Radiation Safety In The Cath Lab

Fluoroscopy-Guided Intervention (FGI)

Radiation Safety in the Workplace (Cardiac Cath Lab)

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Radiation Safety In The Cath LabIs My Cath Lab Doing Enough?

Time To Come Together On Cath Lab Safety

Magdy El-MasryProf. of CardiologyTanta University

Ionizing Radiation Can be Harmful: Nothing New

What you need to know?

Quick ABC’s of X-ray

Occupational Risks In Cath Lab

Radiation Safety Basics

Optimizing Radiation Safety in Cath Lab

Types of “Ionizing” Radiation

These types of radiation are called “ionizing” radiation, because they have enough energy to knock an electron out of its orbit around an atom – creating an ion.

Penetrating capacity of different types of radiation

Fluoroscopic system components

C Arm

Image Intensifier

X-ray Tube

Monitors

X-ray Table

Fluoroscopy-Guided Intervention (FGI)

X-Ray TubeScattered radiation is the main source of radiation exposure to operator and staff

Complete penetration; X-ray passes completely through tissue and into the image recording device.Total absorption; X-ray energy is completely absorbed by the tissue. No imaging information results.Partial absorption with scatter; Scattering involves a partial transfer of energy to tissue, with the resulting scattered X-ray having less energy and a different trajectory. Scattered radiation tends to degrade image quality and is the primary source of radiation exposure to operator and staff

There are three outcomes when X-rays traverse tissue.

Exposure,intensity Couloumb/kg

Absorbed radiation dose Gray

Equivalent dose Sievert

Radiation MeasurementsR.E.A.D.

Radiation.Exposure.Absorbed dose.Dose equivalent

How is Gray different from Sievert?

Absorbed radiation dose

Gray

Biological radiation dose

Sievert

Allow to estimate risk in a tissue or

organ

The Sievert is similar to Gray but takes into account the potential ability of the radiation to cause a biological effect

How high is the patient exposure in cardiac interventions in comparison to chest radiograph?

Radiation exposure distribution in the interventional cardiologist.

Radiation exposure on

the left is almost double

that on the right side.

Did You Know?Interventional Cardiologists

experience the highest amounts

of radiation exposure of any

medical professional.

Cardiac cath lab work carries multiple risks

Your exposure today may not be felt for years to come.

Radiation-induced cancers have a biological latency of more than 10 years

Radiation in cardiology: can’t live without it !Working towards zero operator exposure

Bad backs and aching necks: Occupational hazards of the cath lab

Deterministic & Stochastic Radiation Risks

“Probabilistic”

Deterministic effects, which only occur above a certain dose threshold Stochastic effects, which have a chance of occurring at any range of dose

Biologic Effects of Radiation : Radiation skin (deterministic) effects

A. Dry desquamation (Poikiloderma) at one month in a patient receiving 11 Gy calculated peak skin dose.

B. Skin Necrosis at 6 months in a patient who received 18 Gy calculated peak skin dose.

The wound on the right back healed into a scar while the injury on the arm ultimately required grafting.

The arm was too close to the x-ray source.

Radiation can harm biological systems by damaging the DNA of cells. If this damage is not properly repaired, the cells may divide in an uncontrolled

manner and cause cancer.

Biologic Effects of Radiation : Cancer-inducing (Stochastic)

Post-procedureDocument radiation dose

in recordsFT: Fluoroscopy

Time AK: Air Kerma

DAP: Dose-Area Product

The meaning behind the numbers

Dose exposure is described in terms of the following parameters

Fluoroscopic Time (min): This is the time during a procedure that fluoroscopy is used but does not include cine acquisition imaging. Therefore, considered alone, it tends to underestimate the total radiation dose received.

Air Kerma (Gy): The cumulative air kerma is a measure of X-ray energy delivered to air at the interventional reference point (15 cm from the isocenter in the direction of the focal spot). Kerma (Kinetic Energy Released in MAtter)

This measurement has been closely associated with deterministic skin effects

Dose-Area Product (Gy.cm2): This is the cumulative sum of the instantaneous air kerma and the X-ray field area.

This monitors the patient dose burden and is a good indicator of stochastic effects.

The axis of rotation of the C-arm is depicted as a dashed line.

The isocenter lies on the rotational axis, between the source and detector.

Air Kerma is a measure of X-ray energy delivered to air at

the interventional reference point

(15 cm from the isocenter in the direction of the focal

spot).

Justification Appropriate selection of patients for cardiac imaging is

the first step toward enhancing radiation safety.

Circulation November 4, 2014

Procedure justification and assuring the right test is done on

the right patient for the right reason

No Idea What I’m DoingAs Low As Reasonably Achievable

I Have ”No Idea What I'm Doing”

ALARANIWID

“Time, Distance and Shielding Principles”

Using appropriate shielding, keeping a distance as safely as possible and reducing radiation time are essential principles for radiation reduction

TDS

What is Dosimetry?Dosimetry is the measurement of radiation dose received.

How much dose did I get?

Energy in the form of radiation

Units of Dosimetry Absorbed Dose Equivalent Dose Effective Dose

Do You Know Your Radiation Dose During Your Cath?

Summary of dose quantities commonly used in medical imaging dosimetry with definitions and units.

Equivalent Dose (H) is the absorbed dose (D) multiplied by a radiation weighting factor (WR)

H = D x WR

Effective Dose (E) is the equivalent dose (H) multiplied by a tissue weighting factor (WT)

E = H x WT

Recommended use of at least two dosimeters, one above and one underneath the lead apron. They allow risk estimation for the deterministic effects (such as cataract) and the stochastic effects (such as cancer risks), respectively.

Dosimetry

Real Time Monitoring of Staff Dose in the Cath Lab

Real time radiation dose monitoring in the cath lab enables staff to see their level of exposure any time and can alert them when their

levels are spiking.

The patient should be placed away from the radiation source and close to the image intensifier

A lower table setting without changing the source-intensifierdistance results in higher dose due to proximity of the patient to the radiation source

Elevation of the image intensifier results in higher dose owing to geometric magnification by the intensifier

Low Subject-Image Distance

The influence of patient size to patient radiation dose

Thin patient Thick patient

For a larger patient, operators commonly increase the source to image distance(SID )as well as lower the patient table to facilitate the size of the patient. Such changes, in addition to high patient attenuation, contributes

to an increase of patient dose.

Source

Image

SID

Whenever possible, angulations should be avoided. In lateral (or craniocaudal) angulations, x-rays cross more tissues, which increases attenuation and decreases image quality. To compensate, the system increases the

beam energy to maintain image quality.

( a ) Posteroanterior projection where the dose rate is less than the oblique angulation ( b )

Effect of angulation on patient dose.

Magnification increases the

dose

*Field of view, diameter 17 cm Dose rate = 0.6 mGy/s*Field or view, diameter 12 cm Dose rate = 1.23 mGy/s.

Normal mode Mag mode

*Field of view, diameter 25 cm Dose rate= 0.3 mGy/s

The FOV will decrease, and the dose delivered to the patient’s skin will increase

Benefits from using collimationOptimal collimation on the area of interest allows significant dose reduction

The collimator is an adjustable lead shutter attached to the beam exit port of the x-ray source that can be closed down to limit the area of the body that is irradiated.

By collimating the beam to the diagnostically appropriate field of view, you will minimize radiation to the patient, as well as to yourself.

Does moving the X ray beam to different areas of the patient’s body during a procedure have an effect on the exposure to the patient?

The peak skin dose is the absorbed dose at the skin location that has received the highest dose. This quantity is used to predict a skin injury.

Spread the Dose

Minimize frame rate of fluoroscopyLower pulse rates lead to greater dose reduction per unit time.

(pulses per second)

A reduction of the fluoroscopic pulse rate from 15 frames/sec to 7.5 frames/sec with a fluoroscopic mode to low dose reduces the radiation exposure by 67%.

The diagrams depict scatter radiation for a C-arm fluoroscopy system with the x-ray tube under the table (left) and in lateral projection on the same side as the operator (right).

Note the high dose to the operator when standing on the same side of the patient as the tube.

If the operator stands upright, scattered radiation to the face is perhaps one-fourth as great as when the operator is leaning down toward the patient.

Short operators receive more radiation to the face than do tall operators. They may wish to stand on a platform.

The lateral projection is not recommended when the lead shield is not protecting the operator.

The lateral projection is recommended when the lead shield is protecting the operator.

Do not step on fluoroscopy pedalwhen not looking at screen

Decrease Cine Use

Thyroid collar

Lead Apron

Radiation shields

A – image intensifier;

B – Articulated, ceiling-mounted radiation protection screen;

C – patient position;

D – table-side shields.

Patient position and shielding in the cath lab.

A – digital flat panel detector mounted on C-arm;

B – ceiling-mounted articulated protection screen;

C – monitors;

D – patient;

E – C-arm and image control panel;

F – tableside protective shielding.

Your Lead is Cracked?

The “Interventionalist disc disease”:How to protect against it?

The Zero-Gravity™ radiation protection system

The future Robots Moving Into The Cath LabRobotic-Assisted PCI

The CorPath 200 cath lab robotic system is designed for more precise movements and less radiation exposure to physicians during

PCI.

Radiation Protection in

Cardiovascular Interventions:

What Can We Do?

Implementing a Culture and Philosophy of Radiation Safety

1• Precautions to Minimize

Exposure to Patient and Operator

2• Precautions to Specifically

Minimize Exposure to Operator

3• Precautions to Specifically

Minimize Exposure to Patient

Precautions to Minimize Exposure to Patient and Operator Utilize radiation only when imaging is necessary .Avoid

the”heavy foot“

Minimize use of cine.

Minimize use of steep angles of X-ray beam.( LAO Cr – AP Cr )

Minimize use of magnification modes.

Minimize frame rate of fluoroscopy and cine.(7.5 frames/sec fluoroscopy setting)

Keep the image detector close to the patient (low subject-image distance)

Utilize collimation to the fullest extent possible.

Monitor radiation dose in real time.

Precautions to Specifically Minimize Exposure to Operator

Use and maintain appropriate protective lead garments.

Maximize distance of operator from X-ray source and patient.

Keep above-table (hanging) and below-table shields in optimal position at all times.

Keep all body parts out of the field of view at all times

A robotic PCI system may be considered

Precautions to Specifically Minimize Exposure to Patient

Keep table height as high as comfortably possible for the operator.

Every 30 minutes, vary the imaging beam angle to minimize exposure to any specific skin area .

Keep the patient's extremities out of the beam.

Commonly employed strategies to minimize radiation exposure

End of Presentation Thank you for your attention

Radiation Safety In The Cath Lab

Healthcare

Transcript of Radiation Safety In The Cath Lab