All articles starting with R
22,461 articles
Radiofrequency ablation
Radiofrequency ablation (RFA): catheter-based cardiac procedure using RF-heated tips to destroy arrhythmic tissue; standard for AF pulmonary vein isolation since Haissaguerre's 1998 work, with ~4.5% major complication rate.
Radiofrequency neurotomy
Radiofrequency neurotomy is a pain procedure that heats small spinal nerves, such as the facet joint's medial branch nerves, to interrupt chronic back or neck pain for months.
Radiofrequency Therapy
Radiofrequency therapy is the use of radio waves to heat, stimulate, or ablate tissue, encompassing radiofrequency ablation, pulsed radiofrequency, and non-invasive techniques used for pain, arrhythmias, and tumors.
Radiofrequency thermocoagulation
Radiofrequency thermocoagulation is a minimally invasive pain procedure that heats and destroys nerve tissue with an electrode, most often for trigeminal neuralgia and facet joint pain.
Radiografía de la pampa
Radiografía de la pampa is a 1933 essay by the Argentine writer Ezequiel Martínez Estrada, his most famous book, diagnosing Argentine society through its pampas.
Radiographer
Radiographer (radiologic technologist): allied health professional producing diagnostic images (X-ray, CT, MRI, PET) or delivering radiotherapy. Distinct from the radiologist, a physician who interprets images; UK titles protected by HCPC registration.
Radiographic Image Enhancement
Radiographic image enhancement is the digital processing of X-ray and other radiation images after acquisition, adjusting contrast and frequency properties so clinically important features stand out.
Radiographic Magnification
Radiographic magnification: enlargement of an X-ray image, factor M = SID/SOD. Used in magnification mammography for microcalcifications; geometric magnification outperforms electronic zoom; must be corrected in hip templating.
Radiographics : a review publication of the Radiological Society of North America, Inc
RadioGraphics (ISSN 0271-5333 print, 1527-1323 online) is RSNA's peer-reviewed education journal in diagnostic radiology, launched 1981, edited by Christine Cooky Menias, publishing solicited RSNA meeting exhibits; 2025 impact factor 6.2.
Radiography
Radiography (projection X-ray imaging) records a static image after an X-ray beam passes through the body, distinct from fluoroscopy and CT. Discovered via Röntgen's 1895 X-rays; lower dose than CT; now digital and AI-assisted.
Radioguided surgery
Radioguided surgery is a technique in which a radioactive tracer, detected with a handheld gamma probe, guides surgeons in removing tissue, notably for sentinel lymph node biopsy.
Radiohead
Radiohead are the English rock band from Oxford: Thom Yorke, Jonny Greenwood, Ed O'Brien, Colin Greenwood, and Philip Selway. Known for "Creep" (1993), OK Computer (1997), the electronic turn of Kid A (2000), the pay-what-you-want In Rainbows, and a 2025 reunion tour after seven years.
Radiohead discography
Radiohead discography: nine studio albums by the Oxford rock band, from Pablo Honey (1993) and OK Computer (1997) to In Rainbows (2007) and A Moon Shaped Pool (2016), plus singles, live albums, and reissues.
Radioimmunoassay
Radioimmunoassay (RIA), developed by Rosalyn Yalow and Solomon Berson at the Bronx VA hospital, is a competitive antibody-based technique using radioactive labels such as iodine-125 to measure hormones like insulin at nanogram or picogram levels; it won Yalow the 1977 Nobel Prize.
Radioimmunodetection
Radioimmunodetection (RAID), also called radioimmunoscintigraphy, is a nuclear medicine technique using radiolabeled monoclonal antibodies to image tumors; it evolved into immunoPET after FDG-PET displaced it for staging.
Radioimmunoprecipitation Assay
Radioimmunoprecipitation assay (RIPA, Farr assay): sensitive immunoassay using radiolabeled antigens to detect and quantify specific antibodies in serum or CSF; gold standard for AChR antibodies in myasthenia gravis, limited by radioisotope handling.
Radioimmunotherapy
Radioimmunotherapy is a cancer treatment in which a monoclonal antibody linked to a radioactive isotope is given intravenously, carrying radiation to tumor cells; FDA-approved agents treat non-Hodgkin lymphoma.
Radioiodine therapy
Radioiodine therapy is a nuclear medicine treatment using orally taken radioactive iodine-131 to destroy thyroid tissue, treating hyperthyroidism and differentiated thyroid cancer such as papillary and follicular types.
Radioisotope Diagnostic Techniques
Radioisotope diagnostic techniques, the basis of nuclear medicine, use radiotracers imaged by SPECT and PET to show organ function; Tc-99m, F-18 FDG, and I-123 are the workhorse isotopes.
Radioisotope Dilution Technique
Radioisotope dilution technique: MeSH-defined method of injecting a known radionuclide quantity into a system and monitoring downstream concentration over time; used for blood volume (51Cr, 131I), cardiac output, and industrial flow measurement.
Radioisotope heater unit
A radioisotope heater unit (RHU) is a small spacecraft device that warms components through plutonium-238 decay, producing about one watt of heat with no moving parts or electrical power.
Radioisotope Teletherapy
Radioisotope teletherapy, also called teleradioisotope therapy, is external beam radiotherapy using gamma rays from a sealed radioisotope source, chiefly cobalt-60 units introduced in Canada in 1951 after radium teletherapy, now largely replaced by linacs in high-income countries.
Radioisotope thermoelectric generator
A radioisotope thermoelectric generator (RTG) is a spacecraft power source that turns heat from decaying plutonium-238 into electricity with no moving parts, powering missions where sunlight is too faint for solar panels.
Radiolabeled metal–organic frameworks
Radiolabeled metal–organic frameworks are highly porous crystalline materials built from metal ions and organic linkers, carrying a radionuclide for PET or SPECT imaging and cancer therapy.
Radiolabeling
Radiolabeling is a technique that covalently attaches a radioactive isotope to a biomolecule, cell, or material so the decay signal can detect, quantify, and track it.
Radiolaria
Radiolaria: marine planktonic protists with axopodia and a central capsule, once classified by Haeckel into four legions; modern molecular work recognizes six orders, silica or strontium sulfate skeletons, and a fossil record used in biostratigraphy.
Radiolarian fossil record and radiolarian ooze
The radiolarian fossil record runs from early Cambrian rocks to modern seafloor sediments, and radiolarian ooze slowly converts to chert, making radiolarians valuable for dating oceanic strata.
Radiolarite
Radiolarite is a hard siliceous sedimentary rock made of radiolarian skeletons, the lithified equivalent of radiolarian ooze, and a raw material for prehistoric stone tools.
Radiole
Radiole: the ciliated, feather-like feeding filament forming the radiolar crown of fan worms (Sabellida: Sabellidae, Serpulidae, Fabriciidae); each bears pinnules, filters particles and oil droplets, aids respiration, and may carry eyes or form the serpulid operculum.
Radioligand Assay
A radioligand assay is an analytical technique that quantitatively determines receptors or binding proteins in body fluids or tissue using a radioactively labeled binding reagent, including the radioimmunoassay.