Which Cancer Scan is Best?

Thyroid cancer can spread to the bones but the right scan may catch it

/ Author:  / Reviewed by: Joseph V. Madia, MD

(RxWiki News) With cancer, catching its growth early is always best. Accurate diagnostic tools like scans can mean the difference between catching or missing cancer and whether or not the cancer has spread.

A recent study tested three different types of scans to see if thyroid cancer had spread to bone.

This study’s findings suggest two of the three tests should be used together and that one test should no longer be used at all.

"Diagnostic test options? Speak with an oncologist."

Z.L. Qiu, MD, from the Department of Nuclear Medicine at the Shanghai Sixth People’s Hospital and Shanghai Jiao Tong University in China, worked with an investigative team to determine the best scans.

Differentiated thyroid cancer can sometimes spread to the bones.

For this study, researchers tested three different types of body scans to detect whether or not thyroid cancer had spread to the bones.

1) Tc-MDP-planar bone scintigraphy is a body scan focusing on the skeleton. For the scan, patients are injected with a radioactive dye, which makes it possible to see if any cancer has spread to the bone.

2) I single-photon emission computed tomography/computed tomography (I-SPECT/CT) is another type of scan using gamma rays for a 3-dimensional view of the thyroid cancer and surrounding bone.

3) F-fluorodeoxyglucose positron emission tomography/ computed tomography (F-FDG)-PET/CT) uses a glucose injection to make cancer visible in this 3-dimensional scan.

The study group consisted of 80 thyroid cancer patients with a total of 148 thyroid cancer spots. Forty-three of the patients had 106 spots already positively diagnosed as having spread to the bone going into the study.

There were five measures by which each scan was rated in its ability to detect thyroid cancer spreading to the bones:

  1. How sensitive was the scan? 
  2. How specific was the scan? 
  3. The scan’s ability to predict the presence of spreading cancer.
  4. The scan’s ability to predict the lack of presence of spreading cancer.
  5. The scan’s diagnostic accuracy.

Results were as follows for patient-based analysis:

  • For the Tc-MDP-BS scan: 1) 79 percent, 2) 84 percent, 3) 85 percent, 4) 77 percent and 5) 81 percent
  • For the I-SPECT/CT scan: 1) 93 percent, 2) 97 percent, 3) 98 percent, 4) 92 percent and 5) 95 percent
  • For the F-FDG-PET/CT scan: 1) 86 percent, 2) 95 percent, 3) 95 percent, 4) 85 percent and 5) 88 percent

Authors concluded the combination of I-SPECT/CT and F-FDG-PET/CT scans were the best diagnostic method. Researchers recommended no longer using Tc-MDP-BS at all, or F-FDG-PET/CT by itself.

Using the right scan helps doctors design the best treatment plans.

This study was published in November in Nuclear Medicine Communications.

No financial information was given. No conflicts of interest were reported.

Reviewed by: 
Review Date: 
November 2, 2012
Last Updated:
November 6, 2012