1. Slackers Radiation Oncology Fact Stack Mike Ori

2. Disclaimer These represent my understanding of the subject and have not been vetted or reviewed by faculty. Use at your own peril. I can’t type so below are common missing letters you may need to supply e r l I didn’t use greek letters because they are a pain to cut and paste in.

3. What are the five stages of cancer diagnosis and therapy

4. Screening Diagnosis Staging Therapy Follow-up

5. What is the most successful use of radiology for screening

6. Mammography

7. What is one area where radiology techniques have not been successful in screening

8. Ultrasound screening of the prostate

9. Explain the role of contrast kinetics in MRI

10. Wash-in and wash-out times help differentiate benign and malignant Normal tissue tends to have slower wash-in and wash-out kinetics than tumor.

11. What is a sestamibi scan

12. Use of 99m Tc-sestamibi to identify areas of angiogenesis and tumor.

13. Compare sestamibi scans to MRI

14. Uses ionizing radiation Not as available as MR Faster Cheaper

15. What is octreotide scanning

16. A somatostatin-like compound that can interact wit somatostatin receptors on the surface of cells. Some types of cancer (neuro- endocrine mostly) are notable for such receptors.

17. Compare octreotide scanning to MRI/CT

18. Sometimes shows mets when other modalities don’t Poorer anatomic localization than other modalities Can be used to indicate treatment with yttrium 90-octrotide

19. What is MRI spectroscopy

20. The use of the MRI machine to perform spectroscopic analysis of tissue to look for marker compounds that indicate growth or abnormal metabolism. Rarely used capability due to reimbursement

21. What radiographic techniques can be used to stage cancer

22. CT – The workhorse PET – Especially when combine with CT MRI – Increasing in use. Dominant in some areas Radionucleotide bone scans – For skeletal mets Ultrasound – Rarely

23. How does PET scanning work

24. Fluoro-D-Glucose is injected into the body. Hot spots appear in any tissue actively metabolizing glucose. This includes tumors but also inflammed and regnerating areas.

25. For what cancers is PET scanning approved

26. Non-small cell lung cancer Colorectal cancer Melanoma Lymphoma Head and neck cancer (not thyroid or CNS) Esophageal Cervical Breast monitoring and restaging Thyroid restaging

27. Explain radionucleotide bone scans

28. 99m TC-methylene diphosphonate is injected into the body and incorporated into hydroxyapatite in the bone by osteoblasts. Thus areas of bone growth are visible. Needs follow-up anatomic imaging

29. What is the role of radioactive iodine in the treatment of thyroid neoplasia

30. RAI is used post surgery to destroy remaining thyroid tissue.

31. What is image guided therapy

32. The use of radiology techniques in the performance of treatment Intra arterial chemo catheter Embolization – Simple – Chemo Alcohol ablation/cryotherapy RF ablation Focused ultrasound

33. What is RECIST

34. Response evaluation criteria in solid tumors is an heuristic used to quantify the change in a solid tumor over time. – CR = complete response – PR = partial response, 30% decrease – PD = progressive disease, 20% increase – SD = stable disease

35. What type of radiation is used in radiotherapy

36. Ionizing radiation such as x-rays, gamma rays, electrons, protons

37. What device produces the radiation used most predominantly in the US

38. The linear accelerator or linac

39. How many linacs can fit on the head of a pin?

40. None.

41. Differentiate teletherapy from brachytherapy

42. Teletherapy uses a radiation beam generated by source remote to the patient. This is your classic sci-fi death ray. Brachytherapy places an intrinsically radioactive substance in close approximation to the target tissue.

43. What is linear energy transfer

44. The amount of energy transferred per unit length of track

45. What is the bragg peak

46. The point of maximum energy release along a track.

47. Differentiate directly ionizing from indirectly ionizing radiation

48. Directly ionizing radiation has sufficient energy to directly disrupt the atomic structure of DNA. Protons. Indirectly ionizing radiation creates free radicals that damage DNA. X-rays.

49. What is the primary method of cell killing caused by radiation

50. Double stand DNA breaks that are improperly repaired.

51. Why are oxygenated cells more susceptible to radiation than are hypoxic cells

52. The ionizing process generates free electrons which are taken up by oxygen to generate oxygen radicals which attack DNA. In hypoxic conditions, less oxygen is available to generate free radicals.

53. Which phase of the cell cycle is sensitive to radiation? Which is resistant?

54. G1/M are sensitive S is resistant

55. What factors influence the survival of a radiated cell?

56. Position in the mitotic cycle Molecular checkpoint activation Hypoxia Repopulation

57. Describe how a 50Gy dose of radiation is delivered to patients

58. The dose is usually fractionated into multiple doses of ~2Gy. These are then delivered over the course of many days until the total prescription is delivered.

59. Describe image modulated radiation therapy

60. IMRT uses a multi-leaf collimator shape a radiation beam to limit exposure of adjacent structures.

61. List several benign diseases for which radiotherapy can be prescribed

62. Omas of the CNS – Schwanoma – Chordoma – Meningioma – Pituitary adenoma AVM Trigeminal neuralgia Pterygium Heterotopic ossification Trigeminal neuralgia