Ligma Bones
How much of the bone is inorganic?
45%
How much of the bone is H2O?
20-30%
How much of the bone is organic?
30%
what are some questions to ask about patient history?
- Hx of fractures and/or trauma - Hx current symptoms - Hx of recent nuc med scans - Hx of therapies or surgeries - Hx of renal abnormalities
factors determining uptake
- bone remodeling - growth - capillary and membrane permeability
what are the steps of a normal bone scan?
- confirm patient and explain exam - inject 20-30 mCi of RPx (mark injection site) - wait 2-3 hours - make sure patient urinates - make sure they remove metal and things from pockets - whole body scan or SPECT scan - static images of oblique views of head and chest
what are the steps of a three-phase bone scan
- confirm patient explain exam - inject 20-30 mCi RPx - acquire blood flow image (dynamic video) - pooling image (static) - wait 2-3 hrs delayed tissue image (static) - optional whole body scan
what are causes of superscans?
- metastatic disease - pagets disease - hyperparathyroidism - osteomalacia
what is fibrous dysplasia?
- overgrown fibrous tissue - sites of increased uptake
what are the steps of bone marrow imaging
-explain patient procedure and confirm patient -inject Tc sulfur colloid (specific uptake in only bone marrow) -wait 5-10 minutes -take static image of bone marrow (should show displacement if there is an infection)
how does cellulitis present itself in a bone scan?
-increased uptake in soft tissue -only shows up in the first two images of a three phase bone scan
How does avascular necrosis present itself in a bone scan?
-should see a cold center of bone surrounded by increased uptake - may not show up on x-ray for up to 6 months
what is metastatic disease?
a form of late stage cancer that has the original cancer site plus multiple mets throughout the body
how would a fracture present itself in a bone scan?
a single hot spot of increased uptake that can show for up to 2 years
what is loosening
an issue with a prosthetic where is starts to move around and rub against the bones causing damage
what is hyperostosis frontalis interna?
bilateral increase in activity in the frontal skull; most common in bitches
what is the critical organ for bone scans?
bladder
what is the purpose of osteoblasts?
bone formation
what is shoulder-hand syndrome
burning pain, stiffness in hand, sensitivity to cold (do not know what it is caused by)
what causes arthritis?
cartilage wears down from aging
what causes Paget's disease?
caused by the excessive breakdown and formation of bone
how does HPO present on bone scan
center of bone is cold and outside is hot
what is diabetic feet?
disease due to chronic effects of diabetes
What is osteomyelitis?
disease in bone and soft tissue
what is cellulitis?
disease in tissue or muscle
how do diabetic feet present itself in bone scans?
feet and toes present as hot in all three phases of bone scans (hot dogs)
how does Legg-perthes present itself in a scan?
growth plates appear cold
what is HPO
healing of the cortical surface of the bone; common in long bones only
what does HPO stand for
hypertrophic pulmonary osteoarthropathy
how does hyperostosis frontalis interna appear in a bone scan?
increased activity in the frontal skull (dark)
how does shoulder-hand present
increased uptake in extremities
how does arthritis present itself in a bone scan?
increased uptake in joints
what is MDP?
known as medronate; a less expensive RPx of Tc99m
what is HDP?
known as oxidronate; cheaper, clears from the blood faster, more uptake; most commonly used
what is a superscan?
little tissue uptake, no renal activity, and early uptake in bones
what are osteocytes?
mature bone cells
how would metastatic disease present itself in a bone scan?
multiple hot spots in bones; most are in the axial skeleton (80%)
how does loosening show up on 3 phase-scans
normal flow and pool imaging increased uptake on delays
What causes avascular necrosis?
occurs as a result of fractures, metabolic disorders, and embolisms
how does Paget's disease present itself in a scan?
presents whole bones as hot; bow-legged
what is Legg-perthes disease?
problems with blood supply to the femoral epiphysis that leads to bone necrosis
What is TNT (target to non-target) for?
ratio of RPx uptake in bone to blood
how does osteomyelitis present itself in a bone scan?
shows up hot in all three phases of the bone scan
what does TNT stand for?
target to non-target ratio
what is the purpose of osteoclasts?
to break down bone
why would we use gallium to look at diabetic feet?
to show the presence of infection in toes
how does fibrous dysplasia present itself in a bone scan?
usually has lesions on the skull, face, and long bones
