**3.3 Benign bone tumors**

 Skeletal imaging is highly sensitive for detecting osteoid osteomas (Figure 9), which can be difficult to find by standard radiography, especially in the spine.

Fig. 9. Three phase bone scan (bottom row) of a 13 years old boy with history of pain and swelling in the right shin. The swelling was localized to the mid shaft of right tibia. Plain x-ray revealed a large area of sclerosis in the mid shaft of right tibia. Bone scan showed normal blood flow phase, high soft tissue uptake in the blood pool phase and a double density hot lesion in delayed image over the mid-shaft of right tibia. Surgical excision of the tumor resulted in total relief of symptoms. Histology confirmed the diagnosis of osteoid osteomas.

Fig. 8. Multiple myeloma, showed multiple focal accumulation of radioactivity in bone.

Fig. 9. Three phase bone scan (bottom row) of a 13 years old boy with history of pain and swelling in the right shin. The swelling was localized to the mid shaft of right tibia. Plain x-ray revealed a large area of sclerosis in the mid shaft of right tibia. Bone scan showed normal blood flow phase, high soft tissue uptake in the blood pool phase and a double density hot lesion in delayed image over the mid-shaft of right tibia. Surgical excision of the tumor resulted in total relief of symptoms. Histology confirmed the diagnosis of osteoid osteomas.

difficult to find by standard radiography, especially in the spine.

Skeletal imaging is highly sensitive for detecting osteoid osteomas (Figure 9), which can be

**3.3 Benign bone tumors** 

#### **3.4 Trauma and athletic injuries**

Skeletal trauma is common and presents both an opportunity and a problem in skeletal scintigraphy. As we known, the first choice for suspected bone fracture is radiography, which shows the fracture line and type clearly. But SPECT bone imaging has its own advantages in some aspects. SPECT is a useful adjunct in the course of process such as stress fracture. Normal bone is constantly remodelling, bone resorption and deposition are balanced. When the skeleton is placed under stress the rate of remodelling increases, and that will result in change of activity in bone scintigraphy,

The time a fracture takes to return to normal scintigraphically depends primarily on its location and the degree of damage to the skeleton.

Fig. 10. Occult fracture of the left foot 4th toe, which can not be detected by radiography.

#### **3.5 Osteomyelitis**

In addition to being used in the evaluation of malignant disease involving the skeleton, radionuclide bone imaging is helpful in the assessment of several other non-malignant processes, such as patients with suspected osteomyelitis and diskitis. Acute hematogenous osteomyelitis typically begins by seeding of the infectious organism in the marrow space.

A three-phase bone scan is performed by acquiring a rapid blood flow sequence of images over the interested area during agent injection. Early images (blood flow phase) are important in evaluating inflammatory processes. Flow images are performed 40 to 60sec and 2 to 4 sec for each frame. Blood pool images are then immediately obtained for totally 300 to 500 kcounts without moving the patient, and delayed images are taken as necessary. Both osteomyelitis and cellutitis can cause early increased radioactivity accumulation due to an increased vascular response to the affected area. The third phase is routine scanning at 2 to 3 hr after injection. Sometimes there will be a forth phase that can be added 24hr delay. Osteomyelitis demonstrates focally increased activity in the involved bone on both the blood-pool and routine images (Figure 11). Since the use of bone imaging for detecting osteomyelitis, it has been found that several patients do not subsequently develop the typical radiographic changes because the early treatment prevents the development of radiographic abnormalities.

Skeleton System 301

skeleton-to-soft tissue ratio and faint or absent visualization of the kidneys. Increased skull activity, involvement of the long bones of the extremities, and increased periarticular uptake are features that distinguish scan in these conditions from the supers can of metabolic

Non-invasive imaging techniques have been used in the past for visualization the functional activity of the bone marrow compartment. Imaging with radiolabelled compounds may allow different bone marrow disorders to be distinguished. These imaging techniques, almost all of which use radiolabelled tracers, such as 99mTc-nanocolloid, 99mTc-sulphur colloid (99mTc-SC), 111In-chloride, and radiolabelled white blood cells (99mTc-WBC), have been used in nuclear medicine for several decades. The results support that the

Metastatic bone cancer is a common complication of malignant tumor. It is reported that 20%-75% of cancer patients has developed bone metastases according to necropsy results. Malignant bone pain is still a challenging clinical problem. Pain due to bone metastases will greatly decrease the patient's quality-of-life because of patient's gradual deterioration, local body dysfunction, and mental and physical collapse. Recently, there are several reports on therapy of painful bone metastases by radiotherapy or anticancer drugs showing therapeutic efficacy. The studies, however, were generally heterogeneous trials involving stage of diagnosis, radiopharmaceuticals dosage, combination with other therapeutic modalities and methods of pain assessment. In addition, there are few reports on the study of comparison of radionuclide therapy with chemotherapy for evaluating the therapeutic

Radionuclide internal-radiation therapy of severe bone pain due to multiple skeletal metastases has recently achieved successful stage in nuclear medicine, which has been much considered and widespread used. In this chapter we described the principle of treatment of painful disseminated skeletal metastases, therapeutic approaches, evaluation of effective treatment according to our clinical experience in routine clinical treatment and its future

89Sr-chloride (Metastron) has been approved by the FDA for relief of bone pain in cases of painful skeletal metastases. The compound behaves biologically like calcium and localizes in hydroxyapatite crystal by ion exchange. Strontium uptake occurs preferentially at sites of active osteogenesis. This allows primary bone tumors and areas of metastatic involvement to accumulate significantly higher concentrations of strontium than surrounding normal bone. 89Sr decays by beta- emission with a half life of 50.6 days. The conventional dose of 89Sr-chloride is 148 MBq (4mCi), and can be reinjection after three months if necessary.

Another two radiotherapeutic agents, 186Re-HEDP and 153Sm-EDTMP are also used in the area. 186Re decays by beta- and gamma emission with a half life of 90.6 hr and 153Sm decays by beta- emission and has a half life of 46.3 hr. Both of these beta-emitting radionuclides are complex with bone-seeking ligands, which localize by chemisorption. The duration of

radiolabelled agents can be alternatives to bone marrow scan.

effectiveness of the patients with painful bone metastases.

Before administration, a blood regulation test should be checked.

**4.1 Radionuclide internal-radiation therapy** 

applications.

**4. Radionuclide therapy of skeletal tumors** 

disease.

**3.7 Bone marrow disorders** 

Fig. 11. Plantar view flow image show increased perfusion to the right proximal tibia. Bloodpool image also demonstrate abnormal accumulation in the same area. Delayed image have persistent radiopharmaceutical collection consistent with osteomyelitis. Focal hyerperfusion, focal hyperemia, and focally increased bony activity in the proximal right tibial metaphysic are the classic findings of osteomyelitis.

### **3.6 Metabolic bone diseases**

A number of metabolic conditions can result in marked abnormalities on bone imaging. Although these do not represent important clinical indications for bone imaging, they may be encountered incidentally in other applications, most importantly during metabolic skeletal survey. Hyperthyroidism, primary hyperparathyroidism, renal osteodystrophy, osteomalacia, and hypervitaminosis D all can result in generalized increased tracer uptake throughout the skeleton that has some features in common with the "supers can" seen in metabolic disease(Figure 12). These features are described before, such as increased

Fig. 12. Supers can in metabolic disease from the patient with hyperparathyroidism

Fig. 11. Plantar view flow image show increased perfusion to the right proximal tibia. Bloodpool image also demonstrate abnormal accumulation in the same area. Delayed image have persistent radiopharmaceutical collection consistent with osteomyelitis. Focal hyerperfusion, focal hyperemia, and focally increased bony activity in the proximal right tibial metaphysic

A number of metabolic conditions can result in marked abnormalities on bone imaging. Although these do not represent important clinical indications for bone imaging, they may be encountered incidentally in other applications, most importantly during metabolic skeletal survey. Hyperthyroidism, primary hyperparathyroidism, renal osteodystrophy, osteomalacia, and hypervitaminosis D all can result in generalized increased tracer uptake throughout the skeleton that has some features in common with the "supers can" seen in metabolic disease(Figure 12). These features are described before, such as increased

Fig. 12. Supers can in metabolic disease from the patient with hyperparathyroidism

are the classic findings of osteomyelitis.

**3.6 Metabolic bone diseases** 

skeleton-to-soft tissue ratio and faint or absent visualization of the kidneys. Increased skull activity, involvement of the long bones of the extremities, and increased periarticular uptake are features that distinguish scan in these conditions from the supers can of metabolic disease.
