Introduction to Radiotherapy technology I.pptx

Radiotherapy

1. Introduction to Radiotherapy technology I Dr. J. M. Eltabib Radiation Oncology Tripoli Medical Center M.R.C.P medicine UK, L.B.M. S Radiotherapy

2. Introduction to Radiotherapy I Objectives: Why radiology? Classification of radiology What is radiation and it’s types? What is principle of radiobiology? What is cancer cell? What is the importance of studying cancer? What is different mode of delivering radiotherapy? What is therapeutic index and how to improve it? What are different steps involved in delivering radiotherapy?

3. Introduction to Radiotherapy I Why is Radiology? Hampton (BMJ, 1975): Medical interview: 82% Physical exam: 9% Laboratory: 9% Kirch (Medicine, 1996): Medical interview +Physical exam: 70% Imaging: 30%

4. Introduction to Radiotherapy I Benefits of radiology: Non invasive & painless. Help to diagnosis diseases& monitor therapy. Support medical& surgical treatment planning (MDT = Multi Disciplinary Team). Treatment of benign& malignant diseases.

5. Introduction to Radiotherapy I Classification of Radiology in general can be either: Diagnostic: Helping in diagnosis of diseases then physician decided how to treat. eg. U/S, X-ray, CT scan, MRI, PET scan Therapeutic: Intervention radiology: eg. use of flouroscopy to remove blood clots during catheterization. Radiotherapy: use of ionizing radiation to treat diseases (either benign or malignant)

6. Introduction to Radiotherapy I What is radiation? Form of energy emitted by nucleus of atom (eg. Co 60 ϒ ray) or orbital electron (x-ray) released in form of electromagnetic waves or particles.

7. Introduction to Radiotherapy I Atom: The electrons (-) orbiting in specific shells around the nucleus (+). These shells are K,L,M,N…………… # of electrons in the shell =2 n 2 , n=1,2,3,…… for example 11 Na 22 # of electrons in the shells K=2,L=8,M=1 The atom is normally electrically neutral Electron binding energy: Determined by the magnitude of Coulomb forces of attraction of the nucleus and orbital e - Depends on Z & distance from nucleus Binding energy (B.E K >B.E L >B.E M ………..)

8. Introduction to Radiotherapy I Electromagnetic (EM) Radiation: Carried by photons. Photons carry electromagnetic force in the form of 2 sine waves (electric field and magnetic field) that are perpendicular to each other v = c/λ E= hν Photons have both electrical and magnetic properties and are not deflected by either electrical or magnetic fields

9. Introduction to Radiotherapy I Non Ionizing radiations Have long wavelengths ≥10 -7 m. have low frequencies. Have low energies of <12eV. No enough energy to pull electron from orbit, but can excite the electron. Types: Radio waves. Microwaves. Infrared light. Visible light. Ultraviolet light. Ionizing radiation Have short wavelengths <10 -7 m. have high frequencies. Have high energies of ≥ 12eV. High enough energy to pull electron from orbit. Mean energy of 33.85eV is transferred during the ionization process. Types: X- ray, γ ray. Ionizing Particulate Radiation: Electrons, Protons, Alpha particles, β particle, Neutrons, Pi mesons and Heavy ions.

10. Introduction to Radiotherapy I Radiobiology: The science that investigates the interactions between ionizing radiation and living systems, and the consequences of these interactions. Cell: All living creatures are made of different systems → organs → tissues → cells. Cell is the smallest unit can exist independently. All cells have generally similar structures, but they specialize according to the location of the tissue. In humans, there are approximately 10 14 cells.

11. Introduction to Radiotherapy I Non direct Ionizing radiations Neutral particles: photon (x ray, gamma ray), neutron Radiobiological effect: H2O− →H + OH− (free radicals) Direct ionizing radiation Charged particles: Electron, proton, alpha particle, heavy ion, β particle Radiobiological effect: Single-strand DNA break Double-strand DNA break Direct effect

12. Introduction to Radiotherapy I What is Cancer? Growths of cells which are out of control mostly because of gene mutations. They have their own nutrients& blood supply but they do not perform their physiological function.

13. Introduction to Radiotherapy I The doubling process Normal cell Malignant transformation Dividing Doubling Doubling 4 cells Doubling Doubling 8 cells 16 cells 1 million cells (20 doubling) undetectable 1 billion cells (30 doubling) lump appears 1 trillion cells (40 doubling – 2 lb/1kg) 41 – 43 doubling — Death

14. Eukaryotic Cell Cycle T S = 6-8 hrs DNA 2n→ 4n T G1 = 6-12 hr DNA =2n T M =1hr DNA 4n→ 2n T G2 = 3-4 hrs DNA = 4n G0 Introduction to Radiotherapy I

15. Introduction to Radiotherapy I Why studying cancer? > 20 million new cancer cases are anticipated worldwide in 2025. Four fifths of the burden falling on low and middle-income countries. Cancer is the fourth leading cause of death in the Eastern Mediterranean Region, with approximately 419,000 deaths, in 2018. Breast, prostate, colorectal, liver, and lung cancers being the most prevalent. Oncology as a specialty was established in 1965, after American Society of Clinical Oncology (ASCO) was founded in the USA in 1964; since then, the field of oncology continues to advance at a remarkable pace.

16. Introduction to Radiotherapy I Surgery Drugs Radiotherapy How we treat cancer?

17. Introduction to Radiotherapy I What is Radiotherapy? It is use of ionizing radiation to treat cancer and some benign diseases (eg. graves disease, keloid, osteoarthritis, ......). The aim of radiation therapy is to cause damage to the cancerous cells whilst minimizing the risk to surrounding healthy tissue = (Therapeutic index) . Radiotherapy can be given after surgery (adjuvant) or before surgery (neoadjuvant) or instead of surgery (radical to cure or palliative to palliate symptoms) Radiotherapy can be given with chemotherapy (concurrent) or after chemotherapy (sequential).

18. Introduction to Radiotherapy I Classification of radiotherapy: Based on the distance: External Beam RT (EBRT): giving radiation from a far distance of the body (teletherapy) = 80cm in C060 machine& 100cm in linear accelerator.

19. Introduction to Radiotherapy I Classification of radiotherapy: Based on the distance: Brachytherapy: giving radiation from a close distance of the body (brachys) = close in contact to the tumor site.

20. Introduction to Radiotherapy I Classification of radiotherapy: Based on the type: EBRT: photon, electron& proton therapy. Brachytherapy: intracvitary, interstitial, intraluminal, intravasicular &contact.

21. Introduction to Radiotherapy I Brachytherapy unite

22. Introduction to Radiotherapy I Therapeutic index: The therapeutic index (= therapeutic window) increases if the region between two curves becomes large, and the expected benefit from treatment increases. TCP = Tumor Control Probability NTCP = Normal Tissue Complication probability TCD 50 = Tumor Control Dose

23. Introduction to Radiotherapy I Relationship between dose& RT technique and therapeutic index 2POP 3DCRT 3 fields IMRT 9 fields 3DCRT 5 fields

24. Introduction to Radiotherapy I Relationship between cell cycle& radiosensetivity

25. Introduction to Radiotherapy I How is the radiotherapy given? Radical EBRT radiotherapy usually given in 5 fractions/week, daily for 3 - 7 wks with 2 days off treatment depending on tumor type& radiosensetivity. Palliative EBRT radiotherapy usually given in one fraction in one day or 5 fractions/week, daily for 1 - 2 wks, with 2 days off treatment depending on symptoms& general condition of the patient. Brachytherapy usually given in 2 - 6 fractions with 72hrs apart till the end of the sessions using HDR brachytherapy.

26. Introduction to Radiotherapy I Processes of radiotherapy 1 2 3 4 5 6 7

27. Introduction to Radiotherapy I

28. Thank you for your attention Any Questions?