Radiation therapy involves using high-energy beams to damage cancer cells' DNA and destroy their ability to reproduce. It can be used as the primary treatment for some cancers or alongside surgery and chemotherapy. The document outlines the radiation therapy process, including initial consultation, simulation to plan treatment, quality assurance of the plan, daily treatment sessions, and follow-up care. Potential side effects are usually localized to the treatment area and can include skin changes, fatigue, and organ-specific issues depending on the cancer location.

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Introduction to Radiation Therapy
Katherine Tzou, M.D.
Assistant Professor of Radiation Oncology

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Objectives
• What is radiation therapy?
• Indications for radiation treatment
• Potential side effects
• Preview the process patients go through for
treatment

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What is Radiation Therapy?
• Radiation therapy is a high voltage energy
X-rays operate in kV range
Radiotherapy operates in MV range

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What is Radiation Therapy?
• An accelerator
produces high energy
photons (X-rays) or
particles (electrons,
protons)
Khan F. The Physics of Radiation Therapy, 4th ed.Varian

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What is Radiation Therapy?
• Damage DNA within
cancer cells,
destroying their
ability to reproduce
• Normal cells can be
affected by radiation,
but are able to repair
themselves
OH

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Different Forms of Radiation Therapy
• External Beam • Brachytherapy
• Radioisotope

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Indications for Radiation Therapy
• Local or adjuvant therapy
• Pre-op rectal, sarcoma
• Post-op endometrial, breast
• Definitive treatment
• Head and neck, skin, prostate
• Palliative treatment
• Pain, bleeding, SOB

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Potential Side Effects
• Localized to the area of treatment
• Skin
• Redness, tanning, fatigue, fibrosis
• Prostate
• Bladder, bowel, fatigue, erectile dysfunction
Pre-treatment 2 mo after XRT

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1. Prior to treatment 2. @ 2400 cGy
3. @ 6000 cGy 4. 1 month after XRT

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What To Expect ….

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A Patient’s Path in Radiation Oncology…
• Consultation
• Simulation
• Treatment Planning
• Quality Assurance
• Treatment
• Follow-up
Time lapse varies
depending on the
complexity of treatment
1-10 days

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Consultation
• Evaluation by a Radiation Oncologist to
determine if the patient is a candidate for
radiation therapy and the best course of action

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Simulation
• Immobilized to improve
accuracy
• CT scan with patient in the
treatment position

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Simulation
Crosshairs or tattoos
marked to accurately
align the patient to our
laser system for daily
treatment

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Contouring
• Outline tumor and areas at risk for disease
• Normal tissue structures to avoid
Prostate

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Treatment Planning
• Dosimetrist works with the physician to optimize
dose to the tumor while sparing nearby organs

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Quality Assurance
Medical physicists ensure treatment plans are
safe and deliverable prior to patient arrival

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Treatment
• Radiation therapists
• Meticulously align
patients
• Administer radiation
daily as per the
doctor’s prescription

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Image Guidance: Prostate Cancer
DRR
DRR
Treatment
XRay
Treatment
XRay
Treatment
XRay
DRR

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Multidisciplinary Mayo Cancer Team
Medical
Genetics
Psychology
Social
Work
Radiology
Pathology
You
Surgical
Oncology
Radiation
Oncology
Medical
Oncology

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Questions?

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Immobilization: Prone breast board

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Image Guidance: Breast Cancer
DRR Treatment
XRay