Lung V/Q

Question 1

RP
Dose
Admin
TTI

Answer 1

Xe133 Gas: 10 - 20 mCi
Tc99m DTPA aerosol: 40 - 50 mCi, 1 - 2 to patient
Tc99m MAA: 4 - 6 mCi IV

Question 2

Indications

Answer 2

Rule out PE
Chest pain, SOB
History of previous PE or DVT
MAA - Pre/post surgery

Question 3

Contraindications

Answer 3

Known active pneumonia

MAA - Right to left shunt

Question 4

Patient Prep

Answer 4

Recent chest x-ray (w/i 24 hrs)

Question 5

Positioning

Images

Answer 5

Xe133 - Sitting with back to camera. Breath hold, equilibrium, and washout. Point source
Tc99m DTPA - Supine with arms down. All views
Tc99m MAA - Supine with arms down. All views

Question 6

Target Organ
Critical Organ
Route of Excretion
Localization

Answer 6

Target: Lung
Critical: Lung
Excretion: Expiration
Localization: Compartmentalization

Question 7

Xe133 Ventilation Procedure

Answer 7

Imaging room should have negative pressure
Position patient in sitting position with back to camera
Use point source to mark suprasternal notch and sides
Explain THOROUGHLY when to breath/ hold
Apply mask or mouth piece/clip firmly
Turn to home position, insert Xe
Instruct patient to take 3 breaths, between 2nd & 3rd add Xenon and turn to xenon setting. Pt holds breath.
Breath hold for 15 - 30 sec, “pinky”
Image static for entire time
Breath normally
Image static for 30 seconds
Turn to washout setting
Image Dynamic every 30 seconds for 2 minutes
Remove mask and allow patient to breathe normally

Question 8

Tc99m DTPA Ventilation Procedure

Answer 8

Patient should be sitting
Place ventilator in the mouth - ensure tightly held
Open and inject 40 - 50 mCi DTPA liquid
Connect wall O2
Clip nose
Turn on wall O2 - 10 L
Patient should breathe normally for 3 - 5 minutes, longer if difficulty breathing
Turn off wall O2 - remove ventilator and give tissue
Entire apparatus, tissue - logged and labeled to decay

Question 9

Tc99m MAA Perfusion Procedure

Answer 9

Inject 4 - 6 mCi Tc MAA IV
Position patient supine with arms down
Acquire statics 500k - 1mil counts: All views
Arms should be above head for LATS

Question 10

Xe133 Ventilation Computer Set Up

Answer 10

64 x 64
LEHR
Statics for 30 seconds
Dynamic: 30 seconds a frame for 2 minutes

Question 11

Tc99m DTPA Ventilation Computer Set Up

Answer 11

64 x 64
LEHR
Statics for 2 - 4 minutes or 200 - 500k counts

Question 12

Tc99m MAA Perfusion Computer Set Up

Answer 12

512 x 512
LEHR
Statics for 500k - 1 mil counts

Question 13

Ventilation Processing

Answer 13

Pegasys - Lung Imaging: Xenon. Lung: Xenon Cine/MAA
JetStream - Lung Xenon and perfusion. Lung perfusion only. Lung Washout - GV
Xeleris - Lung Xenon. Lung Aerosol.

Question 14

Perfusion/ Quantification Processing

Answer 14

Pegasys - Lung Imaging
JetStream - Lung Perfusion only
Xeleris - Lung Xenon. Lung Aerosol

Question 15

Labels

Answer 15

Name
DOB
MRN
Date of exam
Hospital
Referring physician
Dose 
Dose Rate
Frame Rate
View IDs
Right / Left
Tech initials

Question 16

Probabilities of PE

Answer 16

High: 2 or more large mismatched defects
Med: 1 moderate mismatched defect. 1 large & 1 moderate
Low: Matched defect, smaller than x ray defect, non segmental perfusion defects