Ergebnisse der Radiojod-Behandlung von Patienten mit immunogener und nicht-immunogener Hyperthyreose bei Anwendung unterschiedlicher Herddosen

The aim of this study was to check the efficacy of radioiodine (131I) therapy (RIT) in a large number of patients (n = 506) suffering from immunogenic or non-immunogenic hyperthyroidism (Graves’ disease, Plummer’s disease). Since there is no causal cure for immunogenic hyperthyroidism RIT provides, like all other modalities, only a moderate rate of success which is clearly dose-related. Applying 60 Gy, normal thyroid function can be achieved in only 54% of the cases. A dose of 150 Gy succeeds in 86% of the cases. The solitary decompensated autonomous adenoma (DAA) can be eliminated surgically as well as by RIT with a high degree of success (95%). Contrary to surgery, RIT does not have any noticeable early or late morbidity. The high rate of success of RIT in patients with DAA could be confirmed in two groups with different follow-up periods (16 and 65 months). As expected, the rate of hypothyroidism increased from 11 % in the early group to 23% in the late group. Multinodular autonomous adenomas can be eliminated successfully using RIT as well. The concept to apply a dose of 400 Gy to the total functional autonomous tissue as determined by ultrasound yields better results (95%) than 150 Gy to the whole thyroid gland as measured by ultrasound (88%). The rate of hypothyroidism as shown by these results (up to a maximum of 62% after RIT of Graves’ disease using 150 Gy) is the lesser evil compared to remaining or recurrent hyperthyroidism since these patients can be treated with thyroid hormones without problems.

Physical aspects of scintigraphybased dosimetry for nuclear medicine therapy

In nuclear medicine therapy the treatment of tumours by radiation exposure from internally deposited labelled antibodies or labelled peptides is currently an active field of investigation. To permit the efficient delivery of high amounts of radiation dose to tumours while limiting the radiation dose to critical organs dosimetry calculations have to be performed. These are relying on scintigraphic data being input to the well known MIRD formalism.

This paper focuses on the methods and the difficulties associated with the scintigraphic determination of organ kinetics. The physical properties of the well-known scintigraphic imaging modalities, PET, SPECT and planar scintigraphy, are discussed thereby taking into account the properties of the appropriate radionuclides currently being available for therapy and dosimetry. Several arguments are given and disputed for the limited clinical use of PET and SPECT in dosimetry and the ongoing preference of planar whole-body imaging as the method of choice. The quantitative restrictions still inherent to this method are also discussed in detail. Procedural recommendations are proposed covering all processes related to data acquisition, data correction and data analysis which finally lead to reliable estimations of organ dose.

[Positron emission tomography and scintigraphy. Nuclear imaging in clinical orthopaedics]

Nuclear medicine uses the function of organs or organ systems to diagnose and treat disease. The source of radiation is brought into the patient's body by means of a radioactive labelled pharmaceutical. Its way through the body is recorded by appropriate equipment on the outside. Of the many nuclear medical procedures, those primarily applicable to orthopaedic problems are explained here, such as bone scintigraphy, scintigraphy of inflammatory lesions, and tumour scintigraphy. Besides their use in diagnostics, therapeutic applications are covered as well. Using examples from clinical practice, "conventional" nuclear medicine and positron emission tomography are also covered.

[Guideline for therapy of malignant thyroid tumours: pleading for an actualization]

Total (or near total) thyroidectomy (TE) followed by radioiodine ((131)I) ablation (RIA) of residual thyroid tissue is considered to be the ideal treatment for differentiated thyroid carcinoma. However, the actual guideline of the DGN (German Society of Nuclear Medicine) recommends for the so-called papillary micro-carcinoma of the thyroid (PMC) no further therapeutic strategy (no complete TE, no (131)I-ablation of the remaining lobe). PMC has been defined as papillary carcinoma measuring 1 cm (T1) in maximal diameter according to the World Health Organization classification system for thyroid tumours (1988). The new WHO-classification (starting in 2003) defines the T1-tumour measuring 2 cm in maximal diameter. The authors demand a new, modern guideline, following the new WHO classification. This includes, that despite the overall excellent prognosis for patients with PMC, the treatment of patients with T1-tumours of the new WHO-classification (including the "old" PMC) should be no different from the treatment of patients with conventional papillary thyroid carcinoma, i.e. complete surgery (TE and central lymph node dissection) followed by RIA of residual thyroid tissue. The authors argue that it is not appropriate to consider the tumour size as the single most important key factor for therapy and prognosis. Even small tumours may have poor prognostic factors, such as lymph node metastasis, multifocality or molecular characteristics (expression of oncogenes).

[Optimization of radiotherapy planning for non-small cell lung cancer (NSCLC) using 18FDG-PET]

AIM

In recent years, FDG-PET examinations have become more important for problems in oncology, especially in staging of bronchogenic carcinoma. In the retrospective study presented here, the influence of PET on the planning of radiotherapy for patients with non-small-cell lung cancer (NSCLC) was investigated.

METHODS

The study involved 39 patients with NSCLC who had been examined by PET for staging. They received radiotherapy on the basis of the anterior/posterior portals including the primary tumour and the mediastinum planned according to CT- and bronchoscopic findings. The results of the PET examination were not considered in initial radiotherapy planning. The portals were retrospectively redefined on the basis of FDG uptake considering the size and localization of the primary tumour; and FDG activities outside the mediastinal part of the portals.

RESULTS

In 15 out of 39 patients, the CT/PET-planned portals differed from the CT-planned ones. In most causes (n = 12) the CT/PET field was smaller than the CT field. The median geometric field size of the portals was 179 cm2, after redefinition using PET 166 cm2. In 20 patients with disturbed ventilation caused by the tumour (atelectasis, dystelectosis), a correction of the portal was suggested significantly more frequently than in the other patients (p = 0.03).

CONCLUSIONS

Our results demonstrate the synergism of topographical (CT) and metabolic (FDG-PET) information, which could be helpful in planning radiotherapy of bronchial carcinoma, especially for patients with disturbed ventilation.

Successful low-dose intracavitary irradiation of a Rathke's cleft cyst with colloidal rhenium-186

Symptomatic recurrence of an histologically verified intra- and suprasellar Rathke's cleft cyst (RCC) was observed 4 months following transsphenoidal microsurgery. The space-occupying cyst was treated by endocavitary irradiation with colloidal rhenium-186 via a previously implanted catheter with an attached subcutaneous reservoir. The calculated dose of 4.4 Gy was able to stop the production of cyst fluid. Follow-up after intracavitary irradiation extends over 13 months. The cyst, with an initial size of 3 x 3 x 4 cm, has been reduced to 1.1 x 1.06 x 1.2 cm. The production of cyst fluid has decreased from 25 - 30 ml within 2 months before treatment to zero. The patient's visual and mental status as well as her quality of life are normal.

[Kinetics and dosimetry of monoclonal antibody MAb-170: evaluation of possibilities for intraperitoneal radioimmunotherapy]

The monoclonal antibody MAb-170 is directed against adenocarcinomas of different origin. Recent experience in radioimmunoscintigraphy revealed a positive uptake of this MAb in peritoneal metastases of ovarian carcinoma (FIGO III/IV).

AIM

The present investigation should clarify the question whether this antibody could be of use in an adjuvant intraperitoneal radioimmunotherapy (RIT) in patients with minimal residual disease after first-look surgery.

METHODS

Four patients underwent intraperitoneal application of Tc-99m MAb-170. Subsequent quantitative whole-body scintigraphy, serum and urine sampling were performed for a 48 h period. In one case tumour tissue specimen were sampled during the first surgical procedure 15 h p.i..

RESULTS

The quantitative evaluation revealed no relevant accumulation in liver, spleen and bone marrow never exceeding 5% of the whole-body activity. The critical organs are the kidneys that showed 8 to 11% uptake at 24 h p.i.. The effective serum curve had a maximum at 24 h p.i., the second phase gave a elimination half-time of 53 h. Assuming the worst case, the mean dose to red bone marrow was 0.3 Gy/370 MBq injected dose (ID).

CONCLUSION

These results confirm that a RIT with Re-186 MAb-170 is feasible with activities of up to 3.7 GBq. A kit for labelling MAb-170 with Perrhenate is under investigation.

Utility of fiberoptic bronchoscopy before bronchial artery embolization for massive hemoptysis

OBJECTIVE

We wanted to investigate the utility of performing fiberoptic bronchoscopy before bronchial artery embolization in patients with massive hemoptysis.

MATERIALS AND METHODS

We retrospectively reviewed the cases of all patients with hemoptysis who had presented at either of two local hospitals, one county hospital and one community hospital, between 1988 and 2000 and who had undergone fiberoptic bronchoscopy before bronchial arteriography. All data were abstracted using a standardized coding form, and radiographs were independently reviewed by two of the authors.

RESULTS

Twenty-nine patients meeting the inclusion criteria were identified; one patient was excluded because of missing radiographs. The remaining 28 patients consisted of 19 men and nine women, with an average age of 54.6 years (age range, 16-91 years). The clinically determined diagnoses of their symptoms were tuberculous bronchiectasis (n = 14; 50.0%); bronchogenic carcinoma (n = 4; 14.3%); active tuberculosis (n = 2; 7.1%); nontuberculous bronchiectasis (n = 2; 7.1%); active coccidioidomycosis, pancreaticobronchial fistula, arteriovenous malformation, and tetralogy of fallot (n =1 each; 3.6% each); and unknown cause (n = 2; 7.1%). The bleeding site determined through bronchoscopy was consistent with that determined through radiographs in 23 patients (82.1%); all had either unilateral disease (n = 15), bilateral disease with unilateral cavities (n = 5), or a preponderance of disease on one side (n = 3). Bronchoscopy was an essential tool in determining the bleeding site in only three patients (10.7%), all of whom had bronchiectasis without localizing features visible on chest radiographs. In the remaining two patients (7.1%), bronchoscopic findings were indeterminate, but radiographs were helpful.

CONCLUSION

Fiberoptic bronchoscopy before bronchial artery embolization is unnecessary in patients with hemoptysis of known causation if the site of bleeding can be determined from radiographs and no bronchoscopic airways management is needed.

[Accuracy of positron emission tomography with fluorine-18-fluoro-deoxyglucose]

BACKGROUND

: FDG-PET is a powerful tool for the diagnostic workup of patients with lung cancer. A reduced sensitivity of FDG-PET for the evaluation of lung lesions was reported for bronchioloalveolar carcinoma (BAC). No literature exists about the diagnostic efficacy of FDG-PET in the staging of BAC.

METHODS

: Out of a series of subsequent 630 untreated patients with the final diagnosis of lung cancer, who underwent FDG-PET, all patients with BAC were evaluated with respect to tumour detection, N-staging, and M-staging.

RESULTS

: 35 patients (5.6 %) had BAC, 22 in a localized form (8 x pT1, 14 x pT2), 13 in a disseminated stage. FDG-PET correctly identified 19/22 cases with localized forms. Two of the missed one were classified as pT1. All disseminated forms of BAC were detected. Standardized uptake values (SUV) ranged from 0.9 to 23.3 (mean +/- SD: 11.6 +/- 5.1). Accuracy of N-staging was comparable to known results in lung cancer (FDG-PET 80 %, CT 64 %). With respect to M-staging, sensitivity of FDG-PET was as follows: M1(HEP): 2/3 (67 %), M1(PUL): 7/8 (88 %), M1(OSS): 1/1 (100 %).

CONCLUSIONS

: With some limitations in small localized tumours FDG-PET can detect and stage BAC with an accuracy which is identical to that for other histological types of non-small cell lung cancer.

[Meta-analysis of the efficacy of positron emission tomography with F-18-fluorodeoxyglucose in lung tumors. Basis for discussion of the German Consensus Conference on PET in Oncology 2000]

BACKGROUND

: To analyse current literature on FDG-PET for evaluation of lung lesions, N-staging, M-staging, and recurrence of lung cancer for the third German Consensus Conference on PET in oncology.

METHODS

Specialists in nuclear medicine, pneumology, radiation oncology, diagnostic radiology, and thoracic surgery reviewed the relevant literature as listed in MEDLINE from 1985 to 1999 for further analysis. Out of the published data cumulative test parameters and summary receiver operating characteristic curves (sROC curves) were computed.

RESULTS

Sensitivity, specificity, and accuracy of FDG-PET are 96 %, 80 %, 91 % for evaluating lung lesions (15 studies with at least 35, in total 1144 patients). With corresponding values of 88 %, 92 %, 91 % (20 studies, 1292 patients) for N-staging FDG-PET is superior to CT with 65 %, 76 %, 73 % (19 studies, 1268 patients). With 94 %, 97 %, 96 % (4 studies, 336 patients) M-staging with FDG-PET is very accurate and changed therapeutic management in 18 % of the cases (8 studies, 695 patients), unexpected extrathoracic metastases were found in 12 % (7 studies, 581 patients). FDG-PET is the most accurate non-invasive method to evaluate suspected adrenal metastases (3 studies, 263 patients, sensitivity 96 %, specificity 99 %, accuracy 98 %). Recurrence is detected accurately (4 studies, 224 patients, sensitivity 99 %, specificity 89 %, accuracy 95 %).

CONCLUSIONS

Studies with in total more than 1000 patients show the high diagnostic efficacy of FDG-PET and its superiority to conventional imaging in lung cancer. Based on this analysis the third German Consensus Conference on PET in oncology evaluated FDG-PET on lung cancer. 1a-indications are evaluation of lung nodules in patients at risk for complications during surgery, N-staging, M-staging (except brain), and detection of recurrence.

An unusual complication during central venous catheter placement

A 31-year-old man with disseminated Coccidioides imitis infection required central catheter placement for access. The patient had an inferior vena cava (IVC) filter placed as a result of previous deep venous thrombosis of the left lower extremity. The guidewire could not be removed following placement of the right internal jugular catheter by the Seldinger technique. Fluoroscopic examination revealed entanglement of the J-tip guidewire in the apex of the IVC filter. The catheter was successfully removed by interventional radiologists using a snare tip catheter through the left femoral vein.

Preparation and investigation of tumor affinity, uptake kinetic and transport mechanism of iodine-123-labelled amino acid derivatives in human pancreatic carcinoma and glioblastoma cells

In developing radioiodinated agents for pancreatic and brain tumor imaging by single photon emission tomography (SPET), we prepared p-amino-3-[123I]iodo-l-phenylalanine (IAPA), p-[123I]iodo-l-phenylalanine (IPA), L-8-[123I]iodo-1,2,3,4-tetrahydro-7-hydroxyisoquinoline-3-carboxylic acid (ITIC) and L-3-[123I]iodo-alpha-methyl-tyrosine (IMT) in radiochemical yields up to 95%, and we investigated their uptake in human pancreatic carcinoma and glioblastoma cells as well as the mechanisms promoting the tumor uptake. The radiopharmaceutical uptake into tumor cells was rapid (t(1/2) < or = 5 min) and temperature- and pH-dependent. The radioactivity concentration in tumor cells varied from 10 to 33% of the total activity (105-310 cpm/1000 cells) following a 30-min incubation at 37 degrees C (pH 7.4). In comparison, accumulation of the radiopharmaceuticals into normal brain and pancreatic tissue remained relatively low. Depolarizing the plasma membrane potential in high K+ buffer significantly altered the radioactivity concentration in the tumor cells, suggesting that membrane potential plays a certain role in the cellular uptake. Competitive inhibition experiments with specific amino acid transport inhibitors indicated that the uptake of IAPA, IPA and IMT into human pancreatic carcinoma and glioblastoma cells is predominantly mediated by the L and ASC transport systems, while no substantial involvement of the transport system A in their tumor uptake could be demonstrated. In contrast, results of the present investigation indicated that ITIC is not taken up into tumor cells via the common neutral amino acid carrier systems, including the A, L and ASC system. Furthermore, preloading with naturally occurring L-amino acids failed to stimulate the cellular uptake of the radiopharmaceuticals. These data indicate that the investigated radiopharmaceuticals exhibit interesting characteristics with promise for in vivo tumor investigations to ascertain their potential as radioligands for glioma and pancreatic carcinoma imaging by SPET.

[Radiation exposure to patients caused by single-photon transmission measurement in PET]

AIM

The aim of the study was the determination of the radiation exposure to the patient caused by single-photon transmission measurement for 3D whole-body PET.

MATERIAL AND METHOD

Single-photon-transmission measurement is performed using two Cs-137 point-sources (E gamma = 662 keV, A = 2*614 MBq) on a 3D PET scanner (ECAT ART). During a simulation of a whole body transmission scan (axial length: 75 cm, 6 contigous bed positions) dose measurements with thermoluminescent dosimeters were carried out using a thorax and an abdomen phantom. Following the guidelines of the ICRU report No. 60 an estimation of the effective dose caused by a single-photon transmission measurement was calculated.

RESULTS

For a total acquisition time of 360 min (6 beds with an acquisition time of 60 min per bed) the absorbed doses amounted to: surface (xyphoid) 189 microGy, heart 196 microGy, lungs 234 microGy, vertebra 240 microGy, liver 204 microGy, gonads 205 microGy, thyroid 249 microGy and bladder 185 microGy resulting in a conversion factor of 1.7*10(-4) mSv/(h*MBq). The estimation of the effective dose for a patient's transmission (acquisition time of 3.2 min per bed) yields a value of 11 microSv. An estimation of the ratio of the conversion factors for transmission measurements in single-photon- and in coincidence mode (two Ge-68/Ga-68 rod sources of 40 MBq each), respectively, resulted in a value of 0.18. The comparison of the effective doses caused by single-photon transmission and by emission measurement (injection of 250 MBq of FDG) yields a ratio of 2.3*10(-3).

CONCLUSION

The radiation exposure of the patient caused by the transmission measurement for 3D whole-body-PET can be neglected. In comparison with the coincidence-transmission using uncollimated line sources of low activity the radiation exposure is still reduced using single photon trans-mission with collimated point sources of high activity.

Investigation of iodine-123-labelled amino acid derivatives for imaging cerebral gliomas: uptake in human glioma cells and evaluation in stereotactically implanted C6 glioma rats

In developing iodine-123-labelled amino acid derivatives for imaging cerebral gliomas by single-photon emission tomography (SPET), we compared p-[123I]iodo-L-phenylalanine (IPA), L-[123I]iodo-1,2,3,4-tetrahydro-7-hydroxyisoquinoline-3-carboxylic acid (ITIC) and L-3-[123I]iodo-alpha-methyltyrosine (IMT) with regard to their uptake in human glioblastoma T99 and T3868 cells, and thereafter studied the mechanisms promoting the cellular uptake. The potential of the 123I-iodinated agents for use as SPET radiopharmaceuticals was evaluated in healthy experimental rats as well as in rats with stereotactically implanted C6 gliomas. The radiopharmaceutical uptake into glioblastoma cells was rapid, temperature and pH dependent, and linear during the first 5 min. Equilibrium was reached after 15-20 min, except in the case of ITIC, the initial uptake of which gradually decreased from 15 min onwards. The radioactivity concentration in glioma cells following 30-min incubation at 37 degrees C (pH 7.4) varied from 11% to 35% of the total activity per million cells (ITIC < IMT < or = IPA). Competitive inhibition experiments using alpha-(methylamino)-isobutyric acid and 2-amino-2-norbornane-carboxylic acid, known as specific substrates for systems A and L, respectively, as well as representative amino acids preferentially transported by system ASC, indicated that IPA, like IMT, is predominantly mediated by the L and ASC transport systems, while no significant involvement of the A transport system could be demonstrated. By contrast, none of the three principal neutral amino acid transport systems (A, L and ASC) appear to be substantially involved in the uptake of ITIC into glioblastoma cells. Analysis of uptake under conditions that change the cell membrane potential, i.e. in high K+ medium, showed that the membrane potential plays an important role in ITIC uptake. Alteration of the mitochondrial activity by means of valinomycin or nigericin induces a slight increase or decrease in the radiopharmaceutical uptake, suggesting a minor contribution of the mitochondria in the uptake. IPA, IMT and ITIC passed the blood-brain barrier, and thereafter showed efflux from the brain. The radioactivity concentration in healthy rat brain 15 min following intravenous injection varied from 0.07% (ITIC) to 0.27% ID/g (IPA). In comparison, the brain uptake in the stereotactically implanted C6 glioma rats was substantially higher (up to 1.10% ID/g 15 min p.i.), with tumour-to-background ratios greater than 4. These data indicate that IPA and ITIC, like IMT, exhibit interesting biological characteristics which hold promise for in vivo brain tumour investigations by SPET.

[Influence of single-photon emission scan duration measured with the ECAT ART PET scanner]

AIM

The aim was to study the influence of single-photon-transmission scan duration in 3D-PET on the quantitative values of attenuation coefficients and noise in transmission images and of activity concentrations and noise in attenuation corrected emission images of thorax phantom- and patient data.

METHOD AND MATERIAL

Using dual collimated Cs-137 singles transmission sources (E gamma = 662 KeV, A = 2* 614 MBq) on an ECAT ART tomograph series of transmission scans of a thorax phantom were acquired pre- and post-injection of 18F. 17 patients underwent two transmission scans. The scan time of the short transmission was chosen according to the results of the phantom studies (noise of Poisson statistics less than 4%). Transmission and attenuation corrected emission images were evaluated with respect to estimated linear attenuation coefficients, noise and specific activities in organs.

RESULTS

The phantom studies reveal little variation of the estimated linear attenuation coefficients as a function of scan duration. The estimates of the attenuation coefficients are found to be 1% lower than the expected values for pre- and up to 6.5% lower for post-injection transmissions. The noise level in the transmission images increases as expected for Poisson data. The noise level in the attenuation corrected emission images shows only little increase with decreasing transmission scan time whereas it is strongly influenced by a variation of emission scan time. In patient studies, less than 3% difference was found in the estimated linear attenuation coefficients as well as in the activity concentrations between short (pre or post-injection) and long transmission scans. The noise levels in transmission and emission images are 1% (pre-injection) and 4% (post-injection) higher for short transmission scans.

CONCLUSION

Due to the high photon flux, single photon transmission offers good clinical performance with significantly reduced transmission scan durations (< 2 min/bed in pre-, < 4 min/bed in post-injection transmission).

The incidence of ventilator-associated pneumonia and success in nutrient delivery with gastric versus small intestinal feeding: a randomized clinical trial

BACKGROUND

Enteral feeding provides nutrients for patients who require endotracheal tubes and mechanical ventilation. There is a presumed increase in the risk of ventilator-associated pneumonia (VAP) with tube feeding. This has stimulated the development of procedures for duodenal intubation and small intestinal (SI) feeding as primary prophylaxes to prevent VAP.

OBJECTIVE

To investigate the rate of VAP and adequacy of nutrient delivery with gastric (G) vs. SI feeding.

DESIGN

A prospective, randomized, controlled trial.

SETTING

A medical intensive care unit of a county hospital.

PATIENTS

A total of 44 endotracheally intubated, mechanically ventilated patients requiring enteral nutrition.

INTERVENTION

Subjects were randomized to receive enteral nutrition via G or SI feeding. Protocols directed the placement of the feeding tube and the infusion of enteral nutrition and defined the radiographic and clinical criteria for a diagnosis of VAP.

MEASUREMENTS AND OUTCOMES

The incidence of VAP and the adequacy of nutritional supplementation were prospectively followed. The relative risk of VAP with SI was 1.1 (95% confidence interval 0.96-2.44) compared with G. The SI group received a greater percentage of their caloric requirements (SI 69 +/- 7% vs. G 47 +/- 7%, mean +/- SEM, p < .05). Mortality did not differ between G (26 +/- 9%) and SI (24 +/- 10, p = .86).

CONCLUSIONS

There is no clear difference in the incidence of VAP in SI compared with G enteral nutrition. Patients given feeding into the SI do receive higher calorie and protein intakes.

Cardiac arrest due to succinylcholine-induced hyperkalemia in a patient with wound botulism

Cardiac arrest due to hyperkalemia is a known complication of succinylcholine administration in patients with neuromuscular disease, extensive burns, and prolonged immobility. We report a case of hyperkalemic cardiac arrest following the administration of succinylcholine in a patient suffering from wound botulism.

[Value of positron emission tomography with 18-fluorodeoxyglucose (FDG-PET) in diagnosis of recurrent bronchial carcinoma]

The aim of the present investigation was to evaluate the diagnostic accuracy of positron emission tomography with 18-fluoro-2-deoxyglucose (FDG-PET) in the detection of recurrent lung cancer. PET was performed using an ECAT ART scanner (Siemens CTI) after i.v. injection of 220 +/- 50 MBq 18FDG. PET data were analysed by visual interpretation of coronal, sagittal and transversal slices. PET scans were interpreted independently by two experienced nuclear medicine physicians without prior knowledge of the results of other imaging studies or clinical data. 40 patients (= 41 cases) who had undergone primarily curative tumour treatment, were evaluated. In 29 of 35 cases with recurrent tumour, diagnosis was verified by pathologic means. FDG-PET correctly identified tumour recurrence in 34/35 cases. In 5/6 cases without prevent tumour recurrence PET gave true negative results. The overall accuracy of FDG-PET was 39/41 = 95% (95%-confidence interval 83-99%). FDG-PET shows high diagnostic accuracy in detecting recurrent lung cancer in patients with prior curative tumour treatment, but cannot substitute the need for pathological diagnosis.

[A simple and rapid routine preparation of no-carrier added meta-I-123- and I-131-iodobenzylguanidine (I-123-MIBG and I-131-MIBG) for clinical nuclear medicine applications]

AIM

Low specific activity meta-iodobenzylguanidine (I-123/I-131-MIBG) is currently used in the assessment of abnormalities in the myocardial neuroadrenergic function as well as in the management of neuroendocrine tumors. In recent studies an enhanced cardiac and tumor uptake were reported by the use of high specific activity radiopharmazeuticals, suggesting a potential clinical benefit of no-carrier-added (n.c.a.) I-123/I-131-MIBG. In this paper we describe a simple and improved preparation of I-123-MIBG and I-131-MIBG for routine clinical application, feasible in any nuclear medicine department.

METHODS

N.c.a I-123-MIBG and n.c.a. I-131-MIBG were prepared by Cu(I)-assisted [I-123/I-131]iodo-debromination at 170-175 degrees C with 86 +/- 6% and 80 +/- 10% radiochemical yield respectively and high specific activity (> or = 4.3 TBq/mumol and > or = 0.21 TBq/mumol), starting from meta-bromobenzylguanidine (MBBG). The total time of synthesis including the HPLC purification and the preparation of the injectable solution was less than 60 min.

RESULTS

Neither rechromatography by HPLC nor TLC gave any indication of disintegration products in the injection solution up to 8 h after preparation. Moreover, biological testings confirmed that the buffered and sterile-filtered n.c.a. I-123-MIBG and n.c.a. I-131-MIBG solutions are isotonic, sterile and apyrogenic and thus suitable as injectable solutions for clinical use.

CONCLUSION

High specific activity I-123-MIBG and I-131-MIBG could now be prepared by a simple one-step reaction giving rise to high radiochemical yields and high purity for a widespread clinical applications. Therefore, this encourages clinical validations on a large scale to answer the question of whether n.c.a. I-123-MIBG and I-131-MIBG could play an important role in the assessment of the myocardial sympathetic nervous dysfunction as well as in the diagnosis and therapy of neuroendocrine tumors.

Pneumoparotid due to spirometry

Pneumoparotid has been described in patients who generate increased intraoral pressures when playing wind instruments, while coughing, and when undergoing dental work. Some patients have intentionally created pneumoparotid to avoid duties at school or in the military, or to gain attention. We describe a patient who developed pneumoparotid during pulmonary function testing. The diagnosis of pneumoparotid depends on a suggestive clinical situation and glandular swelling with or without crepitus. Observation of aerated saliva per Stensen's duct or air in the parotid duct and/or gland by any imaging study is diagnostic if infection with a gas-forming organism can be reasonably excluded. No specific treatment is required, other than the avoidance of predisposing activities.

[Radiation exposure of the patient caused by transmission measurement for myocardial perfusion SPECT]

AIM

The aim was the determination of the radiation exposure to the patient caused by the transmission measurement for myocardial perfusion SPECT.

METHOD AND MATERIAL

Beside the emission measurement (Tc-99m-MIBI, A = 500 MBq) the myocardial perfusion SPECT simultaneously includes a transmission measurement using a Am-241-line source (A = 5550 MBq). During a simulation of the myocardial perfusion SPECT (without Tc-99m-MIBI) dose measurements with thermoluminescent dosimeters were carried out using a thorax phantom.

RESULTS

For an acquisition time of 20 min the absorbed doses amounted to: surface (xyphoid) 30 microGy, heart 25 microGy, lung 14 microGy, second thoracic vertebra 16 microGy, upper anterior mediastinum 16 microGy, liver 0 microGy. An estimation of the ratio of the effective doses caused by the transmission and the emission measurement of 3.6 x 10(-3) and 4.1 mSv, respectively, resulted in a value of 9 x 10(-4).

CONCLUSION

The radiation exposure of the patient caused by the transmission measurement can be neglected, and is therefore not a limiting factor regarding the general application of transmission measurement for clinical myocardial perfusion SPECT.

Monoclonal antibody MAb-170 for immunoscintigraphic detection of ovarian tumors

OBJECTIVE

The technetium Tc 99m-labeled monoclonal antibody MAb-170 was designed for diagnostic use in patients with gynecologic adenocarcinoma. Our investigation was initiated to verify its usefulness for radioimmunoscintigraphy of ovarian tumors.

STUDY DESIGN

Most of the 82 patients participating in this study underwent immunoscintigraphy before first-look surgery.

RESULTS

Radioimmunoscintigraphy recognized 36 of 41 patients with adenocarcinoma of the ovaries, corresponding to an overall sensitivity of 88%. Specificity was 90% (38/42). The calculation of accuracy gave a result of 89% (74/83). Of 110 known lesions, 92 were visualized successfully; thus the local-regional sensitivity was 84%. Of 160 benign tumor sites, 154 showed no evidence of tracer accumulation, corresponding to a local-regional specificity of 96%. The smallest lesion visualized was an adenocarcinoma of the corpus uteri with a diameter of 1.5 cm.

CONCLUSION

The monoclonal antibody MAb-170 is a promising radiopharmaceutical for immunoscintigraphy of ovarian adenocarcinoma.

Airway coccidioidomycosis--report of cases and review

Infection due to Coccidioides immitis usually begins in the lungs. Despite the initial pulmonary portal of entry, endotracheal and endobronchial coccidioidomycosis has rarely been described. Since the introduction of fiberoptic bronchoscopy and the AIDS epidemic, more C. immitis lesions of the large airways have been noted. We present data on 38 cases of coccidioidomycosis of the airways, including 6 cases detailed from our own experience and 32 from the literature. Direct infection of the airways (28 cases) is a more common mechanism of airways disease than is erosion into the airways from a lymph node (5 cases). Bronchoscopic findings vary and may show mucosal involvement or intrinsic obstruction. Endotracheal and endobronchial disease is not a self-limited disease and requires antifungal therapy. Disseminated disease in these patients is common. Coccidioidomycosis must be considered in the differential diagnosis of airway pathology.

18F-deoxyglucose positron emission tomography (FDG-PET) for the planning of radiotherapy in lung cancer: high impact in patients with atelectasis

PURPOSE

18F-deoxyglucose positron emission tomography (FDG-PET) is increasingly applied in the staging of lung cancer (LC). This study analyzes the potential contribution of PET in radiotherapy planning for LC with special respect to tumor-associated atelectasis.

METHODS AND MATERIALS

Thirty-four patients with histologically confirmed LC, who had been examined by PET during pretreatment staging, were included. All were irradiated after CT-based therapy planning with anterior/posterior (AP) portals encompassing the primary tumor and the mediastinum (CT portals, CP). The result of the PET examination was unknown in treatment planning. In retrospect, a PET portal (PP) was delineated and compared with the CP.

RESULTS

In 12/34 cases, the shape and/or size of the portals were changed, primarily (n = 10) the size of the fields was reduced. The median area of CP was 182 cm2 versus 167 cm2 of PP. Seventeen of 34 patients had dys- or atelectasis caused by a central primary tumor. In these cases, differences between CP and PP were significantly more frequent than in the other patients (8/17 vs. 3/17, p = 0.03).

CONCLUSION

In this retrospective analysis, the information provided by FDG-PET would have contributed to a substantial reduction of the size of radiotherapy portals. This applies particularly for patients with tumor-associated dys- or atelectasis.

Improved labelling of no-carrier-added 123I-MIBG and preliminary clinical evaluation in patients with ventricular arrhythmias

Meta-[123I]iodobenzylguanidine (123I-MIBG) is currently used to assess myocardial sympathetic innervation by single photon emission tomography (SPET). In recent studies, an enhanced cardiac uptake of 123I-MIBG with high specific activity has been reported, suggesting the clinical potential of no-carrier-added (n.c.a.) 123I-MIBG in the assessment of abnormalities in cardiac sympathetic function. This paper describes the preparation of n.c.a. 123I-MIBG by non-isotopic Cu(I)-assisted [123I]iododebromination and by [123I]iododestannylation, both resulting in n.c.a. 123I-MIBG with radiochemical yields of 88 +/- 6% and high specific activity (> or = 6.3 TBq.mumol-1) in a total synthesis time of less than 50 min. The diagnostic potential of n.c.a. 123I-MIBG (> 6.3 TBq.mumol-1) was studied in 13 patients (nine patients with malignant ventricular arrhythmias and four patients suspected of phaeochromocytoma) and compared to commercial 123I-MIBG (approximately 75 MBq.mumol-1) using a dual-headed SPET camera (MULTISPECT II). High specific activity results in higher 123I-MIBG uptake in the heart and in the liver in all patients. The calculated heart-to-lung and heart-to-liver count ratios 4.5 h post-injection increased by 22 +/- 6% and 10 +/- 5% with n.c.a. 123I-MIBG compared to commercial 123I-MIBG respectively. In contrast, no significant correlation between the specific activity of 123I-MIBG and lung uptake could be established in this study. Analysis of radioactivity in blood after the intravenous injection of n.c.a. and commercially available 123I-MIBG showed an initial rapid clearance of radioactivity from blood, followed by a plateau from 60 min onwards. Within the first 24 h, more than 85% of the plasma activity was unchanged 123I-MIBG. The free 123I-iodide concentration determined 24 h post-injection was 2 +/- 1% with commercial 123I-MIBG and 3 +/- 2% with n.c.a. 123I-MIBG. In conclusion, the results of this investigation indicate that n.c.a. 123I-MIBG is a promising clinical tool for imaging myocardial sympathetic dysfunction by SPET. High specific activity n.c.a. 123I-MIBG can now be prepared by simple one-step methods giving high radiochemical yields and high purity suitable for clinical application. This encourages the further clinical validation of n.c.a. 123I-MIBG on a large scale.

[Brain metastases of lung cancer: diagnostic accuracy of positron emission tomography with fluorodeoxyglucose (FDG-PET)]

The value of FDG-PET in oncology is currently investigated in clinical studies. There is only limited information on the usefulness of FDG-PET in the evaluation of distant metastases of lung cancer. The purpose of the present prospective investigation was to determine the diagnostic accuracy of FDG-PET in the detection of brain metastases of lung cancer. After intravenous injection of 220 +/- 50 MBq F-18-deoxyglucose PET acquisition was carried out using an ECAT ART scanner (CTI Siemens). Images were reconstructed using a filtered backprojection with a Hanning filter. PET data were analyzed by visual interpretation of coronal, sagittal and transversal slices. PET scans were interpreted by two experienced nuclear medicine physicians without prior knowledge of the results of other imaging studies or clinical data. Between March 1997 and July 1998 whole-body PET was performed in 417 patients with suspected lung cancer. 402 patients were used for statistical analysis. Based on conventional brain imaging with CT (occasionally MRI), brain metastases were suspected in 17 patients (prevalence 4.2%). For FDG-PET alone, sensitivity was 82% (14/17) and specificity 38% (14/37). Therefore, diagnostic accuracy of FDG-PET in detection of brain metastases was 93.5%. The low specificity of FDG-PET can be explained by reduced tracer uptake mainly due to brain infarction or vascular encephalopathy in this group of elderly patients. Our results indicate that due to its low specificity FDG-PET is not useful for the evaluation of brain metastases in the primary staging of patients with lung cancer.

Influence of right ventricular stimulation site on left ventricular function in atrial synchronous ventricular pacing

OBJECTIVES

The study investigates the correlation between left ventricular function and QRS duration obtained by alternate right ventricular pacing sites.

BACKGROUND

1. Right ventricular apical pacing is associated with alterations of left ventricular contraction sequence. 2. A stimulation producing narrow QRS complexes is supposed to provide for better left ventricular contraction patterns.

METHODS

Fourteen patients with third degree AV block received one ventricular pacing lead in apical position. The alternate lead was attached to that site on the septum that produced the smallest QRS complex as measured from the earliest to the last deflection in any of the orthogonal Frank leads (xyz). During atrial synchronous ventricular pacing, the AV delay was optimized individually and for each stimulation site using mitral valve doppler or impedance cardiography. By radionuclide ventriculography, the phase distribution histogram of left ventricular contraction was evaluated as area under the curve (AuC); systolic function was determined as ejection fraction (EF) and as absolute ejected counts (EC) in random order. The difference (delta) in QRS duration between apical and septal stimulation (deltaxyz) was correlated with the difference in phase distribution (deltaAuC) and ejection parameters (deltaEF, deltaEC).

RESULTS

QRS duration was shorter with septal than with apical pacing in 9 out of 14 patients (64%); it was longer in 4 (29%), and no difference was seen in 1 patient. There was a significant positive correlation between the change in QRS duration (deltaxvz) and phase distribution (deltaAuC: r = 0.66393, p = 0.010) and a significant negative correlation to systolic function (deltaEF: r = 0.70931, p = 0.004; deltaEC: r = 0.74368, p = 0.002).

CONCLUSIONS

In atrial synchronous right ventricular pacing, if the AV delay is adapted individually, decreased QRS duration obtained by alternate pacing sites is significantly correlated with homogenization of left ventricular contraction and with increased systolic function in acute tests.

Evaluation of l-3-[123I]iodo-alpha-methyltyrosine SPET and [18F]fluorodeoxyglucose PET in the detection and grading of recurrences in patients pretreated for gliomas at follow-up: a comparative study with stereotactic biopsy

Based on the results of stereotactic biopsy, we evaluated in a prospective fashion the efficiency of l-3-[123I]iodo-alpha-methyltyrosine-single-photon emission tomography (SPET) and [18F]fluorodeoxyglucose (FDG) positron emission tomography (PET) in the detection and grading of recurrences in patients previously treated for gliomas. The patient population comprised 30 individuals, nine with astrocytomas of grade II, ten with astrocytomas of grade IV, three with oligoastrocytomas of grade II, six with oligodendrogliomas of grade II and two with anaplastic oligodendrogliomas of grade III) suspected of recurrence and scheduled for further treatment. IMT SPET data were acquired using either by dual-or a triple-headed SPET camera, Multispect 2/3. FDG uptake was measured with an ECAT ART PET camera. Two independent observers classified PET and SPET images as positive or negative for tumour tissue. Uptake of FDG and IMT was evaluated visually and, in the case of IMT, also quantitatively by calculating the ratios between tracer accumulation in the lesion and the unaffected contralateral regions of reference using the region of interest (ROI) technique. The PET and SPET results were compared with the histopathological findings obtained either by stereotactic biopsy or in one case by open surgery. Glucose metabolism and amino acid uptake of recurrences of brain tumours as assessed by FDG-PET and IMT-SPET correlated highly with the histopathological findings. Based on the histopathological data, FDG-PET and IMT-SPET findings confirmed recurrence in all cases of high-grade gliomas (IV). A difference could be demonstrated in low-grade (II-III) tumour recurrences. True-positive IMT-SPET results were found in 86% of grade III and 75% of grade II recurrences, whereas FDG-PET yielded a sensitivity of 71% in tumours of grade III and 50% in those of grade II. With respect to the grade of malignancy of brain tumours at recurrence, IMT-SPET, in contrast to FDG-PET, does not permit adequate in vivo grading of non-mixed brain tumours of astrocytic or oligodendroglial origin. However, in this study FDG-PET did not permit discrimination between upgrading of low-grade oligoastrocytomas (II) into anaplastic oligodendrogliomas (III) and upgrading into glioblastomas (IV) The results of this study indicate that FDG-PET and IMT-SPET are equivalent to stereotactic biopsy in their ability to identify high-grade tumours at recurrence. IMT-SPET proved to be superior to FDG-PET in confirming low-grade recurrences. In the case of suspected progression of the grade of malignancy in ordinary gliomas, FDG-PET correlated significantly with the histopathological grading, whereas IMT-SPET did not. However, tumour grading by FDG-PET has a limitation in mixed brain tumours in that it is not possible to discriminate between progression of the oligo- versus the astrocytic tumour entity. In this case histopathological evaluation of the tumour grade remains necessary.

[Pregnancy and hyperthyroidism]

Because the coincidence of hyperthyroidism and pregnancy is rare, there is come uncertainty in the management of these patients. In order to avoid complications during the course of pregnancy, it is important to know--besides etiology and pathogenesis--the particularities in diagnosis and start of the appropriate therapy in time.

123I-MSP and F[11C]MSP: new selective 5-HT2A receptor radiopharmaceuticals for in vivo studies of neuronal 5-HT2 serotonin receptors. Synthesis, in vitro binding study with unlabelled analogues and preliminary in vivo evaluation in mice

In vitro binding study on bovine brain membranes using [3H]SCH23390, [3H]spiperone, [3H]prazosin and [3H]RP62203 as radioligands (for D1, D2, alpha1 and 5-HT2A receptors respectively) indicate that the new butyrophenones 8-[3-(4-fluorobenzoyl)propyl]-1-methyl-1,3,8-triazaspiro[4,5]de can-4-one (FMSP) and 8-[3-(4-iodobenzoyl)propyl]-1-methyl-1,3,8-triazaspiro[4,5]deca n-4-one (IMSP) exhibit a significantly higher selectivity for the 5-HT2A over D1, D2 and alpha1 receptors. Consequently, the radiolabelled analogues F[11C]MSP and 123I-MSP were prepared in attempt to obtain potential radiopharmaceuticals for in vivo imaging of neuronal 5-HT2A receptors with positron emission tomography (PET) and single photon emission tomography (SPET). F[11C]MSP was synthesized by reaction of [11C]CH3I with 8-[3-(4-fluorobenzoyl)propyl]-1,3,8-triazaspiro[4,5]decan-4- one (DMSP) in 12 +/- 3% radiochemical yield, whereas 123I-MSP was obtained in 82 +/- 8% radiochemical yield by a no-carrier-added Cu(I)-assisted [123I]iododebromination of 8-[3-(4-bromo-benzoyl)propyl]-1-methyl-1,3,8-triazaspiro[4,5]de can-4-ene (BrMSP). In vivo pharmacokinetic and brain binding characterization of 123I-MSP assessed in mice following intravenous injection, showed a fast clearance of 123I-MSP from blood and relatively high initial uptakes in the liver, kidneys and in the lung. Significant uptake and long retention were observed in the brain (up to 1.64% i.d., 60 min p.i.), with a regional accumulation of radioactivity consistent with the reported 5-HT2A receptors distribution in the brain. Frontal cortex to cerebellum ratio of 3.5 was calculated at 60 min p.i. Furthermore, the initial brain uptake was significantly reduced after pretreatment of the animals with ritanserin, a selective 5-HT2 antagonist, and by preinjection of the non-radiolabelled analog IMSP, thus indicating the specificity of the brain uptake. These data suggest that 123I-MSP may be a promising compound for studying the serotoninergic 5-HT2 receptors with SPET. Due to the low specific activity of F[11C]MSP currently obtained by the [11C]methylation reaction, systematic in vivo investigation of F[11C]MSP are as yet not feasable.

[Contribution of nuclear medicine to the diagnosis of recurrent brain tumors and cerebral radionecrosis]

The evaluation of brain tumor recurrence and therapy-induced benign changes following surgery and/or irradiation is a diagnostic challenge for imaging methods based on either morphology (cCT/MRI) or function (SPECT/PET). Current literature and the present data of our own patients demonstrate the diagnostic efficiency of IMT-SPECT and FDG-PET in the detection of recurrence and in-vivo grading. Thirty-nine patients suspected of brain tumor recurrence at follow-up were studied by FDG-PET and IMT-SPECT. Thirty-four of 39 patients showed recurrences; in 12 cases even a change in the grade of malignancy was observed. All high-grade recurrences could be confirmed by either methods. IMT-SPECT showed a higher sensitivity in detecting low-grade tumors at recurrence. In contrast to IMT-SPECT, FDG-PET supports sufficient in-vivo grading. Both methods can be used to differentiate between tumor recurrence and radionecrosis. In conclusion the results of our study demonstrate the efficiency of IMT-SPECT and FDG-PET in confirming recurrences and determining the actual tumor grade.

Intermediate and long-term side effects of high-dose radioiodine therapy for thyroid carcinoma

The present investigation is an evaluation of intermediate and long-term side effects in patients after high-dose radioiodine treatment due to differentiated thyroid carcinoma.

METHODS

A total of 203 patients were interviewed using a standardized questionnaire.

RESULTS

After radioiodine treatment, 76.8% of the patients reported intermediate (from discharge up to 3 mo) or long-term (more than 3 mo after treatment) complaints, and 61.1% reported long-term side effects. Nonstochastic side effects included sialoadenitis, which occurred in 33.0% of cases, and 27.1% of patients suffered from a transient loss of taste or smell. More than 1 yr after the last radioiodine application, 42.9% of patients suffered from reduced salivary gland function. Complete xerostomia occurred in 4.4% of patients. Hematological abnormalities were found in 9 patients. In 28.1% of patients a transient episode of alopecia was reported. In 22.7% of patients chronic or recurrent conjunctivitis was reported, and 4 patients underwent dacryocystorhinostomy; 13.8% of patients suffered from an increased frequency of influenza, but 3.4% reported a reduced occurrence of such infections. For sialoadenitis, the loss of taste/smell and dry mouth, the dependence on accumulated activity was significant.

CONCLUSION

Severe long-term side effects are rare after high-dose radioiodine treatment. Moderate side effects are common. The side effects are commonly the result of radiation damage to the salivary glands. The frequency of such complaints advocates regular protection of the salivary glands.

[Positron emission tomography and bone scintigraphy of an osteoclast metastasis]

We present the case of a 66-year-old-male patient who suffered from a bronchial carcinoma with a rib metastasis which was detected by PET staging with a relevant 18F-FDG-Uptake. The bone scintigram with 99mTc-DPD showed a defect in this area. The aggressive disease induced no osteoblastic response.