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Influence of 2-Nitroimidazoles in the Response of FaDu Cells to Ionizing Radiation and Hypoxia/Reoxygenation Stress. Antioxidants (Basel) 2023; 12:antiox12020389. [PMID: 36829948 PMCID: PMC9951954 DOI: 10.3390/antiox12020389] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2022] [Revised: 02/01/2023] [Accepted: 02/03/2023] [Indexed: 02/08/2023] Open
Abstract
Cellular adaptations to hypoxia promote resistance to ionizing radiation (IR). This presents a challenge for treatment of head and neck cancer (HNC) that relies heavily on radiotherapy. Standard radiosensitizers often fail to reach diffusion-restricted hypoxic cells, whereas nitroimidazoles (NIs) [such as iodoazomycin arabinofuranoside (IAZA) and fluoroazomycin arabinofuranoside (FAZA)] can preferentially accumulate in hypoxic tumours. Here, we explored if the hypoxia-selective uptake of IAZA and FAZA could be harnessed to make HNC cells (FaDu) susceptible to radiation therapy. Cellular response to treatment was assessed through clonogenic survival assays and by monitoring DNA damage (immunofluorescence staining of DNA damage markers, γ-H2AX and p-53BP1, and by alkaline comet assay). The effects of reoxygenation were studied using the following assays: estimation of nucleoside incorporation to assess DNA synthesis rates, immunofluorescent imaging of chromatin-associated replication protein A as a marker of replication stress, and quantification of reactive oxygen species (ROS). Both IAZA and FAZA sensitized hypoxic HNC cells to IR, albeit the former is a better radiosensitizer. Radiosensitization by these compounds was restricted only to hypoxic cells, with no visible effects under normoxia. IAZA and FAZA impaired cellular adaptation to reoxygenation; high levels of ROS, reduced DNA synthesis capacity, and signs of replication stress were observed in reoxygenated cells. Overall, our data highlight the therapeutic potentials of IAZA and FAZA for targeting hypoxic HNC cells and provide rationale for future preclinical studies.
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2
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Cellular mechanism of action of 2-nitroimidzoles as hypoxia-selective therapeutic agents. Redox Biol 2022; 52:102300. [PMID: 35430547 PMCID: PMC9038562 DOI: 10.1016/j.redox.2022.102300] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2022] [Revised: 03/05/2022] [Accepted: 03/18/2022] [Indexed: 02/06/2023] Open
Abstract
Solid tumours are often poorly oxygenated, which confers resistance to standard treatment modalities. Targeting hypoxic tumours requires compounds, such as nitroimidazoles (NIs), equipped with the ability to reach and become activated within diffusion limited tumour niches. NIs become selectively entrapped in hypoxic cells through bioreductive activation, and have shown promise as hypoxia directed therapeutics. However, little is known about their mechanism of action, hindering the broader clinical usage of NIs. Iodoazomycin arabinofuranoside (IAZA) and fluoroazomycin arabinofuranoside (FAZA) are clinically validated 2-NI hypoxic radiotracers with excellent tumour uptake properties. Hypoxic cancer cells have also shown preferential susceptibility to IAZA and FAZA treatment, making them ideal candidates for an in-depth study in a therapeutic setting. Using a head and neck cancer model, we show that hypoxic cells display higher sensitivity to IAZA and FAZA, where the drugs alter cell morphology, compromise DNA replication, slow down cell cycle progression and induce replication stress, ultimately leading to cytostasis. Effects of IAZA and FAZA on target cellular macromolecules (DNA, proteins and glutathione) were characterized to uncover potential mechanism(s) of action. Covalent binding of these NIs was only observed to cellular proteins, but not to DNA, under hypoxia. While protein levels remained unaffected, catalytic activities of NI target proteins, such as the glycolytic enzyme glyceraldehyde-3-phosphate dehydrogenase (GAPDH) and the detoxification enzyme glutathione S-transferase (GST) were significantly curtailed in response to drug treatment under hypoxia. Intraperitoneal administration of IAZA was well-tolerated in mice and produced early (but transient) growth inhibition of subcutaneous mouse tumours. Hypoxic cells display preferential sensitivity to IAZA and FAZA. They alter cell morphology and induce cytostasis. IAZA and FAZA generate covalent adducts of proteins but not DNA. GAPDH and GST activities, but not protein levels, are significantly reduced.
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Dimitrakopoulou-Strauss A, Pan L, Sachpekidis C. Parametric Imaging With Dynamic PET for Oncological Applications: Protocols, Interpretation, Current Applications and Limitations for Clinical Use. Semin Nucl Med 2021; 52:312-329. [PMID: 34809877 DOI: 10.1053/j.semnuclmed.2021.10.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Nuclear medicine imaging modalities, and in particular positron emission tomography (PET), provide functional images that demonstrate the mean radioactivity distribution at a defined point in time. With the help of mathematical model's, it is possible to depict isolated parameters of the radiotracers' pharmacokinetics and to visualize them. These so called parametric images add a new dimension to the existing conventional PET images and provide more detailed information about the tracer distribution over time and space. Prerequisite for the calculation of parametric images, which reflect specific pharmacokinetic parameters, is the dynamic PET (dPET) data acquisition. Hitherto, PET parametric imaging has mainly found use for research purposes. However, it has not been yet implemented into clinical routine, since it is more time-consuming, it requires a complicated analysis and still lacks a clear benefit over conventional PET imaging. However, the recent introduction of new PET-CT scanners with an ultralong field of view, which allow a faster data acquisition and are associated with higher sensitivity, as well as the development of more sophisticated evaluation software packages will probably lead to a renaissance of dPET and parametric maps even of the whole body. The implementation of dPET imaging in daily routine with appropriate acquisition protocols, as well as the calculation, interpretation and potential clinical applications of parametric images will be discussed in this review article.
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Affiliation(s)
| | - Leyun Pan
- Clinical Cooperation Unit Nuclear Medicine, German Cancer Research Center, Heidelberg, Germany
| | - Christos Sachpekidis
- Clinical Cooperation Unit Nuclear Medicine, German Cancer Research Center, Heidelberg, Germany
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4
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Wang L, Wang H, Shen K, Park H, Zhang T, Wu X, Hu M, Yuan H, Chen Y, Wu Z, Wang Q, Li Z. Development of Novel 18F-PET Agents for Tumor Hypoxia Imaging. J Med Chem 2021; 64:5593-5602. [PMID: 33901402 DOI: 10.1021/acs.jmedchem.0c01962] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Tumor hypoxia is a major factor responsible for tumor progression, metastasis, invasion, and treatment resistance, leading to low local tumor control and recurrence after radiotherapy in cancers. Here,18F-positron emission tomography (PET) probes are developed for visualizing viable hypoxic cells in biopsies. Pimonidazole derivatives and nitroimidazole-based agents bearing sulfonyl linkers were evaluated. A small-animal PET study showed that the tumor uptake of [18F]-23 [poly(ethylene glycols) (PEG)-sulfonyl linker] of 3.36 ± 0.29%ID/g was significantly higher (P < 0.01) than that of [18F]-20 (piperazine-linker tracer, 2.55 ± 0.49%ID/g) at 2 h postinjection in UPPL tumors. The tumor-to-muscle uptake ratio of [18F]-23 (2.46 ± 0.48 at 2 h pi) was well improved compared with that of [18F]-FMISO (1.25 ± 0.14 at 2 h pi). A comparable distribution pattern was observed between ex vivo autoradiography of [18F]-23 and pimonidazole staining of the neighboring slice, indicating that [18F]-23 is a promising PET agent for hypoxia imaging.
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Affiliation(s)
- Li Wang
- Biomedical Research Imaging Center, Department of Radiology, and UNC Lineberger Comprehensive Cancer Center, University of North Carolina-Chapel Hill, Chapel Hill, North Carolina 27514, United States.,Department of Nuclear Medicine, Affiliated Hospital of Southwest Medical University, Luzhou 646000, China.,Nuclear Medicine and Molecular Imaging Key Laboratory of Sichuan Province, Luzhou 646000, Sichuan, China
| | - Hui Wang
- Biomedical Research Imaging Center, Department of Radiology, and UNC Lineberger Comprehensive Cancer Center, University of North Carolina-Chapel Hill, Chapel Hill, North Carolina 27514, United States
| | - Kun Shen
- Department of Chemistry, Duke University, Durham, North Carolina 27708, United States
| | - Hyejin Park
- Department of Chemistry, Duke University, Durham, North Carolina 27708, United States
| | - Tao Zhang
- Biomedical Research Imaging Center, Department of Radiology, and UNC Lineberger Comprehensive Cancer Center, University of North Carolina-Chapel Hill, Chapel Hill, North Carolina 27514, United States
| | - Xuedan Wu
- Biomedical Research Imaging Center, Department of Radiology, and UNC Lineberger Comprehensive Cancer Center, University of North Carolina-Chapel Hill, Chapel Hill, North Carolina 27514, United States
| | - Mei Hu
- Department of Nuclear Medicine, Affiliated Hospital of Southwest Medical University, Luzhou 646000, China.,Nuclear Medicine and Molecular Imaging Key Laboratory of Sichuan Province, Luzhou 646000, Sichuan, China
| | - Hong Yuan
- Biomedical Research Imaging Center, Department of Radiology, and UNC Lineberger Comprehensive Cancer Center, University of North Carolina-Chapel Hill, Chapel Hill, North Carolina 27514, United States
| | - Yue Chen
- Department of Nuclear Medicine, Affiliated Hospital of Southwest Medical University, Luzhou 646000, China.,Nuclear Medicine and Molecular Imaging Key Laboratory of Sichuan Province, Luzhou 646000, Sichuan, China
| | - Zhanhong Wu
- Biomedical Research Imaging Center, Department of Radiology, and UNC Lineberger Comprehensive Cancer Center, University of North Carolina-Chapel Hill, Chapel Hill, North Carolina 27514, United States
| | - Qiu Wang
- Department of Chemistry, Duke University, Durham, North Carolina 27708, United States
| | - Zibo Li
- Biomedical Research Imaging Center, Department of Radiology, and UNC Lineberger Comprehensive Cancer Center, University of North Carolina-Chapel Hill, Chapel Hill, North Carolina 27514, United States
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2-Nitroimidazole-Furanoside Derivatives for Hypoxia Imaging-Investigation of Nucleoside Transporter Interaction, 18F-Labeling and Preclinical PET Imaging. Pharmaceuticals (Basel) 2019; 12:ph12010031. [PMID: 30781409 PMCID: PMC6469291 DOI: 10.3390/ph12010031] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2018] [Revised: 02/04/2019] [Accepted: 02/12/2019] [Indexed: 11/16/2022] Open
Abstract
The benefits of PET imaging of tumor hypoxia in patient management has been demonstrated in many examples and with various tracers over the last years. Although, the optimal hypoxia imaging agent has yet to be found, 2-nitroimidazole (azomycin) sugar derivatives—mimicking nucleosides—have proven their potential with [18F]FAZA ([18F]fluoro-azomycin-α-arabinoside) as a prominent representative in clinical use. Still, for all of these tracers, cellular uptake by passive diffusion is postulated with the disadvantage of slow kinetics and low tumor-to-background ratios. We recently evaluated [18F]fluoro-azomycin-β-deoxyriboside (β-[18F]FAZDR), with a structure more similar to nucleosides than [18F]FAZA and possible interaction with nucleoside transporters. For a deeper insight, we comparatively studied the interaction of FAZA, β-FAZA, α-FAZDR and β-FAZDR with nucleoside transporters (SLC29A1/2 and SLC28A1/2/3) in vitro, showing variable interactions of the compounds. The highest interactions being for β-FAZDR (IC50 124 ± 33 µM for SLC28A3), but also for FAZA with the non-nucleosidic α-configuration, the interactions were remarkable (290 ± 44 µM {SLC28A1}; 640 ± 10 µM {SLC28A2}). An improved synthesis was developed for β-FAZA. For a PET study in tumor-bearing mice, α-[18F]FAZDR was synthesized (radiochemical yield: 15.9 ± 9.0% (n = 3), max. 10.3 GBq, molar activity > 50 GBq/µmol) and compared to β-[18F]FAZDR and [18F]FMISO, the hypoxia imaging gold standard. We observed highest tumor-to-muscle ratios (TMR) for β-[18F]FAZDR already at 1 h p.i. (2.52 ± 0.94, n = 4) in comparison to [18F]FMISO (1.37 ± 0.11, n = 5) and α-[18F]FAZDR (1.93 ± 0.39, n = 4), with possible mediation by the involvement of nucleoside transporters. After 3 h p.i., TMR were not significantly different for all 3 tracers (2.5–3.0). Highest clearance from tumor tissue was observed for β-[18F]FAZDR (56.6 ± 6.8%, 2 h p.i.), followed by α-[18F]FAZDR (34.2 ± 7.5%) and [18F]FMISO (11.8 ± 6.5%). In conclusion, both isomers of [18F]FAZDR showed their potential as PET hypoxia tracers. Differences in uptake behavior may be attributed to a potential variable involvement of transport mechanisms.
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Salem A, Asselin MC, Reymen B, Jackson A, Lambin P, West CML, O'Connor JPB, Faivre-Finn C. Targeting Hypoxia to Improve Non-Small Cell Lung Cancer Outcome. J Natl Cancer Inst 2018; 110:4096546. [PMID: 28922791 DOI: 10.1093/jnci/djx160] [Citation(s) in RCA: 161] [Impact Index Per Article: 26.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2017] [Accepted: 07/03/2017] [Indexed: 12/18/2022] Open
Abstract
Oxygen deprivation (hypoxia) in non-small cell lung cancer (NSCLC) is an important factor in treatment resistance and poor survival. Hypoxia is an attractive therapeutic target, particularly in the context of radiotherapy, which is delivered to more than half of NSCLC patients. However, NSCLC hypoxia-targeted therapy trials have not yet translated into patient benefit. Recently, early termination of promising evofosfamide and tarloxotinib bromide studies due to futility highlighted the need for a paradigm shift in our approach to avoid disappointments in future trials. Radiotherapy dose painting strategies based on hypoxia imaging require careful refinement prior to clinical investigation. This review will summarize the role of hypoxia, highlight the potential of hypoxia as a therapeutic target, and outline past and ongoing hypoxia-targeted therapy trials in NSCLC. Evidence supporting radiotherapy dose painting based on hypoxia imaging will be critically appraised. Carefully selected hypoxia biomarkers suitable for integration within future NSCLC hypoxia-targeted therapy trials will be examined. Research gaps will be identified to guide future investigation. Although this review will focus on NSCLC hypoxia, more general discussions (eg, obstacles of hypoxia biomarker research and developing a framework for future hypoxia trials) are applicable to other tumor sites.
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Affiliation(s)
- Ahmed Salem
- Division of Cancer Sciences and Division of Informatics, Imaging and Data Sciences, University of Manchester, Manchester, UK; Department of Radiation Oncology (MAASTRO Lab), GROW School for Oncology and Developmental Biology, Maastricht University Medical Centre, Maastricht, the Netherlands
| | - Marie-Claude Asselin
- Division of Cancer Sciences and Division of Informatics, Imaging and Data Sciences, University of Manchester, Manchester, UK; Department of Radiation Oncology (MAASTRO Lab), GROW School for Oncology and Developmental Biology, Maastricht University Medical Centre, Maastricht, the Netherlands
| | - Bart Reymen
- Division of Cancer Sciences and Division of Informatics, Imaging and Data Sciences, University of Manchester, Manchester, UK; Department of Radiation Oncology (MAASTRO Lab), GROW School for Oncology and Developmental Biology, Maastricht University Medical Centre, Maastricht, the Netherlands
| | - Alan Jackson
- Division of Cancer Sciences and Division of Informatics, Imaging and Data Sciences, University of Manchester, Manchester, UK; Department of Radiation Oncology (MAASTRO Lab), GROW School for Oncology and Developmental Biology, Maastricht University Medical Centre, Maastricht, the Netherlands
| | - Philippe Lambin
- Division of Cancer Sciences and Division of Informatics, Imaging and Data Sciences, University of Manchester, Manchester, UK; Department of Radiation Oncology (MAASTRO Lab), GROW School for Oncology and Developmental Biology, Maastricht University Medical Centre, Maastricht, the Netherlands
| | - Catharine M L West
- Division of Cancer Sciences and Division of Informatics, Imaging and Data Sciences, University of Manchester, Manchester, UK; Department of Radiation Oncology (MAASTRO Lab), GROW School for Oncology and Developmental Biology, Maastricht University Medical Centre, Maastricht, the Netherlands
| | - James P B O'Connor
- Division of Cancer Sciences and Division of Informatics, Imaging and Data Sciences, University of Manchester, Manchester, UK; Department of Radiation Oncology (MAASTRO Lab), GROW School for Oncology and Developmental Biology, Maastricht University Medical Centre, Maastricht, the Netherlands
| | - Corinne Faivre-Finn
- Division of Cancer Sciences and Division of Informatics, Imaging and Data Sciences, University of Manchester, Manchester, UK; Department of Radiation Oncology (MAASTRO Lab), GROW School for Oncology and Developmental Biology, Maastricht University Medical Centre, Maastricht, the Netherlands
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7
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Incerti E, Mapelli P, Vuozzo M, Fallanca F, Monterisi C, Bettinardi V, Moresco RM, Gianolli L, Picchio M. Clinical PET imaging of tumour hypoxia in lung cancer. Clin Transl Imaging 2017. [DOI: 10.1007/s40336-017-0243-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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8
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Spectral Analysis of Dynamic PET Studies: A Review of 20 Years of Method Developments and Applications. COMPUTATIONAL AND MATHEMATICAL METHODS IN MEDICINE 2016; 2016:7187541. [PMID: 28050197 PMCID: PMC5165231 DOI: 10.1155/2016/7187541] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/09/2016] [Accepted: 10/27/2016] [Indexed: 11/17/2022]
Abstract
In Positron Emission Tomography (PET), spectral analysis (SA) allows the quantification of dynamic data by relating the radioactivity measured by the scanner in time to the underlying physiological processes of the system under investigation. Among the different approaches for the quantification of PET data, SA is based on the linear solution of the Laplace transform inversion whereas the measured arterial and tissue time-activity curves of a radiotracer are used to calculate the input response function of the tissue. In the recent years SA has been used with a large number of PET tracers in brain and nonbrain applications, demonstrating that it is a very flexible and robust method for PET data analysis. Differently from the most common PET quantification approaches that adopt standard nonlinear estimation of compartmental models or some linear simplifications, SA can be applied without defining any specific model configuration and has demonstrated very good sensitivity to the underlying kinetics. This characteristic makes it useful as an investigative tool especially for the analysis of novel PET tracers. The purpose of this work is to offer an overview of SA, to discuss advantages and limitations of the methodology, and to inform about its applications in the PET field.
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Kramer GM, Frings V, Heijtel D, Smit EF, Hoekstra OS, Boellaard R. Parametric Method Performance for Dynamic 3'-Deoxy-3'- 18F-Fluorothymidine PET/CT in Epidermal Growth Factor Receptor-Mutated Non-Small Cell Lung Carcinoma Patients Before and During Therapy. J Nucl Med 2016; 58:920-925. [PMID: 28572289 DOI: 10.2967/jnumed.116.178418] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2016] [Accepted: 10/21/2016] [Indexed: 01/04/2023] Open
Abstract
The objective of this study was to validate several parametric methods for quantification of 3'-deoxy-3'-18F-fluorothymidine (18F-FLT) PET in advanced-stage non-small cell lung carcinoma (NSCLC) patients with an activating epidermal growth factor receptor mutation who were treated with gefitinib or erlotinib. Furthermore, we evaluated the impact of noise on accuracy and precision of the parametric analyses of dynamic 18F-FLT PET/CT to assess the robustness of these methods. Methods: Ten NSCLC patients underwent dynamic 18F-FLT PET/CT at baseline and 7 and 28 d after the start of treatment. Parametric images were generated using plasma input Logan graphic analysis and 2 basis functions-based methods: a 2-tissue-compartment basis function model (BFM) and spectral analysis (SA). Whole-tumor-averaged parametric pharmacokinetic parameters were compared with those obtained by nonlinear regression of the tumor time-activity curve using a reversible 2-tissue-compartment model with blood volume fraction. In addition, 2 statistically equivalent datasets were generated by countwise splitting the original list-mode data, each containing 50% of the total counts. Both new datasets were reconstructed, and parametric pharmacokinetic parameters were compared between the 2 replicates and the original data. Results: After the settings of each parametric method were optimized, distribution volumes (VT) obtained with Logan graphic analysis, BFM, and SA all correlated well with those derived using nonlinear regression at baseline and during therapy (R2 ≥ 0.94; intraclass correlation coefficient > 0.97). SA-based VT images were most robust to increased noise on a voxel-level (repeatability coefficient, 16% vs. >26%). Yet BFM generated the most accurate K1 values (R2 = 0.94; intraclass correlation coefficient, 0.96). Parametric K1 data showed a larger variability in general; however, no differences were found in robustness between methods (repeatability coefficient, 80%-84%). Conclusion: Both BFM and SA can generate quantitatively accurate parametric 18F-FLT VT images in NSCLC patients before and during therapy. SA was more robust to noise, yet BFM provided more accurate parametric K1 data. We therefore recommend BFM as the preferred parametric method for analysis of dynamic 18F-FLT PET/CT studies; however, SA can also be used.
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Affiliation(s)
- Gerbrand Maria Kramer
- Department of Radiology and Nuclear Medicine, VU University Medical Center, Amsterdam, The Netherlands
| | - Virginie Frings
- Department of Radiology and Nuclear Medicine, VU University Medical Center, Amsterdam, The Netherlands
| | | | - E F Smit
- Department of Pulmonology, VU University Medical Center, Amsterdam, The Netherlands.,Department of Thoracic Oncology, Netherlands Cancer Institute, Amsterdam, The Netherlands
| | - Otto S Hoekstra
- Department of Radiology and Nuclear Medicine, VU University Medical Center, Amsterdam, The Netherlands
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Iqbal R, Kramer GM, Verwer EE, Huisman MC, de Langen AJ, Bahce I, van Velden FH, Windhorst AD, Lammertsma AA, Hoekstra OS, Boellaard R. Multiparametric Analysis of the Relationship Between Tumor Hypoxia and Perfusion with 18F-Fluoroazomycin Arabinoside and 15O-H2O PET. J Nucl Med 2015; 57:530-5. [DOI: 10.2967/jnumed.115.166579] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2015] [Accepted: 11/18/2015] [Indexed: 01/23/2023] Open
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11
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Thorwarth D. Functional imaging for radiotherapy treatment planning: current status and future directions-a review. Br J Radiol 2015; 88:20150056. [PMID: 25827209 PMCID: PMC4628531 DOI: 10.1259/bjr.20150056] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
In recent years, radiotherapy (RT) has been subject to a number of technological innovations. Today, RT is extremely flexible, allowing irradiation of tumours with high doses, whilst also sparing normal tissues from doses. To make use of these additional degrees of freedom, integration of functional image information may play a key role (i) for better staging and tumour detection, (ii) for more accurate RT target volume delineation, (iii) to assess functional information about biological characteristics and individual radiation resistance and (iv) to apply personalized dose prescriptions. In this article, we discuss the current status and future directions of different clinically available functional imaging modalities; CT, MRI, positron emission tomography (PET) as well as the hybrid imaging techniques PET/CT and PET/MRI and their potential for individualized RT.
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Affiliation(s)
- D Thorwarth
- Section for Biomedical Physics, Department of Radiation Oncology, Eberhard Karls University Tübingen, Tübingen, Germany
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