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Very High Energy Electron Radiotherapy

Very High Energy Electron Radiotherapy. Luke Dyks Oxford Graduate Student Symposium Dennis Sciama Lecture Theatre 13 th March 2019. Outline. Issues in treating cancer Current treatment methods Why VHEE beams? Treatment plans for VHEE therapy Conclusion.

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Very High Energy Electron Radiotherapy

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  1. Very High Energy Electron Radiotherapy Luke Dyks Oxford Graduate Student Symposium Dennis Sciama Lecture Theatre 13th March 2019

  2. Outline • Issues in treating cancer • Current treatment methods • Why VHEE beams? • Treatment plans for VHEE therapy • Conclusion Luke Dyks – 13/03/2019 – Very High Energy Electron Radiotherapy 1

  3. Cancer Diagnosis • The world is living longer. • Cancer is an increasing problem. • Treatment is getting much better. UK 5 Year Survival Rates Data from Cancer Research UK Luke Dyks – 13/03/2019 – Very High Energy Electron Radiotherapy 2

  4. Cancer Treatment • 3 main ways to treat cancer: 11 % 49 % Luke Dyks – 13/03/2019 – Very High Energy Electron Radiotherapy 3

  5. Cancer Treatment Patients cured by treatment method • 3 main ways to treat cancer: 11 % Chemotherapy 40 % 49 % Luke Dyks – 13/03/2019 – Very High Energy Electron Radiotherapy 3

  6. Cancer Treatment Patients cured by treatment method • 3 main ways to treat cancer: 11 % Chemotherapy 40 % Surgery 49 % Luke Dyks – 13/03/2019 – Very High Energy Electron Radiotherapy 3

  7. Cancer Treatment Patients cured by treatment method • 3 main ways to treat cancer: 11 % Chemotherapy 40 % Surgery 49 % Radiotherapy Luke Dyks – 13/03/2019 – Very High Energy Electron Radiotherapy 3

  8. Cancer Treatment Patients cured by treatment method • 3 main ways to treat cancer: 11 % Chemotherapy 40 % Surgery 49 % Radiotherapy • Ideally want to kill the cancer only. Luke Dyks – 13/03/2019 – Very High Energy Electron Radiotherapy 3

  9. Current Radiotherapy Methods • Use particle beams to deposit energy into tumour. • 3 main methods currently used: • X-rays • Low energy electrons • Protons or ions • Each method suits certain tumours. Deposited dose through water A. Lagzda, IPAC 2018 Luke Dyks – 13/03/2019 – Very High Energy Electron Radiotherapy 4

  10. Very High Energy Electron Beams • Currently only low energy electrons used. • Hospitals have a finite size. • Proton accelerators can be circular. • Christie proton cyclotron is 230 MeV. • Electron accelerators must be linear. • CERN’s Linac 4 is 160 MeV, 86 m long. CERN Linac 4 Christie Hospital cyclotron Luke Dyks – 13/03/2019 – Very High Energy Electron Radiotherapy 5

  11. Achieving VHEE Beams • Recently high gradients have been achieved: • ILC ~ 30 MeV/m • CLIC ~ 100 MeV/m • Suitable changes could allow use in a hospital. ILC superconducting cavity Prototype CLIC cavity Luke Dyks – 13/03/2019 – Very High Energy Electron Radiotherapy 6

  12. Why VHEE? • Dose deposited deeper into patient. • Beams can be scanned across tumours. • Less affected by tissue inhomogeneities. • Beams can be focussed inside patient. Deposited dose through water A. Lagzda, IPAC 2018 7 Luke Dyks – 13/03/2019 – Very High Energy Electron Radiotherapy

  13. Inhomogeneities in the body • Proton beams sensitive to inhomogeneities in body. • Bragg peak can be a curse. • Can result in large doses to healthy tissue. • Electrons do not have sharp Bragg Peak. • Less effected by tissue inhomogeneities. A. Lagzda, IPAC 2018 Water Air Water Air Electron dose with 2 cm insert Proton dose with 2 cm insert Luke Dyks – 13/03/2019 – Very High Energy Electron Radiotherapy 8

  14. Focussing of Beams • Electrons carry charge. • Electron beams are of low rigidity. • Can be focussed to vary dose profile. • Reduce dose to healthy tissue. Deposited dose through water A(VHEE) = 0.65 A(Proton) A. Lagzda, IPAC 2018 Luke Dyks – 13/03/2019 – Very High Energy Electron Radiotherapy 9

  15. Treatment Planning – Head and Neck Cancer • VHEE incorporated into treatment plans. • Show big improvements on some difficult to treat tumours. • Up to a 70 % lower dose to organs at risk than x-rays. • Some plans show lower dose than proton therapy. M. Bazalova-Carter, Medical Physics 2015 Mean dose to organs at risk Simulated treatment plan Luke Dyks – 13/03/2019 – Very High Energy Electron Radiotherapy 10

  16. Conclusions • Cancer is a growing problem. • Survival rates increasing. • Treatment methods must be improved. • VHEE beams have several advantages: • Can be scanned across tumour • Insensitive to inhomogeneities • Can be focussed easily • Safer treatment for previously difficult to treat tumours. Luke Dyks – 13/03/2019 – Very High Energy Electron Radiotherapy 11

  17. Thank you for listening! Luke Dyks – 13/03/2019 – Very High Energy Electron Radiotherapy 12

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