Glossary
Adjuvant: Supporting; generally refers to chemotherapy which is used in addition to an operation for cancer therapy.
Benign: Not threatening to life or health; a term used to describe a tumour which has not formed secondaries (metastases).
Cachexia: A significant loss of energy, as associated with general weakness and anaemia, appearing as a symptom of serious illnesses; in medicine this is a disorder marked by the extreme weight loss associated with cancer or other diseases.
Cataract: Opacity or clouding of the lens of the eye (i.e., the cornea).
Chemotherapeutic agents: Drugs used in chemotherapy to inhibit the growth of cancerous cells.
Clinical evidence: From the Latin meaning illustration, clarity, complete, overwhelming certainty; now used in healthcare to summarize current knowledge from the ideological perspective of medicine, as distinguished from scientific concepts such as empiricism or deduction.
Compartment: A small enclosure; herein, an organism enclosed by a cell wall (cell membrane), which essentially has an independent metabolism.
Cyclotron: The type of particle accelerator used in the RPTC.
Cytostatic agents: A group of chemotherapeutic agents (i.e. drugs) which prevent cell division in order to inhibit cancer growth and kill cancer cells.
Deducible: The process of deduction to derive logical statements with the assistance of key rules.
Electrode: A positively or negatively charged plate which attracts or emits electrons in a vacuum, for example, in an x-ray tube.
Empirical: A term from the theory of knowledge which describes the part of knowledge acquisition based on critical experience obtained through measurement, observation or experience, particularly that which is statistically verifiable.
Energy absorption: The uptake of energy (herein, radiation) by the material (herein, the body tissue).
Exponential law: A mathematical function which arises when a physical quantity grows or decays at a rate elevated to a power of a value placed as a superscript to the right of that value so as to indicate the number of times the number or quantity is to be multiplied by itself (e.g. 105); the exponential function of x-ray dosage is shown as a falling curve, initially slanting steeply and then flattening out, only reaching the zero point at infinity.
Flat panel: Large (30 x 40 cm), high-resolution detectors for x-ray radiation, in which the incident x-ray radiation is detected by a semiconductor structure made of amorphous silicon within these detectors, being similar to the setup in a CCD digital camera; given the extreme sensitivity of this verification method, very low x-ray dosages can be used by comparison to films, producing a digital image which can be immediately processed through electronic means.
Fractionation: Subdivision; the division of a total dosage of x-ray radiation into multiple dosages, usually administered once each day.
Gantry: A radiation targeting unit which is used in large radiation delivery systems involving a device for rotation of the apparatus for radiation delivery.
Gene therapy: A distinction must be drawn between gene therapy and treatment with genetically engineered drugs (recombinant drugs), the latter of which are drugs which have been synthesized, e.g. from genetically modified bacteria, such as certain insulin products or interferon; by contrast, gene therapy involves the administration of genes acting on the metabolism or the blockade of unwanted genetic material in cells of the human body; this technology is in its infancy, so to date there is no available procedure which will attack all cancer cells in the body.
Gray: A unit of absorbed energy dosage, i.e. the amount of energy absorbed by the tissue; one gray equals one joule per kilogram. This unit is used to define the radiation absorbed by the body; named after the British physicist L. H. Gray (1905-1965).
Ionizing radiation: A general term for any electromagnetic waves or particle beam which triggers ionization; ionization involves displacing one or more electrons from an atom or a molecule, leaving behind a positively charged particle (ion) due to the loss of the negatively charged electron(s); all types of ionizing radiation transfer relatively high levels of energy, while relatively low energy levels only result in the visible illumination of the affected material.
Isocentre: A fixed target point in space for the proton beam, the target point being positioned at the site of the tumour.
Joule: The joule (J) is the basic physical unit (SI) for energy, being named after James P. Joule (1818 - 1889), who formulated the law of conservation for mechanical and thermal energy (1 J = 1 kg · m_ · sec-2 = 1 Nm = 1 Ws); the calorie is an older unit of energy, where 1 cal = 4.19 J, equal to the amount of energy required to heat 1 g of water by 1°C.
Lawrence: Ernest Orlando, 1901 - 1958. American physicist And winner of the 1939 Nobel Prize for physics based on his development of the "cyclotron" particle accelerator during the 1930s.
Leukaemia: Any of various diseases characterized by the uncontrolled division of stem cells in the blood-forming system, resulting in the formation white blood cells in excessive numbers, such proliferation ultimately resulting in death; the historic diagnosis was made on the basis of white blood cells forming a thick, whitish layer in a test tube; leukaemias, by contrast to "solid" tumours, which are not disseminated via the bone marrow, occur as clumps of cells.
Linear acceleration: All charged particles, whether they are electrons or protons, can be accelerated in an electrical field; when a potential difference is applied--preferably in a vacuum--the negatively charged electrons are accelerated from the electrode with the negative voltage towards the electrode with the positive voltage; and when configured properly a beam of electrons is liberated. Once the electrons hit a metal target and the energy of impact is sufficient, the radiation of x-rays occurs. The greater the acceleration of the electrons, the shorter the radiation's wavelength and the higher its energy level. In modern linear accelerators, electrons are accelerated along potential gradients ranging between 10 and 30 million volts; however, voltages in this order aren't practical. Pairs of electrodes are therefore configured in a row (hence the term linear), thereby accelerating the electrons through the electrode pairs at increasing speeds. Splitting up this voltage gradient reduces the operating voltage to manageable values.
Local recurrence: The recurrence of a tumour at the original tumour site, a consequence of the failure to destroy all the cells in the tumour cell mass. Some cells survive, for example because the x-ray dosage was too low or didn't cover a sufficiently large area.
Lymph nodes: Filter nodules which may be felt under the skin in the body's fluid drainage system; these nodules are often sites for tumour metastases.
Magnetic field strength: Determines the force of attraction of a magnet; the unit tesla, named after the physicist Nikola Tesla (1856 - 1943) is used to measure the strength of a magnetic field. The unit gauss is used to measure weaker magnetic fields, named after the German mathematician Karl Friedrich Gauss (1777 - 1855); one tesla is equal to 10,000 gauss, while the earth's magnetic field may measure as much as 0.5 gauss.
Malignant: Derived from Latin and meaning acting maliciously; a term for infiltrative tumours (particularly when invading other tissues) which form secondary tumours or metastases.
Metachronous: Occurring at different times.
Metastasis: Secondary growth of a primary tumour, such metastases spreading through the circulatory system, the lymph vessels or by direct cell division, e.g. in the abdominal cavity or in the mammary ducts; herein, metastasis only occurs subsequent to the removal of the primary cancer.
Millisievert: A unit for low dosages of ionizing radiation; also used for the measurement of energy absorption; however, the conditions of absorption are different than as defined by Gray, the millisievert generally being used to measure low-level radiation as found in the workplace or in everyday life.
Mutation: Change in the genetic material, resulting spontaneously from chemical instability in the molecules involved, or through ionizing radiation, or due to toxins; the mutations aren't directed towards a specific function but are therefore divided statistically into mutations which are lethal, neutral and exert no effect, or mutations which change the characteristics of the organism.
Non-invasive: Intervention in the body of the patient without causing pain or injury.
Nozzle: The device connected to the end of the tube emitting the beam of protons and used to deliver protons to the patient; the setup used in the RPTC controls the direction of the beam by using a magnetic beam which bends it to one side.
Palliative: The quality of providing relief, used in reference to therapies which will not result in a complete cure for the disease process but will extend life or alleviate pain.
ProHealth AG: A listed company, with registered office in Munich, Germany, for the set-up and operation of proton centres; the parent company of RPTC.
Radiation poisoning: The general term used in reference to any damage caused by ionizing radiation; the radiation which penetrates healthy tissue also places a general strain on the body and affects the patient's psyche, so that the patient may suffer from one or more specific acute injuries caused by radiation as well as the impairment of his or her overall well-being, such condition often being accompanied by persistent nausea; the short- and long-term manifestations of radiation poisoning can be significantly reduced when proton radiation is used.
Radioactivity: A phenomenon first described in uranium salts by the French physicist Henri Bequerel (1852 - 1908) in 1896; today, a term used to describe any physical process which emits electromagnetic waves or a stream of particles with energy sufficient to remove electrons from the atoms or molecules which impacted, thus leading to ionization or the destruction of the nucleus.
Radiotherapy (x-ray) side effects: All injuries to tissue, as triggered by radiation which has been inaccurately targeted; these are short-term processes similar to inflammation, and always result in scarring. The way in which this is manifested depends on the organ, e.g. short-term mucosal bleeding and ulcerations in the gastrointestinal tract, inflammation of the liver, pneumonia, long-term skin scarring, drying of the salivary glands, cataracts in the eye lenses, neuritis, etc.
Randomized prospective comparative studies: Empirical testing must be carried out when it is not possible to establish a causal relationship between its therapy and its effect, a process that involves the comparison of two patient samples, respectively before and after the therapeutic effect. Many errors may be made when samples are selected, and this can distort the statistical probability result; therefore, the samples must be selected randomly (randomized) in order to ensure scientific validity. The results must not be analyzed retrospectively, the details of the experiment must be defined in advance, and follow-up with the patient must be conducted "into the future" (i.e. prospectively).
Resistances: In medicine this refers to the lack of sensitivity shown by bacteria to antibiotics and by different types of cancer to chemotherapeutic agents; resistances of this nature always occur if the complex toxic (poisonous) effects of antibiotics or chemotherapeutic agents on the bacterium or cell can be counteracted by activating a different gene, in other words by mutations. Such mutations may be inherited, and in the process bacterial strains become increasingly resistant. Parts of cancer tumours may also develop with resistance to chemotherapeutic agents.
Scanning system: A system installed at RPTC which delivers the desired dosage distribution to the target region in three dimensions by deflecting the beam to one side and varying the energy of the beam; the depth dimension (Z) is traversed by varying the speed of the protons, thereby adjusting the penetration depth. The pencil beam of protons is bent to the side by two special electromagnets, which can be very quickly adjusted (one for the X-axis and one for the Y-axis). This process is controlled by computer in such a way that each volume element (voxel) receives precisely the number of protons required in order to apply the planned dosage. The electron beam is deflected across the screen of an oscillograph or a television monitor in the same way.
Second opinion: In the case of complex diseases (such as cancer), the commonly accepted practice of seeking the additional of another physician and/or therapist.
Secondary carcinoma: A term used in reference to a carcinoma which has been triggered as a secondary phenomenon following treatment of the primary carcinoma, as a result of the ionizing radiation being directed towards healthy tissue; the interval elapsing until a secondary carcinoma occurs (latency time) may be decades. The probability of secondary carcinomas depends on the total amount of radiation which has penetrated healthy tissue (integral dosage, the product of the dosage level and the irradiated tissue volume. This consequence of radiation has a significant role in the context of treating a child.
Stem cell: The human egg (ovum) differentiates into approximately 200 different types of cells (based on the counting method used); accordingly, as a cell progresses from one division to the next, growing more specialized in the process, its development potential becomes increasingly limited. "Pluripotent cells," which still have the potential to "read" their genomes (meaning they can form, for example, heart-muscle cells as well as blood cells), are designated as stem cells (which give rise to derivatives with different specializations). Researchers today are investigating the mechanism of the gene activation or blockade, thus encouraging the progress of this specialization.
Stereotactic treatment: This term refers to the geometric aspect of radiation treatments which may be used, for example, to treat closely circumscribed brain tumours; such treatment is carried out using a specialized cobalt radiation source in a gamma knife or proton radiation system with a pencil beam.
Sublethal: Not sufficient to cause death; although the sublethal irradiation of a cell will not lead to death, it is dangerous because it can trigger mutations and result in late carcinoma.
Synchrotron: A type of accelerator in which particles are accelerated along a circular or oval path through a tube, in contrast to the cyclotron where particles form spirals in a disc-shaped vacuum chamber; in order to compensate for the centrifugal forces which cause the beam to spiral, the current intensity of the bending magnets is increased synchronously during the acceleration process. This leads to the synchrotron's emission of discontinuous radiation, whereby a proton cloud is accelerated at 2-second intervals and then ejected. This timing instability for the beam would be a substantial disadvantage for the scanning system used in the RPTC, and consequently a cyclotron was used.