What is the difference between a CT and a PET-CT scan?


CT and PET-CT scans are very common procedures that doctors administer every day to help localize their examination and to provide the most thorough diagnosis. Both procedures contain varying, minimal risks but can provide huge benefits for patients that need a more in-depth examination and specialized treatment.

What is a CT scan?

A CT scan or a Computed Tomography scan is a medical procedure that uses x-ray radiation and fascinating computer technology to create cross-sectional images of the body’s organs and tissues. CT scans can also be called CAT or Computed Axial Tomography. CT scans take helical images of the examined part of the body which produces better 3-dimensional imaging. The better the image, the better the diagnosis your doctor can make. CT scans are particularly useful in the examination of tissues, cancer staging, and determining vascular disease.

What is a PET-CT scan?

A PET-CT scan or Positron Emission Tomography is a medical procedure similar to a CT scan but PET-CT scans are commonly used in determining the difference between healthy and diseased tissue. Using nuclear medicine these exams allow particular focus on oncological symptoms in the brain and heart as well as any vascular or tissue abnormalities.

What are the procedures like?

The biggest difference between a CT and a PET-CT scan is the machinations of the procedure. There are varying states of discomfort between both procedures, but both are relatively painless and easy to complete for any patient.

A CT machine looks like a large tire with the patient placed inside the “hole.” The patient is placed on the examination table and will be administered contrast material through the mouth or intravenously. The feet will be the first to enter into the machine and the body will be slowly moved into the chamber. The procedure lasts approximately 10-30 minutes. Patients typically report that they hear a slight whirring sound which is the machine rotating around them gathering imaging. The doctor will able to speak to you and you will be able to respond.

A PET-CT scan is similar to a CT scan in some ways but the biggest difference between the two is the instructions prior to the exam. Most doctors and facilities will request that a patient not eat at least 4 hours prior to the scan and to drink lots of water. The exam also lasts slightly longer at about 30-45 minutes. Contrast material is commonly used as well and will either be  administered through an IV or by inhalation. If the PET-CT scan is being administered because of possible heart disease, the patient will often be asked to perform a stress test. The body will be examined at rest and during exercise in efforts to determine any cardiovascular problems. You may also hear a buzzing or clicking sound during this procedure.

Which procedure is more painful?

Both procedures have a minimal amount of pain and discomfort. The most common complaint is concerning the IV injection site or a claustrophobic feeling. But the contrast material is necessary for properly determining the condition of tissues and veins as well as highlighting possible cancerous cells. Furthermore, the body moves through the machine. It only covers the area that will be examined — it does not encapsulate the entire body.

Are there any risks?

Doctors and imaging facilities have been able to minimize the risks surrounding these procedures to practically nothing. Both a CT and PET-CT scan use small amounts of radiation to image the examined area. If you are pregnant or could possibly be pregnant, you should let your doctor know. There is no medical evidence that the amount of radiation is dangerous for an unborn child. But if there is another safer method to examine, your doctor can help you understand your options. Also if you have any implanted devices, artificial body parts or features such as hearing aids or dentures, talk to your doctor about what needs to removed for the procedure.

Ready to make your appointment? You can use our request an appointment form online or just call us at 504-883-8111.

Can I Have an MRI During Pregnancy?

When we become injured or sick, it can be troubling, but with support and medicine, we can treat ourselves and our symptoms. However, when a woman is pregnant and becomes sick or injured, there are more lives than hers to consider during treatment. There are lists of activities and products that pregnant woman have to avoid but should medical imaging be one of these? We are going to discuss the precautions and protections in place to help keep both mommy and baby healthy.

The first thing that probably comes to mind when considering the danger of medical imaging while pregnant is radioactive substances and procedures that utilize this kind of medicine. And when we think of radioactive medical procedures, the first that come to mind are X-rays, CTs, and PET-CT scans. All of these procedures have a radioactive element. But before expectant mothers become worried, they should know that there are safety guidelines for their benefit.

Expectant mothers should not be barred from accessing potentially life-saving imaging procedures. As such, medical imaging equipment manufacturers and researchers work hard to give the best quality equipment along with the safest for all potential patients. Being the oldest form of medical imaging technology, X-rays have been used by pregnant women since their invention. Having your X-rays performed at a facility like Doctors Imaging means that your doctor and our radiologists will seek alternatives to radiation and, if unavoidable, will work to reduce the dosage of radiation exposure. As with all medical procedures, if you think that you might be pregnant, be sure to let your doctor or the radiology technician know.

At Doctors Imaging, the procedures that seem to cause mothers the most worry are CT scans and MRIs. Please know that CT scans use X-rays combined with computer technology in order to compose images for medical use. Pregnant women: Please talk to your doctor about the risks and benefits of CT scans.

The other procedure we hear the most concern about from expectant mother is an MRI. Fortunately, we can often alleviate these concerns because MRIs are one of the safest procedures for pregnant women. Having an MRI during pregnancy is safe because MRIs, or magnetic resonance imaging, only use the magnetic mechanical components along with radio frequencies in order to map the interior of the body. There are absolutely no radioactive components for mothers to worry about and the detail that can be gleaned from MRIs during pregnancy is both valuable and necessary. At Doctors Imaging, our 3T MRI technology is the most powerful MRI in clinical use for every part of the body. For MRI patients with claustrophobia, we also have an open MRI machine this tends to be much less intimidating.

Finally, please know that we don’t recommend PET-CT scans for pregnant or breastfeeding mothers. PET (positron emission tensor imaging CT scans) use nuclear medicine in order to highlight differences between healthy and diseased tissue in the body and brain. This test utilizes a radioactive drug that is administered directly into the body. This drug can be harmful to the baby. Often, physicians will find an alternative diagnostic method in these cases.

We are committed to keeping both mom and baby as comfortable and healthy as possible at Doctors Imaging. If you have more questions about X-rays, CT scans or MRIs during pregnancy, please feel free to call our offices in Metairie at 504-883-8111, Monday through Friday.

How Invasive are Medical Imaging Procedures?

The innovations made within the medical technology field have taken away a vast amount of risk and pain done during these procedures, but sometimes in order to get the best images so that your doctor can make the most informed diagnosis possible requires a bit of discomfort. Depending on the concern or condition, there are a variety of medical imaging procedures that can be performed with various degrees of invasiveness. Luckily most of these procedures do not take long and if you have serious concerns or a condition that would make performing these procedures unbearably painful, you should speak to your doctor about different options and features that can still be performed. For this article, the procedures will be ordered from least to most invasive.

X-Ray

X-rays are painless and not invasive at all. The joints and bone structures of the body are imaged while the patient remains still on the procedure table. If a patient is pregnant or may be pregnant, they should inform their doctor. The radiation used in X-rays is an extremely small amount and a lead shield can protect the fetus if the test is medically necessary, but there may be other avenues of imaging that your doctor can perform instead.

PET-CT Scan

For these scans, your facility or doctor may request that you not eat anything for four hours prior to the exam and drink a lot of water. Contrast material is also used in this procedure. Contrast material will be administered intravenously and will require that the patient remain still for 30-90 minutes so that the contrast material has opportunity to circulate.

MRI Procedure

MRI is extremely low in its degree of invasiveness. Despite the slight prick of IV administration of contrast fluid, some patients experience a sense of claustrophobia entering the MRI machine. If this an issue for you, speak to your doctor about having a friend or family member in the procedure room with you or for more serious cases, your doctor may be able to provide you with a mild sedative.

CT Scans

CT scans are a painless procedure. Some doctors may require patients to not eat at least an hour prior to the examination. Contrast material is also used in CT scans and can be administered either through IV or by swallowing. Some describe a metallic taste in the mouth, or slight itchiness around the injection site. If a patient experiences more serious symptoms, it could be indicative of an allergic reaction or a type of condition that reactions to the contrast fluid.

Ultrasounds

Depending on the area or conditioned being examined, an ultrasounds procedure has varying degrees of invasiveness. None are particularly painful just slightly uncomfortable. Speaking with your doctor about your concerns can help to minimize the unpleasantness. And for determining and monitoring pregnancy, detecting signs of infertility or for examining reproductive organs, some patients may have to undergo a transvaginal ultrasound in which the transducer is placed in the vagina to image organs like the uterus and ovaries.

On the whole, imaging procedures performed today are minimally or non-invasive. If you’re looking for safe and comfortable imaging procedures in the New Orleans, Metairie, or Kenner area, please call 504-883-8111 or schedule your appointment online today.