Introduction to Radiation Therapy Clinical Applications, Pelvic Anatomy and Lymphatic System Overview

Radiobiology

The science that evaluates the effects of radiation in living organisms.

Fractionation (4 R's)

Radiation therapy treatments given in daily fractions (segments) over an extended period of time.

Repopulation

Normal tissue regeneration that occurs during fractionated radiation therapy.

Redistribution

The process of cells moving through different phases of the cell cycle in response to radiation.

Repair

The ability of normal tissue to recover from radiation damage, most important in terms of why we fractionate.

Reoxygenation

The process that applies to tumors only, where oxygen levels increase in tumor cells after radiation treatment.

dmax for cobalt

.5cm

Dmax for 4mev

1 cm

Dmax for orthovoltage and superficial

0 cm(kvp energy)

Dmax for 6mv

1.5cm

Dmax for 10 Mv

2.5

Dmax for 15 Mv

3 cm

Dmax 20 Mv

3.5cm

Dmax for 25mv

5 cm

P53 gene works in what part of the cell cycle

G1

Y do we fractionate the rad treatment

So the healthy cells can repair

What is the most radio resistant part of the cell cycle

S phase because cells r replicating

What part of cell cycle most radiosensitizer

G2 and M

Tumor has how many group layers of cells

4 layers

Top layer of tumor is oxygenated or not

It’s oxygenated (oxic)

Group 2 cells

Mix of hypoxic and oxic cells

Group 3 tumor cells

Hypoxic cells

Group4 tumor cells r

Anoxic or Necrotic or dead

Thoracic duct drains itself into the circulatory system at

The left subclavian vein

What level is the cisterna chyli

L2

Common iliac nodes directly drain

Bladder

Prostate

Cevix

Vagina

Paraaortic provides drainage from

Cisterna chyli

Paraaortic drains directly from

Uterus

Ovaries

Kidney

Testicles

External iliac nodes drain

Urinary bladder
Prostate
Cervix
Testes
Vagina
Ovaries

Internal iliac nodes or hypogastric nodes drain

Vagina

Cervix

Prostate

Bladder

Obturator nodes drain

Prostate cervix

First side of prostate spread comes from what lymph node

Obturator foramen

Inguinal nodes drain

Vulva

Uterus

Ovaries

Vagina

Anus

wHat lymph node is common treated with electrons because it’s very superficial

Inguinal nodes

What is myelitis

Inflammation of spinal cord

Do sacro as spread thru lymph

No only blood

Grading is what

Cell differentiation

If they take two biopsy of the prostate in one quadrant one is g 2 and the others is a score of 8 and another Quadrant comes out with a 2 and a3 what score is it

Gleason score of 10 the highest score is the score

Staging is made by

American cancer society

Lung cancer ad breast cancer is by worse if it's bigger or smaller tumors

Bigger

Gi cancer is based on what layer it's in

So mucosa is a stage 1 and serosa is stage 4

What labs r done when someone cancer could metatstize to the liver

AST and lst liver functions taken thru blood

What is the tumor marker for prostate

psa

Positive pregnancy test for men indicate what cancer

Testicular

Most common pop portals

Ap/pa

Right and left lateral

Pop portal r for treatment or imaging

Treatment

Orthogonal r for treatment or images

Images

Common orthogonal ports

Ap/ and a lateral

pa/ and a lateral

What does temodar do

Radiosensitizer brain breaks blood brain barrier

Cisplatin

Combo drug of a few chemo therapies

When r perm tattoo place during no shift

During simulation

When r perm tats placed during shift method

During first day of treatment

ITV

Involunatary motion

What makes up the itv

Gtv and ctv

Portal image is

Image of the treatment areas CANT portal image vmat or imrt because collimators r closed for those treatments

Where does the most accurate separations come from

Ct images

If u can’t use ct for separations what can u use

Calibers

What is the equivalent square equation

Eq= 4(A/P)

Intrafraction

What’s going on while treating

Respiration

Heart beat

Interfraction

Between fraction to fraction

Ex weight lost

Inter field distance

Patient Separations

What is the average energy of cobalt

1.25 MeV

2 photons of 1.33 and 1.17

Which two dmax r the most similar

Cobalt and 4mev

odi

Optical distance indicator

Ruler for ssd reading

Parallel opposed contradincatd

When patient sep to thin or too small

Graticule

Radioopaque markers on xray helps u make shifts

Parelleopposed make what shape

Hourglass

What is involved in daily qa

Dosimetery

Photon and electron output constancy (3% error range acceptable)

Mechanical

Laser localization

Odi

Colimator size indicator (2 mm error)

safety

Door interlock cuts off beam when door opens

Audio visual monitors do they work

Rad monitor area (prime alert) lights that flash when beam is on

Where do u extend the treatment portal edges when treating lymph nodes of pelvis

Upper border at midsacral level

Lower border is inferior part of prostate

Lateral border 2cm outside Pelvic brim

Anterior is 1cm anterior to pubic symphysis

Posterior border is the partial lateral rectal wall

Function of lymph

Drain interstitial fluid

Absorb fat and transport to blood stream

Major role in the body immunity

What is the main lymph duct

Thoracic duct

What is the only lymph node that dont have afferent function

Spleen

Largest lymph node in body

Spleen

Efferent

Exits lymph nodes

Afferent

Enters lymph nodes

Where’s does lymph dump into circulatory system

Subclavian veins

TD 5/5

Doses of radiation expected to produce a 5% complication rate within 5 years.

Critical Structures

Also referred to as organs at risk (OAR), these are normal tissues whose radiation tolerance limits the deliverable dose.

Therapeutic Ratio

Denotes the relationship between the probability for tumor cure and the likelihood for normal tissue damage.

Simulation

The process of creating a treatment plan for radiation therapy.

Immobilization Devices

Tools used to keep patients in a fixed position during radiation treatment.

Radiopaque Marker

A marker that is visible on imaging studies, used to indicate specific locations on the body.

Field Size

The dimensions of the area being treated with radiation.

ICRU 50 Tumor Volumes

Guidelines for defining tumor volumes in radiation therapy.

ODI - Optical Distance Indicator

A device used to measure the distance from the radiation source to the patient.

AP/PA

Anteroposterior (CAX directed from anterior to posterior) and Posterioranterior (CAX directed from posterior to anterior) positioning terminology.

Parallel opposed (POP)

Treatment given 180 degrees apart, commonly using AP/PA or right lateral/left lateral portals.

Orthogonal Images

Port images taken 90 degrees apart.

Source to Skin Distance (SSD)

The distance from the radiation source to the patient's skin surface.

Source to Axis Distance (SAD)

The distance from the radiation source to the central axis of the treatment beam.

Separations

Measurement used for treatment planning, determining the thickness of the body part from entrance to exit point of the treatment beam.

Calipers

A tool used to measure separations in treatment planning.

Leveling

The process of ensuring that the patient is set up correctly for every treatment.

Patient Marking System

A system used to mark the patient's position for consistent treatment delivery.

What is the anatomical position of the subject?

The subject stands upright, with feet flat together, toes pointed forward, arms straight down by the sides with palms facing forward, fingers extended, and thumbs pointing away from the body.

What are the three planes of the body?

1. Sagittal: Divides the body into right and left sides.

2. Coronal (Frontal): Divides the body into anterior (ventral) and posterior (dorsal) parts.

3. Axial (Transverse): Divides the body into upper (superior) and lower (inferior) portions.

What are the two main body cavities?

1. Dorsal Cavity: Located posteriorly, includes cranial and spinal cavities

2. Ventral Cavity: The largest body cavity, subdivided into thoracic cavity and abdomino-pelvic cavity.

What subdivisions are found within the thoracic cavity?

The thoracic cavity is subdivided into two lateral pleural cavities and the mediastinum.

What is the difference between the male and female pelvis?

The female pelvis is wider because the wings of the ilia are more open.

What are the three parts of the pelvic girdle?

1. Ilium 2. Pubis 3. Ischium.