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Biomedical subjects

A J Hilson

Publications and source records attributed to A J Hilson.

At least 37 records · Page 2Linked to original sources
PubMed1999

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.

Journal Article↗
PubMed1998

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.

Carcinoid Tumor↗
PubMed1998

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.

Breast Neoplasms↗
PubMed1998

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.

Adult↗
PubMed1998

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.

Aged↗
PubMed1998

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.

Journal Article↗
PubMed1997

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.

Adult↗
PubMed1997

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.

Coronary Angiography↗
PubMed1997

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.

Breast Neoplasms↗
PubMed1996

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.

Adult↗
PubMed1995

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.

Actuarial Analysis↗