Imbriaco et al used the Bone Scan Index (BSI) to quantify metastases to bone seen on a bone scan. The approach can also work for other bone imaging modalities.
bone scan index =
= SUM((percent of bone involved) * (percent of total bones represented by bone))
|
Bone |
Percent of Total By Weight |
|
skull without lower jaw |
16.6 |
|
lower jaw without teeth |
1.8 |
|
left clavicle |
0.5 |
|
right clavicle |
0.5 |
|
left scapula |
1.5 |
|
right scapula |
1.5 |
|
sternum |
0.3 |
|
left humerus |
3.3 |
|
right humerus |
3.3 |
|
left ulna |
1.5 |
|
right ulna |
1.5 |
|
left radius |
1.2 |
|
right radius |
1.2 |
|
left hand with wrist bones |
1.5 |
|
right hand with wrist bones |
1.5 |
|
ribs (all 24) |
4.4 |
|
spine and sacrum |
8.3 |
|
pelvis |
7.5 |
|
left femur |
8.9 |
|
right femur |
8.9 |
|
left tibia |
5.1 |
|
right tibia |
5.1 |
|
left fibula |
1.3 |
|
right fibula |
1.3 |
|
left foot bones |
5.8 |
|
right foot bones |
5.8 |
where:
• The data is from page 120 from Spiers FW. Radioisotopes in the Human Body: Physical and biological aspects. Academic Press. 1968.
• An alternative set of data is also given from pages 63, 85 and 90 from Ingalls NW. Observations on bone weights. Am J Anat. 1931; 48: 45-98.
Interpretation:
• minimum BSI: 0%
• maximum BSI: 100%
• The higher the BSI the more extensive the bone involvement.
Specialty: Hematology Oncology, Surgery, general
