] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2019] [Accepted: 10/24/2019] [Indexed: 01/06/2023]
Affiliation(s)
- R A Pearson
- Northern Centre for Cancer Care, The Newcastle Upon Tyne Hospitals NHS Foundation Trust, Newcastle upon Tyne, UK; Newcastle University Centre for Cancer, Newcastle upon Tyne, UK
| | - R Brooks
- Northern Centre for Cancer Care, The Newcastle Upon Tyne Hospitals NHS Foundation Trust, Newcastle upon Tyne, UK
| | - S Driver
- Northern Centre for Cancer Care, The Newcastle Upon Tyne Hospitals NHS Foundation Trust, Newcastle upon Tyne, UK
| | - J A Frew
- Northern Centre for Cancer Care, The Newcastle Upon Tyne Hospitals NHS Foundation Trust, Newcastle upon Tyne, UK
| | - I D Pedley
- Northern Centre for Cancer Care, The Newcastle Upon Tyne Hospitals NHS Foundation Trust, Newcastle upon Tyne, UK
| | - K Pilling
- Northern Centre for Cancer Care, The Newcastle Upon Tyne Hospitals NHS Foundation Trust, Newcastle upon Tyne, UK
| | - N Richmond
- Northern Centre for Cancer Care, The Newcastle Upon Tyne Hospitals NHS Foundation Trust, Newcastle upon Tyne, UK
| | - C Walker
- Northern Centre for Cancer Care, The Newcastle Upon Tyne Hospitals NHS Foundation Trust, Newcastle upon Tyne, UK
| | - S West
- Northern Centre for Cancer Care, The Newcastle Upon Tyne Hospitals NHS Foundation Trust, Newcastle upon Tyne, UK
| | - M Wilkinson
- Northern Centre for Cancer Care, The Newcastle Upon Tyne Hospitals NHS Foundation Trust, Newcastle upon Tyne, UK
| | - J Wyatt
- Northern Centre for Cancer Care, The Newcastle Upon Tyne Hospitals NHS Foundation Trust, Newcastle upon Tyne, UK; Newcastle University Centre for Cancer, Newcastle upon Tyne, UK
| | - H McCallum
- Northern Centre for Cancer Care, The Newcastle Upon Tyne Hospitals NHS Foundation Trust, Newcastle upon Tyne, UK; Newcastle University Centre for Cancer, Newcastle upon Tyne, UK
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Richmond N, Allen V, Wyatt J, Codling R. Evaluation of the RayStation electron Monte Carlo dose calculation algorithm. Med Dosim 2019; 45:159-167. [PMID: 31629601 DOI: 10.1016/j.meddos.2019.09.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2019] [Revised: 06/25/2019] [Accepted: 09/14/2019] [Indexed: 11/26/2022]
Abstract
The aim of this work was to evaluate the accuracy of the RayStation treatment planning system electron Monte Carlo algorithm against measured data for a range of clinically relevant scenarios. This was done by comparing measured percentage depth dose data (PDD) in water, profiles at oblique incidence and with heterogeneities in the beam path, and output factor data and that generated using the RayStation treatment planning system Monte Carlo VMC++ based calculation algorithm. While electron treatments are widely employed in the radiotherapy setting accurate modelling is challenging (TPS) in the presence of patient being both heterogeneous and nonrectangular. Watertank-based measurements were made on a Varian TrueBeam linear accelerator covering electron beam energies 6 to 18 MeV. These included both normal and oblique incidence, heterogeneous geometries, and irregular shaped cut-outs. The measured geometries were replicated in RayStation and the Monte Carlo dose calculation engine used to generate dosimetric data for comparison against measurement in what were considered clinically relevant settings. Water-based PDDs and profile comparisons showed excellent agreement for all electron beam energies. Profiles measured with oblique beam incidence demonstrated acceptable agreement to the treatment planning system calculations although the correspondence worsened as the angle increased with the planning system overestimating the dose in the shoulder region. Profile measurements under inhomogeneities were generally good. The planning system had a tendency to overestimate dose under the heterogeneity and also demonstrated a broader penumbra than measurement. Of the 170 different output factors calculated in RayStation over the range of electron energies commissioned, 141 were within ± 3% of measured values and 164 within ± 5%. Four of the 6 comparisons beyond 5% were at 18 MeV and all had a cut-out edge within 3 cm of the beam central axis/measurement point. The RayStation implementation of a VMC++ electron Monte Carlo dose calculation algorithm shows good agreement with measured data for a range of scenarios studied and represented sufficient accuracy for clinical use.
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Affiliation(s)
- Neil Richmond
- Department of Radiotherapy Physics, Northern Centre for Cancer Care, Freeman Hospital, Newcastle upon Tyne NE7 7DN, UK.
| | - Vincent Allen
- Department of Radiotherapy Physics, Northern Centre for Cancer Care, Freeman Hospital, Newcastle upon Tyne NE7 7DN, UK
| | - Jonathan Wyatt
- Department of Radiotherapy Physics, Northern Centre for Cancer Care, Freeman Hospital, Newcastle upon Tyne NE7 7DN, UK
| | - Richard Codling
- Department of Radiotherapy Physics, Northern Centre for Cancer Care, Freeman Hospital, Newcastle upon Tyne NE7 7DN, UK
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Iqbal MS, Richmond N, Ogilvie A, Pilling K, Willis N, Byrne J, Walker C, West N. Dosimetric evaluation of VMAT for palliative radiotherapy for non-small cell lung carcinoma. Br J Radiol 2018; 91:20180146. [PMID: 29888967 DOI: 10.1259/bjr.20180146] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
OBJECTIVE: To compare the dosimetric consequences of volumetric modulated arc therapy (VMAT) for high-dose palliative thoracic radiotherapy through comparison with conventionally used isocentric parallel opposed pair (POP) of fields. METHODS: 20 consecutive patients with non-small cell lung cancer who received 36 Gy in 12 fractions using a POP technique were re-planned using a single VMAT arc. Salient dosimetric parameters were compared between the plans using a paired t-test. RESULTS: VMAT demonstrated dosimetric superiority; all PTV dose parameters were significantly improved and importantly the volume of normal lung receiving a high dose was also significantly reduced (mean volume of normal lung receiving 36 Gy was 12.9% in POP vs 1.8% in VMAT, p < 0.005). CONCLUSION: The standard POP technique does not take into account tissue densities which results in higher doses to the normal tissue outside the target volume and reduced conformity to the PTV. ADVANCES IN KNOWLEDGE: With the help of modern VMAT techniques, it is possible to effectively achieve highly conformal dose delivery which may provide an opportunity to escalate the dose to the tumour in this group of patients.
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Affiliation(s)
- Muhammad Shahid Iqbal
- 1 Department of Clinical Oncology, Northern Centre for Cancer Care, The Newcastle upon Tyne Hospitals NHS Foundation Trust , Newcastle upon Tyne , UK
| | - Neil Richmond
- 2 Department of Radiotherapy Physics, Northern Centre for Cancer Care, The Newcastle upon Tyne Hospitals NHS Foundation Trust , Newcastle upon Tyne , UK
| | - Audrey Ogilvie
- 3 Department of Therapeutic Radiography, Northern Centre for Cancer Care, The Newcastle upon Tyne Hospitals NHS Foundation Trust , Newcastle upon Tyne , UK
| | - Karen Pilling
- 3 Department of Therapeutic Radiography, Northern Centre for Cancer Care, The Newcastle upon Tyne Hospitals NHS Foundation Trust , Newcastle upon Tyne , UK
| | - Nicholas Willis
- 4 Department of Radiotherapy Dosimetry, Northern Centre for Cancer Care, The Newcastle upon Tyne Hospitals NHS Foundation Trust , Newcastle upon Tyne , UK
| | - John Byrne
- 2 Department of Radiotherapy Physics, Northern Centre for Cancer Care, The Newcastle upon Tyne Hospitals NHS Foundation Trust , Newcastle upon Tyne , UK
| | - Christopher Walker
- 2 Department of Radiotherapy Physics, Northern Centre for Cancer Care, The Newcastle upon Tyne Hospitals NHS Foundation Trust , Newcastle upon Tyne , UK
| | - Nicholas West
- 2 Department of Radiotherapy Physics, Northern Centre for Cancer Care, The Newcastle upon Tyne Hospitals NHS Foundation Trust , Newcastle upon Tyne , UK
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Iqbal M, West N, Ogilvie A, Willis N, Pilling K, Richmond N, Byrne J. A dosimetric comparative analysis of parallel opposed pair (POP) and volumetric modulated arc therapy (VMAT) techniques for high dose palliative radiotherapy (HDPRT) for non-small cell lung carcinoma. Lung Cancer 2018. [DOI: 10.1016/s0169-5002(18)30187-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Richmond N. The accuracy of treatment planning system dose modelling in the presence of brass mesh bolus. Rep Pract Oncol Radiother 2017; 22:354-359. [PMID: 28761391 DOI: 10.1016/j.rpor.2017.06.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2016] [Revised: 02/17/2017] [Accepted: 06/30/2017] [Indexed: 10/19/2022] Open
Abstract
AIM This work assesses the dosimetric accuracy of three commercial treatment planning system (TPS) photon dose calculation algorithms in the presence of brass mesh used as a bolus. BACKGROUND Bolus material is used in radiotherapy to provide dose build-up where superficial tissues require irradiation. They are generally water equivalent but high density materials can also be used. MATERIALS AND METHODS Dose calculations were performed on Monaco and Masterplan TPS (Elekta AB, Sweden) using phantoms defined by the three DICOM CT image sets of water equivalent blocks (no bolus, 1 layer and 2 layers of brass mesh) exported from the CT scanner. The effect of the mesh on monitor units, build-up dose, phantom exit dose and beam penumbra were compared to measured data. RESULTS Dose calculations for 6 and 15 MV photon beams on plain water equivalent phantoms were seen to agree well with measurement validating the basic planning system algorithms and models. Dose in the build-up region, phantom exit dose and beam penumbra were poorly modelled in the presence of the brass mesh. The beam attenuation created by the bolus material was overestimated by all three calculation algorithms, at both photon energies, e.g. 1.6% for one layer and up to 3.1% for two layers at 6 MV. The poor modelling of the physical situation in the build-up region is in part a consequence of the high HU artefact caused by the mesh in the CT image. CONCLUSIONS CT imaging is not recommended with the brass mesh bolus in situ due to the poor accuracy of the subsequent TPS modelling.
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Affiliation(s)
- Neil Richmond
- Department of Medical Physics, The James Cook University Hospital, Marton Road, Middlesbrough TS4 3BW, UK
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Peedell C, Aynsley E, Shakespeare D, Green J, Summers P, Reynolds J, Burke K, Bayles H, Huntley C, Richmond N. EP-1212: Are the encouraging SABR results for NSCLC reproducible outside of pioneering academic institutions? Radiother Oncol 2016. [DOI: 10.1016/s0167-8140(16)32462-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Richmond N, Tulip R, Walker C. Empirical determination of collimator scatter data for use in Radcalc commercial monitor unit calculation software: Implication for prostate volumetric modulated-arc therapy calculations. Med Dosim 2016; 41:53-8. [DOI: 10.1016/j.meddos.2015.08.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2015] [Revised: 07/28/2015] [Accepted: 08/28/2015] [Indexed: 11/16/2022]
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Shahid Iqbal M, Cyriac A, Aynsley E, Shakespeare D, Richmond N, Walker C, Piling K, Peedell C. 128: Experience of lung stereotactic ablative body radiotherapy (SABR) in a non-academic cancer centre in the UK. Lung Cancer 2015. [DOI: 10.1016/s0169-5002(15)50122-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Fleet J, Adegbola B, Richmond N, Humphries F, Hayes N. 53 * ADVANCE CARE PLANNING FOR CARE HOME RESIDENTS IN HOSPITAL USING PEACE (PROACTIVE ELDERLY ADVANCE CARE): PATIENT PRIORITISATION AND SELECTION, READMISSION AND PLACE OF DEATH. Age Ageing 2014. [DOI: 10.1093/ageing/afu036.53] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Leaning D, Mahtab N, Richmond N, Peedell C. 163 The retreatment of thoracic malignancies with curative doses of external beam radiotherapy – a case series. Lung Cancer 2014. [DOI: 10.1016/s0169-5002(14)70164-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Curtis H, Richmond N, Burke K, Walker C. Determination of monitor unit check tolerances based on a comparison with measurement and treatment planning system data. Med Dosim 2013; 38:81-7. [DOI: 10.1016/j.meddos.2012.07.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2012] [Revised: 07/09/2012] [Accepted: 07/30/2012] [Indexed: 10/27/2022]
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Carr R, Shakespeare D, Aynsley E, Lawless S, Summers P, Green J, Pilling K, Richmond N, Walker C, Peedell C. 178 Stereotactic ablative radiotherapy (SABR) for early stage, medically inoperable NSCLC: initial outcomes from 3 years experience at James Cook University Hospital (JCUH), Middlesbrough. Lung Cancer 2013. [DOI: 10.1016/s0169-5002(13)70178-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Richmond N, Green J, Peedell C, Shakespeare D, Walker C. Dosimetric Evaluation of a Conformal Seven-field Coplanar Technique for Planning Lung Stereotactic Body Radiotherapy. Clin Oncol (R Coll Radiol) 2012; 24:e24-30. [DOI: 10.1016/j.clon.2011.06.009] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2011] [Revised: 05/09/2011] [Accepted: 05/12/2011] [Indexed: 12/25/2022]
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Awunor OA, Lecomber AR, Richmond N, Walker C. A practical implementation of the 2010 IPEM high dose rate brachytherapy code of practice for the calibration of 192Ir sources. Phys Med Biol 2011. [DOI: 10.1088/0031-9155/56/19/6521] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Awunor OA, Lecomber AR, Richmond N, Walker C. A practical implementation of the 2010 IPEM high dose rate brachytherapy code of practice for the calibration of 192Ir sources. Phys Med Biol 2011; 56:5397-410. [PMID: 21804181 DOI: 10.1088/0031-9155/56/16/020] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
This paper details a practical method for deriving the reference air kerma rate calibration coefficient for Farmer NE2571 chambers using the U.K. Institute of Physics and Engineering in Medicine (IPEM) code of practice for the determination of the reference air kerma rate for HDR (192)Ir brachytherapy sources based on the National Physical Laboratory (NPL) air kerma standard. The reference air kerma rate calibration coefficient was derived using pressure, temperature and source decay corrected ionization chamber response measurements over three successive (192)Ir source clinical cycles. A secondary standard instrument (a Standard Imaging 1000 Plus well chamber) and four tertiary standard instruments (one additional Standard Imaging 1000 Plus well chamber and three Farmer NE2571 chambers housed in a perspex phantom) were used to provide traceability to the NPL primary standard and enable comparison of performance between the chambers. Conservative and optimized estimates on the expanded uncertainties (k = 2) associated with chamber response, ion recombination and reference air kerma rate calibration coefficient were determined. This was seen to be 2.3% and 0.4% respectively for chamber response, 0.2% and 0.08% respectively for ion recombination and 2.6% and 1.2% respectively for the calibration coefficient. No significant change in ion recombination with source decay was observed over the duration of clinical use of the respective 192Ir sources.
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Affiliation(s)
- O A Awunor
- The Regional Medical Physics Department, The James Cook University Hospital, Marton Road, Middlesbrough, TS4 3BW, UK.
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Richmond N, Pilling K, Thompson E, Walker C, Dunlop P. Image Guidance Derived Set-up Errors for Head and Neck IMRT Patients. Clin Oncol (R Coll Radiol) 2011. [DOI: 10.1016/j.clon.2011.01.473] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Peedell C, Green J, Shakespeare D, Richmond N, Thompson E, Pilling K, Summers P, Walker C. Building and implementing a lung stereotactic body radiotherapy (SBRT) programme in a non-academic radiotherapy centre The Middlesbrough experience. Lung Cancer 2010. [DOI: 10.1016/s0169-5002(10)70092-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Galea S, Blaney S, Nandi A, Silverman R, Vlahov D, Foltin G, Kusick M, Tunik M, Richmond N. Explaining racial disparities in incidence of and survival from out-of-hospital cardiac arrest. Am J Epidemiol 2007; 166:534-43. [PMID: 17584756 DOI: 10.1093/aje/kwm102] [Citation(s) in RCA: 135] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
A prospective observational study of 4,653 consecutive cases of out-of-hospital cardiac arrest (OOHCA) occurring in New York City from April 1, 2002, to March 31, 2003, was used to assess racial/ethnic differences in the incidence of OOHCA and 30-day survival after hospital discharge among OOHCA patients. The age-adjusted incidence of OOHCA per 10,000 adults was higher among Blacks than among persons in other racial/ethnic groups, and age-adjusted survival from OOHCA was higher among Whites compared with other groups. In analyses restricted to 3,891 patients for whom complete data on all variables were available, the age-adjusted relative odds of survival from OOHCA among Blacks were 0.4 (95% confidence interval: 0.2, 0.7) as compared with Whites. A full multivariable model accounting for demographic factors, prior functional status, initial cardiac rhythm, and characteristics of the OOHCA event explained approximately 41 percent of the lower age-adjusted survival among Blacks. The lower prevalence of ventricular fibrillation as the initial cardiac rhythm among Blacks relative to Whites was the primary contributor. A combination of factors probably accounts for racial/ethnic disparities in OOHCA survival. Previously hypothesized factors such as delays in emergency medical service response or differences in the likelihood of receipt of cardiopulmonary resuscitation did not appear to be substantial contributors to these racial/ethnic disparities.
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Affiliation(s)
- S Galea
- Department of Epidemiology, School of Public Health, University of Michigan, Ann Arbor, MI 48104, USA.
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Dearing JA, Richmond N, Plater AJ, Wolf J, Prandle D, Coulthard TJ. Modelling approaches for coastal simulation based on cellular automata: the need and potential. Philos Trans A Math Phys Eng Sci 2006; 364:1051-71. [PMID: 16537155 DOI: 10.1098/rsta.2006.1753] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
The paper summarizes the theoretical and practical needs for cellular automata (CA)-type models in coastal simulation, and describes early steps in the development of a CA-based model for estuarine sedimentation. It describes the key approaches and formulae used for tidal, wave and sediment processes in a prototype integrated cellular model for coastal simulation designed to simulate estuary sedimentary responses during the tidal cycle in the short-term and climate driven changes in sea-level in the long-term. Results of simple model testing for both one-dimensional and two-dimensional models, and a preliminary parameterization for the Blackwater Estuary, UK, are shown. These reveal a good degree of success in using a CA-type model for water and sediment transport as a function of water level and wave height, but tidal current vectors are not effectively simulated in the approach used. The research confirms that a CA-type model for the estuarine sediment system is feasible, with a real prospect for coupling to existing catchment and nearshore beach/cliff models to produce integrated coastal simulators of sediment response to climate, sea-level change and human actions.
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Affiliation(s)
- J A Dearing
- University of Liverpool, Department of Geography, Liverpool L69 7ZT, UK.
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Byrne J, Richmond N. 481 Head scatter modelling for irregularly shaped Varian MLC fields. Radiother Oncol 2005. [DOI: 10.1016/s0167-8140(05)81457-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Galea S, Blaney S, Silverman R, Kusick M, Vlahov D, Richmond N. 201: Racial Differences in Incidence of and Survival from Out-of-Hospital Cardiac Arrest in New York City. Am J Epidemiol 2005. [DOI: 10.1093/aje/161.supplement_1.s51] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- S Galea
- Center for Urban Epidemiologic Studies, New York City, NY 10029
| | - S Blaney
- Center for Urban Epidemiologic Studies, New York City, NY 10029
| | - R Silverman
- Center for Urban Epidemiologic Studies, New York City, NY 10029
| | - M Kusick
- Center for Urban Epidemiologic Studies, New York City, NY 10029
| | - D Vlahov
- Center for Urban Epidemiologic Studies, New York City, NY 10029
| | - N Richmond
- Center for Urban Epidemiologic Studies, New York City, NY 10029
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Richmond N. Survival from Out-of-hospital Cardiac Arrest in New York City: Ten Years Later. Acad Emerg Med 2005. [DOI: 10.1197/j.aem.2005.03.198] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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35
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Davis H, Richmond N, Lawrence GM. The relevance of clinical audit results to commissioning services. Breast Cancer Res 2004. [PMCID: PMC3300427 DOI: 10.1186/bcr886] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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Lawrence G, Richmond N, Wallon J. The 2001/02 ABS at BASO audit — repeat therapeutic operations and pre-operative history. EJC Suppl 2004. [DOI: 10.1016/s1359-6349(04)90729-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022] Open
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Netting MG, Richmond N. The Green Salamander, Aneides aeneus, in Northern West Virginia. COPEIA 1932. [DOI: 10.2307/1435905] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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