Training of staff for the delivery of PET/CT services in the UK

Evidence for the cost effectiveness of PET/CT imaging is now driving the widespread introduction of PET/CT services throughout the UK. The provision of PET/CT facilities will require a workforce of medical, scientific, technical and engineering staff who are adequately trained and fit for purpose. Suitably trained staff in this speciality are scarce. The development and accreditation of training courses and other educational resources for training programmes in all disciplines will therefore be required at a national and regional level. The implementation of PET/CT training can be achieved more cost-effectively by developing multi-professional learning resources whenever possible. It is intended that the recommendations would be implemented by close co-operation of both public and private healthcare providers together with educational establishments.

A phase I trial of antibody directed enzyme prodrug therapy (ADEPT) in patients with advanced colorectal carcinoma or other CEA producing tumours

Antibody-directed enzyme prodrug therapy is a targeted therapy in which a prodrug is activated selectively at the tumour site by an enzyme, which has been targeted to the tumour by an antibody (antibody-enzyme conjugate). Previous clinical trials have shown evidence of tumour response, however, the activated drug had a long half-life, which resulted in dose-limiting myelosuppression. Also, the targeting system, although giving high tumour to blood ratios of antibody-enzyme conjugate (10 000 : 1) required administration of a clearing antibody in addition to the antibody-enzyme conjugate. The purpose of this current study therefore was to attempt tumour targeting of the antibody-enzyme conjugate without the clearing antibody, and to investigate a new prodrug (bis-iodo phenol mustard, ZD2767P) whose activated form is highly potent and has a short half-life. Twenty-seven patients were treated with antibody-directed enzyme prodrug therapy using A5CP antibody-enzyme conjugate and ZD2767P prodrug, in a dose-escalating phase I trial. The maximum tolerated dose of ZD2767P was reached at 15.5 mg m(-2)x three administrations with a serum carboxypeptidase G2 level of 0.05 U ml(-1). Myelosuppression limited dose escalation. Other toxicities were mild. Patients' quality of life was not adversely affected during the trial as assessed by the measures used. There were no clinical or radiological responses seen in the study, but three patients had stable disease at day 56. Human anti-mouse antibody and human anti-carboxypeptidase G2 antibody were produced in response to the antibody enzyme conjugate (A5CP). The antibody-enzyme conjugate localisation data (carboxypeptidase G2 enzyme levels by HPLC on tumour and normal tissue samples, and gamma camera analysis of I-131 radiolabelled conjugate) are consistent with inadequate tumour localisation (median tumour: normal tissue ratios of antibody-enzyme conjugate of less than 1). A clearance system is therefore desirable with this antibody-enzyme conjugate or a more efficient targeting system is required. ZD2767P was shown to clear rapidly from the circulation and activated drug was not measurable in the blood. ZD2767P has potential for use in future antibody-directed enzyme prodrug therapy systems.

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.

The clinical application of a dual head gamma camera with coincidence detection in 20 women with suspected ovarian cancer

OBJECTIVE

To assess the effectiveness of a dual head coincidence gamma camera in identifying ovarian cancer as a less expensive alternative to the traditional 2-[18F] fluoro-2-deoxy-D-glucose (18FDG) system using positron emission tomography.

DESIGN

Prospective study.

POPULATION

Twenty consecutive women suspected of having ovarian carcinoma. Inclusion was based on abnormal serum CA125 (reference range is 0-35 units/L), ultrasound, computerised tomography or clinical findings.

METHODS

Women underwent assessment before staging laparotomy. Two nuclear medicine physicians, who were blinded to the pre-operative assessment, reported on 18FDG- dual head coincidence gamma camera imaging.

MAIN OUTCOME MEASURES

The histology and operative staging were compared with the 18FDG- dual head coincidence gamma camera findings.

RESULTS

Twelve women had pelvic malignancies (nine primary and three recurrences), seven women had benign pathology and one patient had a borderline malignancy. We were able to image accurately all malignant pelvic masses with dual head coincidence gamma camera, as well as accurately demonstrate disease spread. Two of the benign pelvic masses localised 18FDG. The positive predictive value for detecting malignancy was 86%.

CONCLUSIONS

Dual head coincidence gamma camera offers accurate and affordable imaging in suspected ovarian masses, with improved specificity over CA125, ultrasound and computerised tomography. These results are similar to those obtained on more expensive dedicated PET systems. We report on a series of patients believed to have primary or recurrent carcinoma and recognise the need to include patients more likely to have benign lesions to assess false positive results. However, we believe that dual head coincidence gamma camera is useful in the pre-operative assessment of women with suspected ovarian cancer.

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

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.

Preoperative diagnosis of ovarian carcinoma with a novel monoclonal antibody

OBJECTIVE

This study was undertaken to determine whether preoperative radioimmunoscintigraphy of complex ovarian masses with technetium Tc 99m MAb-170 (Tru-Scint AD; Biomira Inc, Edmonton, Alberta, Canada), a murine whole immunoglobulin G monoclonal antibody that has been found to have panadenocarcinoma affinity, would predict surgical findings.

STUDY DESIGN

The age range of studied patients was 42 to 83 years (mean, 60.3 years). Planar computed tomographic imaging and single-photon emission computed tomographic imaging were performed at 15 minutes, 6 to 8 hours, and 18 to 24 hours after injection of 1000 MBq technetium Tc 99m MAb-170. Laparotomy was performed within 10 days.

RESULTS

Eighteen patients had borderline or invasive ovarian cancers verified by histologic examination. All primary malignancies or deposits (including intrahepatic deposits) yielded positive results on radioimmunoscintigraphic imaging. Radioimmunoscintigraphy was able to identify serosal deposits not seen on computed tomographic or ultrasonographic scans. False-positive localization of the antibody was noted in 6 of the 9 patients with benign pathologic processes.

CONCLUSION

It is possible to detect with technetium Tc 99m MAb-170 all patients who have cancer (including sites not seen on computed tomographic or ultrasonographic scan); however, the low specificity (33%) means that patients still require surgical verification of disease.

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.

Radioimmunoguided surgery in colorectal cancer using a genetically engineered anti-CEA single-chain Fv antibody

In radioimmunoguided surgery (RIGS), a radiolabeled antibody is given i.v. before surgery and a hand-held gamma-detecting probe is used to locate tumor in the operative field. The rapid blood clearance and good tumor penetration of single-chain Fv antibodies (scFv) offer potential advantages over larger antibody molecules used previously for RIGS. A Phase I clinical trial is reported on RIGS with scFv (MFE-23-his) to carcinoembryonic antigen (CEA). Thirty-four patients undergoing surgery for colorectal carcinoma (17 primary tumors, 16 liver metastases, and 1 anastomotic recurrence) and 1 patient with liver metastases of pancreatic carcinoma received 125I-labeled MFE-23-his scFv (125I-MFE-23-his) 24, 48, 72, or 96 h before operation. 125I-MFE-23-his showed biexponential blood clearance with alpha and beta half-lives of 0.32 and 10.95 h, respectively. The abdomen was scanned during surgery with a hand-held gamma detecting probe (Neoprobe Corp.). 125I-MFE-23-his showed good tumor localization; comparison with histology showed overall accuracy of 84%. Highest median ratios for tumor:normal tissue and tumor:blood were recorded 72 or 96 h after scFv injection for patients undergoing resection of liver metastases. High levels of radioactivity were found in the kidneys. Five patients had grade 1 fever, and three had a grade 1 rise in blood pressure according to the Common Toxicity Criteria. There was a significant correlation between these ratios and those measured in excised tissues using a laboratory gamma counter (P < 0.001). MFE-23-his scFv antibody localizes in CEA-producing carcinomas. The short interval between injection and operation, the lack of significant toxicity, and the relatively simple production in bacteria make MFE-23-his scFv suitable for RIGS.

Use of lung and brain perfusion imaging in the HELLP syndrome

Patients with multi-organ disorders may present with a plethora of confusing symptoms and signs. Often early diagnosis of significant disease is essential and can be difficult with standard radiological techniques. This case report presents the use of two radioisotopic techniques to assess brain and lung perfusion in a patient with such an acute-multi-organ disorder-the HELLP syndrome.

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.

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.

Cognitive impairment in patients with renal failure is associated with multiple-infarct dementia

PURPOSE

Patients undergoing long-term renal replacement therapy (such as dialysis) have an increased risk for significant cognitive impairment, which may result in memory problems and subsequently missed attendance at dialysis. The aim of this study was to try to identify any abnormalities of cerebral perfusion that could explain a patient's cognitive impairment and to determine if the pattern of these abnormalities would suggest a cause.

MATERIALS AND METHODS

17 patients (13 men; mean age, 60 years; age range, 29-74 years) in end-stage renal failure or on dialysis had SPECT imaging 10 minutes after injection of 550 MBq (15 mCi) Tc-99m HMPAO. Two of the patients had a history of previous stroke. Other risk factors for stroke were noted in most of the patients (hypertension in 10 patients, smoking or former smoking in 10 patients, and cardiac atherosclerosis in 7 patients). In all patients, attenuation correction was applied and the images were reconstructed into three sets of orthogonal slices. Activity in the frontal and temporal lobes was compared by quantification against the ipsilateral and contralateral cerebellum.

RESULTS

Discrete cortical defects consistent with infarcts were seen in 14 patients. The mean right and left frontal-to-cerebellar ratio was 0.837 (SD, 0.09) and 0.837 (SD, 0.08), respectively. This was not significantly different from the right and left temporal-to-cerebellar ratios of 0.843 (SD, 0.07) and 0.848 (SD, 0.07), respectively. Both were within normally accepted ranges.

CONCLUSIONS

Patients in end-stage renal failure who also had cognitive impairment appear to have a high number of cortical defects consistent with infarcts (suggesting a multiple-infarct type of dementia). There was no evidence of Alzheimer-type dementia.

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

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.

Report of the Radionuclides in Nephrourology Committee for evaluation of transplanted kidney (review of techniques)

Comprehensive evaluation of renal transplants has been important in differential diagnosis of medical and surgical complications in the early post-transplantation period and in the long-term follow-up. If performed well, it yields excellent functional and good anatomic information about the graft that can be effectively used in the patient. That includes selection of patients for biopsy and for various drug regimens. This is true especially in patients with anuric acute tubular necrosis (ATN) and in patients with developing chronic rejection. Improving indices of renal function (effective renal plasma flow, uptake of tubular tracers) can indicate resolution of tubular injury (ATN) while there is still no improvement in plasma creatinine. In patients with chronic rejection, plasma creatinine increases only after approximately 30% of renal function is lost due to graft fibrosis. Early recognition of this condition could permit treatment and delay of retransplantation. The protocol recommended at the Copenhagen meeting includes a flow study, scintigram of the kidneys, prevoid and postvoid bladder image, injection site image (quality control), time/activity curves of the graft and bladder, and quantitative data of perfusion, function, and tracer transit. The flow study obtained during the initial transit of the bolus through the graft could be performed either with 99mTc mercaptoacetyltriglycine, or 99mTc diethylenetriaminepentaacetate (DTPA). Quantitative analysis of perfusion facilitates interpretation of the study during the early post-transplantation period. ATN, common in cadaver transplants, typically shows adequate perfusion. The function phase should include images and time/activity curves. Images alone are insufficient. Quantitative data such as clearance or other indices of function and indices of tracer transit are essential for correct interpretation of the results. Normal images and normal graft function reliably exclude clinically important complications. A single scintigram demonstrating prolonged tracer transit with decreased function cannot separate acute rejection and ATN. On serial studies, decline in function and poor perfusion are indicative of acute rejection. A normally appearing scintigram without cortical retention, but with low function, is consistent with chronic rejection. Pharmacological intervention to exclude obstruction (diuretic renogram) or hemodynamically significant renal artery stenosis (angiotensin converting enzyme challenge) should be used whenever indicated.

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.

Carcinoid tumour

Carcinoid tumours are often indolent asymptomatic tumours. However, a small but significant proportion are malignant and difficult to manage. Multiple endocrine neoplasia type 1 (MEN-1) may be associated with carcinoid tumours and should therefore be considered in the investigation of these patients. This review puts into context the use of newer imaging modalities, including octreotide scintigraphy. The therapeutic treatment options are discussed, including the use of octreotide, the role of receptor-targeted therapy, hepatic-artery embolisation, and the arguments against chemotherapy. We review the need for careful patient selection when considering curative and palliative surgery, including liver transplantation. We conclude that there are now better diagnostic tools and therapeutic options available for those patients with malignant carcinoid tumours, and that these patients are best managed by a multidisciplinary approach. Earlier detection and treatment of these tumours should lead to improved quality of life and survival, which, ideally, should be assessed in formal trials.

The detection of struma ovarii in two patients by radioimmunoscintigraphy

Struma ovarii is a rare benign tumor of the ovary. These cases detail the first identification of this pathologic condition, in vitro, by radioimmunodetection and coregistration.

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.

Scintimammography with technetium-99m methoxyisobutylisonitrile: results of a prospective European multicentre trial

The aim of the trial was to determine the diagnostic accuracy of scintimmammography with technetium-99m methoxyisobutylisonitrile (99mTc-MIBI) in the detection of primary breast cancer and to verify its clinical usefulness. A total of 246 patients with a suspicious breast mass or positive mammogram were included in this prospective European multicentre trial. At 5 min and 60 min (optional) p.i. two lateral prone images were acquired for 10 min each; 30 min p.i. one anterior image was acquired for 10 min. There were 253 lesions (195 palpable and 58 non-palpable), in respect of which histology revealed 165 cancers and 88 benign lesions. Institutional and blinded read results were correlated to core laboratory histopathology results obtained during excisional biopsy. Diagnostic accuracy for the detection of breast cancer was calculated per lesion. The overall sensitivity and specificity of blinded read scintimammography were 71% and 69%, respectively. For palpable lesions, the sensitivity of blinded read and institutional read scintimammography was 83% and 91%, respectively. Sensitivity was not dependent on the density of the breast tissue. Invasive ductal and invasive lobular cancers showed similar sensitivity. The sensitivity and specificity of mammography were 91% and 42%, respectively, and did not depend on the tumour size. In 60% of false-negative mammograms, 99mTc-MIBI was able to diagnose malignancy (true-positive). High-quality imaging with 99mTc-MIBI has a high diagnostic accuracy for the detection of primary breast cancer. Used as a complementary method, scintimammography with 99mTc-MIBI can help to diagnose breast cancer at an earlier stage in patients with dense breasts.

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.

SPECT imaging of feet using uniplanar fad-beam collimators

BACKGROUND

This study was performed to assess the utility of bone SPECT in the feet using a new commercially available uniplanar fan-beam collimator originally designed for cardiac imaging.

METHODS

18 patients with symptoms or signs of probable skeletal pathology in either the foot or ankle were imaged using a two headed gamma camera fitted with uniplanar fan-beam collimators. All patients were imaged 2.5-4 h after administration of 500-750 MBq 99mTc MDP. If indicated planar dynamic and blood pool images were also obtained. The SPECT acquisition was performed in a 128 x 128 matrix, giving a pixel size of 2.00-2.30 mm depending on the radius of orbit. Images were displayed as transaxial, coronal and sagittal slices and a three dimensional volume rendered image and displayed for reading by three readers blind to the clinical results. Sites of abnormal uptake on the foot SPECT scan were then compared with the site of known or suspected pathology and in 17 patients with planar radiology.

RESULTS

The SPECT images produced using the uniplanar fan-beam collimators were of good quality in all patients with all three readers finding localisation easiest on the sagittal and three-dimensional images. In 10 patients abnormalities were found which could explain the patient's symptoms or signs and at the site expected from the patient's clinical history. In 5 patients there were abnormalities on the bone scan in the ipsilateral foot but at a different site, all were interpreted as degenerative disease. 2 patients had contralateral degenerative disease to side suggested by the clinical history and no abnormality in the bones of the foot with symptoms. One patient had bilateral degenerative disease. Planar radiology was normal or unhelpful in 13 of the 17 patients in which it was performed.

CONCLUSION

SPECT imaging of feet is possible and provides accurate localisation of abnormal uptake when performed using uniplanar fan-beam collimators with a standard acquisition time of 15 min for a double headed gamma camera.

The effect of chemotherapy on the uptake of technetium-99m sestamibi in breast cancer

Technetium-99m sestamibi scintimammography has been used primarily in the diagnosis of breast cancer. It has also been suggested that this technique could be used to monitor response to chemotherapy and possibly to predict those patients in whom no response can be expected. An initial study was performed in nine patients with primary breast cancer. All patients underwent prone lateral and anterior 99mTc-sestamibi imaging at diagnosis and 4-7 months later, after they had received cytotoxic chemotherapy. The uptake of 99mTc-sestamibi in the breast was compared with that in normal surrounding breast tissue and this ratio was expressed as the target to background ratio. In all patients treated there was a reduction in uptake of 99mTc-sestamibi after treatment, such that whilst all the tumours could be seen before treatment, only three were visible following chemotherapy. There was a significant fall in the mean target to background ratio of the patients undergoing chemotherapy: the tumour to background ratio was 2.48 before chemotherapy and 1.40 after treatment (P<0.001, paired Student's t test). This fall in tumour activity was observed both in those patients in whom a clinical response was seen and in the two patients in whom the tumour enlarged despite chemotherapy. It appears that the reduced uptake of 99mTc-sestamibi seen after chemotherapy may be a non-specific change and therefore may not be predictive of the clinical response to treatment.

Scintigraphic imaging of breast cancer: a review

Scintimammography is a recently verified technique that will expand the use of nuclear medicine to a new group of patients in whom scintigraphic imaging has not been widely used. If performed correctly, and in certain groups of patients, it delivers a sensitivity as high as X-ray mammography or magnetic resonance imaging (MRI) in palpable tumours but with greater specificity. It is best used in patients in whom X-ray mammography, ultrasound and MRI prove non-diagnostic or unhelpful, particularly those women with dense breasts or who have had previous breast surgery. The mechanism of uptake of 99Tcm-MIBI in breast tissue is only partly understood and in itself may help in determining important aspects of tumour function, such as the response to cytotoxic chemotherapy. Other scintigraphic methods for imaging breast cancer may be able to look at other aspects of cancer function, for example blood supply, metabolic rate or the in vivo assessment of oestrogen or somatostatin receptor status. This in turn may be useful in planning treatment. Metastatic disease may best be monitored with 18F-FDG PET, which has a sensitivity greater than MRI but a similar specificity. Much furtner work will need to be done on the use of nuclear medicine in breast cancer, but the addition of unique functional information to the anatomical data from X-ray and MRI should benefit future patients' management.

Uptake of Tc-99m MIBI related to tumour size and type

The accuracy of Tc-99m MIBI scintimammography depends on the uptake in cancer cells being greater than surrounding normal tissue. The aim of this study was to determine which were the dominant factors affecting uptake of Tc-99m MIBI in breast cancer cells in vivo. The tumour to background ratio (TBR) was measured in 74 focal breast lumps occurring in 70 women, of whom 53 had breast cancer. In patients with breast cancer the TBR was compared in those under and over 45, those with tumours over and under 20 mm, those who had auxiliary disease, the histological type of the tumour and whether ductal on the Bloom Richardson scale. The only factor which appeared to have an influence on uptake of Tc-99m MIBI was the histological type of the tumour. Ductal carcinomas had a mean TBR of 2.07, significantly greater than either other types of breast cancer (TBR = 1.31) and benign tumours (TBR = 1.46). The histological type of tumour appears to be the dominant factor affecting uptake of Tc99m MIBI in vivo.

Computer-generated attenuation correction does not improve the accuracy of myocardial perfusion scintigraphy

A short study was performed to determine if it is possible to increase the accuracy of thallium-201 (201T1) single photon emission tomographic myocardial perfusion imaging using computer-generated ('Chang') attenuation correction. The stress and rest myocardial perfusion studies from 22 patients with suspected or known ischaemic heart disease were reconstructed with and without "Chang' attenuation correction. For all patients, the scintigraphy results were compared with those of coronary angiography. Attenuation correction improved the accuracy of 201T1 myocardial perfusion imaging for defining myocardial ischaemia or infarction in 8% of coronary artery territories (23% of patients), but it was worse in 5% of coronary artery territories (14% of patients). These changes were not significant (McNemar's test). Therefore, computer-generated 'Chang' attenuation correction does not appear to improve the accuracy of myocardial perfusion scintigraphy. It is important that all techniques suggested to improve the accuracy of clinical images should be tested on patients before being widely used.

Clinical evidence of efficient tumor targeting based on single-chain Fv antibody selected from a combinatorial library

We present a system for cancer targeting based on single-chain Fv (scFv) antibodies selected from combinatorial libraries, produced in bacteria and purified by using an engineered tag. Combinatorial libraries of scFv genes contain great diversity, and scFv antibodies with characteristics optimized for a particular task can be selected from them using filamentous bacteriophage. We illustrate the benefits of this system by imaging patients with carcinoembryonic antigen (CEA)-producing cancers using an iodine-123 labeled scFv anti-CEA selected for high affinity. All known tumor deposits were located, and advantages over current imaging technology are illustrated. ScFvs are produced in a cloned form and can be readily engineered to have localizing and therapeutic functions that will be applicable in cancer and other diseases.

Epirubicin-Lipiodol chemotherapy versus 131iodine-Lipiodol radiotherapy in the treatment of unresectable hepatocellular carcinoma

BACKGROUND

Arterially administered iodized oil (Lipiodol) is selectively retained by hepatocellular carcinomas (HCCs), and has been used as a vehicle for delivery of therapeutic agents to these tumors. This study compared the efficacy of Lipiodol-targeted epirubicin chemotherapy with Lipiodol-131I radiotherapy.

METHODS

Ninety-five patients with unresectable HCC confined to the liver were administered either Lipiodol-epirubicin emulsion (n = 69; 61 cirrhotics; Okuda tumor Stage I, 14; II, 37; III, 18; epirubicin dose, 75 mg/m2) or Lipiodol-131I (131I) (n = 26; 18 cirrhotics; Okuda tumor Stage I, 6; II, 19; III, 1; dose 750-1050 MBq). The last 28 patients (17 epirubicin, 11 131I) were treated within a prospective randomized trial. Bolus drug or isotope was injected into the hepatic artery by transfemoral cannulation. Lipiodol and 131I uptake were gauged by 10th day computed tomography and 48-hour scintiscan. Treatments were repeated two-monthly when indicated.

RESULTS

Tumor size at 2 months remained static or diminished partially in 21 of 38 epirubicin recipients (55%) and 15/22 131I recipients (68%). Actuarial survival at 6, 12, and 24 months was 40%, 25%, and 6% with epirubicin, and 58%, 25%, and 0% with 131I; 30-day mortality was 11% and 15%, respectively. Comparison with historic controls indicated survival benefit in Stages I and II. Similar findings were recorded in the 28 patients in the randomized trial.

CONCLUSIONS

Patients with unresectable HCC receiving Lipiodol-epirubicin or Lipiodol-131I show good tumor localization, acceptable toxicity, and comparable survival benefit at 6 and 12 months with either modality.

Case report: localization of lipiodol-radioiodine in hepatic metastases from renal cell carcinoma

Lipiodol, an iodinated derivative of poppyseed oil, is selectively retained in hepatocellular carcinoma and has been used as a vehicle to deliver localized doses of chemotherapeutic and radioactive agents to such tumours, thereby reducing the problems of external beam irradiation and the systemic toxicity of chemotherapy. We describe the first reported case where Lipiodol-targeted radiotherapy has been administered to a patient with secondary renal cell carcinoma in the liver. Localization was good and there were no complications. This case suggests that in future such patients may benefit from this therapy for unresectable lesions.

Diagnostic value of radionuclide phallography with intravenous vasodilator stress in the evaluation of arteriogenic impotence

Arteriogenic impotence is a major cause of organic erectile dysfunction. We evaluated the diagnostic value of quantitative radionuclide phallography with intravenous pharmacological stress in screening impotent patients for penile arterial inadequacy. Using technetium-99m labelled autologous erythrocytes, dynamic scintigraphy of the penile blood pool was performed. Penile haemodynamic changes following intravenous injection of the vasodilator isoxsuprine hydrochloride were assessed by quantitation of penile blood flow and volume. Forty-seven impotent patients (11 psychogenic, 24 arteriogenic, 10 venogenic, 2 endocrine) were studied. Arteriogenic impotent patients demonstrated a lesser degree of increase in penile blood flow and volume than impotent patients with uncompromised penile arterial inflow. Quantitation of penile blood flow and volume yielded a high diagnostic accuracy (> 90%). Radionuclide phallography with intravenous vasodilator stress forms a simple and accurate method for evaluating the functional integrity of penile arterial inflow.

Scintigraphic evidence of abnormal ureteric peristalsis following urological surgery

OBJECTIVE

To investigate the effect of urological surgery on ureteric peristaltic activity.

SUBJECTS AND METHODS

Ureteric peristalsis was assessed in a sample urological population (n = 29 patients) and the findings compared with a control population (n = 14 patients).

RESULTS

The incidence of disordered peristalsis was significantly increased (P < 0.05) following urological surgery and, in particular, the incidence of retrograde peristalsis was very significantly increased (P < 0.01) following ureteric division and re-anastomosis.

CONCLUSION

The results of this study are consistent with a central role for myogenic activity in the conduction of ureteric peristalsis in man.