The document provides a brief history of radiation therapy and x-rays, including their discovery in the late 19th century, and developments in equipment over time. It discusses early radiation therapy methods like orthovoltage and kilovoltage treatments. It also summarizes linear accelerators and how they improved upon older cobalt-60 and betatron technology to allow higher energy photon beams for treating deeper tumors. Simulation equipment is covered, comparing conventional versus CT-based simulation and how various imaging modalities can aid treatment planning.

1. HSC 340 9-7-10 History (Brief overview) Treatment Delivery Equipment Simulation Equipment

2. History Three aspects that paved the way to discovery of xrays: electricity, vacuums, image recording materials Discovery of x-rays by Wilhelm Roentgen 1895, received Nobel Prize in 1901 Edison experimented with x-rays in 1896 (specifically fluoro), stopped experiments due to damage to colleague Clarence Daly (died in 1904 from radiation side effects) Becquerel discovered radioactivity in 1896 Marie Curie discovered radioactive elements (polonium and radium) in 1898 Radium was then used for the first documented cancer treatment in 1898 Soon replaced by Cobalt and Cesium in mid 1900’s Linacs were developed in 1940

3. Isodose Curves Isodose lines- lines connecting points of equivalent relative radiation dose Isodose curve- plotted % depth dose at various points in the beam along the CAX and elsewhere

4. Isodose curve for a 6MV photon beam incident on a flat, homogenous medium

5. Isodose curves differ according to the surface they are incident upon

6. They also differ with different densities in tissues, such as air

7. Isodose curves for different energy beams

8. kV Treatment Kilovoltage characteristics Superficial treatment CAX dose and physical penumbra are based on beam quality Ex. the 50% line of a 200kv beam reaches deeper than the 50% line of a 100kv beam Low energy equipment Grenz Contact Superficial Orthovoltage

9. Grenz 1928 Low energy 10-15kV Superficial Inflammatory disorders, Herpes simplex

10. Contact 1934 40-50kV Superficial Rectal cancer lower to middle third of rectum

11. Superficial 1896 50-150kV Superficial Skin no deeper than 5mm

12. Orthovoltage 1923 150-500 kV Skin, mouth, cervical CA

13. MV Treatment MV characteristics Energy above 1MV Skin sparing Ability to treat deep tumors γ-ray beams produces by Radionuclides are included if energy is above 1 MeV High energy equipment Cyclotron Van de Graaff generator Betatron Cobalt 60 unit Linear accelerator

14. Cyclotron 1928 Charged particle accelerator Neutron and Proton production for clinical use

15. Van de Graff generator 1937 Electrons and X-rays Therapy 2MV

16. Betatron 1941 Electrons and X-rays Therapy 6 to more than 40Mev

17. Cobalt 60 1951 Radioactive source 1.17 MeV and 1.33 MeV

18. Linear Accelerator 1952 Electrons and X-rays Can go as high as 35 MV Ch.7 pg 143-146

19. SSD v SAD SSD The distance from the source of radiation the patients skin SAD The distance from the source of radiation to the axis of rotation of the treatment unit

23. Linac Components Drive stand Klystron, Waveguide, Circulator, Cooling System Gantry Electron gun, accelerator structure, treatment head Couch

24. Auxiliary components Control Console Modulator cabinet Computers

25. Linac accessories Block- usually made of cerrobend (50% bismuth, 26.7% lead, 13.3% tin, 10% cadmium) Wedge MLC Electron Cone Compensator

26. MeV MV

27. HDR/LDR Units LDR- 40-200cGy/hour HDR- 1200cGy/hour or 20cGy per min Both utilize a source Iridium, Cesium, Cobalt, and Radium Require an Afterloader Brain, esophagus, rectum, GYN, breast etc.

28. HDR advantages can be given on outpatient basis Treatment time is short Implant reproducibility is more precise Complete radiation protection exists no general anesthesia or bed rest Ability to treat large volume Increased comfort level

29. Simulator Equipment YouTube - CT vs Traditional Sim - Simple Sim What is simulation? Conventional CT Additions to CT SIM MRI PET

30. What is simulation? Assists in the treatment planning process Original set-up technique is produced Supine Prone FF vs. HF Process: who would be involved in each? Diagnosis Consultation Simulation Treatment Planning Treatment

31. Conventional Simulation Fig. 19-7 Mimics treatment machine Enables field delineation Information is obtained using: Fluoroscopy Radiographs Physical measurements

32. CT Simulation Patient data is obtained using CT “slices” Cost effective for departments: multi-function May have a “virtual simulation” component

33. Conventional & CT sim order of events Conventional Sim: Field location Target defined Fields are shaped CT Sim: Target defined Fields are shaped

34. Additions to CT sim MRI PET Both of the above are able to be merged with the CT to help delineate the tumor site as well as other “critical” structures

35. MRI Utilized for soft tissue imaging

36. PET Nuclear medicine technique which produces a three-dimensional image or picture of functional processes in the body