Radionuclide Bone Scan Research Articles

Imaging of Infectious Arthritis

In general, infectious arthritis can be subclassified into two types 31 : pyogenic (septic) and nonpyogenic. Pyogenic arthritis is most commonly caused by Staphylococcus aureus , Neisseria gonorrhoeae , Klebsiella pneumoniae , Candida albicans , and Serratia marcescens . 33 Among the nonpyogenic arthritides are tuberculous arthritis 29,36 and infections caused by fungi, including actinomycosis, cryptococcosis, coccidioidomycosis, 2,38 histoplasmosis, and sporotrichosis. 33 Nonpyogenic arthritis can also be caused by viruses, such as smallpox, and by spirochetes, such as those responsible for syphilis and yaws. 33 In young children (less than 5 years), Haemophilus influenzae is a frequent cause of septic arthritis. 32 Infectious agents may enter the joint by directly invading the synovial membrane, either by a penetrating wound or after surgery for joint replacement. Entry to the joint can also be secondary to an infection of the adjacent soft tissues or to a blood-borne infection. 18,32 Finally, a focus of osteomyelitis in adjacent bone can also lead to infectious arthritis. A number of imaging techniques are available for diagnosis and evaluation of infectious processes that affect the joints. Although the introduction of MR imaging constituted a revolutionary change in the evaluation of musculoskeletal infections, 6 it did not diminish the role of such conventional techniques as radiography and scintigraphy. 20 Conventional radiography is still a basic diagnostic tool and should always be available when other imaging studies are analyzed. 7,14,31 The ability to diagnose infectious processes has been greatly enhanced by new approaches to radionuclide bone scanning, particularly the use of new radiopharmaceutical agents such as indium 111–labeled autologous white blood cells, 10,21 technetium 99m hexamethylpropylene-amino-oxime, 13 radiolabeled human polyclonal IgG 9 indium 111– or technetium 99m–labeled chemotactic peptide analogues, 12 or immunoscintigraphy with technetium 99m–labeled antigranulocyte monoclonal antibodies. 16 Also of value are other more effective modalities, which are discussed later. It must be stressed, however, that when there is a clinical suspicion of infectious arthritis, particularly septic arthritis, the most rapid approach to final diagnosis, and to avoid irreversible osseous and articular sequelae, is to perform a joint aspiration. 26,37

Insufficiency fractures of the sacrum

Insufficiency fractures of the sacrum are not uncommon. Shared imaging features on radionuclide bone scan, CT, and MR images include linear vertical abnormalities, and unilateral or bilateral distribution. This pattern may be considered sufficiently characteristic to allow a confident correct diagnosis to be made. Radiologists need to have a greater awareness of this condition.

Prognostic significance of the number of bone scan abnormalities at the time of initial bone metastatic recurrence in breast carcinoma.

To gain insight into the factors that contribute to the more favorable prognosis associated with recurrence limited to bone in patients with breast carcinoma, the authors analyzed the number of sites of initial involvement identified on radionuclide bone scans in relation to long term outcome. Records of 641 patients with clinical Stage I-III breast carcinoma that originally was diagnosed in 1974-1985 were reviewed. During follow-up, 295 patients (46%) experienced distant recurrence, including 116 with bone as the sole initial site of metastatic disease. Radionuclide bone scans identified the initial site(s) of recurrence in 113 of these latter 116 patients, and these studies were categorized by the number of skeletal lesions subsequently confirmed as metastases (1, 2, or > or = 3). Survival from time of recurrence and time of original diagnosis was analyzed using Kaplan-Meier methods, and factors associated with recurrence and mortality were examined using logistic and Cox regression. Median survival from time of recurrence was 35 months in the patients with bone-only metastases, compared with 11-26 months for all other sites of visceral recurrence exclusive of bone. Number of positive lymph nodes and estrogen receptor status were the only predictive variables for recurrence. Median survival from time of recurrence and time of original diagnosis for the 3 bone scan categories was: 1 lesion (n = 47), 53 and 86 months; 2 lesions (n = 22), 38 and 68 months; and > or = 3 lesions (n = 44), 22 and 58 months (P < 0.0001 and P < 0.005 for 1 and 2 lesions vs. > or = 3). In the "bone-only" group, the number of scan lesions was the strongest predictor of length of survival. Patients with breast carcinoma who experience a recurrence in bone at only one or two sites initially have a survival advantage over those with more extensive (> or = 3 sites) skeletal metastases and those with metastatic disease involving other visceral organs.

Spinal epidural abscesses in children: a 15-year experience and review of the literature.

We reviewed medical records and laboratory and diagnostic evaluations for 8 pediatric patients with spinal epidural abscesses who were treated during the last 15 years at our institution. Staphylococcus aureus was isolated from 5 of 8 epidural abscesses, including 2 abscesses with methicillin-resistant S. aureus. Unusual isolates were group B Streptococcus in a patient with chronic vesicouretral reflux associated with the posterior urethral valves and Aspergillus flavus in a patient with acute myelogenous leukemia. An analysis incorporating our results and a review of the English-language literature about abscesses in children and adults revealed differences related to age. Abscesses in children were more posterior in epidural location, had greater spinal column extension, and were associated with more favorable clinical outcomes than were abscesses in adults. Magnetic resonance imaging is the diagnostic procedure of choice; however, radionuclide bone scans should be considered for associated distant osteomyelitis in children. Prompt diagnosis and combined medical and surgical treatment remain the cornerstones for the prevention of adverse outcomes.

Peripheral nerve injuries during cardiac surgery: risk factors, diagnosis, prognosis, and prevention.

Neuropathies involving the brachial plexus, phrenic, recurrent laryngeal, and saphenous nerves, as well as the sympathetic chain are complications of cardiac surgery. The reported frequency of nerve injuries varies from 1.5% to 24% for the brachial plexus and 10% to 60",,6 for the phrenic nerve (1-5). Neuropathies of the recurrent laryngeal, lower limb (saphenous) nerves, and the sympathetic chain are less frequent.

Which patients with newly diagnosed prostate cancer need a radionuclide bone scan? An analysis based on 631 patients

Purpose: Although radionuclide bone scans are frequently recommended as part of the staging evaluation for newly diagnosed prostate cancer, most scans are negative for metastases. We hypothesized that Gleason score, prostate-specific antigen (PSA), and clinical stage could predict for a positive bone scan (BS), and that a low-risk group of patients could be identified in whom BS might be omitted. Methods: All patients who had both pathologic review of their prostate cancer biopsies and radionuclide BS at our institution between 1/90 and 5/96 were studied. Gleason score, PSA, and clinical stage (AJCC, 4th edition) were evaluated by univariate and multivariate analyses for their ability to predict a positive BS. Groups analyzed were Gleason of 2–6 vs. 7 vs. 8–10; PSA of 0–15 vs. greater than 15–50 vs. greater than 50; and clinical stage of T1a–T2b vs. T2c–T4. Univariate analysis using χ 2 and multivariate analysis using logistic regression were performed. Results: Of the 631 consecutive patients, 88 (14%) had positive BS. Multivariate analysis (64 excluded due to missing PSA and/or clinical stage) showed Gleason score, PSA, and clinical stage to be significant independent predictors for positive BS ( p < 0.002, p < 0.001, p < 0.001, respectively). The odds ratios were 5.25 (confidence interval [CI], 3.43–8.04) for PSA > 50 vs. 0–15; 2.25 (CI, 1.43–3.54) for Gleason of 8–10 vs. 2–6; 2.15 (CI, 1.54–2.99) for clinical stage T2c–T4 vs. T2b or less. Three of 308 (1%) had a positive BS in patients with Gleason 2–7, PSA of 50 or less, and clinical stage of T2b or less. In the subset of the same risk group with PSA of 15 or less, all 237 had negative bone scans. In patients with PSA greater than 50, 49/99(49.5%) had positive BS. Conclusion: Gleason score, PSA, and clinical stage were independent predictors for a positive radionuclide BS in newly diagnosed prostate cancer patients. PSA is the major predictor for positive BS. About one-half of the patients analyzed were in the low-risk group (Gleason 2–7, PSA ≤ 50, clinical stage ≤ T2b) and elimination of BS in these patients would result in considerable economic savings.

LOCAL INVASION OF PROSTATE CARCINOMA CAUSING VESICORECTAL FISTULA

Rectal involvement by locally advanced adenocarcinoma of the prostate is theoretically prevented by the barrier effect of Denonvilliers’ fascia. Vesicorectal and urethrorectal fistulas have not been reported in the absence of prior radiation or surgery. We report a case of vesicorectal fistula resulting from local invasion of hormone refractory prostate cancer. CASE REPORT A 79-year-old man presented with a urinary tract infection, microscopic hematuria and prostate specific antigen (PSA) 13.7 ng./ml. He had a history of alcohol abuse, malnutrition and transurethral resection of the prostate performed 8 years earlier for histologically confirmed benign prostatic hyperplasia. He denied any history of pneumaturia, fecaluria, diarrhea or urinary tract infection. Rectal examination revealed an irregular, diffusely firm prostate. Cystourethroscopy demonstrated a 3 3 2 cm. sessile, necrotic tumor at the bladder neck overlying the base of the prostate and no other lesions in the bladder. Transrectal ultrasound showed a large hypoechoic lesion extending into the bladder neck and biopsies were positive for Gleason score 8 adenocarcinoma (fig. 1, A). Radionuclide bone scan revealed metastatic spread to the right hemipelvis. Although androgen ablation was recommended, the patient was lost to followup for 6 months, at which time he presented with grossly infected urine and PSA 19.8 ng./ml. After the initial 3-month injection of goserelin acetate, PSA decreased to 3.4 ng./ml. but increased to 6.9 ng./ml. at 6 months. Two months later the patient complained of a 6-week history of watery diarrhea, 9 kg. weight loss, dysuria, frequency and pneumaturia. PSA was 14.0 ng./ml. Rectal examination revealed an irregular mass compromising but not occluding the rectal lumen. Sigmoidoscopy confirmed erosion into the rectum anteriorly 2 to 4 cm. above the anal verge with no other abnormalities in the sigmoid colon. Sigmoidoscopic biopsy demonstrated PSA positive, cytokeratin 7 and cytokeratin 20 negative adenocarcinoma consistent with prostatic origin (fig. 1, B). Computerized tomography showed intravesical air and contrast material tracking between the bladder and rectum through the prostate/bladder neck mass with no evidence of colonic diverticulas or solid masses (fig. 2). Due to the poor medical condition the patient was treated conservatively with enteric nutrition. He died of cachexia 18 months after diagnosis.

Routine bone scintigraphy in primary staging of soft tissue sarcoma; Is it worthwhile?

The incidence of bone metastases in soft tissue sarcoma (STS) patients seems to be low but has not been studied separately. In this study, the authors aimed to determine the value of routine radionuclide bone scanning in preoperative staging of STS patients. Preoperative bone scans were evaluated retrospectively in 109 consecutive patients (median age, 44 years; range, 1-86) with intermediate or high grade STS. Scans were scored in 3 categories: 1, metastases very likely; 2, equivocal; and 3, normal or benign lesions. Category 1 scans were found in 8 of 109 patients (7%); in all 8 patients, bone metastases were confirmed. Six of these eight patients reported pain, and all had additional lung, bone marrow, or lymph node metastases. The highest rate (17%) was found in the rhabdomyosarcoma subgroup (n = 18). Category 2 (equivocal) scans were present in 12 of 109 patients (11%), in all of which bone metastases were excluded through additional investigations. Category 3 (normal) scans were found in 81%. Bone metastases were at least as frequent as lung metastases (4%) and were the single site of systemic disease in 4%. The rate of bone metastases was 55% in patients with bone pain versus 2% in patients without pain. Bone metastases in primary STS patients are rare (7%) yet in this study at least as frequent as lung metastases. The low rate in asymptomatic patients versus the high rate in symptomatic patients supports the use of bone scanning in symptomatic patients only. The yield of routine bone scanning is low.

The pattern of serum markers in patients with androgen-independent adenocarcinoma of the prostate

In this exploratory study, our objectives were to correlate the serum and bone marrow concentrations of putative markers of prostate cancer progression in patients with advanced androgen-independent prostate cancer (AIPC), to assess the frequency and quantity of relative expression of these markers, and to correlate the expression of the markers with extent of disease (EOD) and overall survival. In a cohort of 50 patients with AIPC with bone metastases, we obtained serum and bone marrow samples and measured prostate specific antigen (PSA), serum interleukin-6 (sIL-6), bone marrow interleukin-6, serum chromogranin A (sCgA), bone marrow chromogranin A, and prostate specific membrane antigen (PSMA) by immunoassays. EOD was determined by quantifying identifiable bone lesions on radionuclide bone scans. Each variable was categorized into two groups (low and high) based on the median found in this cohort or on the cutoff based on normal limits when available. Analyses were performed in two subsets of patients with EOD either <20 or ⩾20. Results showed that: (1) PSA is associated with EOD but not with outcome; (2) sIL-6 and sCgA may be intermediate markers of early progression in AIPC, because they are predictive of outcome only in patients with EOD <20; (3) elevated PSMA is associated with elevated sIL-6 but not with PSA, suggesting that PSMA may be a useful marker in AIPC; and (4) the ratio of PSA to putative markers of progression may reflect the complex clonal progression of prostate cancer. We conclude that patients with advanced AIPC exhibit one of two patterns of serologic marker expression: in some patients the disease status is reflected by PSA, and in others it is reflected by other markers. If these data are prospectively confirmed, this would help group patients with advanced AIPC into clinically relevant categories.

Acute Non-Traumatic Knee Pain in the Elderly - Osteoarthritis?

We describe a patient with spontaneous osteonecrosis of the knee presenting with acute knee pain. This condition is less often thought of especially among elderly patients who present with knee pain and with no accompanying history of trauma. They are often assumed to be suffering from osteoarthritis. However, we believe that radionuclide bone scan is helpful especially when the plain radiographs are of little or no diagnostic value.

THE POSITIVE YIELD OF IMAGING STUDIES IN THE EVALUATION OF MEN WITH NEWLY DIAGNOSED PROSTATE CANCER: A POPULATION BASED ANALYSIS

We determine the positive yield of imaging studies performed on men with newly diagnosed prostate cancer. A prospective, population based survey was conducted on 3,690 men with prostate cancer diagnosed between October 1, 1994 and October 31, 1995. Cases were identified by the rapid case ascertainment systems used in 6 geographic regions participating in the Surveillance, Epidemiology and End Results Program. Based on information captured in primary medical record reviews we estimated the positive yield of bone scans, computerized tomography (CT) and magnetic resonance imaging. The positive yield of bone scan and CT was less than 5% and 12%, respectively, for all men with prostate specific antigen (PSA) 4 to 20 ng./ml., and less than 2% and 9%, respectively, for those who also had a Gleason score of 6 or less. Only men with PSA greater than 50 ng./ml. and those with Gleason scores 8 to 10 and PSA greater than 20 ng./ml. had positive yields greater than 10% and 20% for bone scan and CT, respectively. Imaging studies designed to identify metastases and/or extracapsular extension in men with newly diagnosed prostate cancer frequently have a low positive yield. Wide variations exist in the use of imaging studies and are associated with tumor factors, such as Gleason score and serum PSA, and nontumor factors, such as state of residence. More extensive cost-effectiveness analyses are needed to define appropriate guidelines for ordering imaging studies to optimize the positive yield among men with newly diagnosed prostate cancer.

Imaging findings in pediatric adrenocortical carcinoma.

Adrenocortical carcinoma (ACC), a tumor that is rare among children, causes clinically evident hormonal disturbances. Imaging methods are used to stage disease and to plan surgical resection. To describe the findings of the various imaging methods used to evaluate ACC. We reviewed the records of ten consecutive patients (mean age, 8.1 years) who presented from 1987 to 1998 with ACC. All patients underwent computed tomography (CT) scanning; five underwent magnetic resonance (MR) imaging; four underwent ultrasonography (US); and eight underwent radionuclide bone scans. Seven patients presented with signs of hormonally functional tumors. Typical imaging findings consisted of a large, well-defined suprarenal tumor, containing calcifications (seven patients) with a thin capsule and central necrosis or hemorrhage (six patients). The inferior vena cava (IVC) was compressed by tumor in three patients, and ultrasonography demonstrated invasion of the IVC wall in one of these. Three patients' bone scans showed that the primary tumor took up radioactive tracer. Spread to lungs or liver or both was demonstrated in six patients. CT, US and MR imaging are effective methods of imaging the primary tumor. Chest CT and bone scintigraphy should be performed to detect metastases. The presence of a thin tumor capsule, a stellate central zone of necrosis, and evidence of hormonal function help distinguish ACC from neuroblastoma.

Radionuclide Bone Scan Appearances in Asymptomatic Patients following Hip Hemiarthroplasty

We report the radionuclide bone scan appearances following hemiarthroplasty of the hip in 15 asymptomatic, active patients at a mean of 14 months following surgery. All patients had a normal clinical examination, white cell count and erythrocyte sedimentation rates. Tracer activity was graded. Minimal tracer activity especially along the lateral stem and acetabulum were consistent findings. We conclude that this should be regarded as normal in this situation.

Bone Localization

Accurate staging of malignancies is essential to guide the clinician in selecting the most appropriate therapy. Metastases to bone suggested by radionuclide bone scans must be proven histologically because of the high frequency of false-positive results. If the plain bone radiographs, however, are normal and there are no localizing symptoms, precise biopsy of the area of bone scan abnormality is usually difficult and time-consuming. The recently described intraoperative use of the hand-held gamma probe now allows for great accuracy and sensitivity in the radioisotope-guided open biopsy of clinically suspected bone metastases.

Imaging of the rearfoot.

The authors review various pedal conditions affecting the rearfoot, including plantar fasciitis, Achilles tendon pathology, fractures, arthritides, coalitions, and tumors. Various diagnostic imaging modalities such as routine radiography, radionuclide bone scanning, computed tomography, and magnetic resonance imaging are discussed.

Natural history of progression after PSA elevation following radical prostatectomy.

In men who develop an elevated serum prostate-specific antigen level (PSA) after having undergone a radical prostatectomy, the natural history of progression to distant metastases and death due to prostate cancer is unknown. To characterize the time course of disease progression in men with biochemical recurrence after radical prostatectomy. A retrospective review of a large surgical series with median (SD) follow-up of 5.3 (3.7) years (range, 0.5-15 years) between April 1982 and April 1997. An urban academic tertiary referral institution. A total of 1997 men undergoing radical prostatectomy, by a single surgeon, for clinically localized prostate cancer. None received neoadjuvant therapy, and none had received adjuvant hormonal therapy prior to documented distant metastases. After surgery, men were followed up with PSA assays and digital rectal examinations every 3 months for the first year, semiannually for the second year, and annually thereafter. A detectable serum PSA level of at least 0.2 ng/mL was evidence of biochemical recurrence. Distant metastases were diagnosed by radionuclide bone scan, chest radiograph, or other body imaging, which was performed at the time of biochemical recurrence and annually thereafter. The actuarial metastasis-free survival for all 1997 men was 82% (95% confidence interval, 76%-88%) at 15 years after surgery. Of the 1997 men, 315 (15%) developed biochemical PSA level elevation. Eleven of these underwent early hormone therapy after the recurrence and are not included in the study. Of the remaining 304 men, 103 (34%) developed metastatic disease within the study period. The median actuarial time to metastases was 8 years from the time of PSA level elevation. In survival analysis, time to biochemical progression (P<.001), Gleason score (P<.001), and PSA doubling time (P<.001) were predictive of the probability and time to the development of metastatic disease. An algorithm combining these parameters was constructed to stratify men into risk groups. Once men developed metastatic disease, the median actuarial time to death was 5 years. The time interval from surgery to the appearance of metastatic disease was predictive of time until death (P<.02). Several clinical parameters help predict the outcomes of men with PSA elevation after radical prostatectomy. These data may be useful in the design of clinical trials, the identification of men for enrollment into experimental protocols, and counseling men regarding the timing of administration of adjuvant therapies.

A Man with Inflamed Ears

A 23-year-old man presented with fever, dyspnea, nonproductive cough, left eye redness, reduced vision, and bilateral ear pain and tenderness. The symptoms had begun two days earlier, eight days after he was discharged from the hospital with a presumptive diagnosis of Still's disease. He was first seen a month before the current admission for complaints of fever (as high as 39.4°C), nonproductive cough, and asymmetric arthritis. The workup at that time included arthro- centesis of the right knee. Analysis of the joint fluid showed 7,500 white blood cells/mm3 and no crystals. A gram stain and culture of the fluid were negative. HIV and hepatitis tests, bone marrow biopsy and culture, transesophageal echocardiography, abdominal computed tomography, radionuclide bone scanning, and rheumatologic tests failed to identify the problem. The development of an evanescent macular pink rash on day 15 suggested the possibility of Still's disease. Treatment with prednisone (40 mg po qd) was initiated, and the patient was discharged on day 19.

Pelvic insufficiency fractures in patients with pelvic irradiation

Background: Insufficiency fractures (IF) occur as a result of normal physiological stress on bones with deficient elastic resistance. Pelvic insufficiency fractures are a complication of osteoporosis due to postmenopausal status, high dose of corticosteroids, or local irradiation. They are important because differential diagnosis includes pelvic bone metastases. Diagnosis is based on both clinical manifestations and radiographic and scintigraphic findings. Methods and Materials: We examined eight patients with pelvic cancer who had previously undergone external beam radiation therapy as part of their treatment. In the follow-up, they developed insufficiency fractures, and no factor other than pelvic irradiation was present. Diagnosis was confirmed by radionuclide bone scan followed by conventional radiography and computed tomography (CT) scan. Results: The average onset of symptoms was 13.7 months after radiation therapy was completed. The initial symptom in all cases was pain. In all of the patients, the bone scan showed abnormalities. One to four increased uptake foci were observed, in the sacroiliac joint in all cases, and in the pubis in three cases. The initial diagnosis was bone metastases in five patients. CT scan showed fractures in all of the patients, in sacrum and pubis, both endostic and cortical. Treatment, consisting of nonsteroidal anti-inflammatory drugs and rest, led to symptomatic relief in all cases. Conclusion: Knowledge of pelvic insufficiency fractures is essential in order to rule out metastasic disease, and thus avoid inaccurate treatment. Although radionuclide bone scan is useful in early detection of pelvic IF, definitive diagnosis is provided by CT scan.

Suspected non-small cell lung cancer: incidence of occult brain and skeletal metastases and effectiveness of imaging for detection--pilot study.

To estimate the incidence of occult metastases to the brain and skeleton in patients suspected of having non-small cell lung cancer (NSCLC) (stage higher than T1Nomo) with surgically resectable disease, to assess the accuracy of screening magnetic resonance (MR) imaging and radionuclide bone scanning for help in identifying occult metastases, and to determine the effectiveness of a high dose of MR contrast material. Twenty-nine patients suspected of having NSCLC localized to the lung or to the lung and regional nodes underwent preoperative MR imaging with contrast material enhancement and radionuclide bone scanning for detection of brain or skeletal metastases. Patients were followed up for 12 months to determine the incidence of clinical metastatic disease. Eight (28%) patients had occult metastatic disease to the brain or skeleton. Brain metastases were identified on MR images in five of six patients. Bone metastases were identified on MR images in four of five patients and on bone scans in three of five patients. MR imaging was no more accurate than bone scanning for skeletal evaluation. A high dose of MR contrast material allowed detection of more metastases and of small lesions. Contrast-enhanced MR imaging of the brain is indicated for the exclusion of brain metastases in patients with clinically operable known or possible NSCLC and a large (> 3-cm) lung mass. Skeletal imaging may be indicated if an isolated brain metastasis is detected.

Influence of Local Tumour Stage and Grade on Reliability of Serum Prostate-Specific Antigen in Predicting Skeletal Metastases in Patients with Adenocarcinoma of the Prostate

Objective: To determine whether serum prostate-specific antigen (PSA) can be reliably used to predict the absence or presence of skeletal metastases on the bone scan in patients with adenocarcinoma of the prostate. Methods: We studied 450 consecutive men presenting with adenocarcinoma of the prostate between 1991 and 1995. Serum PSA was measured by the Hybritech Tandem-R monoclonal immunoradiometric assay and bone scanning was performed with 99m-technetium-labelled methylene diphosphonate. In total, 46 patients were excluded for one or more of the following reasons: serum PSA not available; radionuclide bone scan inconclusive; histology of the prostate other than adenocarcinoma; hormonal or other therapy given prior to obtaining the serum PSA and/or bone scan. Results: Of the 404 patients incluced, 43% had poorly differentiated (grade 3), 74% had locally advanced (stages T3–4) tumours and 50% had skeletal metastases. The mean and median serum PSA were 348 and 52 ng/ml, respectively, and 77% of the patients had a serum PSA >20 ng/ml. The negative predictive value (for the absence of metastases on bone scan) of a serum PSA <20 ng/ml was 87% for the whole group of patients, 92, 94 and 70% for grade 1, 2 and 3 tumours, and 95, 83 and 50% for stage T1–2, T3 and T4 tumours, respectively. The positive predictive value (for the presence of metastases on bone scan) of a serum PSA >100 ng/ml was 80% for the whole group of patients. Conclusions: In patients presenting with adenocarcinoma of the prostate, serum PSA alone is not sufficiently reliable to predict the absence or presence of metastases on the radionuclide bone scan. In patients with grade 3 and clinical stage T3–4 tumours, a bone scan should be obtained for accurate staging, regardless of the serum PSA value.