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Inhalation Scintigraphy
Inhalation scintigraphy is a type of lung imaging with radioactive aerosols. Inhalation scintigraphy can be accomplished with 99mTc-DTPA or other aerosols. The patient inhales the particles over a special system.

See also Pulmonary Scintigraphy, Aerosol Ventilation Scintigraphy and Gas Ventilation Scintigraphy.
Contrast Media Injector
Contrast media injectors are part of the medical equipment used to deliver fluids in examinations such as CT, MRI, fluoroscopy and angiography. Many of these diagnostic imaging procedures include the administration of intravenous contrast agents to enhance the blood and perfusion in tissues.

Mainly there are two types of injector technology:
Piston-based systems use a plunger/piston to move a piston in the cylinder of a reservoir, which works in two directions to first fill the reservoir and then deliver the fluid from the reservoir to the patient, similar to a hand-held syringe.
Peristaltic-pump-based systems operate as rotary pumps that use rollers to compress sections of flexible tubing, drawing fluid directly from the supply source and delivering it to the patient.

See also Single-Head Contrast Media Injector, Dual-Head CT Power Injector, Syringeless CT Power Injector.

The use of x-ray contrast agents in computed tomography (CT) began with a hand injection by the radiologist in the scan room. During its history, CT scanners have made great improvements in speed and image quality. Actual CT systems with multiple detectors allow scan times of a few seconds per body region. Some CT protocols require multiphase scans, where a body region is imaged with a single bolus of contrast in different blood flow phases. Automatic power (pressure) contrast media injectors are required to provide precise control of flow rate, volume and timing of injection. The use of a saline bolus following contrast administration reduces the volume of contrast required.

Most relevant topics for the use of a power injector in medical imaging procedures such as contrast enhanced computed tomography (CECT):
Avoidance of microbiologic contamination;
workflow efficiency in the use of the contrast media injector;
contrast cost and waste volume;
reimbursement.

Must have basic injector control options:
Flow rate with a usual range from 0.1 to 10 mL/sec in 0.1 mL/sec increments; some injectors can be set to inject in ml/min or ml/hour;
volume range from 1 mL to 200 mL for contrast and saline phases;
pressure limit typically programmable from 50 psi to 300 psi in 1 psi increments (also displayable in kPa and kg/cm²).

Examples of other injector control options:
Warmer/heater; an increase in temperature of the contrast medium results in a decrease in its viscosity; warmed contrast media are less viscous and offer lesser resistance;
pre-filled syringes; the compatibility with many selected syringes makes it easy to change and select the appropriate contrast medium for each patient;
injection reports accessible via RIS/PACS for dose management systems and records of prior injections.

CT Angiography
(CTA) A computed tomographic angiography or computerized tomography angiogram is a diagnostic imaging test that combines conventional CT technique with that of traditional angiography to create images of the blood vessels in the body - from brain vessels to arteries of the lungs, kidneys, arms and legs.
High resolution CT scans with thin slices and intravenous injection of iodinated contrast material provide detailed images of vascular anatomy and the adjacent bony structures. CTA requires rapid scanning as the imaging data are typically acquired during the first pass of a bolus of contrast medium. The selection of acquisition timing is important to optimize the contrast enhancement, which is dependent on contrast injection methods, imaging techniques and patient variations in weight, age and health. CT angiography is less invasive compared to conventional angiography and the data can be rendered in three dimensions.

CTA techniques are commonly used to:
Detect pulmonary embolism with computed tomography pulmonary angiography;
rule out coronary artery disease with coronary CT angiography;
evaluate heart disease with cardiac CT;
identify aneurysms, dissections, narrowing, obstruction and other vessel disease in the aorta or major blood vessels;

See also Cardiovascular Imaging, Magnetic Resonance Angiography MRA, Coronary Angiogram, Computed Tomography Dose Index and Computed or Computerized Axial Tomography.
Gas Ventilation Scintigraphy
A gas ventilation scintigraphy is a diagnostic imaging test of lung ventilation with radioactive noble gases during breathing maneuvers, e.g. with krypton (81mKr) or xenon (133Xe).
The radioactive gas is administered by a mask and requires a special delivery and trapping system (gas trap). The radioactivity in the lungs is measured with a gamma camera and is subsequently evaluated.
The use of krypton or xenon gases involves problems like the relatively short half-lives (about 15-30 seconds) and relatively high costs of xenon and krypton. The short half-life requires that the scan is performed directly after administration of the gas. In addition, the gaseous radiopharmaceutical is expelled from the body almost quantitatively within a few minutes of completing the study.
A ventilation scintigraphy combined with a pulmonary perfusion scintigraphy is highly sensitive for the detection of pulmonary embolism.
Radioactive noble gases are widely used as a ventilation agent to diagnose pulmonary embolism. However, 81mKr and 133Xe are rare and expensive, which limits their continuous availability. Tc99m-Technegas can be an alternative ventilation agent with the advantage of being less expensive and available daily.

See also Inhalation Scintigraphy.
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 [last update: 2023-11-06 02:01:00]