Loading
Electron beams stop within a few centimetres of the skin, so they treat surface tumours, scars and the whole skin without reaching the organs underneath. Most linacs make them; special set-ups spread them over the entire body or deliver them during surgery.
When a medical linac is switched from photon to electron mode the tungsten target is retracted and the electron pencil beam is spread by scattering foils and shaped by a metal applicator and a lead or Cerrobend cut-out placed close to the skin. Electrons of 4 to 20 MeV deposit dose fairly evenly to a depth of roughly a third of their energy in centimetres, then fall away sharply, which suits chest-wall and scar boosts in breast cancer, skin cancers of the nose, ear and eyelid, keloids, and superficial lymph nodes. Total skin electron beam therapy, developed at Stanford, stands the patient several metres from the machine in a set of poses while a degraded low-energy beam treats the entire skin surface for mycosis fungoides and other cutaneous lymphomas. Mobile electron linacs such as IntraOp's Mobetron bring a 6 to 12 MeV electron beam into the operating theatre for intraoperative radiotherapy of the tumour bed, sparing the shielded bunker.
Against superficial and orthovoltage X-rays, electrons treat thicker targets and spare deeper tissue; against protons they are far cheaper and available on almost every linac, but the dose edge is blurrier, bone and air cavities perturb it, and ring-gantry machines such as Halcyon do not offer electrons at all. Very high energy electrons of 100 MeV and above, which would reach deep tumours, exist only in research accelerators.
The accelerated electron beam is scattered and collimated without a photon target, depositing dose to a depth set by its energy and then falling off rapidly, so superficial targets are treated with little exit dose.
Query for this technology: (TITLE:"Electron beam therapy systems" OR ABSTRACT:"Electron beam therapy systems" OR TITLE:"linac electrons, total skin electron units, mobile electron IORT" OR ABSTRACT:"linac electrons, total skin electron units, mobile electron IORT") AND (cancer OR tumor OR tumour OR oncology OR carcinoma OR lymphoma OR leukemia OR leukaemia OR myeloma OR sarcoma OR melanoma OR glioma). Results are unfiltered search hits about Electron beam therapy systems (linac electrons, total skin electron units, mobile electron IORT), not a curated reading list.
Shares C-arm medical linear accelerators (TrueBeam, Versa HD and others), Elekta, Varian (Siemens Healthineers), Breast cancer (all types) and the tag machines-wave2.
Shares Superficial and orthovoltage radiotherapy for skin cancer, Basal cell carcinoma, Skin cancer (all types), Breast cancer (all types) and the tag machines-wave2.
Shares Superficial and orthovoltage radiotherapy for skin cancer, Cutaneous T-cell lymphoma (mycosis fungoides and Sezary syndrome), Basal cell carcinoma, Skin cancer (all types) and the tag machines-wave2.
Shares C-arm medical linear accelerators (TrueBeam, Versa HD and others), Varian (Siemens Healthineers), Breast cancer (all types), IMRT / IGRT (modern external beam) and the tag machines-wave2.
Shares FLASH research accelerators (Oriatron, Mobetron FLASH, ProBeam FLASH), C-arm medical linear accelerators (TrueBeam, Versa HD and others), Breast cancer (all types), IMRT / IGRT (modern external beam) and the tag machines-wave2.
Shares Elekta, Varian (Siemens Healthineers), Breast cancer (all types) and the tag machines-wave2.
Shares Elekta, Varian (Siemens Healthineers), IMRT / IGRT (modern external beam) and the tag machines-wave2.
Shares Basal cell carcinoma, Skin cancer (all types) and the tag machines-wave2.
Open-source projects that implement or serve this technology, from OnCo's own catalogue: licence and last activity as the repository reported them on the day of the fetch. Listing is not endorsement; check the licence before reuse and the validation before clinical use.
The National Research Council of Canada's Monte Carlo code for electron and photon transport, a reference for linac dosimetry.