Accelerator

Also sometimes referred to as linear accelerator or linac. The accelerator is used to create and shape the radiation beams used in radiation therapy. Usually there are one to ten accelerators per cancer clinic. Major manufacturers are Elekta, Siemens, and Varian.

Adaptive Radiation Therapy (ART)

Radiation therapy in which information extracted from image studies (CT, MRI or PET scans) acquired during the course of treatment is used to correct the treatment. This method reduces the effects of uncertainties and erroneous information during planning and improves treatment outcome. Refer also to IGRT.

Algorithms

A method for solving a problem in a number of steps, for example, a calculation procedure is called an algorithm.

Algorithm development

The process of formulating algorithms. Algorithm development focuses on the method itself and not on programming, though programming accounts for a substantial share of algorithm development.

ART

Refer to Adaptive-Radiation Therapy.

Biological optimization

Refer to Radiobiological optimization.

Brachytherapy

Local radiation treatment using radioactive isotopes, usually radium, iridium or cobalt, placed directly on or in the patient.

Carbon ions

By accelerating carbon atoms to speeds approaching half the speed of light, the carbon atom is ionized and can be used for radiation therapy that has a unique biological effect, in addition to the favorable physical properties that this type of radiation shares with protons.

Collimator angles

The collimator used to limit the fl uence profi le’s extension can be rotated around its own axis.

Computer tomography (CT scan)

The usual diagnostic method for cancer today. A method that uses X-rays to produce a three dimensional image of the internal density of the body.

Cone-beam CT

Technology for computer tomography (CT) images by means of a cone-formed X-ray beam, permitting images to be acquired promptly, and is used when CT is integrated with the treatment machine.

Conventional three-dimensional conformal radiation therapy (3D-CRT)

The treatment method used today when IMRT is not used. Involves shaping the beams to conform to the projection of the tumor using an MLC, while the intensity of the beam remains constant.

Curative radiation therapy

Therapy in which clinicians decide to treat patients in an effort to cure the cancer, in other words, completely eradicate the tumor. The opposite is Pallative radiation therapy. See below.

Detector technology

Technology used to measure radiation magnitudes. Technical examples include ion chambers, diodes and electrometers.

Direct optimization of machine parameters

The basis of RayMachine. Direct optimization of machine parameters means that, during optimization, a detailed model of the accelerator with its physical and technical limitations is used.

Dose calculation algorithms

Algorithms for calculating the radiation dose that the patient receives, given a specifi c machine setting.

Dose response relationships

How tissue reacts to radiation.

Dosimetry

An area of science dealing with the measurement of absorbed doses in materials from ionizing radiation.

Fluence optimization

A method used for calculating IMRT plans in which one permits the photon fl uence to vary arbitrarly across each beam’s cross-section. The photon fl uences are then recomputed to machine settings in a stage that adversely impacts on treatment quality. A better method is “Direct optimization of machine parameters.”

Gantry angle optimization

Optimization method which, in addition to com puting the optimal collimator setting or fl uence profi les, also simultaneously calculates optimal beam angle.

IGRT – Image-Guided Radiation Therapy

Radiation therapy in which information extracted from images of patients in the treatment position is used for basic geometric corrections such as the patient positioning. Typical imaging modalities are portal imaging and CT scanners integrated with the treatment machine (see cone-beam CT). By means of this procedure, positioning errors can be reduced and a better treatment gained. Refer also to Adaptive radiation therapy.

IMRT

Intensity Modulated Radiation Therapy is a technique in which the intensity of the beam is varied spatially using a multi-leaf collimator. Traditional radiation therapy uses only homogeneous intensity.

Light ions

An ion is an atom with a negative or a positive charge due to an excess or defi cit of electrons. Ions with a lower atomic number, such as helium (2), beryllium (4) and carbon (6) are referred to as being light.

Magnetic Resonance (MR)

An increasingly common diagnostic technique that can be used on the entire body, using the magnetic resonance of the body’s molecules. A complication-free technique that can clarify where the tumor is located in relation to the rest of the patient’s anatomy.

MLC Multileaf collimator

The multileaf collimator is a device that shapes the radiation beam and is installed in the treatment head of a linear accelerator. Used to shape the beams to conform to the tumor instead of using only a rectangular fi eld and essentially always in conjunction with the supply of IMRT.

Modularity

A property of software, which means that parts of the software can be reused in other contexts and products than those for which they were initially developed.

MR

Refer to Magnetic Resonance.

Multileaf collimator

Refer to MLC.

Oncentra MasterPlan

The new name of Nucletron’s treatment planning system, formerly referred to as Oncentra Treatment Planning (OTP).

Optimization algorithms for radiation therapy

Algorithms for calculating the radiation therapy that gives the best quality of treatment. Quality of treatment is defi ned by the doctor.

ORBIT

Optimization of Radiation Therapy Beams by Iterative Techniques The core of RaySearch’s software, which works as a framework and a toolbox for the software products that RaySearch develops.

Organ contour calculation

The process of automatically identifying the contour (closed curve) that defi nes the area in an image that corresponds to a certain organ.

OTP Oncentra Treatment Planning

The previous name of Nucletron’s treatment planning system.

Palliative radiation therapy

Therapy in which clinicians cannot cure the disease, but only alleviate it or slow its progress. The opposite is referred to as Curative radiation therapy. See above.

Plug-in module

Software that can be plugged into a larger software system and provide enhanced functionality.

Positron emission tomography (PET)

A more recent diagnostic technique, in which tumor markers are labeled with radioactive isotopes that are injected in the blood. Markers move in the circulatory system to the intended position and radioactivity shows where a tumor is positioned.

Quality assurance

Extensive checks are conducted in hospitals of all systems included in the radiation process. Certain checks are conducted daily, other before the treatment of each patient commences. These processes are referred to as quality assurance and are aimed at ensuring that the patients receive exactly the planned dose.

Protons

A type of particle with a substantially larger static mass than electrons and which, accelerated to half the speed of light, has superior radiation therapy properties than traditional photons or electron radiation.

Radiation dose algorithms

See Dose calculation algorithms.

Radiobiological optimization

Optimization of radiation therapy in which mathematical models of how tissue reacts to radiation are used in order to help the user to assess quality of treatment.

Software modules

A software package to solve a specifi c host system’s needs for functionality.

Treatment planning

Using a computer to fi nd one or more recommendations for radiation therapy of the tumor. Usually includes work with CT images, tumor and organs at risk delineation, application of radiation type and beam angle, optimization (manual or automatic) of dose results, as well as evaluation and approval of best recommendation (plan).

Tumor response

How the tumor reacts to radiation treatment.