{"id":"linac-machines-roadmap","name":"Linear accelerator machines: from Clinac to AI-imaging linacs, rings and radiosurgery units","route":"/roadmaps/linac-machines-roadmap/","eras":[{"era":"1953-1990s","title":"Megavoltage linacs replace cobalt","description":"The first clinical linac treated a patient in London in 1953, and through the following decades linacs replaced cobalt-60 units in high-income countries. In the FDA database the Varian Clinac 20 was cleared in August 1977 (K771358) and the Clinac C series in 1986. Cobalt units stayed in service where power and servicing were unreliable; the Theratron Equinox, cleared in 2006, is still sold.","status":"historic","refs":[{"id":"c-arm-linac","kind":"technology","name":"C-arm medical linear accelerators (TrueBeam, Versa HD and others)","route":"/technologies/c-arm-linac/","status":"standard-of-care","tldr":"The standard radiotherapy machine: an electron accelerator in a rotating arm that makes high-energy X-rays or electron beams, shapes them with moving metal leaves, and takes a CT of the patient before each dose. Most people who have radiotherapy are treated on one."},{"id":"cobalt-60-teletherapy","kind":"technology","name":"Cobalt-60 teletherapy","route":"/technologies/cobalt-60-teletherapy/","status":"historic","tldr":"The machine that made curative radiotherapy widely available from the 1950s: a sealed cobalt-60 source in a rotating head. Linacs replaced it in rich countries, but cobalt units still treat many patients where power and servicing are unreliable."},{"id":"varian","kind":"company","name":"Varian (Siemens Healthineers)","route":"/companies/varian/","tldr":"Varian is the largest radiotherapy equipment maker and is running the first human FLASH proton trials."},{"id":"best-theratronics","kind":"company","name":"Best Theratronics","route":"/companies/best-theratronics/","tldr":"Best Theratronics of Ottawa makes cobalt-60 teletherapy machines, the Theratron Equinox, still used where linear accelerators are hard to run and maintain."}],"trials":[],"papers":[]},{"era":"2003-2010","title":"Imaging on the gantry","description":"Varian Trilogy (K033343, December 2003) and Elekta Synergy (K032996, October 2003) mounted a kilovoltage imager on the treatment machine so the patient could be imaged in the treatment position before each dose. Image guidance made intensity-modulated and stereotactic treatment practical outside academic centres.","status":"historic","refs":[{"id":"varian","kind":"company","name":"Varian (Siemens Healthineers)","route":"/companies/varian/","tldr":"Varian is the largest radiotherapy equipment maker and is running the first human FLASH proton trials."},{"id":"elekta","kind":"company","name":"Elekta","route":"/companies/elekta/","tldr":"Elekta is the Swedish radiotherapy company behind Unity, the leading MR-linac, and Gamma Knife."},{"id":"imrt-igrt","kind":"technology","name":"IMRT / IGRT (modern external beam)","route":"/technologies/imrt-igrt/","status":"standard-of-care","tldr":"IMRT and IGRT shape the radiation beam to the tumour's outline from multiple angles and check the patient's position with a scan before every session, so surrounding organs receive less dose. Fewer, larger doses are now standard in breast and prostate cancer, but a low-dose bath still spreads across normal tissue."},{"id":"in-room-imaging-systems","kind":"technology","name":"In-room imaging for radiotherapy (cone-beam CT, ExacTrac, CT-on-rails, HyperSight)","route":"/technologies/in-room-imaging-systems/","status":"standard-of-care","tldr":"The scanners built into or beside the radiotherapy machine that photograph the patient seconds before the beam fires, so the tumour is where the plan expects and, on the newest machines, so the plan can be redrawn to that day's anatomy."}],"trials":[],"papers":[]},{"era":"2011-2018","title":"TrueBeam, Versa HD and radiosurgery-grade linacs","description":"TrueBeam (K111106, August 2011) extended the energy range down to 4 MV and added collision detection; its next clearance (K123291, 2012) brought a six-degree-of-freedom couch, 4D cone-beam CT and a motion management interface. TrueBeam STx and Edge were cleared for radiosurgery indications in 2014 (K140528, which states the device itself was unchanged), and VitalBeam in 2015 as a configuration based on TrueBeam. Elekta's Versa HD and Infinity first appear by name in a 2018 clearance (K182138); Elekta says Versa HD with its high-dose-rate mode delivers stereotactic treatment in a standard 15-minute slot.","status":"historic","refs":[{"id":"c-arm-linac","kind":"technology","name":"C-arm medical linear accelerators (TrueBeam, Versa HD and others)","route":"/technologies/c-arm-linac/","status":"standard-of-care","tldr":"The standard radiotherapy machine: an electron accelerator in a rotating arm that makes high-energy X-rays or electron beams, shapes them with moving metal leaves, and takes a CT of the patient before each dose. Most people who have radiotherapy are treated on one."},{"id":"radiosurgery-srs","kind":"technology","name":"Stereotactic radiosurgery (Gamma Knife, CyberKnife, linac SRS)","route":"/technologies/radiosurgery-srs/","status":"established","tldr":"A single very high dose, or a few doses, aimed at a small brain or spine target with millimetre precision, replacing whole-brain radiotherapy for most brain metastases."},{"id":"sbrt","kind":"technology","name":"SBRT / SABR (stereotactic radiotherapy)","route":"/technologies/sbrt/","status":"standard-of-care","tldr":"Stereotactic body radiotherapy converges multiple beams with sub-millimetre accuracy to deliver tumour-destroying doses in one to five outpatient sessions, doing the job of surgery for inoperable early lung cancer and for metastases in liver, spine and brain. Tumour size and location limit its use, and late toxicity is a concern near the central airways."},{"id":"varian","kind":"company","name":"Varian (Siemens Healthineers)","route":"/companies/varian/","tldr":"Varian is the largest radiotherapy equipment maker and is running the first human FLASH proton trials."},{"id":"elekta","kind":"company","name":"Elekta","route":"/companies/elekta/","tldr":"Elekta is the Swedish radiotherapy company behind Unity, the leading MR-linac, and Gamma Knife."}],"trials":[],"papers":[]},{"era":"2017-2020","title":"Rings and adaptive replanning","description":"Halcyon (K170817, June 2017) put a single-energy 6 MV linac in an enclosed ring with mandatory imaging every fraction; Varian states it uses up to 70 per cent less power and roughly 65 per cent less concrete than a C-arm linac. Ethos (K192377, February 2020) used the same ring for same-session adaptive replanning with automated contouring. Elekta answered with the compact Harmony C-arm (K210500, June 2021).","status":"historic","refs":[{"id":"ring-gantry-linac","kind":"technology","name":"Ring-gantry linacs (Halcyon, Ethos)","route":"/technologies/ring-gantry-linac/","status":"established","tldr":"A radiotherapy machine built like a CT scanner: the accelerator spins inside an enclosed ring, must image the patient before every dose, and treats fast. Ethos adds software that redraws the plan to the anatomy of the day while the patient lies on the couch."},{"id":"adaptive-radiotherapy","kind":"technology","name":"Adaptive radiotherapy (online replanning)","route":"/technologies/adaptive-radiotherapy/","status":"emerging","tldr":"Re-shaping the treatment plan to the anatomy of the day, using the images taken on the treatment couch, so the dose follows a shrinking tumour or a moving bladder."},{"id":"auto-contouring-ai","kind":"technology","name":"AI auto-contouring and adaptive planning","route":"/technologies/auto-contouring-ai/","status":"established","tldr":"Software that draws organs and tumours on scans automatically, saving hours per patient and making daily plan adaptation practical."},{"id":"varian","kind":"company","name":"Varian (Siemens Healthineers)","route":"/companies/varian/","tldr":"Varian is the largest radiotherapy equipment maker and is running the first human FLASH proton trials."},{"id":"elekta","kind":"company","name":"Elekta","route":"/companies/elekta/","tldr":"Elekta is the Swedish radiotherapy company behind Unity, the leading MR-linac, and Gamma Knife."}],"trials":[],"papers":[]},{"era":"2023-2026","title":"CT-quality imaging on the treatment machine","description":"HyperSight cone-beam CT on Halcyon and Ethos (first named in K232113, November 2023) and on TrueBeam (K232870, December 2023) was cleared for simulation and planning; Varian says its Hounsfield accuracy rivals conventional CT so dose can be calculated on it. Elekta Evo, Harmony Pro and Versa HD gained a high-definition reconstruction with machine-learning scatter correction (K252188, January 2026). Imaging good enough to plan on is what makes daily adaptive treatment possible on a conventional linac.","status":"current","refs":[{"id":"c-arm-linac","kind":"technology","name":"C-arm medical linear accelerators (TrueBeam, Versa HD and others)","route":"/technologies/c-arm-linac/","status":"standard-of-care","tldr":"The standard radiotherapy machine: an electron accelerator in a rotating arm that makes high-energy X-rays or electron beams, shapes them with moving metal leaves, and takes a CT of the patient before each dose. Most people who have radiotherapy are treated on one."},{"id":"ring-gantry-linac","kind":"technology","name":"Ring-gantry linacs (Halcyon, Ethos)","route":"/technologies/ring-gantry-linac/","status":"established","tldr":"A radiotherapy machine built like a CT scanner: the accelerator spins inside an enclosed ring, must image the patient before every dose, and treats fast. Ethos adds software that redraws the plan to the anatomy of the day while the patient lies on the couch."},{"id":"adaptive-radiotherapy","kind":"technology","name":"Adaptive radiotherapy (online replanning)","route":"/technologies/adaptive-radiotherapy/","status":"emerging","tldr":"Re-shaping the treatment plan to the anatomy of the day, using the images taken on the treatment couch, so the dose follows a shrinking tumour or a moving bladder."},{"id":"in-room-imaging-systems","kind":"technology","name":"In-room imaging for radiotherapy (cone-beam CT, ExacTrac, CT-on-rails, HyperSight)","route":"/technologies/in-room-imaging-systems/","status":"standard-of-care","tldr":"The scanners built into or beside the radiotherapy machine that photograph the patient seconds before the beam fires, so the tumour is where the plan expects and, on the newest machines, so the plan can be redrawn to that day's anatomy."},{"id":"varian","kind":"company","name":"Varian (Siemens Healthineers)","route":"/companies/varian/","tldr":"Varian is the largest radiotherapy equipment maker and is running the first human FLASH proton trials."},{"id":"elekta","kind":"company","name":"Elekta","route":"/companies/elekta/","tldr":"Elekta is the Swedish radiotherapy company behind Unity, the leading MR-linac, and Gamma Knife."}],"trials":[],"papers":[]},{"era":"1995-2025","title":"Dedicated radiosurgery machines","description":"The Gamma Knife appears in the FDA record from Model B (K924849, 1995) to Perfexion (K061941, 2006), Icon (K151561, 2015), which added mask fixation, cone-beam CT and intrafraction motion monitoring, and Esprit (K222047, 2022). CyberKnife was cleared in 1999 (K984563), the M6 with a multileaf collimator in 2015 (K150873), and Accuray launched the S7 in 2020. ZAP-X (K171804, 2017) is self-shielded, which its maker says removes the need for a radiation bunker. Chinese rotating gamma and hybrid cobalt-linac designs (Our United TaiChi, MASEP Infini) are cleared alongside them.","status":"current","refs":[{"id":"gamma-knife","kind":"technology","name":"Gamma Knife","route":"/technologies/gamma-knife/","status":"established","tldr":"The original radiosurgery machine: about two hundred cobalt-60 sources arranged in a shielded helmet whose beams cross at one point inside the brain, so a metastasis or benign tumour a few millimetres across receives a destructive dose in a single visit while the brain around it is spared."},{"id":"cyberknife","kind":"technology","name":"CyberKnife robotic radiosurgery","route":"/technologies/cyberknife/","status":"established","tldr":"A small accelerator on an industrial robot arm that aims hundreds of pencil-thin beams from any direction and follows the tumour as the patient breathes, so brain, spine, prostate, lung and pancreatic tumours can be treated in one to five sessions without a head frame."},{"id":"zap-x","kind":"technology","name":"ZAP-X gyroscopic radiosurgery","route":"/technologies/zap-x/","status":"emerging","tldr":"A self-shielded brain radiosurgery machine: a compact accelerator swings around the head on two nested gantries inside its own steel shell, so it needs no concrete bunker and no radioactive cobalt, and can be installed in an ordinary outpatient building."},{"id":"rotating-gamma-radiosurgery-systems","kind":"technology","name":"Rotating gamma and hybrid cobalt systems (Our United TaiChi, MASEP Infini, Akesis Galaxy, GammaPod)","route":"/technologies/rotating-gamma-radiosurgery-systems/","status":"established","tldr":"Cousins of the Gamma Knife that spin a smaller number of cobalt-60 sources around the head or body, some built into the same gantry as a linear accelerator. Several were developed in China and are cleared in the United States."},{"id":"elekta","kind":"company","name":"Elekta","route":"/companies/elekta/","tldr":"Elekta is the Swedish radiotherapy company behind Unity, the leading MR-linac, and Gamma Knife."},{"id":"accuray","kind":"company","name":"Accuray","route":"/companies/accuray/","tldr":"Accuray makes the CyberKnife robotic radiosurgery system and the TomoTherapy and Radixact helical radiotherapy platforms, and sponsors trials of stereotactic and adaptive radiotherapy."},{"id":"zap-surgical-systems","kind":"company","name":"ZAP Surgical Systems","route":"/companies/zap-surgical-systems/","tldr":"ZAP Surgical makes ZAP-X, a self-shielded radiosurgery machine that aims beams from thousands of angles at brain tumours, treating brain metastases and meningiomas in one to five outpatient sessions without the concrete bunker or cobalt-60 source that older systems need. It is cleared in the US, Japan and Europe, with installations including Gustave Roussy."},{"id":"our-united","kind":"company","name":"Our United Corporation","route":"/companies/our-united/","tldr":"Our United is a Chinese maker of radiotherapy machines whose TaiChi family includes a linear accelerator, a cobalt rotating gamma unit and a hybrid of the two, all cleared by the US FDA."},{"id":"masep","kind":"company","name":"MASEP Medical Science and Technology Development (Shenzhen)","route":"/companies/masep/","tldr":"MASEP is a Shenzhen maker of rotating cobalt gamma radiosurgery systems, including the Infini, cleared by the US FDA in 2011."}],"trials":[],"papers":[]},{"era":"2002-2025","title":"Helical delivery","description":"TomoTherapy Hi-Art (K013673, 2002) delivered radiotherapy helically from a CT-like ring. Its successor Radixact (K161146, 2016) added Synchrony motion tracking (K182687, 2018) and helical kilovoltage CT imaging, ClearRT (K202412, 2020). Accuray sells regional configurations: Helix for India and similar markets (CE-marked, 2024), Tomo C, approved by the NMPA in China in 2023, and Stellar for the US from 2025.","status":"current","refs":[{"id":"tomotherapy","kind":"technology","name":"TomoTherapy and Radixact (helical radiotherapy)","route":"/technologies/tomotherapy/","status":"established","tldr":"Radiotherapy delivered the way a CT scan is taken: a small accelerator circles the patient while the couch slides through, painting the dose slice by slice with a fast shutter-like collimator. It handles very long or oddly shaped targets and images the patient with the same beam before each session."},{"id":"accuray","kind":"company","name":"Accuray","route":"/companies/accuray/","tldr":"Accuray makes the CyberKnife robotic radiosurgery system and the TomoTherapy and Radixact helical radiotherapy platforms, and sponsors trials of stereotactic and adaptive radiotherapy."}],"trials":[],"papers":[]},{"era":"2019-2026","title":"Makers beyond the two large vendors","description":"United Imaging's uRT-linac 506c, which combines a C-arm linac with a diagnostic 16-slice CT, entered clinical use in China in 2019; no FDA clearance was found. Panacea's Siddharth-II from India was cleared by the FDA in 2021 (K210894) with Halcyon and TrueBeam as predicates, and Our United's TaiChiA linac in 2020. These matter for price and for countries building capacity.","status":"current","refs":[{"id":"united-imaging","kind":"company","name":"United Imaging","route":"/companies/united-imaging/","tldr":"Chinese imaging company that built uEXPLORER, the first total-body PET scanner."},{"id":"panacea-medical-technologies","kind":"company","name":"Panacea Medical Technologies","route":"/companies/panacea-medical-technologies/","tldr":"Panacea Medical Technologies is an Indian maker of radiotherapy equipment whose Siddharth-II linear accelerator is cleared by the US FDA."},{"id":"our-united","kind":"company","name":"Our United Corporation","route":"/companies/our-united/","tldr":"Our United is a Chinese maker of radiotherapy machines whose TaiChi family includes a linear accelerator, a cobalt rotating gamma unit and a hybrid of the two, all cleared by the US FDA."},{"id":"c-arm-linac","kind":"technology","name":"C-arm medical linear accelerators (TrueBeam, Versa HD and others)","route":"/technologies/c-arm-linac/","status":"standard-of-care","tldr":"The standard radiotherapy machine: an electron accelerator in a rotating arm that makes high-energy X-rays or electron beams, shapes them with moving metal leaves, and takes a CT of the patient before each dose. Most people who have radiotherapy are treated on one."},{"id":"global-oncology-access","kind":"technology","name":"Global oncology and access in low- and middle-income countries","route":"/technologies/global-oncology-access/","status":"emerging","tldr":"Seventy percent of cancer deaths occur in low- and middle-income countries, where radiotherapy machines, pathologists, essential medicines and palliative care are scarce. Global oncology works on affordable, adapted care and the systems to deliver it."}],"trials":[],"papers":[]},{"era":"Next","title":"Cheaper bunkers, fewer staff, daily adaptation by default","description":"The unmet needs named in the sources are cost, shielding and staffing: self-shielded radiosurgery, rings that need less concrete, and imaging that lets software replan every day. Proposals already in OnCo include an open-hardware linac designed for unreliable power and service contracts that pay for uptime rather than for the machine.","status":"emerging","refs":[{"id":"idea-acc-open-hardware-linac","kind":"idea","name":"An open-hardware radiotherapy machine built for unreliable power and dust","route":"/ideas/idea-acc-open-hardware-linac/","tldr":"Design a radiotherapy machine from scratch for hospitals with patchy electricity, heat and few engineers, and publish the design so several companies can build it cheaply."},{"id":"idea-acc-linac-uptime-contracts","kind":"idea","name":"Pay for radiotherapy machine uptime, not for the machine","route":"/ideas/idea-acc-linac-uptime-contracts/","tldr":"Governments and donors should buy guaranteed working hours from radiotherapy vendors, with remote monitoring and regional spare-parts depots, instead of buying machines that then sit broken."},{"id":"b-global-access","kind":"bottleneck","name":"Most of the world has almost no cancer care","route":"/bottlenecks/b-global-access/","tldr":"Seven in ten cancer deaths happen in low- and middle-income countries, where radiotherapy, pathology, surgery and drugs are scarce."},{"id":"b-workforce","kind":"bottleneck","name":"Not enough oncologists, nurses, pathologists, physicists","route":"/bottlenecks/b-workforce/","tldr":"The number of people with cancer is rising faster than the workforce trained to treat them."}],"trials":[],"papers":[]}],"watch":[]}