Glossary

Adaptive radiation therapy
A treatment technique that aims to customize each patient’s treatment plan to patient specific variation by evaluating and characterizing the systematic and random variations through image feedback and including them in adaptive planning.

Arteriovenous Malformation (AVM)
In the brain it appears as a tangle of abnormal arteries and veins that usually is present already from birth. When they present symptoms it is via headaches or seizures. In serious cases, the blood vessels rupture, causing bleeding in the brain.

Acoustic neuroma (vestibular schwannomas)
Benign tumors that typically arise from the vestibular portion of the eighth cranial nerve. Most common presenting symptoms are unilateral loss of hearing, tinnitus and imbalance.

Benign
The term benign is used when describing tumors or growths that do not threaten the health of an individual. Benign is the opposite of malignant.

Brachytherapy
Is also known as internal radiation therapy, involves placing a radiation source in or near the treatment area. This allows very high tumor doses to be achieved, while limiting the impact on surrounding organs. The method is typically used to treat gynecological cancer and prostate cancer, but also breast cancer and certain types of skin cancer a radiation source in or near the treatment area. This allows very high tumor doses to be achieved, while limiting the impact on surrounding organs. The method is typically used to treat gynecological cancer and prostate cancer, but also breast cancer and certain types of skin cancer.

Cancer
Uncontolled, abnormal growth of cells.

Chemotherapy
Treatment of cancer diseases with the aid of chemicals that eliminate diseased cells.

Cone beam CT (CBCT)
A CBCT system mounted to a linac or Gamma Knife creates images used for verifying or determining the location of the patient in relation to the treatment beam(s).

Computed tomography (CT)
A radiological method of imaging anatomical structures by means of layering, using computer technology.

Deep brain stimulation (DBS)
A brain ‘pacemaker’ is implanted to stimulate brain activity and block signals that cause unwanted symptoms present in functional neurological disorders, for example tremor. 

Diffusion weighted imaging (DWI)
A method to evaluate the molecular function and microarchitecture of the human body.

Electronic brachytherapy
Type of brachytherapy that uses an X-ray tube to induce radiation. It can deliver radiation to the tumor with a high degree of precision whilst minimizing damage to healthy surrounding tissue. Due to the source of radiation used, electronic brachytherapy can be performed in a room with minimal shielding.

Epilepsy
Disorder characterized by repeated, sudden disturbances of brain function.

External-beam radiation therapy
The most common type of radiation therapy, in which the radiation source is produced by a linear accelerator and delivered by the radiation beam from the linear accelerator head rotated around the patient. By delivering the radiation from various angles, the radiation dose is distributed more evenly in the tumor without excess damage to surrounding healthy tissue.

Fraction
Part of the total radiation dose, delivered at a daily treatment.

Food and Drug Administration (FDA)
Is an agency of the US Department of Health and Human Services. The FDA is responsible for protecting and promoting public health through the regulation and supervision of for example medical devices.

Functional disorders
Diseases in the central nervous system.

Gamma Knife® radiosurgery
Stereotactic radiosurgery with Leksell Gamma Knife.

Glioblastoma
The most common and most aggressive malignant primary brain tumor. They are usually highly malignant as a large number of tumor cells are reproducing at any given time and
are supported by a large network of blood vessels. Glioblastoma often infiltrate with normal healthy brain tissue.

High dose radiation (HDR)
An amount of radiation that is greater than that given in typical radiation therapy. High-dose radiation is precisely directed at the tumor to avoid damaging healthy tissue, and may kill more cancer cells in fewer treatments.

Hypofractionation
A treatment schedule in which the total dose of radiation is divided into large doses and treatments are given once a day or less often.

Image guided radiation therapy (IGRT)
IGRT enables high precision targeting and accuracy using high-resolution multi-dimensional X-ray images of the patient’s tissue.

Image guided radiation therapy (IGRT) with magnetic resonance imaging (MRI)
This provides high-quality images of tissue and tumors while treatment is in progress, and also enables adaptation of the radiation dose in real-time. The method is under development in the MR-linac consortium.

Intensity Modulated Radiation Therapy (IMRT)
IMRT is an advanced type of treatment that uses multiple very small beams of varying intensity rather than a single, large, uniform beam. The radiation can therefore be tailored to the size and shape of the tumor, allowing higher tumor doses while minimizing the impact on healthy tissue.

Incidence
Incidence is the number of new cancer cases arising in a given period in a specified population.

Invasive
Incidence is the number of new cancer cases arising in a given period in a specified population.

LINC
Elekta’s two Learning and Innovation Centers in Atlanta, USA and in Beijing, China. The LINC:s are state-of-the-art facilities that provide Elekta users and employees with an ideal environ-ment for learning.

Linear accelerator (Linac)
Equipment for generating and directing ionizing radiation for treatment of cancer.

Magnetoencephalograph (MEG)
Equipment for real time mapping of the function in different parts of the brain, by measuring the magnetic field generated by brain cells activity.

Magnetic resonance imaging (MRI)
Technology used to visualize and differentiate organs and anatomical structures inside the body. It uses non-ionizing radiation and is thus harmless to the patient.

Malignant
Refers to cancerous cells that usually have the ability to aggressively spread, invade and destroy tissue. Opposite to benign.

Meningioma
A type of tumor that develops from the meninges, the membrane that surrounds the brain and spinal cord. Meningiomas are the most common type of primary brain tumors and are often benign.

Metastase
Secondary malignant tumors originating from primary cancer Multileaf collimator.

Multileaf collimator
An accessory to the linear accelerator, working like an aperture. With a large number of individually adjustable metal leaves, the treatment beam can be shaped to the size and shape of the target volume.

MR-Linac
See image guided radiation therapy (IGRT) with magnetic resonance imaging (MRI).

Neurology
The study of the nervous system and its disorders.

Neurosurgery
Surgery of the brain or other parts of the central nervous system.

Oligometastases
A limited number of metastases.

Oncology
The study of tumor diseases.

Oncology information system (OIS)
All patient information is collected and accessible in an oncology information system, from diagnosis through treatment and follow-up, so that clinics can deliver the best possible care
for every patient. MOSAIQ® is Elekta´s world leading oncology information system.

Parkinson’s disease
Paralysis, with trembling and shaking as well as muscular rigidity, with a change in movements and posture by the patient.

Prevalence
The prevalence of a particular cancer can be defined as the number of persons in a defined population who have been diagnosed with that type of cancer, and who are still alive at the end of a given year, the survivors. Prevalence of cancers based on cases diagnosed within one, three and five are presented as they are likely to be of relevance to the different stages of cancer therapy, namely, initial treatment (one year), clinical follow-up (three years) and cure (five years). Patients who are still alive five years after diagnosis are usually considered cured since the death rates of such patients are similar to those in the general population.

Radiation therapy
Fractionated ionizing radiation treatment of cancer.

Radiosurgery
Non-invasive surgery in which a high, single dose of precise ionizing radiation replaces surgical instruments.

Stereotactic body radiation therapy (SBRT)
SBRT enables accurate delivery of radiation to a tumor and minimizes the radiation dose to surrounding tissue. This enables that small and medium-sized tumors can be treated with higher doses and fewer sessions, known as hypofractionatio.

Stereotactic radiosurgery (SRS)
This is typically used to treat tumors and other disorders in the brain. The method involves the delivery of a single high dose, to small and critically located targets in the brain. The method offers very high precision, with a minimum impact on surrounding brain tissue.

Stereotactic radiation therapy (SRT)
Radiation therapy of cancer, where high precision and accuracy is achieved by delivering the radiation based on an external fixed-coordinate system.

Stereotaxy
A technique in which a fixed-coordinate system can determine the location of a point by specifying the coordinates in terms of height, depth and laterally.

Tesla (T)
MRI requires a magnetic field that is both strong and uniform. The field strength of the magnet is measured in teslas (T). The majority of systems operate at 1.5T, even though there are commercial systems available between 0.2–7T.

Trigeminal neuralgia
A disorder of the trigeminal nerve, which carries sensation from your face to your brain. Episodes of severe, stabbing pain affect the cheek, lips, gums, teeth or chin.

Treatment planning system
Treatment planning systems provide tools for multimodality image registration, organ and tumor contouring, treatment simulation and plan optimization. Monaco® is Elekta´s comprehensive treatment planning system that supports all major treatment techniques.

Tumor
An abnormal mass of tissue that results when cells divide more than they should or do not die when they should. Tumors may be benign (not cancer), or malignant (cancer). Also called neoplasm.

Volumetric modulated arc therapy (VMAT)
VMAT is a more advanced variant of intensity modulated radiation therapy (IMRT). VMAT enables the physician to control the radiation beam, dosage amount and speed of rotation
around the patient, which enables faster and more accurate treatment.