All articles starting with R
22,461 articles
Radio-controlled aerobatics
Radio-controlled aerobatics, known to participants as Pattern, is the FAI-judged flying of radio-controlled model aircraft through precision aerobatic schedules; its main class, F3A, held its first world championship in 1960.
Radio-controlled aircraft
A radio-controlled aircraft, also called an RC airplane, is a model aircraft flown from the ground using a hand-held radio transmitter driving its control surfaces.
Radio-controlled car
A radio-controlled car, also called an RC car, is a self-powered model car, typically 1/5 to 1/18 scale, driven by battery-electric or nitro engines and raced in IFMAR world championships.
Radio-controlled glider
A radio-controlled glider, also known as an RC sailplane, is an unpowered model aircraft kept aloft on thermals and slope lift, and raced in FAI class F3.
Radio-frequency cavity
A radio-frequency cavity is an evacuated metallic chamber that uses oscillating electromagnetic fields to accelerate charged particles in accelerators, from medical machines to the LHC.
Radio-frequency identification
Radio-frequency identification (RFID) is a wireless identification technology in which a reader communicates with a tag over radio waves to identify goods, animals, or people.
Radio-frequency reflectometry
Radio-frequency reflectometry is a technique that measures microsecond-scale impedance changes in quantum devices by analyzing reflected radio waves, widely used for fast readout of spin qubits.
Radio-loud quasar
A radio-loud quasar is a quasar whose radio emission, powered by relativistic jets from its central black hole, is strong compared with its optical emission.
Radio-loudness parameter
The radio-loudness parameter R is the ratio of a quasar's radio to optical flux, classically 5 GHz to 4400 Å, dividing quasars into radio-loud and radio-quiet classes.
Radioactive (film)
Radioactive is a 2019 biographical drama directed by Marjane Satrapi, starring Rosamund Pike as Marie Curie, based on Lauren Redniss's graphic novel. It premiered at TIFF 2019, released on Amazon Prime in July 2020, and received mixed reviews (63% Tomatometer, Metascore 56).
Radioactive (Imagine Dragons song)
"Radioactive" is a 2012 Imagine Dragons song from Continued Silence and Night Visions, produced by Alex Da Kid, recorded at Westlake Audio, peaking at No. 3 on the Hot 100 with a record 87 weeks on the chart, and winning Best Rock Performance at the 56th GRAMMYs.
Radioactive contamination
Radioactive contamination, also called radiation or nuclear contamination, is the presence of radioactive material on surfaces, in the environment, or inside a person's body, distinct from radiation exposure.
Radioactive decay
Radioactive decay, also called nuclear decay, is the process in which an unstable atomic nucleus emits radiation and transforms into a daughter nucleus, following a characteristic half-life.
Radioactive Dreams
Radioactive Dreams is Albert Pyun's post-apocalyptic sci-fi comedy, also dated 1984–85, starring John Stockwell and Michael Dudikoff as shelter-raised noir-detective wannabes hunting two keys to the last nuclear missile; a $210,212-grossing 1986 release with no proper home-video edition.
Radioactive iodine therapy
Radioactive iodine therapy is a nuclear medicine treatment in which radioactive iodine-131 is taken by mouth to destroy thyroid tissue, treating hyperthyroidism and differentiated thyroid cancer.
Radioactive tracer
A radioactive tracer, or radiotracer, is a compound containing a radioactive isotope, added in small amounts to follow physical, chemical, or biological processes by detecting its radiation.
Radioactive waste
Radioactive waste, also called atomic waste or radwaste, is material containing radionuclides above regulatory clearance levels, arising mainly from nuclear power generation, weapons programs, and medical, industrial, and research uses.
Radioactive Waste Management Limited
Radioactive Waste Management Limited was the UK body responsible for geological disposal of higher activity radioactive waste in England and Wales, merged into Nuclear Waste Services in 2022.
Radioallergosorbent Test
Radioallergosorbent test (RAST): the first blood assay for allergen-specific IgE, introduced by Wide, Bennich, and Johansson in 1967 and commercialized as Phadebas RAST in 1974; now replaced by fluorescence enzyme assays but still a colloquial term.
Radiobiological dose modeling
Radiobiological dose modeling is the set of quantitative models linking radiation dose to biological effect, centered on the linear-quadratic model and its BED and EQD2 formalisms.
Radiobiology
Radiobiology, also called radiation biology or radiation biophysics, studies the biological effects of ionizing radiation on cells and tissues, underpinning radiation therapy, which about 50% of cancer patients receive.
Radiocarbon calibration
Radiocarbon calibration is the process of converting a radiocarbon age into a calendar age by comparing it against curves of known-age samples, correcting for past atmospheric carbon-14 fluctuations.
Radiocarbon dating
Radiocarbon dating, also called carbon-14 dating, is a method that determines the age of carbon-bearing materials by measuring their carbon-14 content, usable back about 50,000 years.
Radiochemical analysis
Radiochemical analysis is a family of analytical chemistry methods that detect, quantify, and characterize elements and compounds by measuring radioactivity, spanning neutron activation analysis, isotope dilution, and radioimmunoassay.
Radiochemical separation
Radiochemical separation is a chemical procedure that isolates a radionuclide from its sample matrix and from interfering radionuclides before counting, when radiation detectors alone cannot identify or quantify it reliably.
Radiochemotherapy
Radiochemotherapy (chemoradiotherapy, CRT) is the combination of chemotherapy with radiotherapy, given concurrently or sequentially, and standard of care in cervical, rectal, anal, and nasopharyngeal cancer.
Radiocontrast agent
Radiocontrast agent (contrast medium): iodinated compounds for X-ray/CT, gadolinium chelates for MRI, barium sulfate for GI imaging, and microbubbles for ultrasound; classes differ in osmolality, safety, and kidney and thyroid risks.
Radiodynamic therapy
Radiodynamic therapy is a cancer treatment in which X-rays activate a sensitizing agent that generates reactive oxygen species to kill tumor cells, reaching deep tumors that visible or near-infrared light cannot.
Radioembolization
Therapeutic radioembolization (SIRT, TARE, Y-90 radioembolization): catheter-based liver cancer therapy injecting yttrium-90 glass or resin microspheres into hepatic arteries; used for unresectable HCC and metastases, with FDA-approved TheraSphere and SIR-Spheres devices.
Radiofluorination
Radiofluorination is the chemical introduction of radioactive fluorine-18 into a molecule, most often to make PET radiotracers; fluorine-18's 109.7-minute half-life makes it well suited to molecular imaging.