Bone Density Scan FAQs



Nuclear Medicine (PET/CT) FAQs

CT Scan FAQs

Breast Imaging and Mammogram FAQs

What is an X-ray procedure?
The science behind radiography involves exposing part of the body to a small dose of radiation, which produces an image of the internal organs. When the radiation penetrates the body, it is absorbed in varying amounts by different parts of the anatomy, resulting in either white or light gray images (such as the ribs and spine) or dark images (such as lung tissue). Depending on the medium used, X-rays can be produced as film to be filed or, more commonly, as filmless computerized or digital images that can be stored electronically. Electronically stored images allow your physician to view your X-rays from their office.

How should I prepare for my procedure?
Routine X-rays

  • Most routine X-rays do not require special preparation.
  • Women should inform their doctor or X-ray technologist if there is any possibility that they may be pregnant.
  • You will be asked to change into a gown before the procedure.
  • Remove jewelry, eyeglasses or other objects that may show up on the X-rays.

Upper GI Series
We will provide you with specific preparation instructions for your upper GI series exam. The following are common instructions for most upper GI procedures.

  • Do not eat the day before the procedure and drink only clear liquids such as juice, tea, black coffee, cola or broth. Avoid dairy products.
  • Take nothing by mouth after midnight on the day before the examination. You can take prescribed oral medication with limited amounts of water on the day of the exam.
  • According to your physician’s instructions, cleanse your colon using a preparation that generally includes taking laxatives and an over-the-counter enema the evening before or a few hours prior to the procedure.

What will I experience during the procedure?
The table may feel hard and the room may be cold because the equipment must be kept at a constant temperature. Our staff members are sensitive to your comfort and needs and we will do what we can to minimize any discomfort.

During routine X-rays, you should experience no discomfort.
You will be required to drink barium for upper and lower GI series exams, which may have an unpleasant taste and may cause some abdominal pressure or minor cramping, and the need to move your bowel. These sensations are common and most patients easily tolerate the mild discomfort.

How and where will my X-rays be stored?
Your X-rays are retained in General Electric’s Centricity PACS, a revolutionary picture archival communications system. Centricity stores digital images and data of patient procedures and provides immediate access to the hospital network.

Clinical images created in the diagnostic radiology, CT, MRI, ultrasound, endovascular and nuclear medicine departments are available within seconds of test completion. This means faster test results and treatment for patients.
Note: In compliance with HIPAA regulations, only authorized personnel will have access to patient health care information.

Bone Density Scan FAQs
There is no special preparation required for a bone density (DEXA) scan.

  • You can eat normally, but do not take calcium supplements for at least 24 hours before the procedure. 
  • Inform your doctor if you have had a barium examination or have been injected with a contrast material for a computed tomography (CT) scan or radioisotope (nuclear) scan, as you may need to wait of 5 to 7 days before a bone density test can be performed.

During bone density scans, you should experience no discomfort.

What is an MRI?
Magnetic resonance imaging (MRI)) uses magnetic fields and radio frequencies to produce detailed pictures of organs, soft tissues and bones. An MRI is one of the most accurate methods of diagnostic imaging, enabling your physician to explore organs, soft tissue and bone without using ionizing radiation or invasive procedures. An MRI can identify and assess a number of possible issues:

  • Access blood flow
  • Detect tumors and diagnose many forms of cancer
  • Evaluate infections
  • Assess injuries to bones and joints
  • Examine the heart, brain, liver, pancreas, extremities, spine, male and female reproductive organs, and other soft tissues

How does an MRI scan work?
An MRI scanner is a large, cylindrical (tube-shaped) machine that creates a strong magnetic field around the patient. Computers are then used to form two-dimensional images of a body structure or organ based on the activity of the hydrogen atoms. Cross-sectional views can also be obtained for more detail. An MRI does not use radiation.

Is an MRI for everyone?
If you have any of the following devices, you should not have an MRI scan.

  • Certain cardiac valves
  • Pacemaker
  • Aneurysm clips
  • Certain inner ear implants or metal fragments in one or both eyes

How should I prepare for an MRI procedure?
Most MRI exams do not require any special preparation. If there are any dietary restrictions, the staff at Houston Methodist will inform you of these when you schedule the exam. You may take all of your usual medications on the day of the exam.

Before your exam, be sure to inform your doctor, the MRI staff and Houston Methodist scheduling staff of any of the following conditions

  • You are breastfeeding, pregnant or think you might be pregnant.
  • You are claustrophobic and require sedation or pain medication prior to your exam. You must have a driver with you if you require sedation during the procedure.

What will I experience during the procedure?
Although every hospital has specific protocols in place, an MRI procedure generally follows the same process.

  • You will complete a safety questionnaire.
  • Remove all eye makeup, jewelry and metal objects such as hairpins and hearing aids. Although patients are given a locker for their belongings, it is recommended that you leave all valuables at home.
  • You will wear a hospital gown we provide during the procedure.
  • If a contrast medium is to be given intravenously, an intravenous (IV) line will be started in your hand or arm. The IV line will be used to inject contrast at the appropriate time.
  • An MRI technologist will position you on the padded exam table and you will be asked to lie as still as possible to avoid motion, which can cause blurred images.
  • During the scanning process, a loud knocking noise occurs. You will be given earplugs to wear to help block out the noise from the MRI scanner as well as headphones to hear any instructions given by the technologist. The MRI staff will have you in constant sight and audio speakers inside the scanner enable the staff to communicate with you at all times. You will also have a call bell so that you can make the staff aware if you experience any problem during the MRI examination.
  • For abdominal, cardiac or chest scans, you will be instructed to hold your breath for about 10 to 25 seconds (no longer than 30 seconds to avoid discomfort).

How long will the exam take?
A typical MRI exam takes 30 to 45 minutes, depending on the specific exam requested by your physician.
What is an ultrasound and is it safe?
Ultrasound is a diagnostic imaging technique that uses high frequency sound waves to obtain an image of specific organs functioning in the body. In most cases, a sonographer trained in ultrasound obtains and records the images required for diagnosis. The radiologist or physician reviews the images and then issues an official interpretation.

There are no known harmful effects associated with ultrasound imaging.

How should I prepare for the procedure?
Prior to your procedure, you will be informed of any preparation required for the exam. The type of exam will determine the required preparation. 

For the following upper abdominal studies, you will be required to have nothing by mouth at least six hours prior to the exam.

  • Abdominal
  • Abdominal doppler
  • Gallbladder
  • Pancreas
  • Renal doppler

For the following pelvic or lower abdominal ultrasounds, you will be asked to drink water prior to the exam to fill the bladder.

  • Pelvic sonograms (drink 40 ounces of water 45 minutes prior to study)
  • Obstetrical sonograms
  • Transrectal prostate exam — you will be asked to administer a Fleet-type enema at least one hour prior to the exam

What will I experience during the procedure?
During the procedure, you will lie down on an exam table and the sonographer will apply warm gel to the area being examined. They will then move a handheld transducer back and forth over the area to obtain specific images. You may be asked to move into different positions (lie on your side or sit up).

The exam time will vary between 15 minutes to one hour, depending on the test requested by your physician and the number of images ordered.

Afterwards, the radiologist will interpret the images and send a report with the test results to your physician, who will communicate the results to you.

Nuclear Medicine (PET/CT) FAQs
How does a PET procedure work?
PET is a nuclear medicine procedure that produces images of the body’s metabolic functions. As part of the PET study, you will also receive a CT scan, which improves the accuracy by providing excellent localization to any abnormalities seen on PET. The radiation exposure associated with PET is safe and lower than most conventional radiology examinations.

How do I make an appointment for a PET/CT exam?

  • Patients need to be scheduled at least 24 hours prior to an exam.
  • Approval from the nuclear medicine department must be received for “same day” PET/CT scans.
  • Your physician should fax a written order to the scheduling department or the Department of Nuclear Medicine.

How should I prepare for a PET/CT procedure?
Prior to your procedure, you will be informed of any preparation required for the exam. The type of exam will determine the required preparation.

The following are common guidelines for most patients having a PET/CT procedure.

  • Avoid drinking or eating anything four hours prior to your exam.
  • Inform your doctor of any prescribed medications you are taking. Most medications can be taken the day of the exam unless instructed differently by your physician.
  • Inform your physician if you are diabetic.
  • Avoid strenuous activity 12 hours prior to your test and engage in only minimal physical activity on the day of the exam.
  • Please dress warmly and in comfortable clothes, making sure to leave all valuables at home.
  • Plan to arrive 15 minutes before your scheduled exam. 

What will I experience during the PET/CT procedure?

Before the exam, an IV line will be started in your hand or arm and radioactive tracer will be injected. This tracer is a compound of complex sugars labeled with a short-lived radioisotope.

You will be asked to rest for approximately 45 to 60 minutes while the radioactive tracer travels throughout your body. During this time, you will need to refrain from talking, walking or chewing gum.

The technologist will then ask you to lie on the scanner table. The table slowly passes through the scanner. The PET scanner detects and records the signals the tracer emits, and then the signals are reassembled into actual images through the use of a computer. The images are processed and interpreted by the reading physician.

How long will the PET/CT exam take?
The exam usually takes at least two hours. The type of study being performed will determine the exact length of the exam.

Are there any after-effects of the exam?
There are no known side effects resulting from the injected tracer, so you should feel fine after your exam.

When and how will I receive my test results?
Your PET scan results will not be immediately available. Your physician will be contacted when the results are ready and will inform you of the test results.

CT Scan FAQs
How does a CT scan work?
A computed tomography (CT) scan is a precise, simple and safe examination that creates a cross-sectional image of a specific anatomical part of the body. A thin beam of X-rays is read and recorded by an electronic detector, then fed into a computer. The computer constructs an image based on the data, which then may be transferred to film. Contrast, a substance given intravenously or orally, is sometimes used to assist in viewing a particular area.

Is a CT scan for everyone?
While CT is an effective diagnostic tool, it may not be safe for people with certain medical conditions. Please inform your physician and the clinic personnel at the time of scheduling if any of the following conditions apply to you:

  • Pregnant or breast feeding
  • Kidney problems
  • Diabetes
  • Prior allergy to iodine, contrast media or shellfish

How should I prepare for a CT procedure?
On the evening prior to your procedure, a Houston Methodist staff member will call you to confirm your appointment and inform you of any specific instructions. In general, the following preparations should be made.

  • Inform your physician of any medical conditions listed above that may prevent you from having a CT.
  • Plan to arrive 30 minutes prior to your scheduled procedure time to complete paperwork and, if necessary, change clothes.
  • Wear loose-fitting clothes without zippers or snaps. Metal objects create artifacts on the images.
  • If contrast will be used, do not consume food or beverages four hours prior to the procedure.

What should I expect during the CT procedure?
While the CT procedure requires a few basic steps, some aspects of your procedure may vary depending on the type of exam.

You will be asked to lie on a table that is connected to the CT scanner, with the area of your body that is being examined positioned in the middle of a large, doughnut-shaped scanner ring or gantry. The ring is not enclosed, so claustrophobia is not an issue.

A technologist will be in constant communication with you during the procedure through a two-way intercom and will tell you what to do. You must remain still during the procedure as movement may cause the images to blur, resulting in portions of the exam to be repeated.

The table will move in small increments. You may feel this slight movement and hear a low noise. The noise is due to the rotation of the gantry. This is perfectly normal and should not cause concern.

How long will the CT procedure last?
The length of your CT exam will vary from 10 to 45 minutes depending on the specific examination requested by your physician.

Breast Imaging and Mammogram FAQs
Do I need an appointment?
A mammogram and other imaging department procedures require a written order from your physician and you must call ahead for an appointment. If you have this order, please be sure to bring it with you for your study. The physician’s office can also fax the order to us.

What is a screening mammogram?
A screening mammogram is an annual or baseline study for asymptomatic patients with no signs or personal diagnosis of breast cancer. The exam takes approximately 30 minutes. If the radiologist who interprets your films detects any change or concerns regarding your study, you will be contacted to schedule additional imaging.

If you receive a letter concerning additional imaging, but have not been contacted by phone, please call 713.798.4484 to schedule an appointment. There may be a three or four week wait for a diagnostic appointment. If you are asked to return, please do not be alarmed. Additional evaluation is not uncommon and most such findings are benign (non-cancerous).

What is a diagnostic mammogram?
A diagnostic mammogram is performed to diagnose specific symptoms or to further evaluate a change detected on a screening mammogram. The exam usually includes specialty views called spot magnification.

In some cases, an ultrasound may be requested for further evaluation. This test will be performed during the diagnostic mammogram if necessary. A diagnostic study may take 45 minutes to 2 hours. Each patient’s exam is customized to collect the images required by the radiologist to make a diagnosis.

You will receive a letter with your study results within 14 days and your physician will receive the complete report. Depending on the results, the radiologist may determine a need for further tests and recommend any of the following: breast MRI, stereotactic biopsy, ultrasound biopsy or cyst aspiration.

Any of these further studies will require an order from your physician. A nurse from our imaging department will contact you if a biopsy needs to be scheduled once the physician order is received.

What is a breast ultrasound?
A breast ultrasound helps your radiologist determine if a lump or a mass is filled with fluid or is solid tissue. Masses that are clearly filled with fluid are called cysts and are usually not cancerous. If a lump is thought to be solid, a biopsy will often be needed to make a final diagnosis. This is a painless procedure during which gel and a transducer are used on the breast.

What is a digital mammogram?
A digital mammogram takes an X-ray of the breast and captures it on a computer. Studies show that digital mammography is superior to conventional film mammography, especially for women with dense breasts.

How should I prepare for a mammogram?
  • If you have your physician’s order for the mammogram, please bring it with you.
  • Confirm that you are registered for your mammogram. If you do not receive a call from patient registration, call 713.394.6805 prior to the appointment.
  • Bring your driver’s license and insurance card for registration.
  • Do not wear deodorant, talcum powder or body powder on the day of your exam.
  • Do not wear unnecessary jewelry, such as large earrings and necklaces.
  • Bring or send any mammograms that you have had at a different facility.
  • Bring addresses and fax numbers of additional physicians who should receive the results, not including the physician who ordered the exam.
  • Wear a two-piece outfit, if possible.
  • Do not bring small children. Arrange for childcare during the time of your appointment.
  • If you have developed a breast problem or complaint since scheduling your appointment, call 713.798.4484 in order to reschedule your appointment.

What will I experience during a mammogram?
A mammogram involves compression. If you have sensitive breasts, avoid scheduling the mammogram during the week before your period when breasts are most sensitive. Your technologist will listen and work with you to find a tolerable degree of compression.


Our radiologists at Houston Methodist specialize in imaging and radiology at the following convenient locations.