The prognostic value of baseline (18)F-FDG PET/CT in steroid-naïve large-vessel vasculitis: introduction of volume-based parameters.

PURPOSE: The aim of this study was to analyse if the result of a baseline (18)F-fluorodeoxyglucose (FDG) positron emission tomography (PET)/CT scan, in large-vessel vasculitis (LVV) patients, is able to predict the course of the disease, not only in terms of presence/absence of final complications but also in terms of favourable/complicated progress (response to steroid therapy, time to steroid suspension, relapses, etc.). METHODS: A total of 46 consecutive patients, who underwent (18)F-FDG PET/CT between May 2010 and March 2013 for fever of unknown origin (FUO) or suspected vasculitis (before starting corticosteroid therapy), were enrolled. The diagnosis of LVV was confirmed in 17 patients. Considering follow-up results, positive LVV patients were divided into two groups, one characterized by favourable (nine) and the other by complicated progress (eight), on the basis of presence/absence of vascular complications, presence/absence of at least another positive PET/CT during follow-up and impossibility to comply with the tapering schedule of the steroid due to biochemical/symptomatic relapse. Vessel uptake in subjects of the two groups was compared in terms of intensity and extension. To evaluate the extent of active disease, we introduced two volume-based parameters: "volume of increased uptake" (VIU) and "total lesion glycolysis" (TLG). The threshold used to calculate VIU on vessel walls was obtained by the "vessel to liver" ratio by means of receiver-operating characteristic analysis and was set at 0.92 × liver maximum standardized uptake value in each patient. RESULTS: Measures of tracer uptake intensity were significantly higher in patients with complicated progress compared to those with a favourable one (p < 0.05). Measures of disease extension were even more significant and TLG emerged as the best parameter to separate the two groups of patients (p = 0.01). CONCLUSION: This pilot study shows that, in LVV patients, the combined evaluation of the intensity and the extension of FDG vessel uptake at diagnosis can predict the clinical course of the disease, separating patients with favourable or complicated progress.

New radiopharmaceutical agents for the treatment of castration-resistant prostate cancer.

Prostate cancer (PCa) is the fourth most common cancer worldwide in terms of incidence and third among male, but is becoming the most common cancer in developed countries. In many patients the disease will progress despite of castration levels of testosterone, to become castration-resistant PCa (CRPC). Nearly all patients with CRPC show bone metastases. The treatment of patients with bony metastases has dramatically changed during the past three years because of new therapeutic approaches addressed to obtain pain control, reduced skeletal morbidity, and most importantly, increased survival rate. A possible therapy can be based also on the use of radiopharmaceuticals systemically administered to slow or reverse the bone metastatic progression. In facts bone-homing radiopharmaceuticals are taken up in areas of high bone turnover, including areas with high osteoblastic activity. Recently, a bone targeting radiopharmaceutical, Radium-223 dichloride was added to this group of drugs clearly representing a new generation of radiopharmaceutical in bone therapy. Clinical trials had shown that the treatment with Ra-223 allowed the reduction of the risk of death respect to placebo. No other radiometabolic treatment achieved such result, evidentiating the disease-modifying properties of this bone-homing radiopharmaceutical. In an effort to treat patients with disseminated PCa, who became resistant to hormonal therapy, molecular targets have been recently identified. Prostate specific membrane antigen (PSMA) is one attractive target for diagnosis and therapy of metastasized PCa since its expression levels are directly correlated to androgen independence, metastasis, and progression. Gastrin-releasing peptide receptors (GRPr) are also highly overexpressed in PCa. Numerous studies suggest the possibility of a high PCa-specific signal with radiolabeled bombesin analogs targeting GRPr. Low molecular weight peptides directed against these molecular targets have been radiolabeled with positron emitting radionuclides such as 68Ga in order to improve sensitivity and specificity for detecting primary, metastatic, and recurrent PCa by PET/CT over conventional imaging techniques. Although peptide radionuclide ligand therapy studies have just initiated, the diagnostic relevance of 68Ga labeled specific tracers has already been established its clinical utility and represents a valid tool against this common and deadly cancer.

[Radiometabolic therapy for metastatic thyroid carcinoma: overview of the literature and rational bases for the use of recombinant human TSH]. / La terapia radiometabolica del carcinoma della tiroide metastatico: overview della letteratura e basi razionali all'utilizzo del TSH umano ricombinante.

The established treatment for differentiated thyroid carcinoma (DTC) is founded on total thyroidectomy and subsequent administration of radioiodine (131I) to ablate the thyroid remnant and to treat the metastatic disease. In the case of metastatic or recurrent disease, further cycles of 131I therapy are often necessary. The condition for maximizing the effectiveness of the treatment is to have an adequate stimulation from TSH, which must be >25-30 mIU/L. This elevation is achieved either discontinuing the hormone suppression therapy for an appropriate period, or administering recombinant human TSH (rhTSH). The latter has shown good clinical efficacy in patients with residual thyroid gland and is nowadays commonly employed since it is easy to use and allows to avoid the side effects of hypothyroidism. It thus represents a good alternative to thyroid hormone withdrawal for the remnant ablation, while is still open the question if its efficacy on the management of metastatic disease is superimposable to thyroid hormone withdrawal. To this purpose, a Panel of expert reviewed the literature, assessing the advantages and disadvantages for the patient, as well as the impact in terms of cost and benefit to the National Health Service. The work of the Panel concluded with a proposal for the use of rhTSH in selected patients with metastatic DTC, in which is considered the efficacy and safety of the product and is examined its use in terms of costs; this proposal was accepted by the Italian Drug Agency resulting in an update of the indications for rhTSH.

CA 15.3 determination in patients with breast cancer: clinical utility for the detection of distant metastases.

In 81 healthy women, 26 pregnant women, 25 patients with fibrocystic disease and 144 breast cancer patients, the overall diagnostic sensitivity and specificity of the CA 15.3 test was 27 and 97%, respectively. The positive and negative predictive values were 93 and 43%. In 150 node-negative patients taking part in a chemoprevention trial CA 15.3 was assayed at baseline and every 4 months for a median follow-up of 24 months (range 4-48). In these patients, 5 had local recurrences, 1 had a regional recurrence, 9 had distant metastases and 3 developed cancer in the contralateral breast. Among the patients with recurrences, those with distant metastases showed the highest ratio of CA 15.3 increase (8/9); in local and regional recurrences, this ratio was lower (2/6). The patients with contralateral breast cancer had no significant increase in CA 15.3. Patients in whom metastases were detected showed an increase in CA 15.3 4-48 months before clinical or instrumental detection of the metastases.

Cationic complexes of technetium for myocardial imaging.

Over the past 15 years a major goal of research in cardiovascular nuclear medicine has been the development of 99mTc complexes that could replace 201Tl and thus enhance the utility of myocardial perfusion imaging. This paper presents an overview of the current state-of-art of the development of cationic 99mTc complexes for this purpose. Cationic 99mTc complexes that have been evaluated as myocardial perfusion imaging agents in human volunteers and/or animals are discussed and classified on the basis of the oxidation state of the technetium center.

Gallium-67 scintigraphy evaluation of therapy in non-Hodgkin's lymphoma.

UNLABELLED: Patients with diffuse large cell lymphoma may achieve complete remission (CR) after chemotherapy, and the time to reach CR may be predictive of treatment outcome. Partial remission, or recurrence from CR, is associated with poor survival. Gallium-67 imaging has proven to be useful in evaluating lymphoma patients. In tumor models, this radiotracer is an indicator of tumor viability. Gallium-67 uptake is seen only in avid and viable lymphoma tissue, not in fibrotic or necrotic tissue. In this study, we prospectively assessed the ability of this radiotracer to define residual disease. In addition, we evaluated the possibility of predicting the clinical outcome in patients with diffuse cell lymphoma on the basis of scan positivity during chemotherapy. METHODS: Thirty-three consecutive patients with histologically proven diffuse large cell lymphoma were investigated with 67Ga scintigraphy 48-72 hr after injection of 185-259 MBq 67Ga-citrate for staging and during follow-up after four to six cycles of intensive chemotherapy. Patients were monitored for a mean of 56.0 mo (range 7-90 mo), and they were restaged using physical examination, CT and all necessary imaging modalities. RESULTS: Patients were divided into two groups according to the positivity or negativity of 67Ga scan after four to six cycles of chemotherapy. Of the 33 patients studied, 14 (42.4%) showed persistent abnormal uptake of 67Ga-citrate after four to six cycles of chemotherapy. In this group, 9 patients (64.2%) died of lymphoma at a mean of 24.3 mo from presentation with the diagnosis (range 7-71 mo). Four patients had no evidence of disease at an average of 71.7 mo after diagnosis, and 1 patient was considered to be in partial remission. In the second group of 19 67Ga-negative patients, after four to six cycles of chemotherapy, 4 died and 15 are alive and considered to be in CR. A statistical analysis of the association between 67Ga scan results after four to six cycles of chemotherapy and survival was performed using the log-rank test; there was a statistically significant association between scan results and survival (p=0.00125). CONCLUSION: We conclude that 67Ga scintigraphy is an excellent predictor of residual tumor viability in lymphoma patients and that persistent positivity of the scan predicts poor outcome and may justify a change in treatment.

Assessment of mediastinal involvement in lung cancer with technetium-99m-sestamibi SPECT.

UNLABELLED: This study evaluated the clinical role of SPECT with sestamibi versus CT in the presurgical staging of lung cancer. METHODS: Forty-seven consecutive patients (44 men, 3 women; mean age 63.3 yr, range 49-82 yr) with clinical and radiological suspicion of lung cancer were enrolled in this study. Staging procedures including radiography, CT, fiberoptic bronchoscopy and sestamibi SPECT of the thorax. Radionuclide imaging was performed after intravenous injection of 740-925 MBq of sestamibi. In 36 patients a histological diagnosis was made, and these patients were evaluated for the study of mediastinal lymph node involvement. RESULTS: Mediastinal lymph node involvement was demonstrated in 11 of the 36 patients evaluated. Sestamibi SPECT correctly staged 10 of 11 patients with and 21 of 25 without mediastinal nodes, showing a diagnostic sensitivity of 91% and a specificity of 84%. Computed tomography gave 8 true-positive and 15 true-negative results, with a sensitivity of 73% and a specificity of 60%. Sestamibi SPECT results were also better than those of CT with regard to positive and negative predictive values and accuracy. CONCLUSION: The clinical role of sestamibi SPECT can be fully appreciated when the technique is used in selected patients, combined with CT or MRI, or both, to assess mediastinal involvement and avoid any invasive staging procedures.

Scintigraphic detection of melanoma metastases with a radiolabeled benzamide ([iodine-123]-(S)-IBZM).

UNLABELLED: Iodine-123-(S)-2-hydroxy-3-iodo-6-methoxy-N-[(1-ethyl-2-pyrrolidinyl) methyl] benzamide ([123I]-(S)-IBZM) is a radiolabeled benzamide usually employed to study neuropsychiatric disorders, such as schizophrenia and Parkinson's disease. The ectodermic origin of melanocytes and the presence of melanin in the substantia nigra are the theoretic basis of the experimental use of this class of tracers for melanoma imaging. METHODS: Eleven patients with proven metastatic melanoma entered the study. Whole-body and planar scintigrams were performed 2, 4 and 24 hr after intravenous injection of a mean tracer activity of 205 MBq. The dosimetric evaluation was performed by the Medical Internal Radiation Dose Committee method. RESULTS: The [123I]-(S)-IBZM scans allowed the detection of all six cutaneous lesions, five of six superficial pathologic lymph nodes, four of five pulmonary and one of two hepatic metastases. The maximum tumor-to-background ratio was 2.6 in planar images. The hepatobiliary excretion of the tracer may limit detection of intra-abdominal lesions. Dosimetry is similar to data for nononcologic patients. CONCLUSION: Although it is unclear if the mechanism of radiopharmaceutical uptake in melanoma is due to binding to membrane receptors or due to interactions with intracellular structures, radiolabeled benzamide is a promising tracer to detect melanoma.

Lack of tissue-specificity of mucin markers in a lung-cancer model - biochemical approach.

Mucin-associated epitopes are recognized by monoclonal antibodies in the immunometric assays used for the diagnosis and monitoring of cancer. The recently developed new assays measure mucins as tumor markers, assuming that each mucin is associated with a particular tumor site, i.e. CA 15.3 and MCA with breast cancer, CA 125 with ovarian cancer, CA 19.9 and CA 195 with colon and pancreatic cancer. These associations are based on the frequency and the intensity of expression of the single markers for a certain organ. However, this theoretical organ specificity is not absolute, since the mucins are expressed also by tumors other than those mentioned above and they may also be present in inflammatory conditions and in normal tissues. These observations were confirmed by the present study, which used an experimental model consisting of a pool of 20 lung tissue samples (10 normal and 10 cancer). The tissue concentrations of the mucins MCA, CA 15.3, CA 125, CA 19.9, and of the glycoprotein CEA, were measured both in malignant tissue samples and in their normal counterparts. The marker levels were detected by immunometric assays in mucin fractions separated from the tissue extract by chromatographic methods. The comparison of the chromatographic profiles and the evaluation of the mucin levels in normal and malignant lung tissue specimens confirmed the absence of tissue specificity of these biochemical parameters. Recent developments in molecular biology and the discovery of genes coding for several apomucins may open new perspectives towards the understanding of the mechanisms regulating mucin pathways.

Current applications and perspectives of diagnostic nuclear medicine in oncology. Task Group of Oncology.

The characteristic of nuclear medicine is that it gives images of organs, structures and physiological or pathological processes, detecting the distribution of several radio-pharmaceuticals according to their uptake and metabolism. Its imaging can provide morphological information while at the same time containing data on cellular activity and functions. Such molecular imaging fulfils the modern orientations of oncology, where there is a need to define the presence of a malignancy in the earliest and most effective way, to characterise the neoplasm in terms of biological characteristics (e. g., proliferation, aggressiveness, differentiation, receptor status) and to obtain fundamental issues in patient management such as evaluation of disease extent, monitoring of therapies and study of treatment-induced side effects. The aim of this position paper is to discuss the main indications of nuclear medicine in diagnostic oncology reporting the most recent developments in nuclear medicine, and an extensive list of the major indications for nuclear medicine procedures. The techniques have been labelled as when considered essential in the diagnostic process, when they can give useful additional or information in combination with other instrumental diagnostic approaches, and alternative when they may be performed instead of other tests. These indications were derived by a general consensus within the Task Group of Oncology of the World Federation of Nuclear Medicine and Biology, and it should be stressed that only the current role of nuclear medicine was considered. The Task Group does not claim to have covered the entire range of nuclear medicine indications; in fact it was agreed to include only the most widely used techniques. The highly specific or very exceptionally used applications, or those still in development or under evaluation in clinical trials were not taken into consideration. The conclusion is that the current relationship between nuclear medicine and oncology can be defined not only as satisfactory but also as extremely promising, as nuclear medicine has the potential to compete with the most advanced radiological techniques of imaging, perhaps not so much in terms of sensitivity but more so in terms of specificity and biological characterisation. Several novel diagnostic procedures are able to solve clinical problems for which traditional radiology has shown clear limitations. Nuclear medicine remains today a dynamic medical specialty because it includes a combination of advances in basic science research, technology, cell biology and medical practice and it cannot be excluded that the new lines of research both towards new radiopharmaceuticals and advanced instrumentation will offer in the future new stimulating opportunities.

Axillary lymph node metastases detection with nuclear medicine approaches in patients with newly diagnosed breast cancer.

Three different tracers, Tc-99m-Sesta MIBI, In-111-Pentetreotide and F-18-FDG, were evaluated in a preliminary study in three different groups of 10 breast cancer patients programmed for breast cancer resection and axillary dissection. Planar scintigraphy and single photon emission tomography (SPET) technique were used for imaging with Tc-99m-Sesta-MIBI and In-111-Pentetreotide, positron emission tomography (PET) was used for imaging with F-18-FDG. We studied 30 breast cancer patients; their clinical stage according to the TNM classification was 30 T1-T2, 1 T4 and 1 Tx (one patient had bilateral cancer and one had bifocal cancer). The lymph nodal status ranged from NO to N2 (14 NO, 16 N1, 1 N2). Tc-99m-Sesta MIBI, In-111 Pentetreotide SPET and F-18-FDG PET were randomly performed before surgery to visualize the primary tumors and to detect axillary lymph node invasion. Tc-99m-Sesta MIBI correctly visualized 10 out of 11 primary cancers in 10 patients. In-111-Pentetreotide detected 9 out of 10 primary cancers. F-18-FDG imaged all the tumors (10). As regards the axillary nodes, Tc-99m-MIBI excluded axilla involvement in 7 out of 7 negative axillae (N-), while it was positive in 2 out of 3 positive cases (N+); In-111-Pentetreotide correctly identified 7 out of 8 negative axillae (N-), while it detected 2 of 3 positive sites. F-18-FDG visualized all positive axillary lymph nodes (4 out of 4 N+ patients) and correctly excluded involvement in all negative patients (6 out of 6 N- cases). This study demonstrated that all three tracers are adequate to be proposed as tumor seeking agents with the aim of developing non-invasive diagnostic methods for pre-operative detection of axillary metastases, so that surgical dissection can be limited to selected patients. The authors discuss the advantages and disadvantages of the different radiopharmaceuticals and conclude that in centers with PET facilities F-18-FDG is the best tumor seeking agent for the evaluation of axillary status. Between Tc-99m-Sesta MIBI and In-111-Pentetreotide the former seems to present more advantages in this kind of application, considering also its lower cost and easier availability. These results encourage further study, including the simultaneous comparison of these tracers in breast cancer staging.

Comparing reconstruction with Roux-en-Y to a pouch following total gastrectomy.

BACKGROUND: Although more than 50 methods of gastric replacement after total gastrectomy have been used, none of them has demonstrated a substantial nutritional advantage. The Roux-en-Y esophagojejunostomy is still the preferred type of reconstruction, more because of its simplicity than the lack of postprandial disturbances. STUDY DESIGN: A randomized controlled trial was conducted to compare two reconstructive procedures, Roux-en-Y esophagojejunostomy (n = 24) and Hunt-Rodino-Lawrence pouch (HRL, n = 24), by evaluating nutritional status (body weight, arm circumference, and serum nutritional parameters), nutritional habits (number of meals, energy intake, and postprandial disturbances), and emptying time of the jejunal loop. RESULTS: Twenty-seven patients were studied two years after operation (12 had undergone Roux-en-Y and 15 had undergone HRL). No difference was found in either postoperative morbidity or mortality, emptying time, frequency of meals, or variation of body weight. Postprandial disturbances were more frequent in patients having Roux-en-Y. In a subset of patients, there was a correlation between nutrient intake and change of body weight, but not between nutrient intake and type of reconstruction. CONCLUSIONS: The simple use of a reservoir such as the HRL pouch after total gastrectomy is of no benefit to the patient as compared with the Roux-en-Y reconstruction.

Unusual association between cutaneous melanoma and axillary metastasis from occult breast cancer detected by sentinel node biopsy.

We report a case of cutaneous Stage I melanoma associated with occult breast cancer detected incidentally during a sentinel node biopsy. A brief review of the literature is presented with particular emphasis on this association and on an examination of the theoretical link which may exist between melanoma and breast cancer.

Prone scintimammography in patients with non-palpable breast lesions.

Non-palpable breast lesions are a clinical problem due to the low specificity of mammography and the resulting difficulty in choosing the type and extent of surgery. Twenty-four patients with non-palpable mammographic lesions underwent prone scintimammography after the i.v. injection of 740 MBq of 99m Tc-SestaMIBI (MIBI). For this purpose, we designed a special bed which allows the widest exposure of the breast to the detector and better visualisation of deep mammary tissue without interference from intra-thoracic activity. The day after the scintigraphy, all patients underwent quadrantectomy or a more limited excision. The specimens were X-rayed to check the presence of mammographic microcalcifications or opacities. All surgical specimens were histologically evaluated. The mammographic and scintigraphic findings were compared with the histological ones. Under these conditions, we observed that the MIBI scan has a good specificity (90%) but low sensitivity (50%) for this selected population. When the MIBI scan was positive, the probability of breast cancer was very high (positive predictive value of the test = 88%) as a consequence, a wider excision would be the most accurate surgical choice. On the other hand, if the MIBI scan is normal, the high number of false negative results does not allow any final diagnosis (negative predictive value of the test = 56%). The preliminary results of this work suggest that radionuclide imaging can help the surgeon in surgical planning.

Pilot, multicenter and prospective trials with an anti-CEA antibody.

In this paper we summarize the investigations performed by our group utilizing an anti-CEA monoclonal antibody (F023C5) labelled with different radionuclides in humans. Since 1983 radioimmunoscintigraphy (RIS) was performed on 51 patients with 64 localizations of colo-rectal carcinoma (pilot study). A multicenter clinical trial in a large number of patients (509 pts of which 284 with gastrointestinal cancer) was subsequently carried out in collaboration with ten nuclear medicine centres. High sensitivity and specificity values were obtained by these studies and many unsuspected lesions were recorded. In order to better define the clinical role of RIS, a prospective study was performed on 59 patients with suspected local relapses of colo-rectal cancer. A comparative evaluation of RIS, CT scan, US and MRI was done. RIS and MRI had the highest accuracy (86%) followed by CT scan (68%) and US (54%).

Enhancement of in vivo monoclonal antibody targeting with recombinant interferon and cytokines.

Up to now a number of studies have been performed to determine whether the combined use of cytokines and monoclonal antibodies (MAbs) directed against tumor-associated antigens (TAA) can increase the sensitivity of radioimmunoscintigraphy (RIS). It is well known that human natural and recombinant interferons can enhance the cell surface expression of HLA Class I and II antigens as well as some specific tumor antigens, but there is scanty and conflicting information about the expression and shedding of TAA. Some authors reported that alpha-IFN enhances the expression of a melanoma-associated antigen (MAA), recognized by conventional antiserum. Other authors have found no changes in the expression of MAA identified by MAbs. In a pilot study on patients with malignant melanoma Rosenblum demonstrated an increase in tumor uptake of the anti-melanoma MAb 96.5 after IFN administration. In our study we performed immunoscintigraphy with the anti-melanoma MAb 225.28S in the same patient before and after IFN administration in different doses. We point out the difference in biodistribution in different organs and in blood clearance and discuss the possibility to improve the sensitivity of RIS.

99Tcm-MIBI single photon emission tomography (SPET) for detecting myocardial ischaemia and necrosis in patients with significant coronary artery disease.

The ability of 99Tcm-methoxyisobutylisonitrile (MIBI) single photon emission tomography (SPET) to detect myocardial ischaemia and necrosis was assessed in 56 patients (45 male, 11 female, aged 55 +/- 5 years), with clinically recognized ischaemic heart disease (IHD). All underwent coronary angiography (CA) and left ventriculography (LV). SPET images were obtained at rest and at peak exercise (Modified Bruce) 90 min after injection of 99Tcm-MIBI (650-850 MBq). Data were acquired in 30 min over 180 degrees (from 45 degrees RAO to 45 degrees LPO) with no correction for attenuation, using a 64 x 64 matrix. The presence of persistent (P) or reversible (R) perfusion defects (PD) was then correlated to the resting and exercise ECG and to the results of CA and LV. Of the 56 patients, 34 had reversible underperfusion (RPD), 46 persistent underperfusion (PPD) and 31 had both. The occurrence of RPD correlated well with the occurrence of exercise-induced ST segment depression and/or angina (27 patients of 34 patients, 79%) and with the presence of significant coronary artery disease (CAD) (33 of 44, 73%). In 45 of 46 patients (98%) PPD corresponded to akinetic or severely hypokinetic segments (LV) usually explored by ECG leads exhibiting diagnostic Q waves (42 of 46 patients, 91%). The scan was normal both at rest and after stress in four of 11 patients with no CAD, and in two of 45 patients with CAD. Finally, an abnormal resting scan was seen in seven of 11 patients with normal coronary arteries, of whom six had regional wall motion abnormalities.(ABSTRACT TRUNCATED AT 250 WORDS)

Applications of 99mTc-sestamibi in oncology.

Hexakis (2-methoxyisobutylisonitrile) technetium-99m (99mTc-SestaMIBI) is a radiopharmaceutical used in nuclear medicine for myocardial perfusion imaging. In the literature different non-cardiac applications of 99mTc-SestaMIBI have been reported. Clinical studies have been performed also in non-oncologic disease (such as thyroid adenoma, diabetic foot, osteomyelitis, pulmonary actinomycosis, aneurysmal bone cyst. Sudeck's atrophy). Several models for the uptake mechanism of this radiopharmaceutical have been proposed such as binding to an 8-10 kDa cytosolic protein, simple lipid partitioning, or a membrane translocation mechanism involving diffusion and passive transmembrane distribution. Most evidence points in the direction of the third hypothesis. Many studies have indicated that uptake of hexakis (alkylisonitrile) technetium complexes is dependent on mitochondrial and plasma membrane potentials like other lipophilic cations. This explains the initial biodistribution of 99mTc-SestaMIBI to tissues with negative plasma membrane potentials and with relatively high mitochondrial content (like heart, liver, kidney and skeletal muscle tissue). Malignant tumours also possess these properties in order to maintain their increased metabolism. This behaviour encouraged the study of 99mTc-SestaMIBI as an interesting tracer imaging various tumour types: osteosarcoma, brain, lung, breast, nasopharyngeal, parathyroid and thyroid cancer. Recent research on cell cellular physiology has further revealed an active transport of 99mTc-SestaMIBI out of the tumour cells, against the potential gradient. The same mechanism is also responsible for resistance to a structurally and functionally different group of cytotoxic agents such as vinca alkaloids, epipodophyllotoxins, anthracyclins and actinomycin D. This peculiar type of resistance is due to amplification of the mammalian MDR1 gene, located on chromosome 7. For this reason the 99mTc-SestaMIBI uptake in vivo could permit the prediction of the response to the chemotherapy, when the decreased accumulation of 99mTc-SestaMIBI implies the presence of P-gp enriched tissues. In the next future a particular attention should be dedicated to this matter since one of the most important goals of the clinical trials is the demonstration of the usefulness of 99mTc-SestaMIBI for in vivo assessment of multidrug resistance.

Clinical utility of radioimmunoscintigraphy of non-Hodgkin's lymphoma with radiolabelled LL2 monoclonal antibody, LymphoSCAN: preliminary results.

AIMS AND BACKGROUND: Adequate clinical staging of non-Hodgkin's lymphoma patients is essential because only localized disease can be treated satisfactorily. Many imaging procedures are necessary to stage the disease accurately. The objective of this study was to evaluate the efficacy of an antilymphoma antibody in the Fab' fragment form, labelled with 99mTc, to detect malignant lesions. METHODS: Radioimmunodetection (RAID) with 99mTc-labelled B-cell lymphoma monoclonal antibody IMMU-LL2-Fab' (LymphoSCAN; Immunomedics, Morris Plain, NJ, USA) was investigated in 10 patients (5 females and 5 males; age range, 20-72 years) with histologically proved non-Hodgkin's lymphoma. Of the 10 lymphomas, 7 were intermediate grade and 3 were low grade. Whole body images with multiple planar views were obtained at 30 min, 4-6 and 24 h after i.v. injection of 1 mg LL2-Fab' labelled with 740-925 MBq of 99mTc. SPET of the chest or abdomen was performed in all patients 5-8 h after the immunoreagent injection. RESULTS: No adverse reactions were observed in any patient after Mab infusion, and no appreciable changes were seen in the blood counts, renal or liver function tests. A total of 18 of 21 (85.7%) lymphoma lesions were detected by RAID. All the tumor localizations were confirmed by clinical examination and with other imaging techniques, such as CT scan, MRI or gallium scan. In this series of patients no false-positive results were noted. As regards the biodistribution of the immunoreagent, no appreciable bone marrow activity was seen; splenic targeting was demonstrated in all patients; the tumor-to-non-tumor ratios ranged from 1.2 to 2.8 ad measured by the ROI technique; no difference in uptake was noted for different tumor grades. The images obtained 24 h after injection did not reveal new lesions, but areas of doubtful uptake were seen as positive focal areas in the delayed scan. CONCLUSIONS: LymphoSCAN seems to be useful for detection, staging and follow-up of non-Hodgkin's lymphoma patients.