Radiation treatment planning: Difference between revisions
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In [[Radiation therapy|radiotherapy]], '''radiation treatment planning''' is the process in which a team consisting of [[radiation oncologist]]s, [[radiation therapist]], [[Medical physics|medical physicists]] and [[Dosimetrist|medical dosimetrists]] plan the appropriate external beam radiotherapy or internal [[brachytherapy]] treatment technique for a patient with [[cancer]]. |
In [[Radiation therapy|radiotherapy]], '''radiation treatment planning''' is the process in which a team consisting of [[radiation oncologist]]s, [[radiation therapist]], [[Medical physics|medical physicists]] and [[Dosimetrist|medical dosimetrists]] plan the appropriate external beam radiotherapy or internal [[brachytherapy]] treatment technique for a patient with [[cancer]]. |
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==History== |
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| ⚫ | Typically, medical imaging |
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Early planning was performed on 2D [[Radiography|x-ray]] images, often by hand and with manual calculations. Treatment planning systems began to be used in the 1970s to improve the accuracy and speed of dose calculations.<ref>{{cite journal|last1=Thariat|first1=Juliette|last2=Hannoun-Levi|first2=Jean-Michel|last3=Sun Myint|first3=Arthur|last4=Vuong|first4=Te|last5=Gérard|first5=Jean-Pierre|title=Past, present, and future of radiotherapy for the benefit of patients|journal=Nature Reviews Clinical Oncology|date=27 November 2012|volume=10|issue=1|pages=52–60|doi=10.1038/nrclinonc.2012.203|pmid=23183635}}</ref> |
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By the 1990s [[CT scan]]s, more powerful computers, improved dose calculation algorithms and [[Multileaf collimator]]s (MLCs) had lead to 3D conformal planning (3DCRT), categorised as a Level 2 technique by the European Dynarad consortium.<ref>{{cite journal|last1=Kolitsi|first1=Zoi|last2=Dahl|first2=Olav|last3=Van Loon|first3=Ron|last4=Drouard|first4=Jean|last5=Van Dijk|first5=Jan|last6=Ruden|first6=Bengt Inge|last7=Chierego|first7=Giorgio|last8=Rosenwald|first8=Jean Claude|title=Quality assurance in conformal radiotherapy: DYNARAD consensus report on practice guidelines|journal=Radiotherapy and Oncology|date=December 1997|volume=45|issue=3|pages=217–223|doi=10.1016/S0167-8140(97)00144-8|pmid=9426115}}</ref><ref>{{Citation |last=IAEA |title=Transition from 2-D Radiotherapy to 3-D Conformal and Intensity Modulated Radiotherapy IAEA-TECDOC-1588 |url=http://www-pub.iaea.org/MTCD/publications/PDF/TE_1588_web.pdf |year=2008 |publication-place=Vienna |publisher=International Atomic Energy Agency}}</ref> 3DCRT uses MLCs to shape the radiotherapy beam to closely match the shape of a target tumour, reducing the dose to healthy surrounding tissue.<ref>{{cite journal|last1=Fraass|first1=Benedick A.|title=The development of conformal radiation therapy|journal=Medical Physics|date=1995|volume=22|issue=11|pages=1911|doi=10.1118/1.597446|pmid=8587545}}</ref> |
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Level 3 techniques such as [[Radiation therapy#Intensity-modulated radiation therapy (IMRT)|IMRT]] and [[Radiation_therapy#Volumetric_modulated_arc_therapy_.28VMAT.29|VMAT]] utilise inverse planning to provide further improved dose distributions (i.e. better coverage of target tumours and sparing of healthy tissue).<ref>{{cite journal|title=Intensity-modulated radiotherapy: current status and issues of interest|journal=International Journal of Radiation Oncology*Biology*Physics|date=November 2001|volume=51|issue=4|pages=880–914|doi=10.1016/S0360-3016(01)01749-7|pmid=11704310}}</ref><ref>{{cite journal|last1=Ozyigit|first1=Gokhan|title=Current role of modern radiotherapy techniques in the management of breast cancer|journal=World Journal of Clinical Oncology|date=2014|volume=5|issue=3|pages=425|doi=10.5306/wjco.v5.i3.425|pmc=4127613}}</ref> These methods are growing in use, particularly for cancers in certain locations which have been shown to derive the greatest benefits.<ref>{{cite journal|last1=AlDuhaiby|first1=Eman Z|last2=Breen|first2=Stephen|last3=Bissonnette|first3=Jean-Pierre|last4=Sharpe|first4=Michael|last5=Mayhew|first5=Linda|last6=Tyldesley|first6=Scott|last7=Wilke|first7=Derek R|last8=Hodgson|first8=David C|title=A national survey of the availability of intensity-modulated radiation therapy and stereotactic radiosurgery in Canada|journal=Radiation Oncology|date=2012|volume=7|issue=1|pages=18|doi=10.1186/1748-717X-7-18|pmc=3339388}}</ref><ref>{{Citation |title=Radiotherapy Board - Intensity Modulated Radiotherapy (IMRT) in the UK: Current access and predictions of future access rates |date=2015 |url=http://www.ipem.ac.uk/Portals/0/Documents/Partners/Radiotherapy%20Board/imrt_target_revisions_recommendations_for_colleges_final2.pdf |last1=Society and College of Radiographers |last2=Institute of Physics and Engineering in Medicine |last3=Royal College of Radiologists}}</ref> |
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| ⚫ | Typically, [[medical imaging]] is used to form a ''virtual patient'' for a computer-aided design procedure. A [[CT scan]] is often the primary image set for treatment planning while [[magnetic resonance imaging]] provides excellent secondary image set for soft tissue contouring. [[Positron emission tomography]] is less commonly used and reserved for cases where specific uptake studies can enhance planning target volume delineation.<ref>{{cite journal|last1=Pereira|first1=Gisele C.|last2=Traughber|first2=Melanie|last3=Muzic|first3=Raymond F.|title=The Role of Imaging in Radiation Therapy Planning: Past, Present, and Future|journal=BioMed Research International|date=2014|volume=2014|pages=1–9|doi=10.1155/2014/231090|pmid=24812609}}</ref> Modern treatment planning systems provide tools for multimodality image matching, also known as image coregistration or fusion. Treatment simulations are used to plan the geometric, radiological, and dosimetric aspects of the therapy using radiation transport simulations and [[Mathematical optimization|optimization]]. For [[intensity modulated radiation therapy]] ([[IMRT]]), this process involves selecting the appropriate beam type (which may include photons, electrons and protons), energy (e.g. 6, 18 [[megaelectronvolt]] (MeV) photons) and physical arrangements. In [[brachytherapy]] planning involves selecting the appropriate catheter positions and source dwell times |
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<ref>{{cite conference|last1=Karabis|first1=A|last2=Belloti|first2=P|last3=Baltas|first3=D|title=Optimization of Catheter Position and Dwell Time in Prostate HDR Brachytherapy using HIPO and Linear Programming|conference=World Congress on Medical Physics and Biomedical Engineering|location=Munich|journal=IFMBE Proceedings|year=2009|volume=25|issue=1|pages=612-615|doi=10.1007/978-3-642-03474-9_172|editors=O. Dössel and W.C. Schlegel}}</ref><ref>{{cite journal|last1=Lahanas|first1=M|last2=Baltas|first2=D|last3=Giannouli|first3=S|title=Global convergence analysis of fast multiobjective gradient-based dose optimization algorithms for high-dose-rate brachytherapy.|journal=Physics in medicine and biology|date=7 March 2003|volume=48|issue=5|pages=599-617|doi=10.1088/0031-9155/48/5/304|pmid=12696798}}</ref> |
<ref>{{cite conference|last1=Karabis|first1=A|last2=Belloti|first2=P|last3=Baltas|first3=D|title=Optimization of Catheter Position and Dwell Time in Prostate HDR Brachytherapy using HIPO and Linear Programming|conference=World Congress on Medical Physics and Biomedical Engineering|location=Munich|journal=IFMBE Proceedings|year=2009|volume=25|issue=1|pages=612-615|doi=10.1007/978-3-642-03474-9_172|editors=O. Dössel and W.C. Schlegel}}</ref><ref>{{cite journal|last1=Lahanas|first1=M|last2=Baltas|first2=D|last3=Giannouli|first3=S|title=Global convergence analysis of fast multiobjective gradient-based dose optimization algorithms for high-dose-rate brachytherapy.|journal=Physics in medicine and biology|date=7 March 2003|volume=48|issue=5|pages=599-617|doi=10.1088/0031-9155/48/5/304|pmid=12696798}}</ref> |
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(in HDR brachytherapy) or seeds positions (in LDR brachytherapy). |
(in HDR brachytherapy) or seeds positions (in LDR brachytherapy). |
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The more formal optimization process is typically referred to as ''forward planning'' and ''inverse planning''.<ref> |
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{{citation |first1=James M |last1=Galvin |first2=Gary |last2=Ezzell |first3=Avraham |last3=Eisbrauch |first4=Cedric |last4=Yu |first5=Brian |last5=Butler |first6=Ying |last6=Xiao |first7=Isaac |last7=Rosen |first8=Julian |last8=Rosenman |first9=Michael |last9=Sharpe |first10=Lei |last10=Xing |first11=Ping |last11=Xia |first12=Tony |last12=Lomax |first13=Daniel A |last13=Low |first14=Jatinder |last14=Palta |title= Implementing IMRT in clinical practice: a joint document of the American Society for Therapeutic Radiology and Oncology and the American Association of Physicists in Medicine. |date=April 2004 |periodical= Int J Radiat Oncol Biol Phys. |volume= 58 |issue= 5 |pages= 1616–34. |doi= 10.1016/j.ijrobp.2003.12.008 |pmid= 15050343}} |
{{citation |first1=James M |last1=Galvin |first2=Gary |last2=Ezzell |first3=Avraham |last3=Eisbrauch |first4=Cedric |last4=Yu |first5=Brian |last5=Butler |first6=Ying |last6=Xiao |first7=Isaac |last7=Rosen |first8=Julian |last8=Rosenman |first9=Michael |last9=Sharpe |first10=Lei |last10=Xing |first11=Ping |last11=Xia |first12=Tony |last12=Lomax |first13=Daniel A |last13=Low |first14=Jatinder |last14=Palta |title= Implementing IMRT in clinical practice: a joint document of the American Society for Therapeutic Radiology and Oncology and the American Association of Physicists in Medicine. |date=April 2004 |periodical= Int J Radiat Oncol Biol Phys. |volume= 58 |issue= 5 |pages= 1616–34. |doi= 10.1016/j.ijrobp.2003.12.008 |pmid= 15050343}} |
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</ref><ref> |
</ref><ref> |
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Plans are often assessed with the aid of [[dose-volume histogram]]s, allowing the clinician to evaluate the uniformity of the dose to the diseased tissue (tumor) and sparing of healthy structures. |
Plans are often assessed with the aid of [[dose-volume histogram]]s, allowing the clinician to evaluate the uniformity of the dose to the diseased tissue (tumor) and sparing of healthy structures. |
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| ⚫ | |||
Today, treatment planning is almost entirely computer based using patient [[computed tomography]] (CT) data sets. Modern treatment planning systems provide tools for multimodality image matching, also known as image coregistration or fusion. |
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| ⚫ | |||
[[File:ONSM Radiation Treatment.jpg|thumb|Treatment plan for a [[Optic nerve sheath meningioma]]]] |
[[File:ONSM Radiation Treatment.jpg|thumb|Treatment plan for a [[Optic nerve sheath meningioma]]]] |
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| ⚫ | |||
| ⚫ | In forward planning, the planner places beams into a radiotherapy treatment planning system which can deliver sufficient radiation to a [[tumour]] while both sparing critical [[Organ (anatomy)|organ]]s and minimising the dose to healthy tissue. The required decisions include how many radiation beams to use, which angles each will be delivered from, whether attenuating [[Wedge (radiotherapy)|wedges]] be used, and which MLC configuration will be used to shape the radiation from each beam. |
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| ⚫ | Once the treatment planner has made an initial plan, the treatment planning system calculates the required monitor units to deliver a prescribed dose to a specific area in the |
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| ⚫ | Once the treatment planner has made an initial plan, the treatment planning system calculates the required monitor units to deliver a prescribed dose to a specific area, and the distribution of dose in the body this will create. The dose distribution in the patient is dependent on the anatomy and beam modifiers such as wedges, specialized collimation, field sizes, tumor depth, etc. The information from a prior [[CT scan]] of the patient allows more accurate modelling of the behaviour of the radiation as it travels through the patient's tissues. Different dose calculation models are available, including [[pencil beam]], [[convolution-superposition]] and [[Monte Carlo method|monte carlo simulation]], with precision versus computation time being the relevant trade-off. |
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| ⚫ | |||
===Inverse planning=== |
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| ⚫ | This type of planning is used for the majority of external-beam radiotherapy treatments, but is only sufficiently adept to handle relatively simple |
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| ⚫ | In inverse planning a radiation oncologist defines a patient's critical organs and tumour, after which a planner gives target doses and importance factors for each. Then, an optimisation program is run to find the treatment plan which best matches all the input criteria.<ref>{{cite journal|last1=Taylor|first1=A.|title=Intensity-modulated radiotherapy - what is it?|journal=Cancer Imaging|date=2004|volume=4|issue=2|pages=68–73|doi=10.1102/1470-7330.2004.0003|pmc=1434586}}</ref> |
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| ⚫ | |||
| ⚫ | In contrast to the manual trial-and-error process of forward planning, inverse planning uses the optimiser to solve the [[Inverse problem|Inverse Problem]] as set up by the planner. <ref>{{cite journal|last1=Gintz|first1=D|last2=Latifi|first2=K|last3=Caudell|first3=J|last4=Nelms|first4=B|last5=Zhang|first5=G|last6=Moros|first6=E|last7=Feygelman|first7=V|title=Initial evaluation of automated treatment planning software.|journal=Journal of applied clinical medical physics|date=8 May 2016|volume=17|issue=3|pages=6167|doi=10.1120/jacmp.v17i3.6167|pmid=27167292}}</ref> |
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| ⚫ | |||
==See also== |
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| ⚫ | In contrast to the manual trial-and-error process |
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*[[Brachytherapy#Initial planning|Brachytherapy planning]] |
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*[[Image-guided radiation therapy]] |
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== References == |
== References == |
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Revision as of 18:14, 15 November 2016
In radiotherapy, radiation treatment planning is the process in which a team consisting of radiation oncologists, radiation therapist, medical physicists and medical dosimetrists plan the appropriate external beam radiotherapy or internal brachytherapy treatment technique for a patient with cancer.
History
Early planning was performed on 2D x-ray images, often by hand and with manual calculations. Treatment planning systems began to be used in the 1970s to improve the accuracy and speed of dose calculations.[1]
By the 1990s CT scans, more powerful computers, improved dose calculation algorithms and Multileaf collimators (MLCs) had lead to 3D conformal planning (3DCRT), categorised as a Level 2 technique by the European Dynarad consortium.[2][3] 3DCRT uses MLCs to shape the radiotherapy beam to closely match the shape of a target tumour, reducing the dose to healthy surrounding tissue.[4]
Level 3 techniques such as IMRT and VMAT utilise inverse planning to provide further improved dose distributions (i.e. better coverage of target tumours and sparing of healthy tissue).[5][6] These methods are growing in use, particularly for cancers in certain locations which have been shown to derive the greatest benefits.[7][8]
Image guided planning
Typically, medical imaging is used to form a virtual patient for a computer-aided design procedure. A CT scan is often the primary image set for treatment planning while magnetic resonance imaging provides excellent secondary image set for soft tissue contouring. Positron emission tomography is less commonly used and reserved for cases where specific uptake studies can enhance planning target volume delineation.[9] Modern treatment planning systems provide tools for multimodality image matching, also known as image coregistration or fusion. Treatment simulations are used to plan the geometric, radiological, and dosimetric aspects of the therapy using radiation transport simulations and optimization. For intensity modulated radiation therapy (IMRT), this process involves selecting the appropriate beam type (which may include photons, electrons and protons), energy (e.g. 6, 18 megaelectronvolt (MeV) photons) and physical arrangements. In brachytherapy planning involves selecting the appropriate catheter positions and source dwell times [10][11] (in HDR brachytherapy) or seeds positions (in LDR brachytherapy).
The more formal optimization process is typically referred to as forward planning and inverse planning.[12][13] Plans are often assessed with the aid of dose-volume histograms, allowing the clinician to evaluate the uniformity of the dose to the diseased tissue (tumor) and sparing of healthy structures.
Forward planning
In forward planning, the planner places beams into a radiotherapy treatment planning system which can deliver sufficient radiation to a tumour while both sparing critical organs and minimising the dose to healthy tissue. The required decisions include how many radiation beams to use, which angles each will be delivered from, whether attenuating wedges be used, and which MLC configuration will be used to shape the radiation from each beam.
Once the treatment planner has made an initial plan, the treatment planning system calculates the required monitor units to deliver a prescribed dose to a specific area, and the distribution of dose in the body this will create. The dose distribution in the patient is dependent on the anatomy and beam modifiers such as wedges, specialized collimation, field sizes, tumor depth, etc. The information from a prior CT scan of the patient allows more accurate modelling of the behaviour of the radiation as it travels through the patient's tissues. Different dose calculation models are available, including pencil beam, convolution-superposition and monte carlo simulation, with precision versus computation time being the relevant trade-off.
This type of planning is used for the majority of external-beam radiotherapy treatments, but is only sufficiently adept to handle relatively simple cases in which the tumour has a simple shape and is not near any critical organs.
Inverse planning
In inverse planning a radiation oncologist defines a patient's critical organs and tumour, after which a planner gives target doses and importance factors for each. Then, an optimisation program is run to find the treatment plan which best matches all the input criteria.[14]
In contrast to the manual trial-and-error process of forward planning, inverse planning uses the optimiser to solve the Inverse Problem as set up by the planner. [15]
See also
References
- ^ Thariat, Juliette; Hannoun-Levi, Jean-Michel; Sun Myint, Arthur; Vuong, Te; Gérard, Jean-Pierre (27 November 2012). "Past, present, and future of radiotherapy for the benefit of patients". Nature Reviews Clinical Oncology. 10 (1): 52–60. doi:10.1038/nrclinonc.2012.203. PMID 23183635.
- ^ Kolitsi, Zoi; Dahl, Olav; Van Loon, Ron; Drouard, Jean; Van Dijk, Jan; Ruden, Bengt Inge; Chierego, Giorgio; Rosenwald, Jean Claude (December 1997). "Quality assurance in conformal radiotherapy: DYNARAD consensus report on practice guidelines". Radiotherapy and Oncology. 45 (3): 217–223. doi:10.1016/S0167-8140(97)00144-8. PMID 9426115.
- ^ IAEA (2008), Transition from 2-D Radiotherapy to 3-D Conformal and Intensity Modulated Radiotherapy IAEA-TECDOC-1588 (PDF), Vienna: International Atomic Energy Agency
- ^ Fraass, Benedick A. (1995). "The development of conformal radiation therapy". Medical Physics. 22 (11): 1911. doi:10.1118/1.597446. PMID 8587545.
- ^ "Intensity-modulated radiotherapy: current status and issues of interest". International Journal of Radiation Oncology*Biology*Physics. 51 (4): 880–914. November 2001. doi:10.1016/S0360-3016(01)01749-7. PMID 11704310.
- ^ Ozyigit, Gokhan (2014). "Current role of modern radiotherapy techniques in the management of breast cancer". World Journal of Clinical Oncology. 5 (3): 425. doi:10.5306/wjco.v5.i3.425. PMC 4127613.
{{cite journal}}: CS1 maint: unflagged free DOI (link) - ^ AlDuhaiby, Eman Z; Breen, Stephen; Bissonnette, Jean-Pierre; Sharpe, Michael; Mayhew, Linda; Tyldesley, Scott; Wilke, Derek R; Hodgson, David C (2012). "A national survey of the availability of intensity-modulated radiation therapy and stereotactic radiosurgery in Canada". Radiation Oncology. 7 (1): 18. doi:10.1186/1748-717X-7-18. PMC 3339388.
{{cite journal}}: CS1 maint: unflagged free DOI (link) - ^ Society and College of Radiographers; Institute of Physics and Engineering in Medicine; Royal College of Radiologists (2015), Radiotherapy Board - Intensity Modulated Radiotherapy (IMRT) in the UK: Current access and predictions of future access rates (PDF)
- ^ Pereira, Gisele C.; Traughber, Melanie; Muzic, Raymond F. (2014). "The Role of Imaging in Radiation Therapy Planning: Past, Present, and Future". BioMed Research International. 2014: 1–9. doi:10.1155/2014/231090. PMID 24812609.
{{cite journal}}: CS1 maint: unflagged free DOI (link) - ^ Karabis, A; Belloti, P; Baltas, D (2009). Optimization of Catheter Position and Dwell Time in Prostate HDR Brachytherapy using HIPO and Linear Programming. World Congress on Medical Physics and Biomedical Engineering. IFMBE Proceedings. Vol. 25, no. 1. Munich. pp. 612–615. doi:10.1007/978-3-642-03474-9_172.
{{cite conference}}: Unknown parameter|editors=ignored (|editor=suggested) (help) - ^ Lahanas, M; Baltas, D; Giannouli, S (7 March 2003). "Global convergence analysis of fast multiobjective gradient-based dose optimization algorithms for high-dose-rate brachytherapy". Physics in medicine and biology. 48 (5): 599–617. doi:10.1088/0031-9155/48/5/304. PMID 12696798.
- ^ Galvin, James M; Ezzell, Gary; Eisbrauch, Avraham; Yu, Cedric; Butler, Brian; Xiao, Ying; Rosen, Isaac; Rosenman, Julian; Sharpe, Michael; Xing, Lei; Xia, Ping; Lomax, Tony; Low, Daniel A; Palta, Jatinder (April 2004), "Implementing IMRT in clinical practice: a joint document of the American Society for Therapeutic Radiology and Oncology and the American Association of Physicists in Medicine.", Int J Radiat Oncol Biol Phys., vol. 58, no. 5, pp. 1616–34., doi:10.1016/j.ijrobp.2003.12.008, PMID 15050343
- ^ Hendee W., Ibbott G. and Hendee E. (2005). Radiation Therapy Physics. Wiley-Liss Publ. ISBN 0-471-39493-9.
- ^ Taylor, A. (2004). "Intensity-modulated radiotherapy - what is it?". Cancer Imaging. 4 (2): 68–73. doi:10.1102/1470-7330.2004.0003. PMC 1434586.
- ^ Gintz, D; Latifi, K; Caudell, J; Nelms, B; Zhang, G; Moros, E; Feygelman, V (8 May 2016). "Initial evaluation of automated treatment planning software". Journal of applied clinical medical physics. 17 (3): 6167. doi:10.1120/jacmp.v17i3.6167. PMID 27167292.