This document discusses radiation safety in cath labs. It explains that increasing mA increases radiation exposure while increasing kVp decreases absorption. Fluoroscopy requires less radiation than cineangiography. Key metrics for measuring patient radiation dose include fluoroscopic time, air kerma, and peak skin dose. Both stochastic effects like cancer and deterministic effects like skin burns are risks. Proper techniques like limiting fluoro use, collimation, and distancing can reduce radiation exposure for patients and staff. New technologies also aim to improve radiation protection.

1. RADIATION SAFETY IN CATHLAB

2. • Cathode current (m A) = number of X-ray
photons
• Increasing mA increases absorption and
increases patient dose
• Tube voltage (k Vp) = energy of X-ray
photons
• Increasing kVp decreases absorption, and
reduces patient exposure

3. Fluoroscopy vs. Cineangiography
• Fluoroscopy
– A real-time X-ray image when
it is not necessary to record
it.
– Requires less image quality
than does acquisition (cine)
– With more noise tolerated,
input doses can be lower.
• Cineangiography
– Images are obtained at higher X-
ray input doses for acquisition
– Most units are calibrated such
that patient dose is 10- 15x
greater than fluoroscopy
– Thus, a single frame in cine is
equal to about one second of
fluoro
– A typical acquisition frame rate is
15 frames/sec

4. Patient Dose
Assessment
• Fluoroscopic Time least useful.
• Total Air Kerma at the Interventional
Reference Point (Ka,r , Gy) is the x-ray
energy delivered to air 15cm from for
patient dose burden for deterministic skin
effects.
• Air Kerma Area Product (PKA , Gycm2) is
the product of air kerma and x-ray field
area. PKA estimates potential stochastic
effects (radiation induced cancer).
• Peak Skin Dose (PSD, Gy) is the maximum
dose received by any local area of patient
skin. No current method to measure PSD,
it can be estimated if air kerma and x-ray
geometry details are known. Joint
Commission Sentinel event, >15 Gy.

5. KERMA
• Kinetic Energy Released in MAtter
• A measure of energy delivered (dose)
• Air Kerma = kerma measured in air (low
scatter environment)

7. Biologic Factors for Skin
Reaction (Deterministic)
• Patient-related factors
– hyperthyroidism , diabetes mellitus, connective tissue disorders, obesity,
smoking, and compromised skin integrity
– Medications: actinomycin D, doxorubicin, bleomycin, 5-
fluorouracil, and methotrexate mitoxantrone, 5-fluorourcil,
cyclophosphamide, paclitaxel, docetaxel, and possibly
tamoxifen
• Ethnic differences
– individuals with light-colored hair/ skin are most sensitive
• Defects in DNA repair genes
– autosomal recessive ATM gene, 1% population

8. Tissue Reaction
Radiation Dose
Skin Dose <2wks 2-8 wks 6-52wks >40 wks
0-2 Gy no observable effects expected
2-5 Gy transient epilation recovery none
erythema
5-10 Gy transient erythema recovery none
erythema epilation
10-15 Gy transient dry/moist permanent
erythema desquamation epilation atrophy
>15 Gy acute moist dermal surgery
ulcer desquamation necrosis

9. Patient Effects of X-ray Exposure
Stochastic Effects
• Induced Neoplasm
– Epidemiologic data suggest a linear dose-response
relationship, not a threshold, between ionizing radiation
exposure and induction of solid tumors.
– Fatal cancer risk of 0.04% to 0.12% for whole body exposure of
10 mSv (1 rem).
– Less for people>50 yrs; latent period > 5yrs.
– <1% for DAP of 200 Gycm2, typical PCI
• Heritable Abnormalities
– 0.01%/ 10cGy (1 rad) absorbed does to gonads

10. Determinants of Patient
X-ray Dose
• Equipment
• Procedure/Patient
– Obese patient
– Complex/long case
• Operator
– Procedure technique
– Equipment use
– Dose awareness

15. Distance effect
Distance
from Beam 1 step 2 steps 3 steps 4 steps
Relative
Exposure Rate 100 25 11 6
Use the inverse square law to your advantage and
whenever possible move away from the x-ray source
as far as safety allows.

16. Radiation Safety Principle
• Use the least amount of magnification
consistent with seeing the object adequately.
• BIGGER IS NOT ALWAYS BETTER!!
• A larger image means more radiation
– If it is necessary for adequate visualization, fine
– If it does not improve procedure safety or
performance, reduce the magnification

17. 2011 PCI Guidelines
3.1 Radiation Safety Recommendation
Class I
Cardiac catheterization laboratories should routinely record
relevant patient procedural radiation dose data (e.g.., total
air kerma at the interventional reference point (Ka,r), air
kerma area product (PKA), fluoroscopy time, number of cine
images), and should define thresholds with corresponding
follow-up protocols for patients who receive a high
procedural radiation dose. (Level of Evidence: C)

18. Radiation Dose
Management in PCI
1. Pre-Procedure
• Radiation safety program for cath lab
• Dosimeter use, shielding,
training/education
• Equipment and operator knowledge
• On screen dose assessment (Ka,r , PKA)
• Dose saving: store fluoro, adj. pulse
and frame rate, and last image hold
• Pre-procedure dose planning
– assess patient and procedure including
– patient’s size and lesion(s) complexity
• Informed patient with appropriate
consent
2. Procedure
• Limit fluoro: use petal only when looking at screen
• Limit cine: store fluoro if image quality not key
• Limit magnification, frame rate, and steep angles
• Use collimation and filters to fullest extent possible
• Vary tube angle if possible to change skin exposed
• Position table & image receptor: x-ray tube close to
pt increases dose; high image receptor incr. scatter
• Keep pt & operator body parts out of field of view
• Maximize shielding and distance from x-ray source
for all personnel
• Manage and monitor dose in real time from the
beginning of the case

19. Procedure Related Issues to Minimize Exposure
to Patient and Operator
• Utilize radiation only when
imaging is necessary
• Minimize use of cine
• Minimize steep angle X-ray
beam
• Minimize use of magnification
modes
• Minimize frame rate of
fluoroscopy and cine
• Keep the image receptor close
to the patient
• Utilize collimation to the fullest
extent possible
• Monitor real time radiation dose
DRAPED:
• D-distance: inverse square law
• R-receptor: keep image receptor
close to patient and collimate
• A-angles: avoid steep angles
• P-pedal: keep foot off pedal
except when looking at the
monitor
• E: extremities-keep
patient/operator extremities out
of the beam
• D-dose: limit cine, adjust frame
rate, where personal dosimeter

20. Staff Radiation Protection
• Shielding
– Lead>90%; Proper care of aprons
– Thyroid shielding; most important <40
– Glasses-0.25 mm; must fit
– Portable: above/below table shielding
– Drapes (Bismuth-barium)
• Personnel Dosimeters:
Take Proper Care
of Your Apron

21. New Technologies to Reduce Cath Lab Radiation
Exposure
Increased Shielding Without the Weight
Zero-Gravity Radiation Protection System
Real Time Monitoring of Staff Dose in the
Cath Lab

23. Robotic Systems to Remove Staff From the Radiation
Field

24. BloXR Corp
lightweight Aprons and Anti-X-ray Hand Cream