Association of prostate-specific antigen levels and patterns of benign and malignant uptake detected. on bone scintigraphy in patients with newly diagnosed prostate carcinoma

The bone scan patterns of benign and malignant uptake in 432 patients with newly diagnosed prostate carcinoma were reviewed in relation to prostate-specific antigen (PSA) levels determined within 4 months of scintigraphy. Scan results were categorized in terms of likelihood of metastatic disease and anatomical locations of benign and malignant lesions were tabulated. At least one suspect focus was identified in 138 scans (32%), and metastatic bone disease was present in 38 (9%). Metastatic disease prevalence increased from 1% for PSA <20 ng x ml(-1) to 58% for PSA>100 ng x ml(-1). Among patients with PSA>20 ng x ml(-1) (n = 157), 70 (45%) had at least one bone scan finding of concern for metastases and 35 (22%) proved to have metastatic disease. Almost all scans with metastases had either limited disease (< or = 5 suspicious lesions; n = 16; 42%) or extensive metastases (> 20 abnormalities; n = 19; 50%). The majority of patients with limited skeletal metastases had PSA < 100 ng x ml(-1) (11/16; 69%), while almost all patients with extensive skeletal involvement had PSA >100 ng x ml(-1) (17/19; 89%). Among those with limited metastatic disease, most (13/16; 81%) had at least one lesion in the pelvis or sacrum; the next most common sites were in the thoracic and lumbar spine (six each; 38%). In scans with a low to moderate suspicion for bone metastases, the only anatomical site with a significantly higher prevalence of malignant than benign lesions was the pelvis.     

Enhanced uptake of 99Tcm-MDP in skeletal metastases from prostate cancer following initiation of hormone treatment: potential for increasing delivery of therapeutic agents.

Following androgen ablation therapy, skeletal metastases from prostate cancer appear in some instances to show an increase in 99Tcm-methylene diphosphonate (99Tcm-MDP) uptake. Such a phenomenon could represent a mechanism to increase delivery of bone-seeking therapeutic agents to skeletal metastatic sites. The aim of this study was to characterize more precisely the potential increase in 99Tcm-MDP in skeletal metastases from prostate cancer following initiation of hormone therapy. Baseline bone scans were performed within 1 week of onset of hormone therapy in patients with stage D2 prostate cancer followed by multiple repeat bone scans for up to 4-6 weeks. The count density within metastatic lesions was divided by the average count density from several areas of normal bone to obtain a lesion to normal bone uptake ratio (L/N) for each lesion in each scan. Altogether, 61 skeletal metastases were identified on bone scans from five subjects. Eighty-four percent (51/61) of these lesions showed an increase in 99Tcm-MDP activity relative to normal bone following initiation of hormone therapy with a mean peak increase of 39%. Thirty-nine of these 51 metastatic lesions showed maximum uptake at 3 weeks post-onset of hormone treatment. From our findings, it appears that approximately 3 weeks following initiation of hormone blockade, most skeletal metastases from prostate cancer will demonstrate significantly enhanced 99Tcm uptake relative to normal bone. Consequently, it may be possible to improve the uptake and effectiveness of therapeutic bone-seeking radiopharmaceuticals by administering these agents following hormone therapy in patients with prostate cancer metastases.     

Bone scans with one or two new abnormalities in cancer patients with no known metastases: frequency and serial scintigraphic behavior of benign and malignant lesions

Scintigraphic, radiologic, and clinical follow-up findings were reviewed in cases in which bone scans (n = 301) showed one or two new abnormalities in patients with malignancy but no known metastases. Metastatic disease was confirmed for 25 of 231 scans (11%) with one new abnormality and for 17 of 70 scans (24%) with two new abnormalities. The prevalence of metastases was 0.06 to 0.13 for lesions in all regions of the skeleton, except the sternum (three of six) and the pelvis (10 of 32). On follow-up scans, in the absence of an interval change in therapy, 19 of 21 metastases became more intense, whereas most benign abnormalities either remained unchanged (47%) or resolved (41%). Benign lesions in the ribs, extremities, and pelvis generally resolved within 12-24 months, while most benign skull and spine abnormalities were still apparent after 35-58 months of follow-up.     

24-Hour/4-hour ratio of technetium-99m methylene diphosphonate uptake in patients with bone metastases and degenerative bone changes

The uptake of [99mTc]MDP in metastatic lesions of the vertebrae was compared with the uptake in normal vertebrae. The ratio of these lesion-to-nonlesion uptakes at 4 and 24 hr was called the 24-hr/4-hr ratio (TF ratio). A similar ratio was measured for lesions in the spine due to degenerative bone disease. Lesions in vertebrae with degenerative bone disease and treated metastases had a significantly lower TF ratio than lesions in vertebrae with untreated bone metastases. These findings suggest that the TF ratio might be a reliable method for separating metastatic lesions from degenerative changes in the vertebral column, and could be especially useful in cancer patients whose bone scans demonstrate a single lesion in the spine.     

Evaluation of metastatic bone disease with pentavalent 99Tc(m)-dimercaptosuccinic acid: a comparison with whole-body scanning and 4/24 hour quantitation of vertebral lesions

The aim of this study was to establish the value of 99Tcm(V)-DMSA scintigraphy in the detection of metastatic bone lesions and compare the results to 99Tcm-MDP bone scintigraphy. Thirty-four patients presenting with metastatic bone disease (Group 1) and 12 controls with degenerative skeletal lesions (Group 2) were studied. Conventional bone scanning and 99Tcm(V)-DMSA whole-body scanning were performed on all patients. All scans were interpreted visually. Furthermore, lesion-to-normal bone ratios (L/N) in vertebral metastases on the 4 and 24 h bone scans were obtained in 58 lesions of cancer patients and in 23 benign (degenerative) vertebral lesions of the control group. 99Tcm-MDP L/N ratios at 24 h (3.08 +/- 0.32) were significantly higher than those at 4 h (2.48 +/- 0.24) in the malignant foci (P < 0.001). No significant difference was observed in benign lesions (P > 0.05). In 167 (164 metastatic, 3 traumatic) of 186 99Tcm-MDP positive lesions (90%) of Group 1, 99Tcm(V)-DMSA uptake was observed. The remaining 19 lesions (10%) were 99Tcm(V)-DMSA negative. Fourteen of these 19 sites were diagnosed as benign. The remaining five foci were malignant. In four lung cancer metastases showing no 99Tcm-MDP uptake, 99Tcm(V)-DMSA uptake was observed. There was no 99Tcm(V)-DMSA accumulation in any of the 99Tcm-MDP positive degenerative lesions of Group 2. All quantitatively evaluated (n = 42) vertebral metastatic foci and two compression fractures in Group 1 showed 99Tcm(V)-DMSA accumulation and an increased 99Tcm-MDP L/N ratio at 24 h. A total of 36 degenerative lesions (Groups 1 and 2) and one compression fracture (Group 1) showed neither 99Tcm(V)-DMSA uptake nor an increased 99Tcm-MDP L/N ratio at 24 h. Our results indicate that quantitative 4/24 h analysis of vertebral lesions on 99Tcm-MDP scans has a similar diagnostic value to 99Tcm(V)-DMSA imaging in the detection of bone metastases. However, the accumulation of 99Tcm(V)-DMSA in four lung cancer metastases showing no 99Tcm-MDP uptake is encouraging and justifies further research in patients with proven bone metastases and negative bone scans.     

(99m)Tc-MDP scintigraphic findings in children with leukemia: value of early and delayed whole-body imaging.

The purpose of this study was to reveal the bone scan abnormalities in children with leukemia and to show the value of whole-body scanning in early and delayed phases. METHODS: From a database of all patients with a diagnosis of leukemia from January 1990 to April 2000, 12 children (9 male, 3 female; mean age, 8.0 y; age range, 4.7--13.2 y) were identified for whom the diagnosis of leukemia was suggested on the basis of bone scans obtained as part of the initial work-up for unexplained skeletal pain. Early and delayed whole-body bone scans and radiographs were reviewed retrospectively. Areas of abnormal uptake on early and delayed phases were categorized into locations: metaphysis--diaphysis--epiphysis (MDE), pelvis, ribs, spine, and others. MDE lesions included abnormalities in the metaphysis extending into the diaphysis for some length: metaphysis/diaphysis, metaphysis only, diaphysis only, epiphysis only, and the entire bone. Pelvic and spine lesions were further characterized as focal or diffuse. RESULTS: Ten patients had lesions in 2 or more locations on both phases. Two patients had multiple lesions on the early scans but only rib lesions on the delayed scans. Lesions correlated with symptomatic sites in 8 patients on the delayed scans and in 11 patients on the early scans. The most common sites of abnormalities on the delayed scans were metaphyseal/diaphyseal, pelvis (focal), and ribs. The most common locations of lesions on the early scans were metaphyseal/diaphyseal, pelvis (diffuse or focal), and spine. More metaphyseal/diaphyseal lesions were seen on the early scans than on the delayed scans. Diffuse involvement of the pelvis and spine was seen only on the early phase. However, rib lesions were seen more frequently on the delayed scan. CONCLUSION: Early whole-body imaging in conjunction with delayed whole-body scanning may enhance the diagnostic accuracy of bone scanning in the evaluation of children with skeletal pain of obscure etiology, such as that associated with leukemia.     

The clinical utility of prostate-specific antigen and bone scintigraphy in prostate cancer follow-up.

To assess the value of serum prostate-specific antigen (PSA) in prostate cancer follow-up, we prospectively studied 107 consecutive patients with: (1) pathologically confirmed prostate cancer; (2) definitive prostatectomy and/or radiation therapy greater than or equal to 3 mo prior to bone scanning; and (3) one bone scan and serum PSA sampling within 3 mo of each other. The mean and range of patient follow-up since definitive therapy was 1.6 and 0.5-8 yr, respectively. Abnormal bone scans were correlated with pertinent radiographs. Of 107 bone scans, 16 demonstrated metastatic bone disease. A PSA value of less than or equal to 8 ng/ml excluded bone metastases with a predictive value of a negative test of 98.5%. Without radiographic correlation, abnormal bone scans rarely represented metastases if the PSA value was less than or equal to 8 ng/ml. In summary, serum PSA concentration determines the need for follow-up bone scanning and assists in scan interpretation in patients status post definitive therapy for prostate cancer.     

Bone scans with one or two new abnormalities in cancer patients with no known metastases: reliability of interpretation of initial correlative radiographs

To determine the reliability of radiographs obtained for correlation with bone scans showing one or two new abnormalities in cancer patients without known metastases, a retrospective study of 306 scans showing such lesions was performed. Overall, 14% of the lesions proved to be malignant. The initial radiographic interpretation was normal for 43% of the new bone scan lesions; 17% of these lesions were metastases. A benign process was identified on radiographs for 38% of the abnormalities; only one (1%) was a metastasis. Twelve percent of new bone scan lesions correlated with radiographic abnormalities considered either suggestive of or consistent with metastasis, of which 24% and 71%, respectively, proved to be metastases. In cancer patients with one or two new bone scan abnormalities, correlative radiographs showing a benign abnormality are reliable. However, if the radiographs are either normal or show findings considered suggestive of or consistent with metastasis, further evaluation or follow-up is warranted.     

Clinical value of including the head and lower extremities in 18F-FDG PET/CT imaging for patients with malignant melanoma

OBJECTIVE: To assess the added benefit of scanning lower extremities and skull in addition to 'skull base to upper thigh' images in PET/CT evaluation of metastatic melanoma. SUBJECTS/METHODS: Reports of consecutive whole-body PET/CT scans from January 2003 to March 2006 in patients with melanoma were retrospectively reviewed. PET abnormalities in the brain/scalp and lower extremities were tabulated by location and whether they were 'anticipated' or 'unanticipated' based on previously available data. Findings were correlated with pathology, other imaging studies, and clinical follow-up. RESULTS: Two hundred and ninety-six PET/CT examinations in 173 patients with melanoma were included. Twenty-five of the 296 (8.4%) scans showed brain/scalp abnormalities. Of these, only four (1.4% of all scans) showed unanticipated abnormalities: two were false positive findings, and two (0.7% of all scans) represented metastases in addition to multiple other metastases in the usual field of view. Fifty-nine of the 296 (19.9%) scans showed lower extremity abnormalities. Of these, 13 (4.4% of all scans) showed unanticipated abnormalities which were equivocal or suggestive of malignancy: eight (2.7% of all scans) represented metastases in addition to multiple other metastases in the usual field of view, and five represented false positive findings. In no case was an unanticipated isolated malignant lesion identified in the brain/scalp or lower extremities. CONCLUSIONS: In patients with no known or suspected primary or metastatic melanoma involving the head or extremities, inclusion of these regions on PET/CT is of low yield and appears to offer little significant additional benefit, as detection of additional metastases in these patients is unlikely to change clinical management. Routine skull base to upper thigh images may be adequate for this subset of patients with melanoma.     

Role of skeletal scintigraphy in advanced retinoblastomas

PURPOSE: To document the incidence of skeletal metastases exclusively in advanced cases of retinoblastoma and to rationalize the use of preoperative skeletal scintigraphy in such patients. MATERIAL AND METHODS: Preoperative bone scans of 36 consecutive patients with advanced retinoblastoma who underwent skeletal scintigraphy during 1998 to 2003 were analyzed retrospectively. Bone scans were classified as: Grade 1 (high probability scan for skeletal metastases), Grade 2 (equivocal malignant or benign abnormalities), or Grade 3 (normal or certainly benign lesions). RESULTS: Grade 1 scan was found in 3 (8.33%) patients; bone metastases were confirmed by additional investigations. Grade 2 scan was found in 5 (13.88%) patients; bone metastases were excluded in all by additional investigations. Grade 3 scan was found in the remaining 28 (77.77%) patients. Extraorbital extension of disease was demonstrated by fine needle aspiration of lymph nodes in five patients, which included all three patients with Grade 1 scan. In addition to lymph node metastases, two patients had intracranial extension of the disease; demonstrated by contrast-enhanced magnetic resonance imaging of the head. One patient had liver metastases detected on abdominal ultrasound. None of the patients had skeletal metastases only. CONCLUSION: Routine preoperative bone scan is not justified in patients with locally advanced retinoblastoma. Bone scan should only be performed in patients with documented extraocular metastatic disease.     

The radiotherapeutic effect on bone metastases in relation to the frequency of metastases, sites of metastases and histology of the primary tumor

In a retrospective study on 239 patients irradiated for osseous metastases in 578 different skeletal areas, the therapy effect was evaluated in dependence on the frequency of metastases, the sites of metastases, and the histology of the primary tumors. Furthermore the duration of improved findings was verified. The primary tumor was a mammary carcinoma in 186 patients, a bronchial carcinoma in 21 patients, a renal cell carcinoma in 20 patients, and a prostatic carcinoma in 12 patients. In patients with bronchial carcinoma the relief of pain by radiotherapy was not as good as in other tumor types. However, a significant correlation between subjective therapy effect and histology of the primary tumor was not demonstrated. Remineralization was found in 55% of all irradiated skeletal areas and an unchanged X-ray picture of bone metastases in 35%. A dependence of the objective therapy effect from the histology of the primary tumor was not statistically demonstrated (recalcification rate in mammary carcinoma 62%, in prostatic carcinoma 57%, in bronchial carcinoma 28%, and in renal cell carcinoma 11%). Significant differences of remineralization were found in solitary bone metastases (68%) and in multiple skeletal metastases (56%). A significant correlation between sites of metastases and objective irradiation effect was proved by the fact that osteolytic destructions of spine and pelvis showed a better remineralization than lesions situated in the extremities. The average duration of the objective, radiologically verified amelioration of findings was 16 months in patients with mammary carcinomas and 12 months in patients with prostatic carcinomas, bronchial carcinomas, and renal cell carcinomas.     

Bone and liver images in medullary carcinoma of the thyroid gland: concise communication

Thirty-four patients with surgically documented medullary carcinoma of the thyroid (MCT) and elevated serum calcitonin levels had Tc-99m phosphate bone and/or Tc-99m sulfur colloid liver images for suspected metastases. Liver images demonstrated metastatic lesions in nine of 32 patients (28%). Bone images were positive for metastases in eight of 30 patients (27%). Four of these eight abnormal bone studies detected only skeletal lesions, two demonstrated only extraosseous metastases, and two showed both kinds. Of 18 patients with both radionuclide bone studies and skeletal radiographs, four demonstrated skeletal metastases, and lesions were recognized on both examinations. This study demonstrates that radionuclide bone and liver images frequently detect metastatic lesions in patients with MCT and elevated serum calcitonin levels, and that some nonskeletal metastases in patients with this tumor display an unusual affinity for bone-seeking radiotracers.     

Early MR demonstration of spinal metastases in patients with normal radiographs and CT and radionuclide bone scans

Forty patients with known primary tumor and progressive back pain, suspected of having spinal metastatic disease, underwent magnetic resonance (MR) examinations of the thoracic and lumbosacral spine. Conventional radiographs and CT scans of the spine were all normal. The radionuclide bone scans were equivocal. In 21 patients focal or diffuse vertebral MR abnormalities were detected. In nine patients the lesions were hypointense on T1 sequence, and the same lesions were demonstrated poorly or not at all on T2 and proton density sequences. In eight other patients the bone marrow metastases presented with strong signal intensity on T2 and were poorly or not at all demonstrated on T1 and proton density sequences. In three patients with multiple myeloma, the signal intensity pattern of the vertebrae was diffusely heterogeneous, with alternating small foci of strong and weak signals (a mosaic-like pattern). Following the MR studies, needle biopsy confirmed the malignancy in the 21 patients who had shown abnormalities. No correlation between the type of primary tumor and the signal intensity of the vertebral metastases was shown. Possibly the mosaic pattern shown in three of the multiple myeloma patients represents a special case.     

Screening for bone metastases: whole-body MRI using a 32-channel system versus dual-modality PET-CT

The diagnostic accuracy of screening for bone metastases was evaluated using whole-body magnetic resonance imaging (WB-MRI) compared with combined fluorodeoxyglucose (FDG) positron emission tomography (PET) and computed tomography (CT) (FDG-PET-CT). In a prospective, blinded study, 30 consecutive patients (18 female, 12 male; 24–76 years) with different oncological diseases and suspected skeletal metastases underwent FDG-PET-CT as well as WB-MRI with the use of parallel imaging (PAT). With a 32-channel scanner, coronal imaging of the entire body and sagittal imaging of the complete spine was performed using T1-weighted and short tau inversion recovery (STIR) sequences in combination. PET-CT was conducted using a low-dose CT for attenuation correction, a PET-emission scan and diagnostic contrast-enhanced CT scan covering the thorax, abdomen and pelvis. Two radiologists read the MRI scans, another radiologist in combination with a nuclear medicine physician read the PET-CT scans, each in consensus. The standard of reference was constituted by radiological follow-up within at least 6 months. In 28 patients, 102 malignant and 25 benign bone lesions were detected and confirmed. WB-MRI showed a sensitivity of 94% (96/102), PET-CT exams achieved 78% (79/102; P<0.001). Specificities were 76% (19/25) for WB-MRI and 80% (20/25) for PET-CT (P>0.05). Diagnostic accuracy was 91% (115/127) and 78% (99/127; P<0.001), respectively. Cut-off size for the detection of malignant bone lesions was 2 mm for WB-MRI and 5 mm for PET-CT. WB-MRI revealed ten additional bone metastases due to the larger field of view. In conclusion, WB-MRI and FDG-PET-CT are robust imaging modalities for a systemic screening for metastatic bone disease. PAT allows WB-MRI bone marrow screening at high spatial resolution and with a diagnostic accuracy superior to PET-CT.     

Potential of (99m)Tc-MIBI for detecting bone marrow metastases.

In this study, we evaluated the potential of (99m)Tc-hexakis-2-methoxyisobutylisonitrile (MIBI) for detecting bone metastases in comparison with a conventional bone tracer. METHODS: (99m)Tc-MIBI and (99m)Tc-hydroxymethylene diphosphonate (HMDP) scans were obtained from 99 patients with proven malignant diseases and suspected bone metastases. We compared 373 lesions that showed abnormal uptake on (99m)Tc-MIBI scans or (99m)Tc-HMDP scans (or both). RESULTS: Bone metastases were confirmed in 334 of 373 lesions. Thirty-nine lesions on (99m)Tc-HMDP scans had false-positive findings, but only 2 of these lesions had false-positive findings on (99m)Tc-MIBI scans. (99m)Tc-MIBI and (99m)Tc-HMDP scans were equivalent in 168 of 334 lesions (50.3%). (99m)Tc-MIBI scans correctly detected more lesions than (99m)Tc-HMDP scans: 284 lesions (85.0%) versus 218 lesions (65.3%) (P < 0.005), respectively. (99m)Tc-MIBI scans showed a markedly higher sensitivity for detecting metastases in the femur and humerus compared with (99m)Tc-HMDP scans: 97 of 98 lesions (99.0%) versus 35 of 98 lesions (35.7%) (P < 0.005) and 21 of 22 lesions (95.5%) versus 11 of 22 lesions (50.0%) (P < 0.005), respectively. (99m)Tc-HMDP scans of 17 patients showed no abnormal images. However, (99m)Tc-MIBI scans correctly detected bone metastases, and subsequent development of multiple lesions was observed on follow-up (99m)Tc-HMDP scans of 15 patients. (99m)Tc-MIBI scans were superior to (99m)Tc-HMDP scans in the detection of metastases attributed to breast cancer, multiple myeloma, and hepatoma. On the contrary, (99m)Tc-MIBI scans were less sensitive than (99m)Tc-HMDP scans for detecting bone metastases attributed to prostate cancer in the other skeletal sites except for femur and humerus. CONCLUSION: (99m)Tc-MIBI scans have better sensitivity for detecting bone metastases and provide more specific complementary findings than conventional bone scans. (99m)Tc-MIBI accumulation attributed to bone marrow metastases may occur at an early stage, before the bone remodeling process in the surrounding bone can be detected on conventional bone scans.     

Intertrabecular vertebral metastases: metastases only detectable on MR imaging

Metastatic intertrabecular vertebral tumors that infiltrate the marrow space without trabecular bone alteration are not visible on radiographs or bone scans. To understand the clinical importance of intertrabecular metastases, their histological and radiological aspects were reviewed based on an examination using 69 cadavers. Metastatic tumors were found in 940 of 1653 vertebral bodies. Radiography of the specimen demonstrated lesions in 485 of 940 vertebral bodies (51.6%). Bone scintigraphy showed lesions in 109 of 415 vertebral bodies (26.3%) with tumors examined within 3 months before autopsy, whereas magnetic resonance (MR) images detected 132 of 146 (90.4%) lesions. The intertrabecular metastases were found in 36.9% of the metastatic lesions and was difficult to see on radiography (5.8%) and bone scans (3.3%) whereas MR images detected most of them (94.6%). The intertrabecular metastasis is the most common type of skeletal metastases and is only detectable on MR images.     

Metastases from malignant melanoma to the axial skeleton: a CT study of frequency and appearance

Radiologic detection of bone lesions from malignant melanoma is reported to be uncommon or infrequent. To ascertain the characteristics and frequency of detection of melanoma metastases to the axial skeleton by CT, we retrospectively reviewed 464 body CT studies of 125 consecutive melanoma patients for presence, appearance, and site of skeletal metastases. Results were correlated with patient's age, sex, clinical course, and both the Clark and Breslow classifications of the primary lesion. Of 98 patients with metastatic disease evident on their CT studies, 17 (17%) had bony metastases; two (12%) of these 17 patients had skeletal lesions as the only CT evidence of metastatic disease. Metastatic bony lesions were predominantly osteolytic, slightly expansile, and commonly located in the spine. Associated soft-tissue masses were frequent, but periosteal reaction and identifiable tumor matrix were not seen. Skeletal metastases were found only in those patients with thick or intermediate primary melanoma (Breslow) classified as Clark level III or greater, and the CT demonstration of osseous metastases was a poor prognostic sign. The data suggest that CT detection of skeletal melanoma metastases is not uncommon. When CT is performed to evaluate for metastatic melanoma, the axial skeleton should be carefully examined, especially in those patients with more advanced primary lesions.     

The benefit of SPECT when added to planar scintigraphy in patients with bone metastases in the spine.

PURPOSE: This study compared the efficiency of SPECT with planar bone scans in differentiating malignant from benign lesions and in detecting metastases to the spine. METHODS: Planar scintigraphy and SPECT were performed in 37 patients with low back pain without known malignancy and in 38 patients with confirmed malignancy. The type, location, and intensity of tracer accumulation were compared on the planar and SPECT scans. The malignant or benign nature of lesions was proved by radiologic methods, histologic findings, 6 month follow-up, or all of these. RESULTS: More metastases were detected by SPECT (SPECT, 58 of 64; planar, 42 of 64; P < 0.01). In three of seven patients with known malignancy who had a normal result of planar scan, only SPECT detected metastases. Fifty-nine metastases were radiologically mainly osteolytic, one was osteoblastic and four were mixed. Most lesions showed increased radioactivity (40 of 42 on planar scans vs. 45 of 58 on SPECT) and 2 of 42 (5%) vs. 12 of 58 (21%) were cold with marginally increased uptake. One of 58 metastases was a cold lesion seen on SPECT only. Lesions were more often malignant than benign when seen on SPECT in a pedicle (n = 5; malignant = 3, benign = 2), in the body and pedicle (n = 22; malignant = 14, benign = 8), within the vertebral body (n = 5; malignant = 4, benign = 1) and in the whole vertebra (n = 6; malignant = 4, benign = 2). The lesion to background ratio was higher on SPECT than on planar scans (SPECT, 2.26; planar scans, 1.86; P < 0.05 in malignant lesions). CONCLUSIONS: SPECT of the spine improved the diagnostic accuracy of bone scans when added to a planar scan in patients with known malignancy and clinical suspicion of spinal metastases when the planar scan was borderline abnormal. It helps in differentiating between benign and malignant lesions of the spine.     

^99mTc（V）—DMSA骨显像诊断骨转移瘤的临床价值

目的：评价99mTc（V）－DMSA显像在骨转移瘤诊断中的意义。材料和方法：对91例疑骨转移瘤患者行99mTc（V）DMSA全身显像，并与99mTc-MDP全身骨显像及其它检查对比。结果：74例证实存在骨转移瘤者，99mTc．MDP骨显像均显示异常放射性浓聚，99mTc（V）-DMSA显像72例显示了与99mTc-MDP显像某些相同部位的放射性浓聚，2例99mTc（V）DMSA显像阴性。17例骨良性病变，99mTc－MDP骨显像显示轻度异常放射性浓聚，而99mTc（V）-DMSA显像却未见异常的放射性浓聚。结论：99mTc（V）－DMSA诊断骨转移瘤的特异性比99mTc-MDP骨显像高，在骨良恶性肿瘤鉴别诊断中具有重要的临床价值。     

Comparison of FDG-PET and Bone Scans for Detecting Skeletal Metastases in Patients with Non-small Cell Lung Cancer

Purpose: Positron Emission Tomography (PET) with F18-fluorodeoxyglucose has been proven useful for staging non-small cell lung cancer. Bone scans are frequently performed for suspected skeletal metastases. The purpose of this study was to evaluate if bone scans compared to PET scans provide additional information that changes the stage of disease.Procedures: Nineteen patients with non-small cell lung cancer had PET and bone scans done for staging of the malignancy. The results of both studies were compared.Results: Bone and PET scans agreed on the presence or absence of skeletal metastases in all nineteen patients. The addition of a bone scan to a PET scan did not change the stage of the disease or the management in any of the patients. Bone scans allowed for more precise localization of the lesions in some patients.Conclusions: Bone scans do not change the stage of disease when performed in addition to PET scans, but provide more precise localization of skeletal abnormalities.