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Radiation safety in CT. RADIATION DOSES DURING CT EXAMS ARE CLASSIFIED AS:. LOW DOSE RADIATION. AS COMPARED TO DOSES GENERATED FROM NUCLEAR EVENTS. BODY RESPONE TO RADIATION:. SOMATIC EFFECTS GENETIC EFFECTS. SOMATIC EFFECT. MANIFESTED IN THE INDIVIDUAL EXPOSED.

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Radiation doses during ct exams are classified as
RADIATION DOSES DURING CT EXAMS ARE CLASSIFIED AS:

  • LOW DOSE RADIATION

AS COMPARED TO DOSES GENERATED FROM NUCLEAR EVENTS


Body respone to radiation
BODY RESPONE TO RADIATION:

  • SOMATIC EFFECTS

  • GENETIC EFFECTS


Somatic effect
SOMATIC EFFECT

  • MANIFESTED IN THE INDIVIDUAL EXPOSED


Acute somatic radiation syndrome stages
ACUTE SOMATIC RADIATION SYNDROME STAGES:

  • PRODROMAL- NAUSEA, VOMITING, DIARRHEA

  • LATENT PERIOD – NO SYMPTOMS

  • MANIFEST – ORGAN DAMAGE, DEATH OR RECOVERY

HEMATOPOIETIC

GI

CNS


Most common somatic effects
MOST COMMON SOMATIC EFFECTS

  • CATARACT FORMATION

  • SKIN CANCER

  • THYROID CANCER

  • BREAST CANCER

  • LEUKEMIA


Effect on an embryo or fetus
EFFECT ON AN EMBRYO OR FETUS

  • MOST PRONOUNCED DURING THE FIRST TRIMESTER!!!!



Fetal mri
FETAL MRI PREGNANT


Genetic effect
GENETIC EFFECT PREGNANT

  • MANIFESTED IN THE FUTURE GENERATIONS!


Radiation doses from ct scanners are the highest in diagnostic radiology
RADIATION DOSES FROM CT SCANNERS ARE THE HIGHEST IN DIAGNOSTIC RADIOLOGY!!!!

HOWEVER:


Radiation exposure should occur
RADIATION EXPOSURE SHOULD OCCUR : DIAGNOSTIC RADIOLOGY!!!!

  • AFTER CONSIDERATION BY THE PHYSICIAN


Alara
ALARA DIAGNOSTIC RADIOLOGY!!!!


Radiologic units customary
RADIOLOGIC UNITS (CUSTOMARY) DIAGNOSTIC RADIOLOGY!!!!

  • EXPOSURE, INTENSITY ------ ROENTGEN (R)

  • ABSORBED DOSE ----------- RADIATION

  • ABSORBED DOSE (rad)

  • DOSE EQUIVALENT ---------RADIATION EQUIVALENT MAN (rem)


Radiologic units si
RADIOLOGIC UNITS (SI) DIAGNOSTIC RADIOLOGY!!!!

  • EXPOSURE, INTENSITY ------ C/kg

  • ABSORBED DOSE ----------- GRAY (Gy)

  • DOSE EQUIVALENT ---------SIEVERT (Sv)

1 Gy = 100 rad

1 Sv = 100 rem


Pencil ionization chamber method of measuring ct dose ct dose index ctdi
PENCIL IONIZATION CHAMBER METHOD OF MEASURING CT DOSE DIAGNOSTIC RADIOLOGY!!!! (CT DOSE INDEX---CTDI)


Ct phantom ionization chamber
CT PHANTOM & IONIZATION CHAMBER DIAGNOSTIC RADIOLOGY!!!!



THE AMOUNT OF COLLECTED CHARGE IN I.C. IS PROPORTIONAL TO THE AMOUNT OF IONIZATION WHICH IS PROPORTIONAL TO THE AMOUNT OF RADIATION PASSING THROUGH THE CHAMBER. THE TOTAL ELECTRIC CHARGE GENERATED BY AN X-RAY BEAM IS REPRESENTED BY Q AND IS MEASURED IN COULOMBS.


IN 1981 CENTER FOR DEVICES AND RADIOLOGICAL HEALTH SUGGESTED AN EASY AND ACCURATE METHOD TO MEASURE PATIENT DOSE IN CT. IT RELIED ON ON CTDI AND MSAD (MULTIPLE SCAN AVERAGE DOSE)


MSAD AN EASY AND ACCURATE METHOD TO MEASURE PATIENT DOSE IN CT. IT RELIED ON ON

  • SERIES OF CT SCANS ARE PERFORMED ON A PATIENT . BETWEEN EACH SCAN PATIENT IS MOVED A BED INDEX (BI) DISTANCE.


Msad vs ctdi
MSAD vs CTDI AN EASY AND ACCURATE METHOD TO MEASURE PATIENT DOSE IN CT. IT RELIED ON ON


Factors in patient protection
FACTORS IN PATIENT PROTECTION AN EASY AND ACCURATE METHOD TO MEASURE PATIENT DOSE IN CT. IT RELIED ON ON

  • TIME

  • DISTANCE

  • SHIELDING


Shielding
SHIELDING AN EASY AND ACCURATE METHOD TO MEASURE PATIENT DOSE IN CT. IT RELIED ON ON

  • IF PERSONNEL PRESENT IN THE ROOM DURING SCAN MUST BE SHIELDED AND STAND FAR FROM THE SOURCE

    ( INVERSE SQUARE LAW)


Gonadal shields
GONADAL SHIELDS AN EASY AND ACCURATE METHOD TO MEASURE PATIENT DOSE IN CT. IT RELIED ON ON

  • 4-5 CM WITHIN THE X-RAY BEAM


Contact shields
CONTACT SHIELDS AN EASY AND ACCURATE METHOD TO MEASURE PATIENT DOSE IN CT. IT RELIED ON ON

360 ° AROUND PATIENT


Ct dose in spiral scanning
CT DOSE IN SPIRAL SCANNING AN EASY AND ACCURATE METHOD TO MEASURE PATIENT DOSE IN CT. IT RELIED ON ON

  • CTDI CAN ALSO BE USED

PITCH

MSAD OR CTDI


More useful measurement is
MORE USEFUL MEASUREMENT IS AN EASY AND ACCURATE METHOD TO MEASURE PATIENT DOSE IN CT. IT RELIED ON ON

  • EFFECTIVE DOSE

TAKES INTO ACCOUNT QUALITY

OF RADIATION

AND ORGAN SENSITIVITY

EXPRESSED IN Sv


Effective dose msv

HEAD------------ 2 AN EASY AND ACCURATE METHOD TO MEASURE PATIENT DOSE IN CT. IT RELIED ON ON

CHEST ---------- 8

ABDOMEN --10-20

PELVIS -------10- 20

SKULL -------- 0.07

CHEST PA ---- 0.02

ABDOMEN --- 1

PELVIS -------- 0.7

EFFECTIVE DOSE (mSv)

CT

CONVENTIONAL


Dose reduction in ct

BED INDEX AN EASY AND ACCURATE METHOD TO MEASURE PATIENT DOSE IN CT. IT RELIED ON ON

SPIRAL PITCH

COLLIMATION

(PREPATIENT)

NOISE

DOSE

DOSE

DOSE

DOSE

DOSE REDUCTION IN CT


Dose reduction in ct1

SID AN EASY AND ACCURATE METHOD TO MEASURE PATIENT DOSE IN CT. IT RELIED ON ON

OID

kVp (15 % RULE)

mAs

DOSE

DOSE

DOSE

DOSE

DOSE REDUCTION IN CT


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