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

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

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

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

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

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

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)

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

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

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)

Linear Accelerator

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

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

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

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

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

Types of Radiation - X-rays

Types of Radiation - X-rays

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

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

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

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

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

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.

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.

Brachytherapy

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

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

Consult Simulation Dosimetry QA Treatment Follow-up

Consult Simulation Dosimetry QA Treatment Follow-up

Consult Simulation Dosimetry QA Treatment Follow-up

Consult Simulation Dosimetry QA Treatment Follow-up

Consult Simulation Dosimetry QA Treatment Follow-up

Consult Simulation Dosimetry QA Treatment Follow-up

Consult Simulation Dosimetry QA Treatment Follow-up

Consult Simulation Dosimetry QA Treatment Follow-up

Consult Simulation Dosimetry QA Treatment Follow-up

Consult Simulation Dosimetry QA Treatment Follow-up

Consult Simulation Dosimetry QA Treatment Follow-up

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

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

Pin Point Radiation – RadioSurgery Brain Cancer Lung Cancer Prostate Cancer

Cancer in the Brain – RadioSurgery

Cancer in the Brain – RadioSurgery

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

Cancer in the Brain – Gamma Knife

Cancer in the Brain – Gamma Knife

Cancer in the Brain – RadioSurgery Whole Brain Gamma Knife RadioSurgery

Lung Cancer – RadioSurgery

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

Lung Cancer – RadioSurgery

Prostate Cancer – RadioSurgery

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

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

Prostate Cancer – RadioSurgery

Prostate Cancer – RadioSurgery

Prostate Cancer – RadioSurgery

Prostate Cancer – RadioSurgery

Prostate Cancer – RadioSurgery

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

Prostate Cancer – RadioSurgery Brain Cancer

Prostate Cancer – RadioSurgery Brain Cancer Lung Cancer

Prostate Cancer – RadioSurgery Brain Cancer Lung Cancer Prostate Cancer

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

Pinpoint Radiation – RadioSurgery Questions? mark.bernard@uky.edu 859-323-6486