1
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Drabble J, Das P, George B, Camilleri P, Morris A. Based on 0.35 T magnetic resonance-guided radiotherapy, what are the nonisotropic PTV margins required for conventional prostate radiotherapy? Med Dosim 2022; 47:334-341. [PMID: 35907693 DOI: 10.1016/j.meddos.2022.06.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2021] [Revised: 05/31/2022] [Accepted: 06/23/2022] [Indexed: 10/16/2022]
Abstract
This study aims to calculate planning target volume (PTV) margins for the prostate and seminal vesicles (SVs) from the use of magnetic resonance-guided radiation therapy (MRgRT). And whether nonisotropic PTV margins are beneficial for these structures. Organ motion is linked to the displacement of the prostate and SVs. From the use of MRgRT, the nearby organs at risk (OAR) can be visualized both inter- and intrafraction. This study looked to determine if there is a correlation between interfractional OAR changes and displacements to the prostate and SVs. Inter- and intrafractional data from 20 consecutive prostate cancer patients treated using extreme hypofractionated 0.35 T MRgRT indicated prostate and SV motion during treatment. Tracking points (TPs) on 2D sagittal cine-MRI enabled assessment of this intrafractional motion. To determine a correlation between rectal changes and target displacements, the rectal diameter (RD) changes were compared against the displacement differences (DDs) at the prostate and SVs. Eighty percent of patients required intrafractional imaging corrections during radiotherapy, including 16/100 fractions due to rectal volume increases and 24/100 fractions due to bladder volume increases. The frequency of ≥3 mm intrafraction displacement was considerably greater in TPs in the SV than in the prostate. A moderate positive correlation (R2 = 0.417) was shown between RD changes and DDs at the level of the prostate and SVs. The PTV margins required for 90% of the patient cohort for prostate and SVs are nonuniform in different directions, and the margin is larger for SVs. Organ motion contributed toward prostate and SV displacements and showed the importance of a robust bladder and rectal-filling protocol.
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Affiliation(s)
| | | | - Ben George
- GenesisCare UK, radiotherapy, Oxford, England.
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2
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Souleyman S, Maria KD, Cheikh T, Karima KK. Impact of Acquisition Protocols on Accuracy of Dose Calculation Based on XVI Cone Beam Computed Tomography. J Med Phys 2021; 46:94-104. [PMID: 34566289 PMCID: PMC8415252 DOI: 10.4103/jmp.jmp_128_20] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2020] [Revised: 04/19/2021] [Accepted: 04/23/2021] [Indexed: 11/26/2022] Open
Abstract
Purpose: The objective of this work is to study the impact of acquisition protocols on the accuracy of cone beam computed tomography (CBCT)-based dose calculation and to determinate its limits from image characteristics such as image quality, Hounsfield numbers consistency, and restrictive sizes of volume acquisition, compared to the CT imaging for the different anatomy localizations: head and neck (H&N), thorax, and pelvis. Materials and Methods: In this work, we used a routine on-board imaging CBCT of the XVI system (Elekta, Stockholm, Sweden). Dosimetric calculations performed on CT images require the knowledge of the Hounsfield unit-relative electron density (HU-ReD) calibration curve, which is determined for each imaging technology and must be adapted to the imaging acquisition parameters (filter/field of view). The accuracy of the dose calculation from CBCT images strongly depends on the quality of these images and also on the appropriate correspondence to the electronic densities, which will be used by the treatment planning system to simulate the dose distribution. In this study, we evaluated the accuracy of the dose calculation for each protocol, as already pointed in many studies. Results: As a result, the protocols that give better results in terms of dose calculation are F0S20 for the H&N region and F1M20 for the thoracic and pelvic regions, with an error <2% compared to results obtained with CT images. In addition, the dose distributions obtained with CT and CBCT imaging modalities were compared by two different methods. The first comparison was done by gamma index in three planes (sagittal, coronal, and transverse) with 2%; 2 mm criteria. The results showed good correspondence, with more than 95% of points passed the criteria. We also compared the target volume, the organs at risk (OARs), and the maximum and minimum doses for the three localizations (H&N, thorax, and pelvis) in CT and CBCT imaging modalities using a Rando phantom. Conclusions: The choice of the adequate CBCT acquisition protocol and the appropriate phantom to determine the HU-ReD calibration curve provides a better precision in the calculation of dose on CBCT images. This allows improving the results obtained when using the HU-ReD calibration method for dose calculation in adaptive radiotherapy.
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Affiliation(s)
- Slimani Souleyman
- Department of Radiotherapy, HCA Hospital, Kouba, Algeria.,SNIRM Laboratory, Faculty of Physics, University of Sciences and Technology Houari Boumediene, Algiers, ALGERIA
| | - Khalal Dorea Maria
- Dosage, Analyse and Characterisation in High Resolution Laboratory, Department of Physics, Ferhat Abbas Setif 1 University, Setif, Algeria
| | - Tyeb Cheikh
- Department of Radiotherapy, HCA Hospital, Kouba, Algeria
| | - Khalal-Kouache Karima
- SNIRM Laboratory, Faculty of Physics, University of Sciences and Technology Houari Boumediene, Algiers, ALGERIA
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3
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Scobioala S, Kittel C, Elsayad K, Kroeger K, Oertel M, Samhouri L, Haverkamp U, Eich HT. A treatment planning study comparing IMRT techniques and cyber knife for stereotactic body radiotherapy of low-risk prostate carcinoma. Radiat Oncol 2019; 14:143. [PMID: 31399115 PMCID: PMC6689170 DOI: 10.1186/s13014-019-1353-6] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2019] [Accepted: 08/01/2019] [Indexed: 02/14/2023] Open
Abstract
PURPOSE Comparing radiation treatment plans by using the same safety margins and dose objectives for all techniques, to ascertain the optimal radiation technique for the stereotactic body radiotherapy (SBRT) of low-risk prostate cancer. MATERIAL AND METHODS Treatment plans for 27 randomly selected patients were compared using intensity-modulated (IMRT) techniques as Sliding Window (SW), volumetric modulated arc therapy (VMAT), and helical tomotherapy (HT), as well as Cyber Knife (CK) system. The target dose was calculated to 36.25 Gy delivered in five fractions over 1 week. Dosimetric indices for target volume and organs at risk (OAR) as well as normal tissue complication probability (NTCP) of late rectal and urinary bladder toxicities were analyzed. RESULTS The CK provided lower homogeneity in the target volume, but higher values for most of the conformity indices compared to the IMRT approaches. The SW demonstrated superior rectum sparing at medium-to-high dose range (V18 Gy - V32.6 Gy) compared to other techniques (p < 0.05). The whole urinary bladder experienced the best shielding by SW and VMAT at the medium dose (V18 Gy, p < 0.05 versus CK), however we obtained no relevant differences between techniques at the high dose. Generally, the CK demonstrated significantly superior rectum and bladder exposure at V18 Gy as compared to HT, SW, and VMAT. For the rectum, mean NTCP values were significantly superior for HT (NTCP = 2.3%, p < 0.05), and for urinary bladder, the NTCP showed no significant advantages for any technique. CONCLUSION No absolute dosimetric advantage was revealed to choose between CK or IMRT techniques for the SBRT of low-grade prostate cancer. Using the same safety margins and dose objectives, IMRT techniques demonstrated superior sparing of the rectum and bladder at a medium dose compared to CK. Comparing different IMRT approaches SW displayed superior rectum sparing at a medium-to-high dose range, whereas both SW and RA revealed superior bladder sparing compared to HT. HT demonstrated a significantly lower NTCP outcome compared to CK or IMRT techniques regarding the rectum. Radiation plans can be optimized further by an individual modification of dose objectives independent of the treatment plan strategy.
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Affiliation(s)
- Sergiu Scobioala
- Department of Radiation Oncology of the University Hospital Muenster, Albert-Schweitzer-Campus 1, Gebäude 1, 48149 Muenster, Germany
| | - Christopher Kittel
- Department of Radiation Oncology of the University Hospital Muenster, Albert-Schweitzer-Campus 1, Gebäude 1, 48149 Muenster, Germany
| | - Khaled Elsayad
- Department of Radiation Oncology of the University Hospital Muenster, Albert-Schweitzer-Campus 1, Gebäude 1, 48149 Muenster, Germany
| | - Kai Kroeger
- Department of Radiation Oncology of the University Hospital Muenster, Albert-Schweitzer-Campus 1, Gebäude 1, 48149 Muenster, Germany
| | - Michael Oertel
- Department of Radiation Oncology of the University Hospital Muenster, Albert-Schweitzer-Campus 1, Gebäude 1, 48149 Muenster, Germany
| | - Laith Samhouri
- Department of Radiation Oncology of the University Hospital Muenster, Albert-Schweitzer-Campus 1, Gebäude 1, 48149 Muenster, Germany
| | - Uwe Haverkamp
- Department of Radiation Oncology of the University Hospital Muenster, Albert-Schweitzer-Campus 1, Gebäude 1, 48149 Muenster, Germany
| | - Hans Theodor Eich
- Department of Radiation Oncology of the University Hospital Muenster, Albert-Schweitzer-Campus 1, Gebäude 1, 48149 Muenster, Germany
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4
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Zilli T, Scorsetti M, Zwahlen D, Franzese C, Förster R, Giaj-Levra N, Koutsouvelis N, Bertaut A, Zimmermann M, D'Agostino GR, Alongi F, Guckenberger M, Miralbell R. ONE SHOT - single shot radiotherapy for localized prostate cancer: study protocol of a single arm, multicenter phase I/II trial. Radiat Oncol 2018; 13:166. [PMID: 30180867 PMCID: PMC6123974 DOI: 10.1186/s13014-018-1112-0] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2018] [Accepted: 08/22/2018] [Indexed: 11/14/2022] Open
Abstract
Background Stereotactic body radiotherapy (SBRT) is an emerging treatment alternative for patients with localized prostate cancer. Promising results in terms of disease control and toxicity have been reported with 4 to 5 SBRT fractions. However, question of how far can the number of fractions with SBRT be reduced is a challenging research matter. As already explored by some authors in the context of brachytherapy, monotherapy appears to be feasible with an acceptable toxicity profile and a promising outcome. The aim of this multicenter phase I/II prospective trialis to demonstrate early evidence of safety and efficacy of a single-fraction SBRT approach for the treatment of localized disease. Methods Patients with low- and intermediate-risk localized prostate cancer without significant tumor in the transitional zone will be treated with a single SBRT fraction of 19 Gy to the whole prostate gland with urethra-sparing (17 Gy). Intrafractional motion will be monitored with intraprostatic electromagnetic transponders. The primary endpoint of the phase I part of the study will be safety as assessed by CTCAE 4.03 grading scale, while biochemical relapse-free survival will be the endpoint for the phase II. The secondary endpoints include acute and late toxicity, quality of life, progression-free survival, and prostate-cancer specific survival. Discussion This is the first multicenter phase I/II trial assessing the efficacy and safety of a single-dose SBRT treatment for patients with localized prostate cancer. If positive, results of ONE SHOT may help to design subsequent phase III trials exploring the role of SBRT monotherapy in the exclusive radiotherapy treatment of localized disease. Trial registration Clinicaltrials.gov identifier: NCT03294889; Registered 27 September 2017.
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Affiliation(s)
- Thomas Zilli
- Radiation Oncology, Geneva University Hospital, CH-1211, 14, Geneva, Switzerland. .,Faculty of Medicine, Geneva University, Geneva, Switzerland.
| | - Marta Scorsetti
- Radiation Oncology, Humanitas University, Rozzano, Milan, Italy.,Radiation Oncology, Humanitas Research Hospital and Cancer Center, Rozzano, Milan, Italy
| | - Daniel Zwahlen
- Radiation Oncology, Kantonsspital Graubünden, Chur, Switzerland
| | - Ciro Franzese
- Radiation Oncology, Humanitas Research Hospital and Cancer Center, Rozzano, Milan, Italy
| | - Robert Förster
- Radiation Oncology, University Hospital Zürich, Zürich, Switzerland
| | | | | | - Aurelie Bertaut
- Methodology and biostatistic unit, Centre Georges François Leclerc, Dijon, France
| | | | | | - Filippo Alongi
- Radiation Oncology, Sacro Cuore Don-Calabria, Negrar, Italy.,Faculty of Medecine, University of Brescia, Brescia, Italy
| | | | - Raymond Miralbell
- Radiation Oncology, Geneva University Hospital, CH-1211, 14, Geneva, Switzerland.,Faculty of Medicine, Geneva University, Geneva, Switzerland
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5
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Benedek H, Lerner M, Nilsson P, Knöös T, Gunnlaugsson A, Ceberg C. The effect of prostate motion during hypofractionated radiotherapy can be reduced by using flattening filter free beams. PHYSICS & IMAGING IN RADIATION ONCOLOGY 2018; 6:66-70. [PMID: 33458391 PMCID: PMC7807632 DOI: 10.1016/j.phro.2018.05.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/09/2017] [Revised: 05/04/2018] [Accepted: 05/06/2018] [Indexed: 11/29/2022]
Abstract
Background and purpose Hypofractionated radiotherapy of prostate cancer reduces the overall treatment time but increases the per-fraction beam-on time due to the higher fraction doses. This increased fraction treatment time results in a larger uncertainty of the prostate position. The purpose of this study was to investigate the effect of prostate motion during flattening filter free (FFF) Volumetric Modulated Arc Therapy (VMAT) in ultrahypofractionation of prostate cancer radiotherapy with preserved plan quality compared to conventional flattened beams. Materials and methods Nine prostate patients from the Scandinavian HYPO-RT-PC trial were re-planned using VMAT technique with both conventional and flattening filter free beams. Two fractionation schedules were used, one hypofractionated (42.7 Gy in 7 fractions), and one conventional (78.0 Gy in 39 fractions). Pre-treatment verification measurements were performed on all plans and the treatment time was recorded. Measurements with simulated prostate motion were performed for the plans with the longest treatment times. Results All the 10FFF plans fulfilled the clinical gamma pass rate, 90% (3%, 2 mm), during all simulated prostate motion trajectories. The 10MV plans only fulfilled the clinical pass rate for three of the trajectories. The mean beam-on-time for the hypofractionated plans were reduced from 2.3 min to 1.0 min when using 10FFF compared to 10MV. No clinically relevant differences in dose distribution were identified when comparing the plans with different beam qualities. Conclusion Flattening-filter free VMAT reduces treatment times, limiting the dosimetric effect of organ motion for ultrahypofractionated prostate cancer with preserved plan quality.
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Affiliation(s)
- Hunor Benedek
- Department of Haematology, Oncology and Radiation Physics, Skåne University Hospital, Lund, Sweden.,Department of Medical Radiation Physics, Clinical Sciences, Lund University, Lund, Sweden
| | - Minna Lerner
- Department of Haematology, Oncology and Radiation Physics, Skåne University Hospital, Lund, Sweden
| | - Per Nilsson
- Department of Haematology, Oncology and Radiation Physics, Skåne University Hospital, Lund, Sweden.,Department of Medical Radiation Physics, Clinical Sciences, Lund University, Lund, Sweden
| | - Tommy Knöös
- Department of Haematology, Oncology and Radiation Physics, Skåne University Hospital, Lund, Sweden.,Department of Medical Radiation Physics, Clinical Sciences, Lund University, Lund, Sweden
| | - Adalsteinn Gunnlaugsson
- Department of Haematology, Oncology and Radiation Physics, Skåne University Hospital, Lund, Sweden
| | - Crister Ceberg
- Department of Medical Radiation Physics, Clinical Sciences, Lund University, Lund, Sweden
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6
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Vanasek J, Odrazka K, Dolezel M, Dusek L, Jarkovsky J, Hlavka A, Valentova E, Kolarova I. Searching for an Appropriate Image-guided Radiotherapy Method in Prostate Cancer – Implications for Safety Margin. TUMORI JOURNAL 2018. [DOI: 10.1177/1660.18168] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- Jaroslav Vanasek
- Cancer Center Multiscan, Pardubice
- Faculty of Health Studies, Pardubice University, Pardubice
- Faculty of Military Health Sciences, University of Defence, Hradec Kralove, Czech Republic
| | - Karel Odrazka
- Cancer Center Multiscan, Pardubice
- Faculty of Military Health Sciences, University of Defence, Hradec Kralove, Czech Republic
| | | | - Ladislav Dusek
- Institute of Biostatististics and Analyses, Faculty of Medicine and Faculty of Science, Masaryk University, Brno
| | - Jiri Jarkovsky
- Institute of Biostatististics and Analyses, Faculty of Medicine and Faculty of Science, Masaryk University, Brno
| | - Ales Hlavka
- Cancer Center Multiscan, Pardubice
- Faculty of Military Health Sciences, University of Defence, Hradec Kralove, Czech Republic
| | - Eva Valentova
- Cancer Center Multiscan, Pardubice
- Faculty of Health Studies, Pardubice University, Pardubice
- Faculty of Military Health Sciences, University of Defence, Hradec Kralove, Czech Republic
| | - Iveta Kolarova
- Cancer Center Multiscan, Pardubice
- Faculty of Health Studies, Pardubice University, Pardubice
- Faculty of Military Health Sciences, University of Defence, Hradec Kralove, Czech Republic
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7
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Durrant L, Robinson M, Hawkins MA, Van den Heuvel F, Muirhead R. Quantifying target-specific motion in anal cancer patients treated with intensity modulated radiotherapy (IMRT). Radiother Oncol 2016; 121:92-97. [PMID: 27576432 PMCID: PMC5100804 DOI: 10.1016/j.radonc.2016.08.011] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2016] [Revised: 08/08/2016] [Accepted: 08/13/2016] [Indexed: 02/07/2023]
Abstract
Background and purpose Intensity modulated radiotherapy requires all target areas to be treated by a single radiotherapy plan. In anal cancer, the pelvic nodes, inguinal nodes and primary tumour represent three different targets. We aim to calculate target-specific motion in anal cancer radiotherapy, when delivered using a single pelvic online auto-match. Materials and methods Twenty consecutive patients treated using IMRT at a single institution were studied. CBCTs were retrospectively re-matched around the inguinal nodes and primary tumour. Match values were recorded relative to origin, defined as pelvic CBCT auto-match. Systematic and random errors were quantified to determine target-specific motion and suggested margins calculated using van Herk formulae. Results The suggested margins to cover the independent motion of the inguinal and anal targets for LR, CC and AP set up around the inguinal nodes were 1.5 mm, 2.7 mm and 2.8 mm; and the primary tumour were, 4.6 mm, 8.9 mm and 5.2 mm respectively. Conclusions Target-specific set up will likely result in reduced treatment volumes and as such reduced toxicity. This is the first time a relationship has been described between pelvic bones, inguinal nodes and primary tumour. The PLATO study will prospectively assess the toxicity and outcomes of this target-specific margins strategy.
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Affiliation(s)
- Lisa Durrant
- CRUK/MRC Oxford Institute for Radiation Oncology, University of Oxford, UK
| | - Maxwell Robinson
- CRUK/MRC Oxford Institute for Radiation Oncology, University of Oxford, UK
| | - Maria A Hawkins
- CRUK/MRC Oxford Institute for Radiation Oncology, University of Oxford, UK
| | | | - Rebecca Muirhead
- CRUK/MRC Oxford Institute for Radiation Oncology, University of Oxford, UK.
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8
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McPartlin AJ, Li XA, Kershaw LE, Heide U, Kerkmeijer L, Lawton C, Mahmood U, Pos F, van As N, van Herk M, Vesprini D, van der Voort van Zyp J, Tree A, Choudhury A. MRI-guided prostate adaptive radiotherapy - A systematic review. Radiother Oncol 2016; 119:371-80. [PMID: 27162159 DOI: 10.1016/j.radonc.2016.04.014] [Citation(s) in RCA: 114] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2016] [Revised: 04/08/2016] [Accepted: 04/09/2016] [Indexed: 11/29/2022]
Abstract
Dose escalated radiotherapy improves outcomes for men with prostate cancer. A plateau for benefit from dose escalation using EBRT may not have been reached for some patients with higher risk disease. The use of increasingly conformal techniques, such as step and shoot IMRT or more recently VMAT, has allowed treatment intensification to be achieved whilst minimising associated increases in toxicity to surrounding normal structures. To support further safe dose escalation, the uncertainties in the treatment target position will need be minimised using optimal planning and image-guided radiotherapy (IGRT). In particular the increasing usage of profoundly hypo-fractionated stereotactic therapy is predicated on the ability to confidently direct treatment precisely to the intended target for the duration of each treatment. This article reviews published studies on the influences of varies types of motion on daily prostate position and how these may be mitigated to improve IGRT in future. In particular the role that MRI has played in the generation of data is discussed and the potential role of the MR-Linac in next-generation IGRT is discussed.
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Affiliation(s)
- A J McPartlin
- The Christie NHS Foundation Trust and Manchester Cancer Research Centre, University of Manchester, Manchester Academic Health Sciences Centre, UK
| | - X A Li
- Medical College of Wisconsin, USA
| | - L E Kershaw
- The Christie NHS Foundation Trust and Manchester Cancer Research Centre, University of Manchester, Manchester Academic Health Sciences Centre, UK
| | - U Heide
- Netherlands Cancer Institute, Antoni van Leeuwenhoek Hospital, The Netherlands
| | - L Kerkmeijer
- University Medical Center Utrecht, The Netherlands
| | - C Lawton
- Medical College of Wisconsin, USA
| | - U Mahmood
- MD Anderson Cancer Center, Houston, USA
| | - F Pos
- Netherlands Cancer Institute, Antoni van Leeuwenhoek Hospital, The Netherlands
| | - N van As
- Royal Marsden Hospital, UK; Institute of Cancer Research, UK
| | - M van Herk
- The Christie NHS Foundation Trust and Manchester Cancer Research Centre, University of Manchester, Manchester Academic Health Sciences Centre, UK
| | - D Vesprini
- Sunnybrook Health Sciences Centre, University of Toronto, Canada
| | | | - A Tree
- Royal Marsden Hospital, UK
| | - A Choudhury
- The Christie NHS Foundation Trust and Manchester Cancer Research Centre, University of Manchester, Manchester Academic Health Sciences Centre, UK.
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9
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Mancosu P, Clemente S, Landoni V, Ruggieri R, Alongi F, Scorsetti M, Stasi M. SBRT for prostate cancer: Challenges and features from a physicist prospective. Phys Med 2016; 32:479-84. [PMID: 27061869 DOI: 10.1016/j.ejmp.2016.03.011] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/01/2015] [Revised: 02/29/2016] [Accepted: 03/12/2016] [Indexed: 01/26/2023] Open
Abstract
Emerging data are showing the safety and the efficacy of Stereotactic Body Radiation Therapy (SBRT) in prostate cancer management. In this context, the medical physicists are regularly involved to review the appropriateness of the adopted technology and to proactively study new solutions. From the physics point of view there are two major challenges in prostate SBRT: (1) mitigation of geometrical uncertainty and (2) generation of highly conformal dose distributions that maximally spare the OARs. Geometrical uncertainties have to be limited as much as possible in order to avoid the use of large PTV margins. Furthermore, advanced planning and delivery techniques are needed to generate maximally conformal dose distributions. In this non-systematic review the technology and the physics aspects of SBRT for prostate cancer were analyzed. In details, the aims were: (i) to describe the rationale of reducing the number of fractions (i.e. increasing the dose per fraction), (ii) to analyze the features to be accounted for performing an extreme hypo-fractionation scheme (>6-7Gy), and (iii) to describe technological solutions for treating in a safe way. The analysis of outcomes, toxicities, and other clinical aspects are not object of the present evaluation.
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Affiliation(s)
- Pietro Mancosu
- Humanitas Clinical and Research Hospital, Rozzano, Milano, Italy.
| | | | | | | | - Filippo Alongi
- Ospedale Sacro Cuore Don Calabria, Negrar, Verona, Italy
| | - Marta Scorsetti
- Humanitas Clinical and Research Hospital, Rozzano, Milano, Italy; Department of Biomedical Sciences, Humanitas University, Rozzano, Milano, Italy
| | - Michele Stasi
- Azienda Ospedaliera Ordine Mauriziano di Torino, Torino, Italy
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10
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Juneja P, Kneebone A, Booth JT, Thwaites DI, Kaur R, Colvill E, Ng JA, Keall PJ, Eade T. Prostate motion during radiotherapy of prostate cancer patients with and without application of a hydrogel spacer: a comparative study. Radiat Oncol 2015; 10:215. [PMID: 26499473 PMCID: PMC4619294 DOI: 10.1186/s13014-015-0526-1] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2015] [Accepted: 10/19/2015] [Indexed: 12/16/2022] Open
Abstract
Background and purpose The use of a tissue expander (hydrogel) for sparing of the rectum from increased irradiation during prostate radiotherapy is becoming popular. The goal of this study is to investigate the effect of a tissue expander (hydrogel) on the intrafraction prostate motion during radiotherapy. Methods and material Real time prostate motion was analysed for 26 patients and 742 fractions; 12 patients with and 14 patients without hydrogel (SpaceOAR™). The intra-fraction motion was quantified and compared between the two groups. Results The average (±standard deviation) of the mean motion during the treatment for patients with and without hydrogel was 1.5 (±0.8 mm) and 1.1 (±0.9 mm) respectively (p < 0.05). The average time of motion >3 mm for patients with and without hydrogel was 7.7 % (±1.1 %) and 4.5 % (±0.9 %) respectively (p > 0.05). The hydrogel age, fraction number and treatment time were found to have no effect (R2 < 0.05) on the prostate motion. Conclusions Differences in intrafraction motion in patients with hydrogel and without hydrogel were within measurement uncertainty (<1 mm). This result confirms that the addition of a spacer does not negate the need for intrafraction motion management if clinically indicated.
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Affiliation(s)
- Prabhjot Juneja
- Northern Sydney Cancer Centre, Royal North Shore Hospital, Sydney, NSW, 2065, Australia. .,Institute of Medical Physics, School of Physics, University of Sydney, Sydney, NSW, 2006, Australia.
| | - Andrew Kneebone
- Northern Sydney Cancer Centre, Royal North Shore Hospital, Sydney, NSW, 2065, Australia.
| | - Jeremy T Booth
- Northern Sydney Cancer Centre, Royal North Shore Hospital, Sydney, NSW, 2065, Australia. .,Institute of Medical Physics, School of Physics, University of Sydney, Sydney, NSW, 2006, Australia.
| | - David I Thwaites
- Institute of Medical Physics, School of Physics, University of Sydney, Sydney, NSW, 2006, Australia.
| | - Ramandeep Kaur
- , 5/161A Willoughby Road, Naremburn, NSW, 2065, Australia.
| | - Emma Colvill
- Northern Sydney Cancer Centre, Royal North Shore Hospital, Sydney, NSW, 2065, Australia. .,Radiation Physics Laboratory, School of Medicine, University of Sydney, Sydney, NSW, 2006, Australia.
| | - Jin A Ng
- Radiation Physics Laboratory, School of Medicine, University of Sydney, Sydney, NSW, 2006, Australia.
| | - Paul J Keall
- Radiation Physics Laboratory, School of Medicine, University of Sydney, Sydney, NSW, 2006, Australia.
| | - Thomas Eade
- Northern Sydney Cancer Centre, Royal North Shore Hospital, Sydney, NSW, 2065, Australia.
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11
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Lecavalier-Barsoum M, Souhami L, Cury F, Duclos M, Ruo R, Faria S. Pelvic lymph node displacement in high-risk prostate cancer patients treated with image guided intensity modulated radiation therapy with 2 independent target volumes. Pract Radiat Oncol 2015; 5:406-10. [PMID: 26127006 DOI: 10.1016/j.prro.2015.05.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2015] [Revised: 04/07/2015] [Accepted: 05/10/2015] [Indexed: 01/06/2023]
Abstract
PURPOSE To evaluate the displacement of the pelvic lymph node (PLN) target when using cone beam computed tomography (CBCT) for localization of the prostate in patients treated with simultaneous integrated boost. METHODS AND MATERIALS High-risk prostate cancer patients treated with image guided intensity modulated radiation therapy with simultaneous integrated boost receiving 60 Gy in 20 fractions to the prostate and proximal seminal vesicles (PTV60) and 44 Gy in the same 20 fractions to the PLN (PTV44) were studied. Two hundred weekly CBCTs of 50 patients were retrospectively reviewed to assess the displacement of the iliac vessels compared with the simulation computed tomography. For each CBCT, possible displacements were analyzed at 3 levels of PTV44: a superior, middle, and inferior slice, making a total of 600 slices reviewed. Geographical miss (GM) was defined when any part of the iliac vessels on the CBCT was outside of the PTV44 contour. RESULTS GM was found in 7 of the 600 CBCT slices, all in different patients. All GMs were of ≤5 mm. Four GMs occurred on the middle slice and 3 on the superior slice. In 3 cases, the GM was related to shifts ≥7 mm applied to the prostate. CONCLUSIONS Our review suggests that for high-risk prostate cancer, the chance of not appropriately covering the PLN target after adjusting the prostate is low. GM was uncommon and in the order of only a few millimeters when it occurred.
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Affiliation(s)
- Magali Lecavalier-Barsoum
- Department of Radiation Oncology, McGill University Health Centre, Montreal General Hospital, Montreal, Quebec, Canada
| | - Luis Souhami
- Department of Radiation Oncology, McGill University Health Centre, Montreal General Hospital, Montreal, Quebec, Canada
| | - Fabio Cury
- Department of Radiation Oncology, McGill University Health Centre, Montreal General Hospital, Montreal, Quebec, Canada
| | - Marie Duclos
- Department of Radiation Oncology, McGill University Health Centre, Montreal General Hospital, Montreal, Quebec, Canada
| | - Russel Ruo
- Department of Medical Physics, McGill University Health Centre, Montreal General Hospital, Montreal, Quebec, Canada
| | - Sergio Faria
- Department of Radiation Oncology, McGill University Health Centre, Montreal General Hospital, Montreal, Quebec, Canada.
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Eom KY, Chie EK, Kim K, Chang JH, Koo TR, Park JI, Park YG, Ye SJ, Ha SW. Pilot study on interfractional and intrafractional movements using surface infrared markers and EPID for patients with rectal cancer treated in the prone position. Br J Radiol 2015; 88:20150144. [PMID: 25996578 DOI: 10.1259/bjr.20150144] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
OBJECTIVE To evaluate interfractional and intrafractional movement of patients with rectal cancer during radiotherapy with electronic portal imaging device (EPID) and surface infrared (IR) markers. METHODS 20 patients undergoing radiotherapy for rectal cancer with body mass index ranging from 18.5 to 30 were enrolled. Patients were placed in the prone position on a couch with a leg pillow. Three IR markers were put on the surface of each patient and traced by two stereo cameras during radiotherapy on a twice-weekly basis. Interfractional isocentre movement was obtained with EPID images on a weekly basis. Movement of the IR markers was analysed in correlation with the isocentre movement obtained from the EPID images. RESULTS The maximum right-to-left (R-L) movement of the laterally located markers in the horizontal isocentre plane was correlated with isocentre translocation with statistical significance (p = 0.018 and 0.015, respectively). Movement of the surface markers was cyclical. For centrally located markers, the 95% confidence intervals for the average amplitude in the R-L, cranial-to-caudal (C-C) and anterior-to-posterior (A-P) directions were 0.86, 2.25 and 3.48 mm, respectively. In 10 patients, intrafractional movement exceeding 5 mm in at least one direction was observed. Time-dependent systematic movement of surface markers during treatment, which consisted of continuous movement towards the cranial direction and a sail back motion in the A-P direction, was also observed. CONCLUSION Intrafractional movement of surface markers has both cyclic components and time-dependent systematic components. Marker deviations exceeding 5 mm were mainly seen in the A-P direction. Pre- or post-treatment EPID images may not provide adequate information regarding intrafractional movement because of systematic movement in the A-P direction during radiotherapy. ADVANCES IN KNOWLEDGE This work uncovered a sail back motion of patients in the A-P direction during radiotherapy. Pre- or post-treatment EPID images may not provide accurate positioning of patients in the A-P direction because of this time-dependent intrafractional motion.
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Affiliation(s)
- K-Y Eom
- 1 Department of Radiation Oncology, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - E K Chie
- 1 Department of Radiation Oncology, Seoul National University College of Medicine, Seoul, Republic of Korea.,2 Institute of Radiation Medicine, Medical Research Center, Seoul National University, Seoul, Republic of Korea
| | - K Kim
- 1 Department of Radiation Oncology, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - J H Chang
- 1 Department of Radiation Oncology, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - T R Koo
- 1 Department of Radiation Oncology, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - J I Park
- 1 Department of Radiation Oncology, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Y-G Park
- 1 Department of Radiation Oncology, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - S-J Ye
- 1 Department of Radiation Oncology, Seoul National University College of Medicine, Seoul, Republic of Korea.,3 Department of Transdisciplinary Studies and Advanced Institute of Convergence Technology, Graduate School of Convergence Science and Technology, Seoul National University, Suwon, Republic of Korea
| | - S W Ha
- 1 Department of Radiation Oncology, Seoul National University College of Medicine, Seoul, Republic of Korea.,2 Institute of Radiation Medicine, Medical Research Center, Seoul National University, Seoul, Republic of Korea
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Qin A, Sun Y, Liang J, Yan D. Evaluation of Online/Offline Image Guidance/Adaptation Approaches for Prostate Cancer Radiation Therapy. Int J Radiat Oncol Biol Phys 2015; 91:1026-33. [DOI: 10.1016/j.ijrobp.2014.12.043] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2014] [Revised: 12/08/2014] [Indexed: 10/23/2022]
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Ahn BS, Wu HG, Yoo SH, Park JM. IMPROVEMENT OF DOSE CALCULATION ACCURACY ON kV CBCT IMAGES WITH CORRECTED ELECTRON DENSITY TO CT NUMBER CURVE. ACTA ACUST UNITED AC 2015. [DOI: 10.14407/jrp.2015.40.1.017] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Mellon EA, Javedan K, Strom TJ, Moros EG, Biagioli MC, Fernandez DC, Wasserman SG, Wilder RB. A dosimetric comparison of volumetric modulated arc therapy with step-and-shoot intensity modulated radiation therapy for prostate cancer. Pract Radiat Oncol 2015; 5:11-5. [DOI: 10.1016/j.prro.2014.03.003] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2013] [Revised: 03/03/2014] [Accepted: 03/04/2014] [Indexed: 10/25/2022]
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Ballhausen H, Li M, Hegemann NS, Ganswindt U, Belka C. Intra-fraction motion of the prostate is a random walk. Phys Med Biol 2014; 60:549-63. [DOI: 10.1088/0031-9155/60/2/549] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
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Stereotactic body radiotherapy in prostate cancer: is rapidarc a better solution than cyberknife? Clin Oncol (R Coll Radiol) 2013; 26:4-9. [PMID: 24071450 DOI: 10.1016/j.clon.2013.08.008] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2013] [Revised: 06/27/2013] [Accepted: 07/15/2013] [Indexed: 11/21/2022]
Abstract
AIMS There is increasing interest in stereotactic body radiotherapy (SBRT) for the management of prostate adenocarcinoma, with encouraging initial biological progression-free survival results. However, the limited literature is dominated by the use of the Cyberknife platform. This led to an international phase III study comparing outcomes for Cyberknife SBRT with both surgery and conventionally fractionated intensity-modulated radiotherapy (the PACE study). We aim to compare Cyberknife delivery with Rapidarc, a more widely available treatment platform. MATERIALS AND METHODS The scans of six previous prostate radiotherapy patients with a range of prostate sizes were chosen. The clinical target volume was defined as the prostate gland, with 3 mm added for the Cyberknife planning target volume (PTV) and 5 mm for the Rapidarc PTV. Accuray multiplan v. 4.5 was used for planning with delivery on a Cyberknife VSI system v9.5; Varian Eclipse v10 was used for Rapidarc planning with delivery using a Varian 21EX linear accelerator. Both systems attempted to deliver at least 35 Gy to the PTV in five fractions with PTV heterogeneity <12%. RESULTS All organ at risk (OAR) constraints were achieved by both platforms, whereas the Cyberknife failed to achieve the desired PTV homogeneity constraint in two cases. In other OARs without constraints, Cyberknife delivered higher doses. The volume of the 35 Gy isodose was slightly larger with Rapidarc, but conversely at doses <35 Gy normal tissues received higher doses with Cyberknife. The mean planning and delivery time was in favour of Rapidarc. CONCLUSIONS We have shown that there is no discernible dosimetric advantage to choosing Cyberknife over Rapidarc for SBRT delivery in prostate cancer. Given the significant benefits of Rapidarc in terms of availability, planning and delivery time, the authors suggest that phase III trials of SBRT should include Rapidarc or equivalent rotational delivery platforms.
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Broggi S, Cantone MC, Chiara A, Di Muzio N, Longobardi B, Mangili P, Veronese I. Application of failure mode and effects analysis (FMEA) to pretreatment phases in tomotherapy. J Appl Clin Med Phys 2013; 14:265-77. [PMID: 24036868 PMCID: PMC5714567 DOI: 10.1120/jacmp.v14i5.4329] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2012] [Revised: 04/04/2013] [Accepted: 03/19/2013] [Indexed: 11/23/2022] Open
Abstract
The aim of this paper was the application of the failure mode and effects analysis (FMEA) approach to assess the risks for patients undergoing radiotherapy treatments performed by means of a helical tomotherapy unit. FMEA was applied to the preplanning imaging, volume determination, and treatment planning stages of the tomotherapy process and consisted of three steps: 1) identification of the involved subprocesses; 2) identification and ranking of the potential failure modes, together with their causes and effects, using the risk probability number (RPN) scoring system; and 3) identification of additional safety measures to be proposed for process quality and safety improvement. RPN upper threshold for little concern of risk was set at 125. A total of 74 failure modes were identified: 38 in the stage of preplanning imaging and volume determination, and 36 in the stage of planning. The threshold of 125 for RPN was exceeded in four cases: one case only in the phase of preplanning imaging and volume determination, and three cases in the stage of planning. The most critical failures appeared related to (i) the wrong or missing definition and contouring of the overlapping regions, (ii) the wrong assignment of the overlap priority to each anatomical structure, (iii) the wrong choice of the computed tomography calibration curve for dose calculation, and (iv) the wrong (or not performed) choice of the number of fractions in the planning station. On the basis of these findings, in addition to the safety strategies already adopted in the clinical practice, novel solutions have been proposed for mitigating the risk of these failures and to increase patient safety.
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Lobefalo F, Bignardi M, Reggiori G, Tozzi A, Tomatis S, Alongi F, Fogliata A, Gaudino A, Navarria P, Cozzi L, Scorsetti M, Mancosu P. Dosimetric impact of inter-observer variability for 3D conformal radiotherapy and volumetric modulated arc therapy: the rectal tumor target definition case. Radiat Oncol 2013; 8:176. [PMID: 23837942 PMCID: PMC3720254 DOI: 10.1186/1748-717x-8-176] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2013] [Accepted: 06/26/2013] [Indexed: 11/10/2022] Open
Abstract
Background To assess the dosimetric effect induced by inter-observer variability in target definition for 3D-conformal RT (3DCRT) and volumetric modulated arc therapy by RapidArc (RA) techniques for rectal cancer treatment. Methods Ten patients with rectal cancer subjected to neo-adjuvant RT were randomly selected from the internal database. Four radiation oncologists independently contoured the clinical target volume (CTV) in blind mode. Planning target volume (PTV) was defined as CTV + 7 mm in the three directions. Afterwards, shared guidelines between radiation oncologists were introduced to give general criteria for the contouring of rectal target and the four radiation oncologists defined new CTV following the guidelines. For each patient, six intersections (I) and unions (U) volumes were calculated coupling the contours of the various oncologists. This was repeated for the contours drawn after the guidelines. Agreement Index (AI = I/U) was calculated pre and post guidelines. Two RT plans (one with 3DCRT technique using 3–4 fields and one with RA using a single modulated arc) were optimized on each radiation oncologist’s PTV. For each plan the PTV volume receiving at least 95% of the prescribed dose (PTV V95%) was calculated for both target and non-target PTVs. Results The inter-operator AI pre-guidelines was 0.57 and was increased up to 0.69 post-guidelines. The maximum volume difference between the various CTV couples, drawn for each patient, passed from 380 ± 147 cm3 to 137 ± 83 cm3 after the introduction of guidelines. The mean percentage for the non-target PTV V95% was 93.7 ± 9.2% before and 96.6 ± 4.9%after the introduction of guidelines for the 3DCRT, for RA the increase was more relevant, passing from 86.5 ± 13.8% (pre) to 94.5 ± 7.5% (post). The OARs were maximally spared with VMAT technique while the variability between pre and post guidelines was not relevant in both techniques. Conclusions The contouring inter-observer variability has dosimetric effects in the PTV coverage. The introduction of guidelines increases the dosimetric consistency for both techniques, with greater improvements for RA technique.
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Affiliation(s)
- Francesca Lobefalo
- Radiation Oncology Department, Humanitas Clinical and Research Center, Rozzano, Milan, Italy
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Cantone MC, Ciocca M, Dionisi F, Fossati P, Lorentini S, Krengli M, Molinelli S, Orecchia R, Schwarz M, Veronese I, Vitolo V. Application of failure mode and effects analysis to treatment planning in scanned proton beam radiotherapy. Radiat Oncol 2013; 8:127. [PMID: 23705626 PMCID: PMC3679803 DOI: 10.1186/1748-717x-8-127] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2012] [Accepted: 05/19/2013] [Indexed: 11/21/2022] Open
Abstract
Background A multidisciplinary and multi-institutional working group applied the Failure Mode and Effects Analysis (FMEA) approach to the actively scanned proton beam radiotherapy process implemented at CNAO (Centro Nazionale di Adroterapia Oncologica), aiming at preventing accidental exposures to the patient. Methods FMEA was applied to the treatment planning stage and consisted of three steps: i) identification of the involved sub-processes; ii) identification and ranking of the potential failure modes, together with their causes and effects, using the risk probability number (RPN) scoring system, iii) identification of additional safety measures to be proposed for process quality and safety improvement. RPN upper threshold for little concern of risk was set at 125. Results Thirty-four sub-processes were identified, twenty-two of them were judged to be potentially prone to one or more failure modes. A total of forty-four failure modes were recognized, 52% of them characterized by an RPN score equal to 80 or higher. The threshold of 125 for RPN was exceeded in five cases only. The most critical sub-process appeared related to the delineation and correction of artefacts in planning CT data. Failures associated to that sub-process were inaccurate delineation of the artefacts and incorrect proton stopping power assignment to body regions. Other significant failure modes consisted of an outdated representation of the patient anatomy, an improper selection of beam direction and of the physical beam model or dose calculation grid. The main effects of these failures were represented by wrong dose distribution (i.e. deviating from the planned one) delivered to the patient. Additional strategies for risk mitigation, easily and immediately applicable, consisted of a systematic information collection about any known implanted prosthesis directly from each patient and enforcing a short interval time between CT scan and treatment start. Moreover, (i) the investigation of dedicated CT image reconstruction algorithms, (ii) further evaluation of treatment plan robustness and (iii) implementation of independent methods for dose calculation (such as Monte Carlo simulations) may represent novel solutions to increase patient safety. Conclusions FMEA is a useful tool for prospective evaluation of patient safety in proton beam radiotherapy. The application of this method to the treatment planning stage lead to identify strategies for risk mitigation in addition to the safety measures already adopted in clinical practice.
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Affiliation(s)
- Marie Claire Cantone
- Dipartimento di Fisica, Università degli Studi di Milano, Via Celoria 16, 20133, Milano, Italy
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Ballhausen H, Reiner M, Kantz S, Belka C, Söhn M. The random walk model of intrafraction movement. Phys Med Biol 2013; 58:2413-27. [DOI: 10.1088/0031-9155/58/7/2413] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
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Duffton A, McNee S, Muirhead R, Alhasso A. Clinical commissioning of online seed matching protocol for prostate radiotherapy. Br J Radiol 2012; 85:e1273-81. [PMID: 23175493 DOI: 10.1259/bjr/72368557] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
OBJECTIVES Our aim was to clinically commission an online seed matching image-guided radiotherapy (IGRT) protocol using modern hardware/software for patients undergoing prostate radiotherapy. An essential constraint was to achieve this within a busy centre without reducing patient throughput, which had been reported with other techniques. METHODS 45 patients had 3 fiducial markers inserted into the prostate and were imaged daily using kilovoltage orthogonal images with online correction applied before treatment. A total of 1612 image pairs were acquired and analysed to identify interfractional motion, seed migration and interobserver variability, and assess ease of use. RESULTS This method of IGRT was implemented successfully in our centre with no impact on treatment times and patient throughput. Systematic (Σ) interfractional set-up errors were 2.2, 2.7 and 3.9 mm in right-left (RL), superoinferior (SI) and anteroposterior (AP) directions, respectively. Random (σ) interfractional set-up errors were 3.2 (RL), 3.7 (SI) and 5.7 mm (AP). There were significant differences between patients. Seed migration and interobserver variability were not significant issues. CONCLUSIONS The described technique is facilitated by the advanced imaging system, allowing a fast and effective method of correcting set-up errors before treatment. Extended implementation of this technique has improved treatment delivery to the majority of our prostate radiotherapy patients. The measurement of interfractional motion in this study is potentially valuable for margin reduction in intensity-modulated radiotherapy/volumetric arc therapy. ADVANCES IN KNOWLEDGE This technique can be used within treatment time constraints, benefiting large numbers of patients by helping to avoid geographical miss and potentially reducing toxicity to organs at risk.
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Affiliation(s)
- A Duffton
- Department of Radiotherapy, Beatson West of Scotland Cancer Centre, Glasgow, UK.
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Harmon J, Yoshikawa H, Custis J, LaRue S. EVALUATION OF CANINE PROSTATE INTRAFRACTIONAL MOTION USING SERIAL CONE BEAM COMPUTED TOMOGRAPHY IMAGING. Vet Radiol Ultrasound 2012; 54:93-8. [DOI: 10.1111/j.1740-8261.2012.01986.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2012] [Accepted: 08/11/2012] [Indexed: 11/26/2022] Open
Affiliation(s)
- Joseph Harmon
- Bon Secours Cancer Institute; Richmond Radiation Oncology Center; Henrico; VA; 23230
| | - Hiroto Yoshikawa
- Department of Environmental and Radiologic Health Sciences; College of Veterinary Medicine and Biomedical Sciences; Fort Collins; Colorado; 80523-1620
| | - James Custis
- Department of Environmental and Radiologic Health Sciences; College of Veterinary Medicine and Biomedical Sciences; Fort Collins; Colorado; 80523-1620
| | - Susan LaRue
- Department of Environmental and Radiologic Health Sciences; College of Veterinary Medicine and Biomedical Sciences; Fort Collins; Colorado; 80523-1620
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Ghasroddashti E, Smith WL, Quirk S, Kirkby C. Clinical consequences of changing the sliding window IMRT dose rate. J Appl Clin Med Phys 2012; 13:3810. [PMID: 22766951 PMCID: PMC5716514 DOI: 10.1120/jacmp.v13i4.3810] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2011] [Revised: 03/12/2012] [Accepted: 03/03/2012] [Indexed: 11/30/2022] Open
Abstract
Changing pulse repetition frequency or dose rate used for IMRT treatments can alter the number of monitor units (MUs) and the time required to deliver a plan. This work was done to develop a practical picture of the magnitude of these changes. We used Varian's Eclipse Treatment Planning System to calculate the number of MUs and beam‐on times for a total of 40 different treatment plans across an array of common IMRT sites including prostate/pelvis, prostate bed, head and neck, and central nervous system cancers using dose rates of 300, 400 and 600 MU/min. In general, we observed a 4%–7% increase in the number of MUs delivered and a 10–40 second decrease in the beam‐on time for each 100 MU/min of dose rate increase. The increase in the number of MUs resulted in a reduction of the “beam‐on time saved”. The exact magnitude of the changes depended on treatment site and planning target volume. These changes can lead to minor, but not negligible, concerns with respect to radiation protection and treatment planning. Although the number of MUs increased more rapidly for more complex treatment plans, the absolute beam‐on time savings was greater for these plans because of the higher total number of MUs required to deliver them. We estimate that increasing the IMRT dose rate from 300 to 600 MU/min has the potential to add up to two treatment slots per day for each IMRT linear accelerator. These results will be of value to anyone considering general changes to IMRT dose rates within their clinic. PACS number: 87.55.N
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Mancosu P, Castiglioni S, Reggiori G, Catalano M, Alongi F, Pellegrini C, Arcangeli S, Tozzi A, Lobefalo F, Fogliata A, Navarria P, Cozzi L, Scorsetti M. Stereotactic body radiation therapy for liver tumours using flattening filter free beam: dosimetric and technical considerations. Radiat Oncol 2012; 7:16. [PMID: 22296849 PMCID: PMC3292972 DOI: 10.1186/1748-717x-7-16] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2011] [Accepted: 02/01/2012] [Indexed: 12/25/2022] Open
Abstract
Purpose To report the initial institute experience in terms of dosimetric and technical aspects in stereotactic body radiation therapy (SBRT) delivered using flattening filter free (FFF) beam in patients with liver lesions. Methods and Materials From October 2010 to September 2011, 55 consecutive patients with 73 primary or metastatic hepatic lesions were treated with SBRT on TrueBeam using FFF beam and RapidArc technique. Clinical target volume (CTV) was defined on multi-phase CT scans, PET/CT, MRI, and 4D-CT. Dose prescription was 75 Gy in 3 fractions to planning target volume (PTV). Constraints for organs at risk were: 700 cc of liver free from the 15 Gy isodose, Dmax < 21 Gy for stomach and duodenum, Dmax < 30 Gy for heart, D0.1 cc < 18 Gy for spinal cord, V15 Gy < 35% for kidneys. The dose was downscaled in cases of not full achievement of dose constraints. Daily cone beam CT (CBCT) was performed. Results Forty-three patients with a single lesion, nine with two lesions and three with three lesions were treated with this protocol. Target and organs at risk objectives were met for all patients. Mean delivery time was 2.8 ± 1.0 min. Pre-treatment plan verification resulted in a Gamma Agreement Index of 98.6 ± 0.8%. Mean on-line co-registration shift of the daily CBCT to the simulation CT were: -0.08, 0.05 and -0.02 cm with standard deviations of 0.33, 0.39 and 0.55 cm in, vertical, longitudinal and lateral directions respectively. Conclusions SBRT for liver targets delivered by means of FFF resulted to be feasible with short beam on time.
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Affiliation(s)
- Pietro Mancosu
- IRCCS Istituto Clinico Humanitas, Rozzano (Milano), Italy.
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