1
|
Malicki J, Piotrowski T, Guedea F, Krengli M. Treatment-integrated imaging, radiomics, and personalised radiotherapy: the future is at hand. Rep Pract Oncol Radiother 2022; 27:734-743. [PMID: 36196410 PMCID: PMC9521689 DOI: 10.5603/rpor.a2022.0071] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2022] [Accepted: 06/13/2022] [Indexed: 11/25/2022] Open
Abstract
Since the introduction of computed tomography for planning purposes in the 1970s, we have been observing a continuous development of different imaging methods in radiotherapy. The current achievements of imaging technologies in radiotherapy enable more than just improvement of accuracy on the planning stage. Through integrating imaging with treatment machines, they allow advanced control methods of dose delivery during the treatment. This article reviews how the integration of existing and novel forms of imaging changes radiotherapy and how these advances can allow a more individualised approach to cancer therapy. We believe that the significant challenge for the next decade is the continued integration of a range of different imaging devices into linear accelerators. These imaging modalities should show intra-fraction changes in body morphology and inter-fraction metabolic changes. As the use of these more advanced, integrated machines grows, radiotherapy delivery will become more accurate, thus resulting in better clinical outcomes: higher cure rates with fewer side effects.
Collapse
Affiliation(s)
- Julian Malicki
- Department of Electroradiology, University of Medical Sciences, Poznan, Poland
- Department of Medical Physics, Greater Poland Cancer Centre, Poznan, Poland
| | - Tomasz Piotrowski
- Department of Electroradiology, University of Medical Sciences, Poznan, Poland
- Department of Medical Physics, Greater Poland Cancer Centre, Poznan, Poland
| | - Ferran Guedea
- Department of Radiation Oncology, Catalan Institute of Oncology, University of Barcelona, L’Hospitalet de Llobregat, Barcelona, Spain
| | - Marco Krengli
- Radiation Oncology Unit, University Hospital “Maggiore della Carità”, Novara, Italy
- Department of Translational Medicine, University of Piemonte Orientale, Novara, Italy
| |
Collapse
|
2
|
Høyer M, Grau C, Overgaard J. No time to die - BiGART is back. The 20th Acta Oncologica Symposium - BIGART 2021. Acta Oncol 2022; 61:117-119. [PMID: 34991422 DOI: 10.1080/0284186x.2021.2022206] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022]
Affiliation(s)
- Morten Høyer
- Danish Centre for Particle Therapy, Aarhus University Hospital, Aarhus, Denmark
| | - Cai Grau
- Danish Centre for Particle Therapy, Aarhus University Hospital, Aarhus, Denmark
| | - Jens Overgaard
- Department of Experimental Clinical Oncology, Aarhus University Hospital, Aarhus, Denmark
| |
Collapse
|
3
|
Chin S, Eccles CL, McWilliam A, Chuter R, Walker E, Whitehurst P, Berresford J, Van Herk M, Hoskin PJ, Choudhury A. Magnetic resonance-guided radiation therapy: A review. J Med Imaging Radiat Oncol 2020; 64:163-177. [PMID: 31646742 DOI: 10.1111/1754-9485.12968] [Citation(s) in RCA: 89] [Impact Index Per Article: 22.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2019] [Accepted: 09/24/2019] [Indexed: 12/11/2022]
Abstract
Magnetic resonance-guided radiation therapy (MRgRT) is a promising approach to improving clinical outcomes for patients treated with radiation therapy. The roles of image guidance, adaptive planning and magnetic resonance imaging in radiation therapy have been increasing over the last two decades. Technical advances have led to the feasible combination of magnetic resonance imaging and radiation therapy technologies, leading to improved soft-tissue visualisation, assessment of inter- and intrafraction motion, motion management, online adaptive radiation therapy and the incorporation of functional information into treatment. MRgRT can potentially transform radiation oncology by improving tumour control and quality of life after radiation therapy and increasing convenience of treatment by shortening treatment courses for patients. Multiple groups have developed clinical implementations of MRgRT predominantly in the abdomen and pelvis, with patients having been treated since 2014. While studies of MRgRT have primarily been dosimetric so far, an increasing number of trials are underway examining the potential clinical benefits of MRgRT, with coordinated efforts to rigorously evaluate the benefits of the promising technology. This review discusses the current implementations, studies, potential benefits and challenges of MRgRT.
Collapse
Affiliation(s)
- Stephen Chin
- Department of Clinical Oncology, The Christie NHS Foundation Trust, Manchester, UK
- Westmead Clinical School, University of Sydney, Sydney, New South Wales, Australia
| | - Cynthia L Eccles
- Department of Radiotherapy, The Christie NHS Foundation Trust, Manchester, UK
- Division of Cancer Sciences, The University of Manchester, Manchester, UK
| | - Alan McWilliam
- Division of Cancer Sciences, The University of Manchester, Manchester, UK
- Christie Medical Physics and Engineering, The Christie NHS Foundation Trust, Manchester, UK
| | - Robert Chuter
- Division of Cancer Sciences, The University of Manchester, Manchester, UK
- Christie Medical Physics and Engineering, The Christie NHS Foundation Trust, Manchester, UK
| | - Emma Walker
- Christie Medical Physics and Engineering, The Christie NHS Foundation Trust, Manchester, UK
| | - Philip Whitehurst
- Christie Medical Physics and Engineering, The Christie NHS Foundation Trust, Manchester, UK
| | - Joseph Berresford
- Christie Medical Physics and Engineering, The Christie NHS Foundation Trust, Manchester, UK
| | - Marcel Van Herk
- Division of Cancer Sciences, The University of Manchester, Manchester, UK
- Christie Medical Physics and Engineering, The Christie NHS Foundation Trust, Manchester, UK
| | - Peter J Hoskin
- Department of Clinical Oncology, The Christie NHS Foundation Trust, Manchester, UK
- Division of Cancer Sciences, The University of Manchester, Manchester, UK
| | - Ananya Choudhury
- Department of Clinical Oncology, The Christie NHS Foundation Trust, Manchester, UK
- Division of Cancer Sciences, The University of Manchester, Manchester, UK
| |
Collapse
|
4
|
Affiliation(s)
- Jens Overgaard
- Department of Experimental Clinical Oncology, Aarhus University Hospital, Aarhus, Denmark
| | - Ludvig Paul Muren
- Department of Medical Physics, Aarhus University Hospital, Aarhus, Denmark
| | - Morten Høyer
- Danish Centre for Particle Therapy, Aarhus University Hospital, Aarhus, Denmark
| | - Cai Grau
- Department of Oncology and Danish Centre for Particle Therapy, Aarhus University Hospital, Aarhus, Denmark
| |
Collapse
|
5
|
Garibaldi C, Jereczek-Fossa BA, Marvaso G, Dicuonzo S, Rojas DP, Cattani F, Starzyńska A, Ciardo D, Surgo A, Leonardi MC, Ricotti R. Recent advances in radiation oncology. Ecancermedicalscience 2017; 11:785. [PMID: 29225692 PMCID: PMC5718253 DOI: 10.3332/ecancer.2017.785] [Citation(s) in RCA: 60] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2017] [Indexed: 12/18/2022] Open
Abstract
Radiotherapy (RT) is very much a technology-driven treatment modality in the management of cancer. RT techniques have changed significantly over the past few decades, thanks to improvements in engineering and computing. We aim to highlight the recent developments in radiation oncology, focusing on the technological and biological advances. We will present state-of-the-art treatment techniques, employing photon beams, such as intensity-modulated RT, volumetric-modulated arc therapy, stereotactic body RT and adaptive RT, which make possible a highly tailored dose distribution with maximum normal tissue sparing. We will analyse all the steps involved in the treatment: imaging, delineation of the tumour and organs at risk, treatment planning and finally image-guidance for accurate tumour localisation before and during treatment delivery. Particular attention will be given to the crucial role that imaging plays throughout the entire process. In the case of adaptive RT, the precise identification of target volumes as well as the monitoring of tumour response/modification during the course of treatment is mainly based on multimodality imaging that integrates morphological, functional and metabolic information. Moreover, real-time imaging of the tumour is essential in breathing adaptive techniques to compensate for tumour motion due to respiration. Brief reference will be made to the recent spread of particle beam therapy, in particular to the use of protons, but also to the yet limited experience of using heavy particles such as carbon ions. Finally, we will analyse the latest biological advances in tumour targeting. Indeed, the effectiveness of RT has been improved not only by technological developments but also through the integration of radiobiological knowledge to produce more efficient and personalised treatment strategies.
Collapse
Affiliation(s)
- Cristina Garibaldi
- Unit of Medical Physics, European Institute of Oncology, 20141 Milan, Italy
| | - Barbara Alicja Jereczek-Fossa
- Department of Radiation Oncology, European Institute of Oncology, 20141 Milan, Italy
- Department of Oncology and Hemato-Oncology, University of Milan, 20122 Milan, Italy
| | - Giulia Marvaso
- Department of Radiation Oncology, European Institute of Oncology, 20141 Milan, Italy
| | - Samantha Dicuonzo
- Department of Radiation Oncology, European Institute of Oncology, 20141 Milan, Italy
- Department of Oncology and Hemato-Oncology, University of Milan, 20122 Milan, Italy
| | - Damaris Patricia Rojas
- Department of Radiation Oncology, European Institute of Oncology, 20141 Milan, Italy
- Department of Oncology and Hemato-Oncology, University of Milan, 20122 Milan, Italy
| | - Federica Cattani
- Unit of Medical Physics, European Institute of Oncology, 20141 Milan, Italy
| | - Anna Starzyńska
- Department of Oral Surgery, Medical University of Gdańsk, 80–211 Gdańsk, Poland
| | - Delia Ciardo
- Department of Radiation Oncology, European Institute of Oncology, 20141 Milan, Italy
| | - Alessia Surgo
- Department of Radiation Oncology, European Institute of Oncology, 20141 Milan, Italy
| | | | - Rosalinda Ricotti
- Department of Radiation Oncology, European Institute of Oncology, 20141 Milan, Italy
| |
Collapse
|
6
|
Grau C, Høyer M, Poulsen PR, Muren LP, Korreman SS, Tanderup K, Lindegaard JC, Alsner J, Overgaard J. Rethink radiotherapy - BIGART 2017. Acta Oncol 2017; 56:1341-1352. [PMID: 29148908 DOI: 10.1080/0284186x.2017.1371326] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Affiliation(s)
- Cai Grau
- Department of Oncology, Aarhus University Hospital, Aarhus, Denmark
| | - Morten Høyer
- Department of Oncology, Aarhus University Hospital, Aarhus, Denmark
| | | | - Ludvig Paul Muren
- Department of Medical Physics, Aarhus University Hospital, Aarhus, Denmark
| | | | - Kari Tanderup
- Department of Medical Physics, Aarhus University Hospital, Aarhus, Denmark
| | | | - Jan Alsner
- Department of Experimental Clinical Oncology, Aarhus University Hospital, Aarhus, Denmark
| | - Jens Overgaard
- Department of Experimental Clinical Oncology, Aarhus University Hospital, Aarhus, Denmark
| |
Collapse
|
7
|
Malinen E, Hysing LB, Waldeland E, Muren LP. Bridging imaging and therapy: the role of medical physics in development of precision cancer care. Acta Oncol 2017; 56:757-760. [PMID: 28464737 DOI: 10.1080/0284186x.2017.1316869] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Affiliation(s)
- Eirik Malinen
- Department of Physics, University of Oslo, Oslo, Norway
- Department of Medical Physics, Oslo University Hospital, Oslo, Norway
| | - Liv Bolstad Hysing
- Department of Oncology and Medical Physics, Haukeland University Hospital, Bergen, Norway
- Department of Physics and Technology, University of Bergen, Bergen, Norway
| | - Einar Waldeland
- Department of Medical Physics, Oslo University Hospital, Oslo, Norway
| | - Ludvig Paul Muren
- Department of Medical Physics, Aarhus University Hospital, Aarhus, Denmark
| |
Collapse
|
8
|
Grau C, Overgaard J, Høyer M, Tanderup K, Lindegaard JC, Muren LP. Biology-guided adaptive radiotherapy (BiGART) is progressing towards clinical reality. Acta Oncol 2015; 54:1245-50. [PMID: 26390238 DOI: 10.3109/0284186x.2015.1076992] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- Cai Grau
- a Department of Oncology , Aarhus University Hospital , Aarhus , Denmark
| | - Jens Overgaard
- b Department of Experimental Clinical Oncology , Aarhus University Hospital , Aarhus , Denmark
| | - Morten Høyer
- a Department of Oncology , Aarhus University Hospital , Aarhus , Denmark
| | - Kari Tanderup
- a Department of Oncology , Aarhus University Hospital , Aarhus , Denmark
- c Department of Medical Physics , Aarhus University Hospital , Aarhus , Denmark
| | | | - Ludvig Paul Muren
- a Department of Oncology , Aarhus University Hospital , Aarhus , Denmark
- c Department of Medical Physics , Aarhus University Hospital , Aarhus , Denmark
| |
Collapse
|
9
|
Team-based clinical simulation in radiation medicine: value to attitudes and perceptions of interprofessional collaboration. JOURNAL OF RADIOTHERAPY IN PRACTICE 2015. [DOI: 10.1017/s1460396915000060] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
AbstractIntroductionSimulation has been effective for changing attitudes towards team-based competencies in many areas, but its role in teaching interprofessional collaboration (IPC) in radiation medicine (RM) is unknown. This study reports on feasibility and IPC outcomes of a team-based simulation event; ‘Radiation Medicine Simulation in Learning Interprofessional Collaborative Experience’ (RM SLICE).MethodsRadiation therapy (RTT), medical physics (MP) and radiation oncology (RO) trainees in a single academic department were eligible. Scheduled closure of a modern RM clinic allowed rotation of five high-fidelity cases in three 105-minute timeslots. A pre/post-survey design evaluated learner satisfaction and interprofessional perceptions. Scales included the Readiness for Interprofessional Learning Scale (RIPLS), UWE Entry Level Interprofessional Questionnaire (UWEIQ), Trainee Test of Team Dynamics and Collaborative Behaviours Scale (CBS).ResultsTwenty-one trainees participated; six ROs (28·57%), six MPs (28·57%) and nine RTTs (42·86%). All cases were conducted, resolved and debriefed within the allotted time. Twenty-one complete sets (100%) of evaluations were returned. Participants reported limited interaction with other professional groups before RM SLICE. Perceptions of team functioning and value of team interaction in ‘establishing or improving the care plan’ were high for all cases, averaging 8·1/10 and 8·9/10. Average CBS scores were 70·4, 71·9 and 69·5, for the three cases, scores increasing between the first and second case for 13/21 (61·9%) participants. RIPLS and UWEIQ scores reflected positive perceptions both pre- and post-event, averaging 83·5 and 85·2 (RIPLS) and 60·6 and 55·7 (UWEIQ), respectively. For all professions for both scales, the average change in score reflected improved IP perceptions, with agreement between scales for 15/20 (75·0%) participants. Overall, perception of IPC averaged 9·14/10, as did the importance of holding such an event annually.ConclusionsTeam-based simulation is feasible in RM and appears to facilitate interprofessional competency-building in high-acuity clinical situations, reflecting positive perceptions of IPC.
Collapse
|
10
|
Magnetic resonance imaging of the tumor microenvironment in radiotherapy: perfusion, hypoxia, and metabolism. Semin Radiat Oncol 2015; 24:210-7. [PMID: 24931096 DOI: 10.1016/j.semradonc.2014.02.002] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The tumor microenvironment is characterized by hypoxia, low pH, and high interstitial fluid pressure. Hypoxic regions in tumors with low partial pressure of oxygen (pO2) levels can result in resistance to radiotherapy, thus causing local failure. Therefore, it would be desirable to noninvasively measure pO2 levels in the tumor before, during, and after treatment to better customize therapy and follow treatment response. Several techniques used in preclinical and clinical studies to obtain the pO2 status of tissue, such as dynamic contrast-enhanced magnetic resonance imaging, blood oxygen level-dependent imaging, and electron paramagnetic resonance imaging, are reviewed. Furthermore, the ability to hyperpolarize specific metabolic substrates that are isotopically labeled with (13)C coupled with magnetic resonance spectroscopy enables noninvasive imaging of tissue metabolism, such as glycolysis.
Collapse
|
11
|
An adaptive radiotherapy planning strategy for bladder cancer using deformation vector fields. Radiother Oncol 2014; 112:371-5. [DOI: 10.1016/j.radonc.2014.07.012] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2014] [Revised: 06/03/2014] [Accepted: 07/15/2014] [Indexed: 11/18/2022]
|
12
|
Grimes DR, Kelly C, Bloch K, Partridge M. A method for estimating the oxygen consumption rate in multicellular tumour spheroids. J R Soc Interface 2014; 11:20131124. [PMID: 24430128 PMCID: PMC3899881 DOI: 10.1098/rsif.2013.1124] [Citation(s) in RCA: 177] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2013] [Accepted: 12/13/2013] [Indexed: 12/11/2022] Open
Abstract
Hypoxia occurs when oxygen levels within a tissue drop below normal physiological levels. In tumours, hypoxia is associated with poor prognosis, increased likelihood of metastasis and resistance to therapy. Imaging techniques, for example, positron emission tomography, are increasingly used in the monitoring of tumour hypoxia and have the potential to help in the planning of radiotherapy. For this application, improved understanding of the link between image contrast and quantitative underlying oxygen distribution would be very useful. Mathematical models of tissue hypoxia and image formation can help understand this. Hypoxia is caused by an imbalance between vascular supply and tissue demand. While much work has been dedicated to the quantitative description of tumour vascular networks, consideration of tumour oxygen consumption is largely neglected. Oxidative respiration in standard two-dimensional cell culture has been widely studied. However, two-dimensional culture fails to capture the complexities of growing three-dimensional tissue which could impact on the oxygen usage. In this study, we build on previous descriptions of oxygen consumption and diffusion in three-dimensional tumour spheroids and present a method for estimating rates of oxygen consumption from spheroids, validated using stained spheroid sections. Methods for estimating the local partial pressure of oxygen, the diffusion limit and the extents of the necrotic core, hypoxic region and proliferating rim are also derived. These are validated using experimental data from DLD1 spheroids at different stages of growth. A relatively constant experimentally derived diffusion limit of 232 ± 22 μm and an O2 consumption rate of 7.29 ± 1.4 × 10(-7) m(3) kg(-1) s(-1) for the spheroids studied was measured, in agreement with laboratory measurements.
Collapse
Affiliation(s)
- David Robert Grimes
- The Gray Institute for Radiation Oncology and Biology, University of Oxford, Old Road Campus Research Building, Oxford OX3 7DQ, UK
| | | | | | | |
Collapse
|
13
|
|
14
|
Grau C, Høyer M, Alber M, Overgaard J, Lindegaard JC, Muren LP. Biology-guided adaptive radiotherapy (BiGART)--more than a vision? Acta Oncol 2013; 52:1243-7. [PMID: 23984809 DOI: 10.3109/0284186x.2013.829245] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Affiliation(s)
- Cai Grau
- Department of Oncology, Aarhus University Hospital , Aarhus , Denmark
| | | | | | | | | | | |
Collapse
|
15
|
Krishna MC, Matsumoto S, Saito K, Matsuo M, Mitchell JB, Ardenkjaer-Larsen JH. Magnetic resonance imaging of tumor oxygenation and metabolic profile. Acta Oncol 2013; 52:1248-56. [PMID: 23957619 DOI: 10.3109/0284186x.2013.819118] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
The tumor microenvironment is distinct from normal tissue as a result of abnormal vascular network characterized by hypoxia, low pH, high interstitial fluid pressure and elevated glycolytic activity. This poses a barrier to treatments including radiation therapy and chemotherapy. Imaging methods which can characterize such features non-invasively and repeatedly will be of significant value in planning treatment as well as monitoring response to treatment. The three techniques based on magnetic resonance imaging (MRI) are reviewed here. Tumor pO2 can be measured by two MRI methods requiring an exogenous contrast agent: electron paramagnetic resonance imaging (EPRI) and Overhauser magnetic resonance imaging (OMRI). Tumor metabolic profile can be assessed by a third method, hyperpolarized metabolic MR, based on injection of hyperpolarized biological molecules labeled with (13)C or (15)N and MR spectroscopic imaging. Imaging pO2 in tumors is now a robust pre-clinical imaging modality with potential for implementation clinically. Pre-clinical studies and an initial clinical study with hyperpolarized metabolic MR have been successful and suggest that the method may be part of image-guided radiotherapy to select patients for tailored individual treatment regimens.
Collapse
Affiliation(s)
- Murali C Krishna
- Radiation Biology Branch, Center for Cancer Research, National Cancer Institute, NIH , Bethesda, Maryland , USA
| | | | | | | | | | | |
Collapse
|
16
|
Glimelius B. Multidisciplinary treatment of patients with rectal cancer: Development during the past decades and plans for the future. Ups J Med Sci 2012; 117:225-36. [PMID: 22512246 PMCID: PMC3339554 DOI: 10.3109/03009734.2012.658974] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
In rectal cancer treatment, both the local primary and the regional and systemic tumour cell deposits must be taken care of in order to improve survival. The three main treatments, surgery, radiotherapy, and chemotherapy, each with their own advantages and limitations, must then be combined to improve results. Several large randomized trials have shown that combinations of the modalities have markedly reduced the loco-regional recurrences, but have not yet had any major influence on overall survival. The best integration of the weakest modality, to date the drugs (conventional cytotoxics and biologicals), is not known. A new generation of trials exploring the best sequence of treatments is required. Furthermore, treatment of rectal cancer is administered to populations of individuals, based upon clinical factors and imaging, and can presently not be further individualized. There is an urgent need to develop response predictors.
Collapse
Affiliation(s)
- Bengt Glimelius
- Department of Radiology, Oncology and Radiation Science, Uppsala University, Akademiska Sjukhuset, Uppsala, Sweden.
| |
Collapse
|
17
|
|
18
|
Muren LP, Glimelius B. And they lived happily ever after… The marriage of Nordic Association for Clinical Physics and Acta Oncologica. Acta Oncol 2011; 50:835-7. [PMID: 21767182 DOI: 10.3109/0284186x.2011.590527] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
|
19
|
Nyström H, Blomqvist E, Høyer M, Montelius A, Muren LP, Nilsson P, Taheri-Kadkhoda Z, Glimelius B. Particle therapy - a next logical step in the improvement of radiotherapy. Acta Oncol 2011; 50:741-4. [PMID: 21767169 DOI: 10.3109/0284186x.2011.590150] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
|
20
|
|
21
|
Ottosson W, Baker M, Hedman M, Behrens CF, Sjöström D. Evaluation of setup accuracy for NSCLC patients; studying the impact of different types of cone-beam CT matches based on whole thorax, columna vertebralis, and GTV. Acta Oncol 2010; 49:1184-91. [PMID: 20831511 DOI: 10.3109/0284186x.2010.500303] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
PURPOSE The aim of this study is to evaluate the patient setup accuracy by investigating the impact of different types of CBCT matches, performed with 3 (translations only) or 6 (including rotations) degrees-of-freedom (DOF). The purpose is also to calculate and compare CTV to PTV margins based on the various CBCT matches, setups using 2D kV planar imaging or setups using skin markers only (non-IGRT). MATERIAL AND METHODS Setup images from 16 NSCLC patients with weekly CBCT and daily 2D kV planar imaging were analyzed retrospectively. The CBCT matches were based on the columna vertebralis (CV), the whole thorax (WT) and the soft tissue (ST) delineated GTV, where the ST match was chosen as reference. Thus the translational and rotational shifts in three dimensions were assessed. Finally, setup margins were calculated using van Herk's margin recipe. RESULTS For 80% of the investigated 3 DOF/2D kV CV setups, the translational shifts were within [-3, 2] mm for all three directions. Corresponding values for the 6 DOF/non-IGRT CV and the 6 DOF/non-IGRT ST matches were [-5, 8] mm. Furthermore, 80% of all setups were within ± 2° for pitch-, roll- and yaw-rotations, and none exceeded 5°. The calculated margins for non-IGRT, about 10 mm, were reduced to approximately 4 mm, regardless of using IGRT setup by CBCT or 2D kV imaging on CV. However, if using WT CBCT setup, the margin in LNG direction was slightly larger, approximately 6 mm. CONCLUSION IGRT for NSCLC is an essential tool for margin reduction, since patient setups based on IGRT leads to approximately half the margin sizes compared to non-IGRT setups. Both CBCT and 2D kV planar imaging yields approximately the same margins for CV/ST matches. The magnitudes of the patient rotations were <5°.
Collapse
MESH Headings
- Carcinoma, Non-Small-Cell Lung/diagnostic imaging
- Carcinoma, Non-Small-Cell Lung/pathology
- Carcinoma, Non-Small-Cell Lung/radiotherapy
- Cone-Beam Computed Tomography/methods
- Cone-Beam Computed Tomography/standards
- Humans
- Lung Neoplasms/diagnostic imaging
- Lung Neoplasms/pathology
- Lung Neoplasms/radiotherapy
- Matched-Pair Analysis
- Phantoms, Imaging
- Radiographic Image Interpretation, Computer-Assisted/methods
- Radiographic Image Interpretation, Computer-Assisted/standards
- Radiography, Thoracic/methods
- Radiography, Thoracic/standards
- Radiotherapy Planning, Computer-Assisted/instrumentation
- Radiotherapy Planning, Computer-Assisted/methods
- Radiotherapy Planning, Computer-Assisted/standards
- Reference Values
- Reproducibility of Results
- Retrospective Studies
- Spine/diagnostic imaging
- Thorax/physiology
- Tumor Burden/physiology
Collapse
Affiliation(s)
- Wiviann Ottosson
- Department of Oncology, Division of Radiophysics, Copenhagen University Hospital Herlev, Herlev, Denmark.
| | | | | | | | | |
Collapse
|
22
|
Partridge M, Yamamoto T, Grau C, Høyer M, Muren LP. Imaging of normal lung, liver and parotid gland function for radiotherapy. Acta Oncol 2010; 49:997-1011. [PMID: 20831488 DOI: 10.3109/0284186x.2010.504735] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
There is growing clinical evidence that functional imaging is useful for target volume definition and early assessment of tumour response to external beam radiotherapy. A subject that has perhaps received less attention, but is no less promising, is the application of functional imaging to the prediction or measurement of radiation adverse effects in normal tissues. In this manuscript, we review the current published literature describing the use of positron emission tomography (PET), four-dimensional computed tomography (4D-CT), single photon emission computed tomography (SPECT) and magnetic resonance imaging (MRI) to study normal tissue function in the context of radiotherapy to the lung, liver and head & neck. Published results to date demonstrate that functional imaging can be used to preferentially avoid normal tissues not easily identifiable on solely anatomical images. It is also a potentially very powerful tool for the early detection of radiotherapy-induced normal tissue adverse effects and could provide valuable data for building predictive models of outcome. However, one of the major challenges to building useful predictive models is that, to date, there are very little data available with combined images of normal function, 3D delivered radiation dose and clinical outcomes. Prospective data collection through well-constructed studies which use established morbidity scores is clearly a priority if significant progress is to be made in this area.
Collapse
Affiliation(s)
- Mike Partridge
- Joint Department of Physics, The Royal Mardsen NHS Foundation Trust & The Institute of Cancer Research, Sutton, UK.
| | | | | | | | | |
Collapse
|
23
|
Korreman SS, Ulrich S, Bowen S, Deveau M, Bentzen SM, Jeraj R. Feasibility of dose painting using volumetric modulated arc optimization and delivery. Acta Oncol 2010; 49:964-71. [PMID: 20831483 PMCID: PMC3055798 DOI: 10.3109/0284186x.2010.498440] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
PURPOSE Dose painting strategies are limited by optimization algorithms in treatment planning systems and physical constraints of the beam delivery. We investigate dose conformity using the RapidArc optimizer and beam delivery technique. Furthermore, robustness of the plans with respect to positioning uncertainties are evaluated. METHODS A head & neck cancer patient underwent a [(61)Cu]Cu-ATSM PET/CT-scan. PET-SUVs were converted to prescribed dose with a base dose of 60 Gy, and target mean dose 90 Gy. The voxel-based prescription was converted into 3, 5, 7, 9, and 11 discrete prescription levels. Optimization was performed in Eclipse, varying the following parameters: MLC leaf width (5 mm and 2.5 mm), number of arcs (1 and 2) and collimator rotation (0, 15, 30 and 45 degrees). Dose conformity was evaluated using quality volume histograms (QVHs), and relative volumes receiving within ±5% of prescribed dose (Q(0.95-1.05)). Deliverability was tested using a Delta4(®) phantom. Robustness was tested by shifting the isocenter 1 mm and 2 mm in all directions, and recalculating the dose. RESULTS Good conformity was obtained using MLC leaf width 2.5 mm, two arcs, and collimators 45/315 degrees, with Q(0.95-1.05)=92.8%, 91.6%, 89.7% and 84.6%. Using only one arc or increasing the MLC leaf width had a small deteriorating effect of 2-5%. Small changes in collimator angle gave small changes, but large changes in collimator angle gave a larger decrease in plan conformity; for angles of 15 and 0 degrees (two arcs, 2.5 mm leaf width), Q(0.95-1.05) decreased by up to 15%. Consistency between planned and delivered dose was good, with ∼90% of gamma values <1. For 1 mm shift, Q(0.95-1.05) was decreased by 5-15%, while for 2 mm shift, Q(0.95-1.05) was decreased to 55-60%. CONCLUSIONS Results demonstrate feasibility of planning of prescription doses with multiple levels for dose painting using RapidArc, and plans were deliverable. Robustness to positional error was low.
Collapse
Affiliation(s)
- Stine S Korreman
- University of Wisconsin School of Medicine and Public Health, Department of Human Oncology, Clinical Sciences Center, Madison, Wisconsin, USA.
| | | | | | | | | | | |
Collapse
|
24
|
Thörnqvist S, Petersen JBB, Høyer M, Bentzen LN, Muren LP. Propagation of target and organ at risk contours in radiotherapy of prostate cancer using deformable image registration. Acta Oncol 2010; 49:1023-32. [PMID: 20831491 DOI: 10.3109/0284186x.2010.503662] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
BACKGROUND Successful deformable image registration is an essential component of both dose accumulation and plan adaptation in radiotherapy. The aim of this study was to evaluate the performance of a deformable image registration application for propagation of contours using repeat CT scans of the pelvis, a region where considerable deformations are expected. MATERIAL AND METHODS The study involved four prostate cancer patients, each with 9-11 repeat CT scans. An oncologist contoured bladder, rectum, clinical target volume of pelvic lymph nodes (CTV-ln) and prostate (CTV-p) in all CT scans. The reference CT was retrospectively registered to the repeat CT scans with both rigid and deformable registration using a recently released commercial clinical software application. Two different diffusion-based 'demons' deformable registration algorithms were applied, differing in the amount of deformations being allowed, with algorithm A being more generous than algorithm B. The evaluation of the propagated structures included both quantitative measures and qualitative scoring. RESULTS We found the differences between the algorithms to be most evident for bladder and rectum. An increase in mean Dice similarity coefficient relative the rigid registrations of 12% and 13% was obtained with algorithm A for bladder and rectum, compared to 2% with algorithm B. For bladder the mean sensitivity and positive predictive value was 0.92 and 0.87 with algorithm A and 0.82 and 0.83 with algorithm B. Corresponding values for rectum was 0.81 and 0.76 with algorithm A and 0.75 and 0.69 with algorithm B. This translated into 57% and 26% passing the clinical evaluation for bladder and rectum, with algorithm A, compared to 17% and 14% with algorithm B. For CTV-ln and CTV-p both algorithms performed well by all measures, e.g. with 86% of the target structures passing the clinical evaluation. CONCLUSIONS Deformable image registration improved contour propagation in the pelvis for all organs investigated. Differences in the performance of the algorithms were seen which became more pronounced for the highly deformable organs of bladder and rectum.
Collapse
|
25
|
Buhl SK, Duun-Christensen AK, Kristensen BH, Behrens CF. Clinical evaluation of 3D/3D MRI-CBCT automatching on brain tumors for online patient setup verification - A step towards MRI-based treatment planning. Acta Oncol 2010; 49:1085-91. [PMID: 20831500 DOI: 10.3109/0284186x.2010.498442] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
BACKGROUND Magnetic Resonance Imaging (MRI) is often used in modern day radiotherapy (RT) due to superior soft tissue contrast. However, treatment planning based solely on MRI is restricted due to e.g. the limitations of conducting online patient setup verification using MRI as reference. In this study 3D/3D MRI-Cone Beam CT (CBCT) automatching for online patient setup verification was investigated. MATERIAL AND METHODS Initially, a multi-modality phantom was constructed and used for a quantitative comparison of CT-CBCT and MRI-CBCT automatching. Following the phantom experiment three patients undergoing postoperative radiotherapy for malignant brain tumors received a weekly CBCT. In total 18 scans was matched with both CT and MRI as reference. The CBCT scans were acquired using a Clinac iX 2300 linear accelerator (Varian Medical Systems) with an On-Board Imager (OBI). RESULTS For the phantom experiment CT-CBCT and MRI-CBCT automatching resulted in similar results. A significant difference was observed only in the longitudinal direction where MRI-CBCT resulted in the best match (mean and standard deviations of 1.85±2.68 mm for CT and -0.05±2.55 mm for MRI). For the clinical experiment the absolute difference in couch shift coordinates acquired from MRI-CBCT and CT-CBCT automatching, were ≤2 mm in the vertical direction and ≤3 mm in the longitudinal and lateral directions. For yaw rotation differences up to 3.3 degrees were observed. Mean values and standard deviations were 0.8±0.6 mm, 1.5±1.2 mm and 1.2±1.2 mm for the vertical, longitudinal and lateral directions, respectively and 1.95±1.12 degrees for the rotation (n=17). CONCLUSION It is feasible to use MRI as reference when conducting 3D/3D CBCT automatching for online patient setup verification. For both the phantom and clinical experiment MRI-CBCT performed similar to CT-CBCT automatching and significantly better in the longitudinal direction for the phantom experiment.
Collapse
Affiliation(s)
- Sune K Buhl
- Department of Oncology, Copenhagen University Hospital, DK-2730 Herlev, Denmark.
| | | | | | | |
Collapse
|
26
|
Grau C, Olsen DR, Overgaard J, Høyer M, Lindegaard JC, Muren LP. Biology-guided adaptive radiation therapy - presence or future? Acta Oncol 2010; 49:884-7. [PMID: 20831476 DOI: 10.3109/0284186x.2010.516010] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
MESH Headings
- Adaptation, Biological/physiology
- Adaptation, Biological/radiation effects
- Biology/methods
- Biology/trends
- Dose Fractionation, Radiation
- Fluorodeoxyglucose F18
- Humans
- Radiation Oncology/methods
- Radiation Oncology/trends
- Radiosurgery/methods
- Radiosurgery/trends
- Radiotherapy Dosage
- Radiotherapy, Computer-Assisted/methods
- Radiotherapy, Computer-Assisted/trends
- Radiotherapy, Conformal/adverse effects
- Radiotherapy, Conformal/methods
- Radiotherapy, Conformal/trends
- Surgery, Computer-Assisted/methods
- Surgery, Computer-Assisted/trends
Collapse
|
27
|
Thor M, Væth M, Karlsdottir A, Muren LP. Rectum motion and morbidity prediction: Improving correlation between late morbidity and DVH parameters through use of rectum planning organ at risk volumes. Acta Oncol 2010; 49:1061-8. [PMID: 20831497 DOI: 10.3109/0284186x.2010.505200] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
BACKGROUND AND PURPOSE The rectum is a major dose-limiting organ at risk (OR) in radiotherapy (RT) of prostate cancer. Methods to predict adverse effects in the rectum are therefore important but their precision often limited, not the least by the internal motion of this organ. In this study late rectal morbidity is investigated in relation to the internal motion of the rectum by applying the 'Planning organ at Risk Volume' (PRV) concept. MATERIALS AND METHODS Late rectal morbidity was analysed in 242 prostate cancer patients treated to 70 Gy with conformal RT to either the prostate, the prostate and seminal vesicles or the whole pelvis (initial 50 Gy only). Late rectal morbidity was classified by the late gastro-intestinal (GI) RTOG toxicity scoring system. Cumulative dose-volume histograms (DVHs) were derived for the rectum OR and six rectum PRVs i.e. the OR expanded with six different margins (narrow/intermediate/wide in anterior direction or in both anterior and posterior direction). The difference in rectum dose-volume parameters between patients with Grade 0-1 vs. Grade 2 or higher morbidity was investigated by logistic regression and permutation tests. RESULTS Late Grade 2 or higher morbidity was observed in 25 of 242 (10%) patients. The logistic regression analysis and the permutation tests reached significance (p ≤ 0.05) for only one dose level of the rectum OR (40 Gy). For the PRVs, several dose levels were found to be significant (p-value range: 0.01-0.046), most pronounced for the PRV with narrow margins of 6 mm anterior and 5 mm posterior with five intermediate (38-42 Gy) and ten high (62-71 Gy) dose levels. CONCLUSIONS The statistical methods applied displayed consistently a small though significant difference in DVH parameters between patients with vs. without Grade 2 or higher late rectal morbidity for intermediate and high dose levels. The difference became most evident when using a PRV with narrow margins.
Collapse
Affiliation(s)
- Maria Thor
- Department of Medical Physics, Aarhus University Hospital, Aarhus, Denmark.
| | | | | | | |
Collapse
|
28
|
Vestergaard A, Søndergaard J, Petersen JB, Høyer M, Muren LP. A comparison of three different adaptive strategies in image-guided radiotherapy of bladder cancer. Acta Oncol 2010; 49:1069-76. [PMID: 20831498 DOI: 10.3109/0284186x.2010.501813] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
UNLABELLED The urinary bladder shows considerable individual variation in shape and position during a course of radiotherapy (RT). In this study we have developed and compared three different adaptive RT (ART) strategies for bladder cancer involving daily cone beam CT (CBCT) imaging and plan selection. MATERIAL AND METHODS Ten patients treated for bladder cancer had daily CBCTs acquired that were registered online using bony anatomy registration. Seven patients received intensity modulated RT (IMRT) with a simultaneous integrated boost (SIB) technique to the bladder and pelvic lymph nodes. Three patients received treatment to the bladder only. Retrospectively, we compared three ART strategies that were all based on daily selection of the most suitable plan from a library consisting of three IMRT-plans corresponding to a small, medium and large target volume. ART method A utilised population-based margins while methods B and C used the bladder as seen on CBCT-scans from the first week of treatment; method B without delineation of the bladder on CBCT and method C with delineation of the bladder. Total dose distributions were calculated using the planning CT. For each patient, we calculated ratios of the dose volume histograms (DVHs) for the three ART strategies relative to non-adaptive therapy. RESULTS The inter-patient variation was large for all three ART strategies. The mean ratios of the volumes receiving 57 Gy or more (corresponding to 95% of prescribed dose) for methods A, B and C were 0.66 (SD: 0.11), 0.67 (SD: 0.13) and 0.67 (SD: 0.16) respectively when compared to the non-adaptive plan. CONCLUSION When using any of the ART strategies, it is possible to reduce significantly the volumes receiving high doses compared to the use of a standard non-adaptive plan. The differences in dose volume parameters between the three methods were small compared with the differences from the standard plan.
Collapse
Affiliation(s)
- Anne Vestergaard
- Department of Medical Physics, Aarhus University Hospital - Arhus Sygehus, DK-8000 Aarhus C, Denmark.
| | | | | | | | | |
Collapse
|
29
|
Elstrøm UV, Wysocka BA, Muren LP, Petersen JB, Grau C. Daily kV cone-beam CT and deformable image registration as a method for studying dosimetric consequences of anatomic changes in adaptive IMRT of head and neck cancer. Acta Oncol 2010; 49:1101-8. [PMID: 20831502 DOI: 10.3109/0284186x.2010.500304] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
PURPOSE Evaluating a method for anatomic changes assessment and actually delivered doses during head and neck (H&N) cancer radiotherapy (RT) utilizing volumetric images from cone-beam CT (CBCT) and a commercially available deformable image registration (DIR) software. MATERIAL AND METHODS Thirty-three daily acquired CBCT image sets and the planning CT of one H&N cancer patient were retrospectively transferred from a standard treatment planning system (TPS) to the DIR software. The planning CT was deformed to each CBCT and the contours delineated for planning purposes were propagated. Transfer of each deformed planning CT back into the TPS enabled re-calculation of the actual daily delivered dose distribution based on online image-guidance. For both normal tissues and target volumes the deformed contours were visually evaluated and dose-volume histogram (DVH) parameters were calculated. RESULTS The workflow of the method took 45 minutes to estimate delivered dose for each treatment fraction. Propagated deformed contours were acceptable for evaluating changes in anatomy. Based on daily DVH parameters the actual delivered dose could be monitored. CONCLUSION A proof-of-principle method to quantitatively monitor anatomical changes and delivered dose during the course of fractionated RT for H&N cancer has been demonstrated. This provides a tool for exploring adaptive re-planning strategies.
Collapse
|
30
|
Søvik Å, Rødal J, Skogmo HK, Lervåg C, Eilertsen K, Malinen E. Adaptive radiotherapy based on contrast enhanced cone beam CT imaging. Acta Oncol 2010; 49:972-7. [PMID: 20831484 DOI: 10.3109/0284186x.2010.498433] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Cone beam CT (CBCT) imaging has become an integral part of radiation therapy, with images typically used for offline or online patient setup corrections based on bony anatomy co-registration. Ideally, the co-registration should be based on tumor localization. However, soft tissue contrast in CBCT images may be limited. In the present work, contrast enhanced CBCT (CECBCT) images were used for tumor visualization and treatment adaptation. Material and methods. A spontaneous canine maxillary tumor was subjected to repeated cone beam CT imaging during fractionated radiotherapy (10 fractions in total). At five of the treatment fractions, CECBCT images, employing an iodinated contrast agent, were acquired, as well as pre-contrast CBCT images. The tumor was clearly visible in post-contrast minus pre-contrast subtraction images, and these contrast images were used to delineate gross tumor volumes. IMRT dose plans were subsequently generated. Four different strategies were explored: 1) fully adapted planning based on each CECBCT image series, 2) planning based on images acquired at the first treatment fraction and patient repositioning following bony anatomy co-registration, 3) as for 2), but with patient repositioning based on co-registering contrast images, and 4) a strategy with no patient repositioning or treatment adaptation. The equivalent uniform dose (EUD) and tumor control probability (TCP) calculations to estimate treatment outcome for each strategy. Results. Similar translation vectors were found when bony anatomy and contrast enhancement co-registration were compared. Strategy 1 gave EUDs closest to the prescription dose and the highest TCP. Strategies 2 and 3 gave EUDs and TCPs close to that of strategy 1, with strategy 3 being slightly better than strategy 2. Even greater benefits from strategies 1 and 3 are expected with increasing tumor movement or deformation during treatment. The non-adaptive strategy 4 was clearly inferior to all three adaptive strategies. Conclusion. CECBCT may prove useful for adaptive radiotherapy.
Collapse
|
31
|
Abstract
With the introduction of new biologically based imaging possibilities, a higher degree of individualisation and adaptation of radiotherapy will be possible. Better knowledge of the biology of the target and its sub-volumes will enable dose prescriptions tailored to the individual patients, tissues and sub-volumes. Repeated imaging during the course of treatment will in addition enable adaptation of the treatment to cope with anatomical, as well as biological changes of the patient and of the target tissues. To translate these bright future perspectives into significant improvements in clinical outcome, advanced tools to tailor the physical dose distributions are needed. The most conformal radiotherapy technique known to mankind and clinically available today is proton therapy; in particular Intensity Modulated Proton Therapy (IMPT) with active spot scanning can not only tailor the dose to the desired target, but also effectively avoid sensitive structures in the proximity of the target to a degree far better than other conformal techniques such as Intensity Modulated Radiotherapy with photons (IMRT). The development of IMPT is now mature enough for clinical introduction on a broad scale. Proton therapy is still more expensive than conventional radiotherapy, but with the present rapid increase in the number of proton facilities worldwide and new initiatives to improve efficiency, the difference in affordability will continue to decrease and in comparison with the benefits, soon diminish even further. Contrary to what is sometimes claimed, the demands for better physical dose distributions and better avoidance of non-target tissue, has never been higher. Prolonged expected survival in many groups of patients emphasises the need to reduce late toxicities. The success of concomitant systemic therapies, with their tendency to cause higher morbidity stresses even further the increased need for subtle dose-sculpting methodologies and tools. There is no contradiction between striving for better physical dose distributions and a more biologically based approach. On the contrary, physical dose distributions are the tools to which achieve a treatment that can meet the biological demands.
Collapse
|
32
|
Muren LP, Petersen JB, Hansen J, Hafslund R. Medical physics in the Nordic countries: the past, the present and the future. Acta Oncol 2009; 48:165-8. [PMID: 19031283 DOI: 10.1080/02841860802558946] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
|