Computed tomography: Commonly known as a CT or CAT scan, this test uses a rotating x-ray beam to create a series of pictures of your body from many angles. A computer combines the information from all these pictures to produce detailed cross-sectional images.

Usually a contrast agent is introduced into the body via a drink, injection into a vein and perhaps into the rectum. This enables the radiologist to more precisely determine structures.  While a BS only sees bone, CT scans see everything - bone and soft tissues.  CT Scans thus provide insight into the possible invasion of cancer into organs such as the lymph nodes, lung, liver, adrenal glands or elsewhere and can provide additional information related to sites showing up on a BS.  The areas most often scanned include the upper pelvic region, pelvis and lower pelvis -- this covers the lower lungs to the upper thighs.  Sometimes the head is also included if there is suspicion of metastases in that area.  

The CT is a necessary companion test with the bone scan - it is possible to schedule these for the same day with the IV line being used for the BS radiopharmaceutical and for the venous contrast solution with the CT.

Websites with more detail on CT Scans are:

• The CT Scan - What to Expect (from Cancer.net).

• Computed CT - Questions and Answers (NCI)

• Interactive Tutorials: CT Scan (MedlinePlus, National Library of Medicine, National Institues of Health.

• What a CT Scan is, how done, how to prepare for a CT (Mayo Clinic).
   

Always obtain a copy of the written report for your personal records.

Suggested interval for HRPCa patients: every 6 months.

Magnetic Resonance Imaging Scan (MRI)

Instead of X-Rays, the MRI uses a strong magnetic field and radiofrequency waves to produce computer-generated pictures of internal organs. The pictures look very similar to those of a CT scan, but are generally more detailed. There may nor may not be any contrast used during an MRI, though less contrast is required for an MRI than a CT scan.

Be aware that an MRI is more expensive, there is a lot of noise while the machine is running and you may experience claustrophobia due to the closeness of the tunnel you are in during the scan. You may be given ear plugs to block out most of the noise.

http://www.radiologyinfo.org/content/mr_of_the_body.htm

Your oncologist can recommend whether a CT or MRI Scan is needed.

Positron emission tomography(PET imaging or PET Scan ).

PET scanning is one of the newer imaging techniques. It does not use X-rays, but does involve radioactive material. PET scans are used most often to detect cancer and to examine the effects of cancer therapy by characterizing biochemical changes in the cancer. The scanners use photomultiplier-scintillator detectors to detect the gamma rays given off by the collision of a positron and and an electron and a computer takes it from there to form the image/map of the area where the radioactive substance had accumulated (in the tumor.)

It is not often used for prostate cancer but there have been a number of clinical trials run to determine if more use is warranted. One trial published in 2002 on 11C-Choline showed it to be a good substance to be used with the scanner. Visualization of Prostate Cancer with 11C-Choline Positron Emission Tomography. de Jong et al Eur Urol 2002 Jul;42(1):18-23. The conclusion of this study was that 11C-Choline is well taken up by primary tumors and lymph nodes with little urinary radioactivity.

The following articles are helpful to understand PET.

PET Scan - What to expect (from Cancer.net)

Cancer.net also lists the following websites:

A particularly sensitive technique for detecting bone metastases is the 18F-Fluoride PET/CT. This combination scan is performed on the same machine at the same time. See the article at cancer.net - Integrated PET/CT Scan - What to Expect

Even-Sapir E, Metser U, Mishani E, et al: The detection of bone metastases in patients with high-risk prostate cancer: 99mTc-MDP Planar bone scintigraphy, single- and multi-field-of-view SPECT, 18F-Fluoride PET, and 18F-Fluoride PET/CT. J Nucl Med. 47:287-297, 2006. PMID 16455635.

ProstaScint™ Monoclonal Antibody Scan (111 In-CYT-356)

The Prostascint scan may prove useful in the staging of prostate cancer prior to any local therapy. It involves the use of an Indium-111 labeled monoclonal antibody which reacts with prostate cancer, benign prostatic hypertrophy and to a lesser extent, normal prostate tissue. An abnormal scan may detect metastatic prostate cancer to lymph nodes or other sites and identify patients who are not candidates for local therapy. It may also prove valuable in assessing patients who have a PSA elevation after RRP. If an abnormal Prostascint scan is found confined to the prostatic bed it may support the rationale for local radiation therapy.  Note: sometimes having a ProstaScint scan may disqualify you for clinical trials involving other monoclonal antibodies. The Cytogen corporation manufacturers ProstaScint Kits -- the full prescribing information is at http://www.cytogen.com/professional/prostascint/pi.php

You should also make sure whoever is doing the test/interpretation is very experienced.  A newer emerging technique is the ProstaScint/CT or MRI fusion.  The Prostate Cancer Research Institute's "Update on ProstaScint®: CT and MRI Fusion as Diagnostic Tools."

The American Cancer Website has brief descriptions of the following two diagnostic tests.

X-rays

During diagnosis and evaluation of a cancer, a chest x-ray and bone x-rays may be obtained. These may show a mass in the chest or evidence of the cancer's invasion of the bone. But they are not useful in finding out what type of cancer is present or in what organ it started.

Ultrasound

Sound waves (like sonar) are used to produce images of internal organs. It can help to show masses in some organs that might be due to metastatic cancer. There are both black and white and color doppler ultrasound instruments.

Author: Howard Hansen 2/6/07; updated 4 April 2008 and 31 December 2008