CT Scan information and comparisons
| Radiation exposure: | The effective radiation dose from CT ranges from 2 to 10 mSv, which is about the same as the average person receives from background radiation in 3 to 5 years. Usually, CT is not recommended for pregnant women or children unless absolutely necessary. |
| Cost: | CT Scan costs range from $1,200 to $3,200; they usually cost less than MRIs (about half the price of MRI). |
| Time taken for complete scan: | Usually completed within 5 minutes. Actual scan time usually less than 30 seconds. Therefore, CT is less sensitive to patient movement than MRI. |
| Effects on the body: | Despite being small, CT can pose the risk of irradiation. Painless, noninvasive. |
| Acronym for: | Computed (Axial) Tomography |
| Application: | Suited for bone injuries, Lung and Chest imaging, cancer detection. Widely used on Emergency Room patients. |
| Scope of application: | CT can outline bone inside the body very accurately. |
| Ability to change the imaging plane without moving the patient: | With capability of MDCT, isotropic imaging is possible. After helical scan with Multiplanar Reformation function, an operator can construct any plane. |
| Details of bony structures: | Provides good details about bony structures |
| Principle used for imaging: | Uses X-rays for imaging |
| Details of soft tissues: | A major advantage of CT is that it is able to image bone, soft tissue and blood vessels all at the same time. |
| Principle: | X-ray attenuation is detected by detector & DAS system, followed by math. model (back projection model) to calculate the value of pixelism that becomes a image. |
| History: | The first commercially viable CT scanner was invented by Sir Godfrey Hounsfield in Hayes, United Kingdom. First patient's brain-scan was done on 1 October 1971. |
| Image specifics: | Good soft tissue differentiation especially with intravenous contrast. Higher imaging resolution and less motion artifact due to fast imaging speed. |
| Intravenous Contrast Agent: | Non-ionic iodinated agents covalently bind the iodine and have fewer side effects. Allergic reaction is rare but more common than MRI contrast. Risk of contrast induced nephropathy (especially in renal insufficiency (GFR<60), diabetes & dehydration). |
| Comfort level for patient: | Seldom creates claustrophobia |
| Limitation for Scanning patients: | Patients with metal implants can get CT scan. A person who is very large (e.g. over 450 lb) may not fit into the opening of a conventional CT scanner or may be over the weight limit for the moving table. |