The clinical utility of circulating neuroendocrine gene transcript analysis in well-differentiated paragangliomas and pheochromocytomas.

CONTEXT: Paragangliomas and pheochromocytomas (PPGLs) exhibit variable malignancy, which is difficult to determine by histopathology, amine measurements or tissue genetic analyses. OBJECTIVE: To evaluate whether a 51-neuroendocrine gene blood analysis has clinical utility as a diagnostic and prognostic marker. DESIGN: Prospective cohort study. Well-differentiated PPGLs (n = 32), metastatic (n = 4); SDHx mutation (n = 25); 12 biochemically active, Lanreotide treated (n = 4). Nine patients had multiple sampling. Age- and gender-matched controls and GEP-NETs (comparators). METHODS: Circulating neuroendocrine tumor mRNA measured (qPCR) with multianalyte algorithmic analysis. Metabolic, epigenomic and proliferative genes as well as somatostatin receptor expression were assessed (averaged, normalized gene expression: mean ± s.e.m.). Amines were measured by HPLC and chromogranin A by ELISA. Analyses (2-tailed): Fisher's test, non-parametric (Mann-Whitney), receiver-operator curve (ROC) and multivariate analysis (MVA). All data are presented as mean ± s.e.m. RESULTS: PPGL were NETest positive (100%). All exhibited higher scores than controls (55 ± 5% vs 8 ± 1%, P = 0.0001), similar to GEP-NETs (47 ± 5%). ROC analysis area under curve was 0.98 for differentiating PPGLs/controls (cut-off for normal: 26.7%). Mutation status was not directly linked to NETest. Genetic and molecular clustering was associated (P < 0.04) with NETest scores. Metastatic (80 ± 9%) and multicentric (64 ± 9%) disease had significantly (P < 0.04) higher scores than localized disease (43 ± 7%). Progressive disease (PD) had the highest scores (86 ± 2%) vs stable (SD, 41 ± 2%) (P < 0.0001). The area under the curve for PD from SD was 0.93 (cut-off for PD: 53%). Proliferation, epigenetic and somatostatin receptor gene expression was elevated (P < 0.03) in PD. Metabolic gene expression was decreased in SDHx mutations. Repeat NETest measurements defined clinical status in the 9 patients (6 SD and 3 PD). Amine measurement was non-informative. Multivariate analysis identified NETest >53% as an independent prognostic factor. CONCLUSION: Circulating NET transcript analysis is positive (100% diagnostic) in well-differentiated PCC/PGL, scores were elevated in progressive disease irrespective of mutation or biochemical activity and elevated levels were prognostic.

Three-dimensional personalized dosimetry for 188Re liver selective internal radiation therapy based on quantitative post-treatment SPECT studies.

We demonstrate that accurate patient-specific distributions of microspheres labeled with 188Re and resulting absorbed doses can be obtained from single-photon emission computed tomography (SPECT) studies performed after 188Re selective internal radiation therapy when accurate correction methods are employed in image reconstruction. Our quantitative image reconstruction algorithm includes corrections for attenuation, resolution degradations and scatter as well as a window-based compensation for contamination. The procedure has been validated using four phantom experiments containing an 18 ml cylindrical source (82-93 MBq of 188Re activity) simulating a liver tumor. In addition, we applied our approach to post-therapy SPECT studies of ten patients with progressive primary or metastatic liver carcinomas. Our quantitative algorithm accurately (within 9%) recovered 188Re activity from four phantom experiments. In addition, for two patients that received three scans, deviations remained consistent between the measured and the reconstructed activities that were determined from studies with differing severity of the dead-time effect. The analysis of absorbed doses for patient studies allowed us to hypothesize that D90 (the minimum dose received by 90% of the tumor volume) may be a reliable metric relating therapy outcomes to the calculated doses. Among several considered metrics, only D90 showed statistically significant correlation with the overall survival.

Pathways of lymph and tissue fluid flow during intermittent pneumatic massage of lower limbs with obstructive lymphedema.

Questions remain on the use of sequential pneumatic compression including where does the fluid flow to and whether fluid can be moved to the non-swollen tissues of the hypogastrium and gluteal region? During pneumatic massage of the limb, we studied pathways of lymph and mobile tissue fluid flow using lymphoscintigraphy: a) from the calf and thigh across the inguinal region to the healthy non-swollen tissues of the hypogastrium and b) in the hypogastrium to the lateral and upper abdominal quadrants. To examine if there was effective fluid flow during pneumatic massage, plethysmographic flow measurements were also carried out. We demonstrated that: (i) pneumatic compression moved isotope in lymph remaining in functioning lymphatics and in tissue fluid in the interstitial space toward the inguinal region and femoral channel, (ii) there was no isotope crossing the inguinal crease or moving to the gluteal area, and (iii) isotope injected intradermally in the hypogastrium did not spread during manual massage to the upper and contralateral abdominal quadrants. In conclusion, intermittent pneumatic compression is effective in pushing mobile tissue fluid and relocating large fluid volumes toward the groin. However, the question that still remains is how to facilitate further flow toward the non-swollen tissues and thereby increase local absorption of fluid.

Brucella canis in a HIV-infected patient.

The true incidence of Brucella canis in humans is unknown, but immunocompromised patients in direct contact with dogs are thought to be at a higher risk for infection. In this case report, we present a human case of B. canis in a patient infected with human immunodeficiency virus.

Efficacy of radionuclide treatment DOTATATE Y-90 in patients with progressive metastatic gastroenteropancreatic neuroendocrine carcinomas (GEP-NETs): a phase II study.

BACKGROUND: To evaluate the clinical and radiological effectiveness of [DOTA(0), D-Phe(1), Tyr(3)]-octreotate (DOTATATE) Y-90 in patients with extensive progressive gastroenteropancreatic neuroendocrine carcinomas (GEP-NETs). MATERIALS AND METHODS: Sixty patients with histologically proven GEP-NETs were treated with DOTATATE Y-90. Clinical responses were assessed 6 weeks after completing therapy and then after each of the 3- to 6-month intervals. The radiological response was classified according to RECIST criteria. RESULTS: At 6 months after final treatment, radiological partial response (PR; at least a 30% decrease in the sum of the longest diameter of target lesions) was observed in 13 patients (23%), and the remaining patients had stable disease (SD; less than 30% decrease in the sum of the longest diameter of target lesions or less than 20% increase in the sum of the longest diameter of target lesions) (77%). Clinical PR at 6 months was in 43 patients (72%), nine patients had SD and progressive disease (PD) was noted in eight patients. Median progression-free survival (PFS) was 17 months, while the median overall survival (OS) was 22 months. In eight patients with early PD, the PFS was 4.5 and OS 9.5 months, while in those with SD or PR, PFS and OS were 19.5 and 23.5 months, respectively. After 12 months of follow-up, five patients had World Health Organization (WHO) grade 2 or 3 renal toxicity. Haematological toxicity (WHO grade 3 and 4) was noted during therapy in 10% of patients and persisted in 5%. CONCLUSIONS: DOTATATE Y-90 therapy is effective and relatively safe in patients with GEP-NET. Standard doses of DOTATATE Y-90 result in a relatively low risk of myelotoxicity. However, due to ongoing risk of renal toxicity, careful monitoring of the kidney is recommended.

Can scintimammography with (99m)Tc-MIBI identify multifocal and multicentric primary breast cancer?

Scintimammography with (99m)Tc-MIBI has been shown to be an effective adjunct to imaging of the breast with mammography. Uptake of (99m)Tc-MIBI is particularly high in sites of non-calcified cancer and ductal carcinoma in situ (DCIS), and as a consequence it may be possible to use this method of imaging in identifying multifocal or multicentric disease. The aim of this study was to evaluate the efficacy of preoperative scintimammography in the detection of multifocal and multicentric breast cancer and compare these results with mammography. A retrospective review was performed of 353 women imaged with (99m)Tc-MIBI as part of the clinical assessment of their suspected primary breast cancer. The results of the scintimammography and mammography were then compared with the final pathological diagnosis obtained after mastectomy in all patients. Histopathological assessments of breast tissue from mastectomy confirmed 40 women (12%) had multifocal (34) or multicentric (six) breast cancer. Scintimammography correctly identified 39 of these cancers and the multifocal or multicentric character of the cancer was identified in 22 (52%) of these patients. Anatomical imaging performed in all 40 patients including 25 with mammography alone, mammography and ultrasound in 11 cases and ultrasound alone in four patients. Anatomical imaging identified cancer to be present in 28 patients (70%) and the combination of mammography and ultrasound identified correctly that the cancer was multifocal or multicentric in eight patients (22%). In this study scintimammography was able to identify more cases of multifocal and multicentric cancer than mammography and/or ultrasound. In patients where pre-operative identification of multicentric or multifocal disease can alter treatment scintimammography may be a useful investigative tool.

Prediction of the usefulness of combined mammography and scintimammography in suspected primary breast cancer using ROC curves.

UNLABELLED: The aim of this study was to compare the accuracy of 99mTc-methoxyisobutylisonitrile scintimammography (SMM) and conventional mammography in patients presenting with suspected primary breast cancer. Receiver-operating-characteristic (ROC) curve analysis was applied to determine if a combination of x-ray mammography (XMM) and SMM was more accurate than a single test alone. METHODS: The results of SMM, XMM, and a combination of both studies performed over a 3-y period on 374 suspicious lesions in 353 patients with no previous history of breast cancer were reviewed. Each scan report was reviewed and graded as follows: grade 1, definitely normal or benign; grade 2, probably normal or benign; grade 3, equivocal; grade 4, probably cancer; and grade 5, definitely cancer. The results were verified by pathologic examination of biopsy material obtained from each suspicious mass. ROC curves were generated from these results. RESULTS: There were 204 malignant breast tumors and 170 nonmalignant breast lesions. SMM diagnosed correctly 181 breast cancers and was true-negative in 122 benign breast lesions: sensitivity, 89%; specificity, 71%; positive predictive value (PPV), 79%; and negative predictive value (NPV), 84%. XMM diagnosed correctly 143 malignant tumors and was true-negative in 117 nonmalignant lesions. The sensitivity, specificity, PPV, and NPV for XMM were 70%, 69%, 73%, and 66%, respectively. Using a combination of the two tests, the combined sensitivity was 93%, specificity was 72%, PPV was 80%, and NPV was 90%. Using the index of the area under the ROC curve obtained by the rating method showed that the combination of XMM and SMM was significantly more accurate than either of the individual tests if performed alone (P < 0.05). CONCLUSION: This study shows that the combination of XMM and SMM produces more accurate results than either modality alone. Therefore, if there is doubt about the accuracy of XMM, SMM should be used as the second-line test in breast imaging.

The role of scintimammography and mammography in recurrent breast cancer. Evaluation of their accuracy using ROC curves.

BACKGROUND: With the increasing demand for breast conservation surgery, the probability of recurrent tumour within the breast increases. Traditionally x-ray mammography (XMM) was used to assess the post-surgical breast, but post-surgery and radiotherapy changes have reduced the accuracy of this method. Scintimammography (SMM) has also been proposed and appears to be more accurate than XMM. MATERIAL AND METHODS: A total of 101 women received (Tc99m) MIBI SMM and 88 had a subsequent XMM. There were 142 sites suspected of loco-regional recurrence breast cancer. During the study the patients did not receive any treatment other then hormonotherapy. SMM was performed by the standard Diggles-Khalkhali method and XMM was performed using standard 2 views. Analysis was performed and the results of each type of imaging compared with histology. In the ROC curve analysis 5 points of certainty were used: from 1 being definitely normal to 5 being definitely cancer; grades 4 and 5 were counted as positive. RESULTS: The overall sensitivity value of SMM was 84% and specificity was 85%, compared with a sensitivity of 52% for XMM and a specificity of 84%. Analysis of areas under ROC curves provides statistically significant difference between SMM and XMM (p < 0.05). Combining the two tests did not significantly improve the diagnostic accuracy of sequence imaging over SMM. CONCLUSION: ROC curve analysis demonstrates that scintimammography should be the primary investigation in suspected local recurrence following breast conservation surgery.

Comparison of functional imaging and standard CT in evaluation of disease extent in patients with tumours showing neuroendocrine features.

BACKGROUND: The diagnostic approach that should be used in disseminated neuroendocrine tumours (NET) remains a significant clinical problem. A novel approach has been the use of 111In Octreotide as functional imaging to find NETs. Therefore, the aim of this retrospective study is to report our comparison with direct CT as standard anatomical imaging. MATERIAL AND METHODS: A total of 48 patients (aged 16-79 years; mean age 55, SD 14 years) were imaged using both techniques with final histological confirmation of NET. Histology was as follows: 26 carcinoids; 2 pheochromocytomas; 4 gastrinomas, 1 islet tumour; 2 paragangliomas, 1 modullary carcinoma of the thyroid, 8 undetermined NET and 4 other tumours with signs of neuro-ectodermal cancers (2 hepatocellular carcinomas (HCC), fibrolamellar HCC and fibrous tumour). All patients had (111)In Octreotide and 30 had (123)I mIBG scans followed by spiral CT with contrast enhancement. 26 patients had single functional scans and 22 had multiple, up to 6 scans. Extent of disease as number of lesions was compared between CT and octreotide. RESULTS: CT was the best modality in 11 patients, in 6 it was as good as (111)In Octreotide. mIBG was the best in 6 patients; in 3 patients mIBG was as good as octreotide study. In 22 patients (111)In Octreotide was the most effective modality. In one patient there was no advantage with any of the tests. Comparison of the number of organs involved indicated that an octreotide study was much more effective than CT scanning (Wilcoxon matched pairs test, p < 0.001) and also the overall number of lesions detected using (111)In Octreotide was greater than with CT (Wilcoxon Matched Pairs test p < 0.01). CONCLUSION: Our results confirm the recommendation of the European NET group that functional imaging should be performed in patients with suspected NET.

Tc-99m MIBI in suspected recurrent breast cancer.

A prospective trial was performed to assess the accuracy of Tc-99m MIBI scintimammography in 63 women (mean age 65, range 33-85 years) with suspected recurrent breast cancer in the breast and/or loco-regional tissues. All patients had been diagnosed with breast cancer 1-23 years before the scintimammography. A total of 27 breasts had been removed by mastectomy so scintimammography was compared with mammography in the remaining 99 breasts. Pathological follow-up of patients confirmed 33 sites of recurrent disease within the breast, 26 (78%) were identified by scintimammography and 14 (42%) by mammography; 30 (90%) were positive on one test or the other. In addition Tc-99m MIBI scintimammography identified 10/16 (63%) of axillary lymph nodes with recurrent tumour and 4/6 sites of recurrent tumour present elsewhere. Tc-99m MIBI scintimammography is more accurate in identifying recurrent disease in the breast than mammography and can identify loco-regional recurrence outside of the breast.

Diagnostic accuracy of mammography and scintimammography in detection of primary breast cancer related size of the tumour.

BACKGROUND: The detection of breast cancer relies on physical examination and mammography (XMM). The sensitivity of conventional imaging is lesions-size dependent. However, mammography has good sensitivity in small tumours when microcalcification is present, but the sensitivity is relatively low in other small tumours. The use of scintimammography with Tc-99m sestaMIBI (SMM) may be helpful in this situation. The aim of this study is to compare the diagnostic accuracy of mammography and scintimammography across all groups with different sizes of lesions. METHODS: Data for 273 patients aged 26 to 84 years (mean 52; SD 12) with 298 lesions were analysed. All lesions were removed and final histology and pathological size of the tumours were retrospectively reviewed (mean size 2.9 cm, SD 2.4 cm). All patients had XMM and SMM. Each imaging study was graded using five grades of certainty. SMM images were reviewed by an independent specialist blinded to clinical presentation and XMM results. The diagnostic accuracy of each test, overall and by each lesions size subgroup, was compared using receiver operating characteristic curve (ROC) analysis. RESULTS: The sensitivity of scintimammography was consistently high across all size groups; overall 89% (82?100%) compared with 68% (51?88%) for mammography. In those tumours below 2 cm, the area under the ROC was significantly larger with SMM than XMM (p < 0.05), with 80% certainty indicative of greater diagnostic accuracy. Also in all patients the area under the ROC was significantly larger with SMM than XMM (p < 0.05), with 90% certainty indicative of greater diagnostic accuracy. In other groups of lesions size the area under ROC for SMM was larger in lesions size between 2 and 4 cm and slightly smaller in lesions over 4 cm, but it was not significant. CONCLUSION: Scintimammography using Tc-99m sestaMIBI seems to be a sensitive and consistently reliable diagnostic test for breast cancer independent of the size of the tumour.

Detection of DCIS using 99mTc-MIBI scintimammography in patients with suspected primary breast cancer, comparison with conventional mammography.

BACKGROUND: Scintimammography using Tc-99m MIBI (SMM) is often used clinically as a second line diagnostic test for the detection of breast cancer in cases where there is concern about the results of x-ray mammography (XMM) and ultrasound. Both of these methods, but particularly XMM, may miss a significant proportion of ductal carcinoma in situ (DCIS). MATERIAL AND METHODS: This study was performed to determine the possible accuracy of SMM in finding DCIS and comparing this with the accuracy of XMM in the same patient. Over a 3 year period 353 patients with no previous history of breast cancer were imaged with both XMM and SMM. The histology of any suspect area was verified by pathological examination of biopsy material. There were 203 malignant breast tumours. RESULTS: In those 203 cancers there were 15 pure DCIS cancers. SMM correctly diagnosed 12 of these (sensitivity was 80%). XMM diagnosed correctly 8 DCIS (sensitivity 53%) and was equivocal in 2. Combining of both SMM and XMM provided the best result with all but one DCIS identified (sensitivity 93%). CONCLUSIONS: This study shows that the SMM is helpful in detecting DCIS in those cases where XMM failed to detect DCIS or was equivocal. The combination of the two techniques produces a higher sensitivity result than either modality alone.

Correlation between uptake of Tc-99m sestaMIBI and prognostic factors of breast cancer.

UNLABELLED: The purpose of this retrospective study was assessment of correlation between Tc-99m sestaMIBI uptake and some prognostic factors of breast cancer. The following prognostic factors have been included in this study: size of the tumour, age of the patients, axilla node involvement, oestrogen and progesterone receptor (ER, PR) status, grading system of Bloom-Richardson and Ki-67 antigen expression. METHODS: 79 patients were enrolled in this study, with 85 lesions confirmed as primary breast cancers. Mean age of patients was 53 years. Scintimammography (SMM) was performed after intravenous injection of 740MBq. At 5-10 min after injection standard planar images were obtained in prone lateral and anterior supine views. Assessment of correlation between known prognostic factors of breast cancer and uptake of MIBI (evaluated as a tumour to background ratio-TBR) was performed used non-parametric (Kendall-tau correlation) statistical analysis. RESULTS: There were 85 breast cancers (73 invasive ductal carcinomas, 11 DCIS (ductal carcinoma in situ) and 1 lobular carcinoma. There was positive correlation between TBR Tc-99m MIBI uptake and size of the tumour (t = 0.19, p = 0.01), presence of axilla node involvement (t = 0.2, p = 0.006) and also grade of the IDC tumours evaluated using Bloom-Richardson's criteria (t = 0.18, 0.03). There were negative correlation between TBR and presence of PR (t = -0.16, p = 0.02) and borderline negative correlation between TBR and age of patients (t = -0.137, p = 0.06) and also TBR and ER status (t = -0.135, p = 0.065). Patients who are younger and/or have PR or ER negative cancers have higher Tc-99m MIBI uptake. Patients who presented with high grade of malignancy (B-R) also have higher uptake of radiotracer. Also those with higher uptake of radiotracer often had axillary node involvement. This would suggest that more aggressive tumours have higher uptake of Tc-99m MIBI. Finally this study suggest correlation between in vivo uptake of MIBI and some of the known prognostic factors of breast cancer.

Prone SPET scintimammography.

Prone single photon emission tomography (SPET) was performed in 24 patients with suspected primary or recurrent breast cancer to determine if this technique offers more accurate imaging than that obtained from planar scintimammography. All patients were imaged on a specially designed couch with two cushion inserts. The first insert was lined with lead and was used to perform prone lateral planar scintimammography 5 min after the injection of 740 MBq 99Tcm-MIBI. The second insert did not contain lead and was used to perform a prone SPET acquisition for 30 min immediately after planar imaging. The results of both studies were read independently and there was agreement between the two techniques in 23 cases (96%). All cases of cancer proven on histology were found on planar imaging, but a 4-mm ductal cancer was missed on prone SPET. This was thought to be due to activity from this medial cancer being obscured by the star artefact produced by back-projection reconstruction from activity in the heart. There were two false-positive studies with both techniques. However, prone SPET enabled better localization and characterization of breast cancers than planar imaging. Prone SPET imaging of the breast produces results similar to prone lateral imaging and may be used instead of planar imaging if a reduced total acquisition time is desirable. Care must be taken when reading scans in the presence of small tumours near the heart when back-projection reconstruction techniques are used.

Scintimammography: a review.

Scintimammography with 99mTc-MIBI is a new technique which has expanded the use of nuclear medicine to a new group of patients in whom scintigraphy was not been widely used. When performed correctly, and in those patients, such as the young, where x-ray mammography is often non-diagnostic, the sensitivity of scintimammography can exceed that of x-ray mammography with a similar specificity. A combination of the two techniques in this patient group can provide sensitivities greater than 98%. The mechanism of uptake of 99mTc-MIBI in breast tissue is better understood as is the efflux of the pharmaceutical from the tumour cell. The relationship between the efflux rate of 99mTc-MIBI and the expression of the multi-drug resistance gene may help in determining important aspects of tumour function, such as the response to cytotoxic chemotherapy. More recently the role of scintimammography has been found in those patients with suspected breast cancer recurrence where methods depending on the anatomical structure of the breast, such as mammography and MRI, are of less use. Scintimammography, when correctly performed and correctly applied, is able to deliver unique information which is of use to the patient with suspected primary or recurrent breast cancer.

Use of 99Tcm-MIBI in the assessment of patients with suspected recurrent breast cancer.

A prospective trial was performed to assess the accuracy of 99Tcm-methoxyisobutyl isonitrile (99Tcm-MIBI) scintimammography and X-ray mammography in 18 patients (mean age 58 years, range 46-79 years) with suspected recurrent breast cancer in the breast and/or loco-regional tissues. All patients had been diagnosed to have breast cancer 1-23 years before scintimammography. Two patients had undergone mastectomy, so that a total of 34 breasts were studied with X-ray mammography and with prone-lateral and anterior scintimammography. Any abnormalities on X-ray mammograms and scintimammograms were noted, as was any additional local or nodal uptake of 99Tcm-MIBI. The nature of any lesion seen with either modality, or in which there was a clinical suspicion of recurrence, was confirmed by cytological or histological examination of tissue samples. There were nine breasts with recurrent cancer in eight patients. X-ray mammography identified six of these cancers. 99Tcm-MIBI scintimammography identified eight of nine recurrent breast cancers (the one cancer not seen was positive on X-ray mammography). In the 26 breasts without cancer, two were reported as having changes consistent with cancer and one was reported equivocal. There were three false-positive and one equivocal scintimammograms. The accuracy of 99Tcm-MIBI scintimammography within the breast (85%) was similar to X-ray mammography (82%). Axillary lymph node recurrence occurred in five patients, four of whom were positive with 99Tcm-MIBI. An additional patient had focal uptake of 99Tcm-MIBI at the site of recurrent cancer on the anterior chest wall. In conclusion, 99Tcm-MIBI scintimammography may provide useful complementary information in patients with suspected recurrence of cancer in the breast or loco-regional tissues.

Comparison of accuracy of scintimammography and X-ray mammography in the diagnosis of primary breast cancer in patients selected for surgical biopsy.

Mammography, whilst remaining the first line imaging investigation of suspected primary breast cancer, can be difficult to interpret in patients with fibrous or dense breasts. Radionuclide imaging of the breast (scintimammography) has been suggested as an additional test. The aim of this study was to perform prospectively a comparison of the two techniques in a population with suspected breast cancer. Seventy such patients, mean age 54 years (range 57 years, 28-85) with 74 suspicious breast lesions were studied. They were imaged 5-10 min after intravenous injection of 740 MBq of Tc-99m sestamibi. Prone lateral and anterior supine views with and without markers were performed. All patients had histological confirmation of the nature of the breast lesions by limited incisional biopsy or definitive wide local excision, or cytological confirmation on fine needle aspiration. All patients had X-ray mammography. There were 53 malignant breast tumours and 21 benign lesions. Scintimammography correctly diagnosed 47 breast cancers, and yielded true-negative results in 12 benign breast lesions. There were six cases of false-negative results and nine false-positive results. Four scans were reported as equivocal. The sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) were 89%, 52%, 84% and 67%, respectively. X-ray mammography diagnosed correctly 37 malignant tumours, and in 12 benign lesions the results were true negatives. Ten studies were reported as equivocal. The sensitivity, specificity, PPV and NPV were 70%, 57%, 80% and 43%, respectively. The accuracy of Tc-99m sestamibi scintimammography was better than X-ray mammography though this was not significant (McNemar's test). Fewer equivocal results were obtained with scintimammography. Scintimammography may therefore have a role in the diagnosis of primary breast cancer when X-ray mammography is equivocal or unhelpful.