{"entity":{"id":"tomotherapy","kind":"technology","name":"TomoTherapy and Radixact (helical radiotherapy)","aka":[],"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.","summary":"TomoTherapy grew out of work at the University of Wisconsin in the 1990s and treated its first patients in the early 2000s. A 6 MV linac is mounted on a CT-style ring gantry that rotates continuously while the couch advances, and a binary multileaf collimator opens and closes each leaf in fractions of a second to modulate a fan beam, so the dose is laid down helically. Before each fraction the same beam at low output produces a megavoltage CT for positioning. Because the field of view runs the length of the couch travel, it treats craniospinal axis, total marrow irradiation before transplant, long spinal or pelvic volumes and multiple targets without field junctions, and it gives highly homogeneous head and neck plans. The current Radixact generation adds Synchrony, which tracks tumour motion with kilovoltage imaging and moves the beam with it, and kilovoltage CT for better image quality.\n\nAgainst a C-arm linac it offers no electrons, no non-coplanar beams and a single photon energy, treatment can be slow for large volumes, and departments need staff comfortable with a distinct planning system. Accuray, which also makes the CyberKnife, is the sole vendor.","status":"established","asOf":"2026-09-17","wikipedia":"https://en.wikipedia.org/wiki/Tomotherapy","links":[{"label":"Accuray: Radixact","url":"https://www.accuray.com/radixact/"},{"label":"Wikipedia","url":"https://en.wikipedia.org/wiki/Tomotherapy"}],"tags":["machines-wave"],"related":["c-arm-linac","ring-gantry-linac","cyberknife"],"cancers":["head-and-neck","prostate","medulloblastoma","all-leukemia","breast-cancer"],"sections":["radiation","devices"],"technologies":["imrt-igrt","total-body-irradiation","respiratory-motion-management"],"targets":[],"drugs":[],"companies":["accuray"],"institutions":["uw-carbone","the-christie","heidelberg-nct"],"pathways":[],"terms":[],"trials":[],"people":[],"bottlenecks":[],"keyPapers":[],"journals":[],"dependsOn":[],"notes":[],"principle":"A 6 MV linac on a continuously rotating ring delivers a fan beam modulated by a binary multileaf collimator while the couch translates, producing helical intensity-modulated dose with megavoltage or kilovoltage CT guidance from the same gantry.","strengths":["Long and complex targets without field junctions","Daily CT with the treatment beam","Very homogeneous dose in head and neck plans"],"limitations":["Single photon energy, no electrons","Slower for large volumes","One vendor and a separate planning system"],"since":2003},"route":"/technologies/tomotherapy/","neighbours":{"technology":[{"id":"c-arm-linac","kind":"technology","name":"C-arm medical linear accelerators (TrueBeam, Versa HD and others)","route":"/technologies/c-arm-linac/"},{"id":"cyberknife","kind":"technology","name":"CyberKnife robotic radiosurgery","route":"/technologies/cyberknife/"},{"id":"imrt-igrt","kind":"technology","name":"IMRT / IGRT (modern external beam)","route":"/technologies/imrt-igrt/"},{"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/"},{"id":"respiratory-gating-tumour-tracking-systems","kind":"technology","name":"Respiratory gating and tumour tracking systems (RPM, ABC, Calypso, Synchrony)","route":"/technologies/respiratory-gating-tumour-tracking-systems/"},{"id":"respiratory-motion-management","kind":"technology","name":"Respiratory motion management (4D-CT, gating, breath-hold, tracking)","route":"/technologies/respiratory-motion-management/"},{"id":"ring-gantry-linac","kind":"technology","name":"Ring-gantry linacs (Halcyon, Ethos)","route":"/technologies/ring-gantry-linac/"},{"id":"total-body-irradiation","kind":"technology","name":"Total body and total marrow irradiation","route":"/technologies/total-body-irradiation/"}],"cancer":[{"id":"all-leukemia","kind":"cancer","name":"Acute lymphoblastic leukaemia","route":"/cancers/all-leukemia/"},{"id":"breast-cancer","kind":"cancer","name":"Breast cancer (all types)","route":"/cancers/breast-cancer/"},{"id":"head-and-neck","kind":"cancer","name":"Head and neck squamous cell carcinoma","route":"/cancers/head-and-neck/"},{"id":"medulloblastoma","kind":"cancer","name":"Medulloblastoma","route":"/cancers/medulloblastoma/"},{"id":"prostate","kind":"cancer","name":"Prostate cancer","route":"/cancers/prostate/"}],"section":[{"id":"devices","kind":"section","name":"Devices & Physical Therapies","route":"/fronts/devices/"},{"id":"radiation","kind":"section","name":"Radiation Therapy","route":"/fronts/radiation/"}],"company":[{"id":"accuray","kind":"company","name":"Accuray","route":"/companies/accuray/"}],"institution":[{"id":"heidelberg-nct","kind":"institution","name":"Heidelberg University Hospital / NCT / DKFZ","route":"/institutions/heidelberg-nct/"},{"id":"the-christie","kind":"institution","name":"The Christie NHS Foundation Trust","route":"/institutions/the-christie/"},{"id":"uw-carbone","kind":"institution","name":"University of Wisconsin Carbone Cancer Center","route":"/institutions/uw-carbone/"}]}}