Lung scan with quantitative analysis

Indications:
Indications for Lung Ventilation:
  • Evaluation and detection of PE (pulmonary embolism).
  • Evaluation of COPD.
  • Evaluation of pulmonary retention.
  • Evaluation of chest pain.
  • Evaluation of respiratory distress sydrome, (ie. emphysema, inflammation, chronic bronchitis, pneumonia).
  • Evaluation of staging COPD patiets.
  • Evaluation of low blood oxygen saturation.
  • Evaluation of obstructed/ constricted airways alveolar space, and air distribution causing shortness of breath.
  • Shortness of breath
  • Detection of right to left cardiac shunt
  • Preoperative evaluation
  • Evaluating lung transplantation

Contraindications:
  • Studies on patients with known active pneumonia or other lung disease will show a result for PE.
  • Should not be performed on patients with pulmonary hypertension.
    • If study is done the does must be decreased.
    • If pulmonary hypertension is known, some will get a chest x-ray and/or venous pressure measurement before the perfusion study.
  • If the study is done on patients with pneumonia or any other known debilitating lung disease it will yeild a nondeterminable result for PE.
  • Right to left shunts (unless it is the reason for the scan)
  • Hypersensitivity to human serum albumin.

Questions asked in Patient History:

List the common questions asked when taking a patient history for this specific procedure.

  • Are they pregnant?
  • Any recent nuclear imaging test done prior to this one?
  • Any pulmonary hypertension?
  • Are they on any medications?
  • Any injury are trauma?
  • Any past surgery?
  • Chest pain? How long, where?
  • What was seen on the chest X-ray?
  • Is the patient being treated with anticoagulants
  • Did or do they smoke? How much do/did they smoke?
  • Shortness of breath? note the respiration rate, is it fast? slow?
  • Does your family have a history of cancer? If so what type and how long?
  • Any difficulty or pain when breathing? If so, where?
  • Are you coughing up blood?
  • Do you have fainting spells?

Radiopharmaceutical information:
  • Radionuclide: gas- Xe-133 OR aerosol/ perfusion- Tc-99m
  • Radiopharmaceutical:perfusion- Tc-99m MAA / Xe-133 gas or aerosol- Tc-99m DTPA
  • Adult dosing: Tc-99m MAA 1-4 mCi, Xe-133- 10-20mCi, Tc-DTPA-30- 40 mci with particle size 0.1- 0.5micrometer
  • Pediatric dosing: Tc-99m MAA- 0.5-2mci,
  • Method of administration:intravenously/ inhilation through mask or mouth apparatus, PO
  • Method of Localization: Blood flow to pulmonary cappilary/ Compartmental by inhilation to the lung space
  • Physical Half-life: Tc-99m 6 hours/ 5.3 days for Xe-133

Patient Preparation:

What does the patient need to do prior to coming for the procedure?
  • Have an x-ray done prior
  • The technologist must identity the patient, verify the doctor's order and explain the procedure.


Side Effects:

Will the patient feel any different during or after the procedure?

None

Equipment Used:
Type of Camera:Large field of view
Collimator used: Xe-133: LEAP or low energy high sensitivity; Tc-99m DTPA LEAP or LEHR

Acquisition Setup:

Photopeak(s):140 keV for Tc-99m/ 81 keV for Xe-133

Window(s):20%


Dynamic: View(s):ant/post
Matrix:128x128x16
Time/Frame: 20-60 sec/frame for 6-8 min. (for Xe-133) (the wash-in, equilibrium, and wash-out)
Number of Frames:

Statics: View(s): For perfusion all 8 views, (ant/post, RAO, RLAT, RPO, LPO, LLAT, AND LAO)
Matrix:
Total Counts or Duration: Perfusion - 500-750kcts

SPECT:
180
Total Rotation: 360
Starting point: 0
Matrix: 64x64
Time/Azmuiths: 17sec/azimuth
Number of Azmuiths: 64

Processing:


Filter: Butterworth
Cut-off: 6
Frequency: 0.35


Procedure:
Describe the procedure from verifying the requisition to completing the scan. Include any patient instructions pre- or post- injection/scan, delays between injection and imaging, and any side effects.

Explain the procedure to the patient and confirm that they have had a chest x-ray done before performing the next set of studies. If possible, ask the patient to cough and take a couple deep breaths. After making sure that the patient is supine, inject 4mCi of Tc-99m MAA into patient intravenously, making sure that the camera begins imaging a couple seconds before injection and also, not to draw back blood into the syringe because that would cause "clumping" and hot spots would appear in the images. Make sure to get 500k-750k counts for each image; image anterior, posterior, laterals, anterior and posterior obliques. A SPECT could also be done after the perfusion.

After the perfusion scan, a possible ventilation scan may need to be performed. The ventilation scan can be done either with a radioaerosol or radioactive gas. The purpose is to compare the radioaerosol or radioactive gas image with the perfusion images and see if there is a mismatch between the two.

Radiactive Gas: Place the gamma camera behind the patient and move the camera face right onto the surface of their back. Make sure that the room that this procedure is done in has a negative pressure and has the ventilation system on the floor of the room. Place a marker over the suprasternal notch and make sure that that lungs are completely in the field of view. After explaining the procedure to the patient, ask the patient to breath out completely, and then place the mask onto the patient's face; ask the patient to take in a deep breath and then start imaging. There are three phases necessary for this test: the initial breath that lasts 10-15seconds, equilibrium phase that lasts 2seconds (1sec/frame for 2 frames) and washout that lasts 10-15seconds.

Radioaerosol: Patient can be either supine or upright for this procedure. This procedure utilizes a nebulizer that contains an injected 30-40mCi of Tc-99m DTPA. Explain the procedure to the patient, and place a noseclamp onto the patient to decrease likelihood of the radiotracer escaping. Have the patient put the mouthpiece into their mouth and ask them to breath normally for approximately 5minutes. After 5 minutes, remove the mouthpiece and nose plug and beging obtaining anterior, posterior, laterals, and obliques for anterior and posterior for 250k counts each.

Normal Uptake and common varients:
Insert an image of a normal scan. Describe the normal uptake, and any normal varients visualized.
external image Ventperf.jpg
(http://en.wikipedia.org/wiki/Ventilation/perfusion_scan)

Abnormal Uptake and causes:
Insert an image of an abnormal scan. Describe the abnormal uptake, and the cause of the abnormal uptake.

external image Pulmonary_embolism_scintigraphy_PLoS.png
(http://en.wikipedia.org/wiki/Ventilation/perfusion_scan)

Artifacts:
Insert an image with an artifact, and explain what the artifact is.


References: