Treatment planning
Encyclopedia
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
.
Typically, medical imaging (i.e., computed tomography
, magnetic resonance imaging
, and positron emission tomography
) are used to form a virtual patient for a computer-aided design procedure. Treatment simulations are used to plan the geometric and radiological aspects of the therapy using radiation transport simulations and optimization
. For intensity modulated radiation therapy (IMRT), this process involves selecting the appropriate beam type (electron or photon), energy (e.g. 6 MeV
, 12 MeV) and arrangements. For brachytherapy
, involves selecting the appropriate catheter positions and source dwell times
(in HDR brachytherapy) or seeds positions (in LDR brachytherapy). The more formal optimization process is typically referred to as forward planning and inverse planning.
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.
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.
system which can deliver sufficient radiation to a tumour while both sparing critical 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 wedges be used, and which multileaf collimator
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 a predicted dose to the patient. The information from a prior CT scan of the patient allows more accurate modeling of the behaviour of the radiation as it travels through the patient's tissues. Different dose prediction models are available, including pencil beam
, cone beam 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—cases in which the tumour has a simple shape and is not near any critical organs. For more sophisticated plans, inverse planning is used to create an intensity-modulated treatment plan. This is now also used as a part of PMRT planning.
The term "inverse planning" is somewhat of a misnomer; it was devised in contrast to the manual trial-and-error process known in oncology as "forward planning". It has stuck for historical reasons. Outside of the field of oncology, this procedure would be better described as "automated planning
".
HIPO (Hybrid Inverse Planning & Optimization), developed by Pi-Medical Ltd., is one algorithm.
Non-commercial
Radiation therapist
The Radiation Therapist is an allied health professional who works in the field of radiation oncology...
, medical physicists
Medical physics
Medical physics is the application of physics to medicine. It generally concerns physics as applied to medical imaging and radiotherapy, although a medical physicist may also work in many other areas of healthcare...
and medical dosimetrists plan the appropriate external beam radiotherapy or internal brachytherapy
Brachytherapy
Brachytherapy , also known as internal radiotherapy, sealed source radiotherapy, curietherapy or endocurietherapy, is a form of radiotherapy where a radiation source is placed inside or next to the area requiring treatment...
treatment technique for a patient with cancer
Cancer
Cancer , known medically as a malignant neoplasm, is a large group of different diseases, all involving unregulated cell growth. In cancer, cells divide and grow uncontrollably, forming malignant tumors, and invade nearby parts of the body. The cancer may also spread to more distant parts of the...
.
Typically, medical imaging (i.e., computed tomography
Computed tomography
X-ray computed tomography or Computer tomography , is a medical imaging method employing tomography created by computer processing...
, magnetic resonance imaging
Magnetic resonance imaging
Magnetic resonance imaging , nuclear magnetic resonance imaging , or magnetic resonance tomography is a medical imaging technique used in radiology to visualize detailed internal structures...
, and positron emission tomography
Positron emission tomography
Positron emission tomography is nuclear medicine imaging technique that produces a three-dimensional image or picture of functional processes in the body. The system detects pairs of gamma rays emitted indirectly by a positron-emitting radionuclide , which is introduced into the body on a...
) are used to form a virtual patient for a computer-aided design procedure. Treatment simulations are used to plan the geometric and radiological aspects of the therapy using radiation transport simulations and optimization
Optimization (mathematics)
In mathematics, computational science, or management science, mathematical optimization refers to the selection of a best element from some set of available alternatives....
. For intensity modulated radiation therapy (IMRT), this process involves selecting the appropriate beam type (electron or photon), energy (e.g. 6 MeV
MEV
MeV and meV are multiples and submultiples of the electron volt unit referring to 1,000,000 eV and 0.001 eV, respectively.Mev or MEV may refer to:In entertainment:* Musica Elettronica Viva, an Italian musical group...
, 12 MeV) and arrangements. For brachytherapy
Brachytherapy
Brachytherapy , also known as internal radiotherapy, sealed source radiotherapy, curietherapy or endocurietherapy, is a form of radiotherapy where a radiation source is placed inside or next to the area requiring treatment...
, involves selecting the appropriate catheter positions and source dwell times
(in HDR brachytherapy) or seeds positions (in LDR brachytherapy). The more formal optimization process is typically referred to as forward planning and inverse planning.
Plans are often assessed with the aid of dose-volume histogram
Dose-volume histogram
Dose-volume histogram , a concept used in radiation treatment planning. DVHs were introduced by Goitein and Verhey in 1979 in a publication by Shipley et al.. The purpose of a DVH is to summarize 3D dose distributions in a graphical 2D format...
s, allowing the clinician to evaluate the uniformity of the dose to the diseased tissue (tumor) and sparing of healthy structures.
Today, treatment planning is almost entirely computer based using patient computed tomography
Computed tomography
X-ray computed tomography or Computer tomography , is a medical imaging method employing tomography created by computer processing...
(CT) data sets. Modern treatment planning systems provide tools for multimodality image matching, also known as image coregistration or fusion.
Forward planning
Forward planning is a technique used in external-beam radiotherapy to produce a treatment plan. In forward planning, a treatment oncologist places beams into a radiotherapy treatment planningTreatment planning
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...
system which can deliver sufficient radiation to a tumour while both sparing critical organ
Organ (anatomy)
In biology, an organ is a collection of tissues joined in structural unit to serve a common function. Usually there is a main tissue and sporadic tissues . The main tissue is the one that is unique for the specific organ. For example, main tissue in the heart is the myocardium, while sporadic are...
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 wedges be used, and which multileaf collimator
Multileaf collimator
A multileaf collimator is a device made up of individual "leaves" of a high atomic numbered material, usually tungsten, that can move independently in and out of the path of a particle beam in order to block it....
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 a predicted dose to the patient. The information from a prior CT scan of the patient allows more accurate modeling of the behaviour of the radiation as it travels through the patient's tissues. Different dose prediction models are available, including pencil beam
Pencil beam
In optics, a pencil or pencil of rays is a geometric construct used to describe a beam or portion of a beam of electromagnetic radiation or charged particles, typically in the form of a narrow cone or cylinder....
, cone beam and monte carlo simulation
Monte Carlo method
Monte Carlo methods are a class of computational algorithms that rely on repeated random sampling to compute their results. Monte Carlo methods are often used in computer simulations of physical and mathematical systems...
, 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—cases in which the tumour has a simple shape and is not near any critical organs. For more sophisticated plans, inverse planning is used to create an intensity-modulated treatment plan. This is now also used as a part of PMRT planning.
Inverse planning
Inverse planning is a technique used to design a radiotherapy treatment plan. A radiation oncologist defines a patient's critical organs and tumour and 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.The term "inverse planning" is somewhat of a misnomer; it was devised in contrast to the manual trial-and-error process known in oncology as "forward planning". It has stuck for historical reasons. Outside of the field of oncology, this procedure would be better described as "automated planning
Planning
Planning in organizations and public policy is both the organizational process of creating and maintaining a plan; and the psychological process of thinking about the activities required to create a desired goal on some scale. As such, it is a fundamental property of intelligent behavior...
".
HIPO (Hybrid Inverse Planning & Optimization), developed by Pi-Medical Ltd., is one algorithm.
List of Radiation Treatment Planning Systems (RTPS)
Commercial- ADAC -> Pinnacle3(PhilipsPhilipsKoninklijke Philips Electronics N.V. , more commonly known as Philips, is a multinational Dutch electronics company....
Healthcare) - ISOgray (DOSIsoft)
- BrainSCAN -> BrainLAB; predecessor of iPlan RT Dose
- CAT3D -> Mevis
- Focus -> XiO (CMS, recently purchased by Elekta)
- iPlan RT Dose -> BrainLAB ; successor of Brainscan
- Render-Plan 3-D -> PrecisePLAN (ElektaElektaElekta is a swedish company that provides radiation therapy, radiosurgery, related equipment and clinical management for the treatment of cancer and brain disorders.-History:...
) - Monaco (CMS/Elekta)
- Theraplan Plus (Theratronics -> Nucletron)
- Oncentra MasterPlan - External Beam and Brachy Therapy (Nucletron)
- Oncentra Prostate - Prostate HDR Brachytherapy (Nucletron / developed by Pi-Medical & MedCom)]
- Oncentra GYN - Gynecologic brachytherapy (Nucletron / developed by Pi-Medical & MedCom)
- Plato RTS (Nucletron)
- Plato BPS (Nucletron)
- Cad Plan - predecessor of EclipseVarian Medical SystemsVarian Medical SystemsVarian Medical Systems of Palo Alto, California, is a manufacturer of medical devices and software for treating cancer and other medical conditions with radiotherapy, radiosurgery, proton therapy, and brachytherapy. The company supplies informatics software for managing comprehensive cancer...
- Corvus(NomosNomosNomos or Nomoi may refer to:* Nome , a subdivisions of Ancient Egypt* Nome , the administrative division immediately below the peripheries of Greece * law...
) - RAHD
- ROCS
- GE
- KLZ Healthcare
- Prowess
- Brachyvision (Varian)
- Gammaknife (Elekta)
- RIT
- Eclipse - designed by Varian Medical Systems; successor of the CadPlan System
- VariSeed - Prostate LDR Brachytherapy (Varian)
Non-commercial
- PLUNC (planning system written by University of North Carolina-Chapel HillUniversity of North Carolina at Chapel HillThe University of North Carolina at Chapel Hill is a public research university located in Chapel Hill, North Carolina, United States...
- Prism (planning system written by Prof Ira Kalet at University of WashingtonUniversity of WashingtonUniversity of Washington is a public research university, founded in 1861 in Seattle, Washington, United States. The UW is the largest university in the Northwest and the oldest public university on the West Coast. The university has three campuses, with its largest campus in the University...
) - MMCTP (McGill Monte Carlo Treatment Planning system)