1. Principles of Radiation Therapy
Mark E. Bernard, MD
University of Kentucky
Department of Radiation Oncology

2. Radiation Therapy - Outline
1. What is Radiation Therapy
2. Types of Radiation Therapy
3. Process of Radiation Therapy
4. Special Radiation Therapy Treatments

3. What is Radiation Therapy
Cancer treatment aimed at killing macroscopic and microscopic cancer cells
Induces its damage at a cellular level
Radiation is (mainly) daily X – ray treatments

4. What is Radiation Therapy
Generally works by damaging the DNA
Can cause many different types of DNA damage
Cell death usually occurs of Double Stranded DNA breaks

5. What is Radiation Therapy
Radiation (X-rays) are given as daily treatments – why?
Repopulation – accelerated growth
Reoxygenation – acute and chronic hypoxia
Repair – sublethal damage repair
Reassortment – cell phase effects

6. What is Radiation Therapy
Repopulation – accelerated growth
Cells repopulate after a radiation treatments
Daily treatments are given to prevent cells from continuing to repopulate and prevent accelerate growth

7. What is Radiation Therapy
Reoxygenation
Tumors can be “hypoxic”
By giving daily treatments, it allows blood vessels to open and oxygen to flow in
Oxygen increases the radiation response (makes it stronger)

8. What is Radiation Therapy
Repair
Not all cancer cells will die with first treatment
Daily treatments allow “half-dead” cancer cells to die completely
Also allows normal repair of normal tissue

9. What is Radiation Therapy
Reassortment
Certain phases of cell cycles are
Radioresistant (S)
Radiosensitive (G2/M)
Daily treatments allows for treatment to be captured in sensitive phases

10. How is radiation produced?
Photons (x-rays, γ-rays)
Natural sources
60Co, 192Ir, 125I, 226Ra, etc
Man-made: Linear accelerator
very powerful cathode ray tube
Electrons are accelerated towards a target.
“Bremsstrahlung” = braking radiation
Energy of electron beam (MeV) determines maximum energy of photon beam (MV)

11. Linear Accelerator

13. Radiation Treatment Options
External beam RT
(i.e. the linear accelerator or Linac)
Most common form of radiation treatment
Image courtesy of Varian Medical Systems, Inc. All rights reserved

14. Radiation Therapy - Outline
1. What is Radiation Therapy
2. Types of Radiation Therapy
3. Process of Radiation Therapy
4. Special Radiation Therapy Treatments

15. Types of Radiation X-rays Electrons Brachytherapy (seed radiation)
SBRT (Pin Point)

16. Types of Radiation - X-rays
Most common form of radiation treatment
Used to treat variety of cancers
Breast
Prostate
Lung
Brain
Bone

17. Types of Radiation - X-rays
Daily treatments (M-F)
Purpose is to
Prevent cancer from returning
Increase chances of cure
Help patients live longer
Alleviate pain

18. Types of Radiation - X-rays

19. Types of Radiation - X-rays

20. Types of Radiation - Electrons
Small, negatively charged particles
Directly ionizing
Good for superficial structures (think vulva or skin)

21. Types of Radiation - Electrons
Good for superficial cancers
Skin cancer
Cancers within the Scalp

22. Brachytherapy Involves placing radioactive seeds within a patient
Invasive procedure
Can be permanent
Can be temporary

23. Brachytherapy - LDR Low Dose Rate Benefits Cons
Permanent Seed Implantation
Over the course of a few days
Benefits
RT is delivered throughout the entire cycle cell
Thus allows for RT to be given in radio-sensitive phase
Allows for normal tissue to repair better
Cons
Less conformal
Longer treatment
Can require inpatient hospitalization
“Radioactive” afterwards for short period of time

24. Brachytherapy High Dose Rate Benefits Cons Delivered over minutes
Done in 1-5 treatments
Seeds are not permanent
Benefits
More Conformal dose delivery
Outpatient procedure
Not “radioactive” afterwards
Cons
Theoretical higher risk of complications

25. Brachytherapy Tandem and Cylinder Vaginal Cylinder
Tandem and Cylinder are mainly for endometrial cancers, patients with narrow vaginas, or vaginal cancers. However, if the patient has cervical involvement or pamatrial involvement, then you can consider Tandem and Ovoid/Ring
Vaginal Cylinder are mainly for post-operative endometrial cancers to give treatment to the vaginal cuff.

26. Brachytherapy
Syed Templates are good for advanced cancers that need a boost to the pelvic side wall or a high dose to be delivered to the parametrium
Since there are more places/tracks for the seed to travel, we can conform the dose more than any other applicator.
This allows a higher dose to go to the tumor while allowing for a lower dose to go to the normal tissues.

27. Brachytherapy

28. Radiation Therapy - Outline
1. What is Radiation Therapy
2. Types of Radiation Therapy
3. Process of Radiation Therapy
4. Special Radiation Therapy Treatments

29. Process of Radiation Therapy
Consult
Simulation
Dosimetry QA
Treatment
Follow-up

30. Consult
Simulation
Dosimetry QA
Treatment
Follow-up

31. Consult
Simulation
Dosimetry QA
Treatment
Follow-up

32. Consult
Simulation
Dosimetry QA
Treatment
Follow-up

33. Consult
Simulation
Dosimetry QA
Treatment
Follow-up

34. Consult
Simulation
Dosimetry QA
Treatment
Follow-up

35. Consult
Simulation
Dosimetry QA
Treatment
Follow-up

36. Consult
Simulation
Dosimetry QA
Treatment
Follow-up

37. Consult
Simulation
Dosimetry QA
Treatment
Follow-up

38. Consult
Simulation
Dosimetry QA
Treatment
Follow-up

39. Consult
Simulation
Dosimetry QA
Treatment
Follow-up

40. Consult
Simulation
Dosimetry QA
Treatment
Follow-up

41. Radiation Therapy - Outline
1. What is Radiation Therapy
2. Types of Radiation Therapy
3. Process of Radiation Therapy
4. Special Radiation Therapy Treatments

42. Pin Point Radiation – RadioSurgery
What is it?
Delivers a high dose of radiation into a few treatments
Converts 5-7 weeks of treatments into 1 – 5 days of treatment
It is usually done to completely eradicate the cancer

43. Pin Point Radiation – RadioSurgery
Brain Cancer
Lung Cancer
Prostate Cancer

44. Cancer in the Brain – RadioSurgery

45. Cancer in the Brain – RadioSurgery

46. Cancer in the Brain - RadioSurgery
RadioSurgery is only 1- 3 treatments
Treats only the areas of cancer (not entire brain)
Does a good job of preventing cancer from returning
Does NOT have a high chance of
Memory challenges
Hair loss
Fatigue

47. Cancer in the Brain – Gamma Knife

48. Cancer in the Brain – Gamma Knife

49. Cancer in the Brain – RadioSurgery
Whole Brain
Gamma Knife RadioSurgery

50. Lung Cancer – RadioSurgery

51. Lung Cancer – RadioSurgery
Standard Treatment for early stage lung cancer is surgery
Radiation is an option for patients
Who can NOT get surgery
Patients who do NOT want surgery
RadioSurgery or Stereotactic Body Radiation Therapy
3 – 5 treatments to get rid of cancer
Sometimes even 1 treatment can be given

52. Lung Cancer – RadioSurgery

53. Prostate Cancer – RadioSurgery

54. Prostate Cancer – RadioSurgery
Treatment for prostate cancer involves
Surgery
Radiation
Hormonal Therapy
Chemotherapy

55. Prostate Cancer – RadioSurgery
Radiation Treatment involves
Daily Treatments for 5-9 weeks of treatments
Good treatment
may have diarrhea, rectal symptoms and bladder symptoms
Brachytherapy
Usually One time treatment of implantation of radioactive seeds
Invasive procedure
Irritating symptoms
Pin-Point Radiation
5 total treatments
Low rate of side effects

56. Prostate Cancer – RadioSurgery

57. Prostate Cancer – RadioSurgery

58. Prostate Cancer – RadioSurgery

59. Prostate Cancer – RadioSurgery

60. Prostate Cancer – RadioSurgery

61. Prostate Cancer – RadioSurgery
Safe
Quick
Cheaper
Effective
Convenient
For patients and providers

62. Prostate Cancer – RadioSurgery
Brain Cancer

63. Prostate Cancer – RadioSurgery
Brain Cancer
Lung Cancer

64. Prostate Cancer – RadioSurgery
Brain Cancer
Lung Cancer
Prostate Cancer

65. Pinpoint Radiation – RadioSurgery
Delivers a high dose of radiation therapy
Short treatments (1 – 5)
Short treatment times
Very effective
Low chance of side effects

66. Pinpoint Radiation – RadioSurgery
Questions?