Simulation of Radiative Transfer Within X-ray Microcalorimeter Absorbers.

We present Monte Carlo simulations of radiative transfer within the absorbers of X-ray microcalorimeters, utilizing a numerical model for the photon propagation and photon absorption process within the absorber structure. In our model, we include effects of Compton scattering off bound electrons and fluorescence. Scattered or fluorescence photons as well as Auger and photoelectrons escaping the absorber can result in partial energy depositions. By implementing a simplified description of the physical processes compared to existing comprehensive particle transport software frameworks, our model aims to provide representative results at a small computational effort. This approach makes it possible to use our model for quick assessments, parametric studies, and application in other Monte Carlo-based instrument simulators like SIXTE, a software package for X-ray astronomical instrumentation. To study the impact of the energy loss effects on the spectral response of a microcalorimeter, we apply our model to the sensors of the cryogenic X-ray spectrometer X-IFU onboard the future Athena X-ray observatory.

Technical nuances of commonly used vascularised flaps for skull base reconstruction.

BACKGROUND AND METHODS: Reconstruction with a vascularised flap provides the most reliable outcome, with post-operative cerebrospinal fluid leak rates of less than 5 per cent. This article aims to review and summarise the critical technical aspects of the vascularised flaps most commonly used for skull base reconstruction. RESULTS: Vascularised flaps are classified as intranasal or extranasal. The intranasal group includes the Hadad-Bassagaisteguy nasoseptal flap, the Caicedo reverse nasoseptal flap, the nasoseptal rescue flap, the posteriorly or anteriorly based lateral wall flaps, and the middle turbinate flap. Extranasal flaps include the transfrontal pericranial and transpterygoid temporoparietal flaps. CONCLUSION: The Hadad-Bassagaisteguy nasoseptal flap is overwhelmingly favoured for reconstructing extensive defects of anterior, middle and posterior cranial base. Its pertinent technical features are described. However, it is essential to master the skills required for the various extranasal or regional vascularised flaps because each can offer a reconstructive alternative for specific patients, especially when open approaches are needed and/or intranasal vascularised flaps are not feasible.

[Bone scintigraphy. German Guideline S1]. / Skelettszintigraphie. DGN-Handlungsempfehlung (S1-Leitlinie).

The purpose of this guideline is to provide comprehensive state-of-the-art information about indication and how to perform and analyze bone scintigraphy. Based upon pathophysiology and pharmacology current acquisition techniques including new methodologies are summarized followed by a detailed list of indications. In the main part all relevant practical aspects such as patient preparation, anamnestic information, appropriate choice and dosage of the radiopharmaceutical, and data acquisition including interventions are discussed. Data processing and analysis, interpretation, reporting and documentation are described in the next chapters. Quality control, typical pitfalls and a short outlook to future developments complete the guideline.

Multi-centre calibration of an adaptive thresholding method for PET-based delineation of tumour volumes in radiotherapy planning of lung cancer.

PURPOSE: To evaluate the calibration of an adaptive thresholding algorithm (contrast-oriented algorithm) for FDG PET-based delineation of tumour volumes in eleven centres with respect to scanner types and image data processing by phantom measurements. METHODS: A cylindrical phantom with spheres of different diameters was filled with FDG realizing different signal-to-background ratios and scanned using 5 Siemens Biograph PET/CT scanners, 5 Philips Gemini PET/CT scanners, and one Siemens ECAT-ART PET scanner. All scans were analysed by the contrast-oriented algorithm implemented in two different software packages. For each site, the threshold SUVs of all spheres best matching the known sphere volumes were determined. Calibration parameters a and b were calculated for each combination of scanner and image-analysis software package. In addition, "scanner-type-specific" calibration curves were determined from all values obtained for each combination of scanner type and software package. Both kinds of calibration curves were used for volume delineation of the spheres. RESULTS: Only minor differences in calibration parameters were observed for scanners of the same type (Δa ≤4%, Δb ≤14%) provided that identical imaging protocols were used whereas significant differences were found comparing calibration parameters of the ART scanner with those of scanners of different type (Δa ≤60%, Δb ≤54%). After calibration, for all scanners investigated the calculated SUV thresholds for auto-contouring did not differ significantly (all p>0.58). The resulting sphere volumes deviated by less than -7% to +8% from the true values. CONCLUSION: After multi-centre calibration the use of the contrast-oriented algorithm for FDG PET-based delineation of tumour volumes in the different centres using different scanner types and specific imaging protocols is feasible.

[Nuclear Medicine in Germany. Key data from official statistics]. / Nuklearmedizin in Deutschland. Kennzahlen aus offiziellen Statistiken.

AIM: To explain the spectrum and number of in-vivo nuclear medicine examinations and therapies based on official statistics about out-patient and in-patient care. Trends in time of the frequency and spectrum of procedures as well as data on the health care structure for nuclear medicine in Germany should be collected. METHODS: Data from the Gesundheitsberichterstattung des Bundes, from the frequency statistics of the statutory health insurance for out-patients and from the Bundesärztekammer were used. Customized queries were performed to analyse temporal changes. RESULTS: Nuclear medicine physicians are more frequently consulted by out-patients over the last years (2008: 2024498; 2009: 2164664) and the number of colleagues in private practice increased. For in-patients, the frequency of conventional nuclear medicine procedures (mainly for brain, lymphatic system, lung and heart) increased since 2008 after a decline in previous years (2009: 323515; +4.6%) and the number of PET(/CT) examinations continued to rise (2009: 25123; +18%), even if changes in OPS keys may hamper comparisons. Nearly 600 gamma cameras and 76 PET(/CT) scanners were installed in hospitals in 2008. Nuclear medicine procedures are increasingly performed as cross sectional imaging like SPECT(/CT) and PET(/CT). With the supply shortfall with 99Mo, the frequency of thyroid scans with 123I iodine increased as well as the use of 18F PET as a substitute for conventional bone scans. The number of radionuclide therapies, in particular non-thyroid treatments, increased since the mid-nineties and stabilized at nearly 50000 cases per year with shorter lengths of stay. CONCLUSION: The details of the present analysis may help to understand the positive evolution of key numbers for nuclear medicine.

Retrospective web-based multicenter evaluation of ¹8F-FDG-PET and CT derived predictive factors. Radioimmunotherapy with yttrium-90-ibritumomab tiuxetan in follicular non Hodgkin's lymphoma.

AIM: Although predictive factors (PF) for conventional lymphoma therapy are established and frequently used in clinical practice and medical research, the PF for radioimmunotherapy (RIT) have not been fully defined until now. The aim of this multicenter evaluation is to prove the feasibility of the multicenter web-based data collection and to preliminary explore imaging findings and prediction of therapy response in patients with follicular lymphoma (FL) following radioimmunotherapy (RIT) with 90Y-ibritumomab tiuxetan. PATIENTS, METHODS: We retrospectively analyzed and correlated clinical and imaging data (CT and FDG-PET) before and after RIT as documented by the RIT-Network. Evaluation of treatment response was done on both patient and lesion basis. Every measurable lesion was analyzed in terms of standardized uptake value (SUV), volume (CT and PET) and response. PF were identified using a uni- and multivariate model. A web-based system was used for the documentation and evaluation of clinical and imaging data. RESULTS: 16 patients with at least one PET before and after RIT were eligible for analysis. Concerning response three months postRIT, 5 patients achieved a CR, 6 patients a PR and 4 patients remained with NC. A total of 159 lesions were measured (mean 10±8). In the multivariate model the log lesion volume (p < 0.0001), the total (p = 0.03) and maximum lesion volume (p = 0.05) were predictors for response (CR + PR). Concerning the lesional CR initial small lesion volume (p = 0.009) and its high metabolic activity (p = 0.01) were identified as predictors. The web-based system showed no major disturbances allowing secure data transfer and central image interpretation in a reasonable time. CONCLUSION: The use of a web-based multicenter archiving system for clinical and imaging data is technically feasible in a multicenter setting and allows a central analysis. This preliminary analysis suggests that FDG-PET may predict the likelihood of response to RIT.

Physical aspects of scintigraphy-based 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.

Para-[(123)I]iodo-L-phenylalanine in patients with pancreatic adenocarcinoma: tumour uptake, whole-body kinetics, dosimetry.

UNLABELLED: Recently, p-[(123)I]iodo-L-phenylalanine (IPA) was clinically validated for brain tumour imaging. Preclinical studies demonstrated uptake of IPA into pancreatic adenocarcinoma suggesting its diagnostic application in patients with pancreatic tumours. The aim was to study the tumour uptake of IPA in patients with pancreatic adenocarcinoma and to analyse its biodistribution and dosimetry to assess the radiation dose resulting from its diagnostic use. PATIENTS, METHODS: Seven patients with pancreatic adenocarcinoma underwent whole-body scintigraphies and SPECT up to 24 h after administration of 250 MBq of IPA. Tumour uptake of IPA was assessed visually. Time activity curves and the corresponding residence times were determined for whole-body, kidneys, liver, spleen, lung, heart content, brain, and testes. Mean absorbed doses for various organs and the effective dose were assessed based on the MIRD formalism using OLINDA/EXM. RESULTS: IPA exhibited no accumulation in proven manifestations of pancreatic adenocarcinomas. IPA was exclusively eliminated by the urine and showed a delayed clearance from blood. Residence times were 0.26 +/- 0.09 h for kidneys, 0.38 +/- 0.19 h for liver, 0.15 +/- 0.07 h for spleen, 0.51 +/- 0.20 h for lungs, 0.22 +/- 0.07 h for heart content, 0.11 +/- 0.05 h for brain, 0.014 +/- 0.005 h for testes and 6.4 +/- 2.2 h for the remainder. The highest absorbed doses were determined in the urinary bladder wall and in the kidneys. According to the ICRP 60 the effective dose resulting from 250 MBq IPA was 3.6 +/- 0.7 mSv. CONCLUSION: Para-[(123)I]iodo-L-phenylalanine can be used in diagnostic nuclear medicine with acceptable radiation doses. Besides its proven validity for brain tumour imaging, IPA does not appear to be suitable as tracer for pancreatic cancer.

Olfactory anomalies in CHARGE syndrome: imaging findings of a potential major diagnostic criterion.

BACKGROUND AND PURPOSE: CHARGE syndrome is a genetic disorder resulting in the association of multiple congenital anomalies. Although a high prevalence of olfactory anomalies in CHARGE syndrome has been reported in autopsy and functional studies, to our knowledge, such anomalies have not been included among the diagnostic criteria, and their radiographic prevalence has not been assessed. The purpose of this research was to determine the radiographic prevalence of olfactory anomalies in a small sample of subjects with diagnosed CHARGE syndrome. MATERIALS AND METHODS: The medical records and high-resolution MR images (section thickness < or =3 mm and in-plane resolution < or =1 mm) in 10 patients with clinically proved CHARGE syndrome were retrospectively reviewed by 3 neuroradiologists who consensually evaluated the status of the olfactory bulbs and sulci as either normal, hypoplastic, or absent. The prevalence (p) of congenital anomalies found in the medical records and of the olfactory structures was calculated with a 95% confidence interval (CI). RESULTS: MR imaging demonstrated olfactory anomalies in all 10 patients, including either absence or hypoplasia of the olfactory bulbs and olfactory sulci (p, 100%; CI, 0.65-1.00). CONCLUSION: These findings suggest that olfactory abnormalities detectable on high-resolution MR imaging are among the most prevalent features of CHARGE syndrome.

False-positive positron-emission tomography-CT of a Teflon granuloma in the parapharyngeal space occurring after treatment for a patulous eustachian tube.

This report presents a 55-year-old woman who underwent 2 Teflon injections in 1971 for a patulous eustachian tube. The patient returned in 2006 with a bloody left otorrhea. A positron-emission tomography-CT scan demonstrated a 2-cm hypermetabolic parapharyngeal mass, initially interpreted as a skull base tumor. Repeat neck CT confirmed a 2-cm hyperattenuated left parapharyngeal granulomatous mass. This is the first reported case of a Teflon granuloma presenting as a false-positive parapharyngeal mass.

Striatal FP-CIT uptake differs in the subtypes of early Parkinson's disease.

In idiopathic Parkinson's disease (PD), a tremor-dominant type (TDT), an akinetic-rigid type (ART), and a mixed type (MT) are distinguished. We compared cerebral [I-123]FP-CIT SPECT in the PD subtypes (67 patients Hoehn and Yahr stage 1:26 with ART, 19 with MT, 22 with TDT). We measured the ratios putamen/occipital lobe binding and caudate nucleus/occipital lobe binding. Parkinsonian motor symptoms were quantified by UPDRS motor scale. In both putamen and caudate nucleus contralateral to the clinically affected body side TDT patients showed a significantly higher FP-CIT uptake than ART or MT patients (ANOVA; p<0.01). Contralateral putamen and caudate nucleus FP-CIT uptake correlated significantly with severity of rigidity (p<0.01) and hypokinesia (p<0.01) but not with severity of resting or postural tremor (p>0.05). The missing correlation between striatal FP-CIT uptake and tremor suggests, that further systems besides the nigrostriatal dopaminergic system may contribute to generation of parkinsonian tremor.

[Positron emission tomography and scintigraphy. Nuclear imaging in clinical orthopaedics]. / Positronenemissionstomographie und Szintigraphie. Nuklearmedizinische Verfahren in der Orthopädie.

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.

Randomized trial of rifabutin-based triple therapy and high-dose dual therapy for rescue treatment of Helicobacter pylori resistant to both metronidazole and clarithromycin.

BACKGROUND: The clinical management of Helicobacter pylori infected patients who failed standard eradication therapies remains a challenge. AIM: To investigate the efficacy of rifabutin-based triple therapy and high-dose dual therapy for rescue treatment of H. pylori, and the correlation between cytochrome P450 2C19 (CYP2C19) polymorphisms and treatment outcome. METHODS: Patients infected with H. pylori resistant to both metronidazole and clarithromycin (n = 145) were randomized to either esomeprazole 20 mg, rifabutin 150 mg and amoxicillin 1 g, each given b.d. for 7 days (ERA), or to omeprazole 40 mg and amoxicillin 1000 mg, each given t.d.s. for 14 days (OA). Crossover therapy was offered in cases of persistent infection. CYP2C19 polymorphisms were determined by polymerase chain reaction restriction fragment length polymorphism. RESULTS: Intention-to-treat and per-protocol eradication rates were: ERA 74% (62.4-83.6) and 78% (66.7-87.3); high-dose OA 70% (57.5-79.7) and 75% (62.5-84.5). Crossover therapy was successful in seven of 10 patients with ERA and in eight of 10 patients with OA. Premature discontinuation of treatment occurred in 2% and 5% of patients, respectively. There was only a non-significant trend to lower eradication rates in homozygous extensive metabolizers. CONCLUSIONS: Triple therapy with esomeprazole, rifabutin and amoxicillin and high-dose omeprazole/amoxicillin are comparable and effective and safe for rescue therapy of H. pylori regardless of the patient's CYP2C19 genotype.

Intragastric acidity during treatment with esomeprazole 40 mg twice daily or pantoprazole 40 mg twice daily--a randomized, two-way crossover study.

BACKGROUND: Patients with severe or complicated reflux disease may require higher than standard doses of a proton pump inhibitor for sufficient acid suppression. AIM: To test the hypothesis that esomeprazole 40 mg twice daily is superior to pantoprazole 40 mg twice daily in lowering intragastric acidity. METHODS: In a randomized, single-blinded, two-way crossover study, healthy subjects received esomeprazole 40 mg twice daily or pantoprazole 40 mg twice daily orally for five consecutive days. Continuous ambulatory 24-h intragastric pH was recorded on day 5 of each treatment. RESULTS: Thirty subjects were analysed. Esomeprazole provided significantly higher intragastric pH-values over the 24-h period [median intragastric pH 6.4 for esomeprazole and 5.1 for pantoprazole (P < 0.00005)]. Intragastric pH > 4 was maintained for 21.1 h with esomeprazole and 16.8 h with pantoprazole (P < 0.0001). An intragastric pH > 4 for more than 16 h was achieved in 96.7 and 56.7% of subjects, respectively (P = 0.0002). During night-time the proportion of time with intragastric pH > 4 was 85.4% with esomeprazole and 63.6% with pantoprazole (P = 0.0001). Nocturnal acid break through occurred less frequently on esomeprazole. CONCLUSIONS: Esomeprazole 40 mg twice daily provides better and more consistent intragastric acid control than pantoprazole 40 mg twice daily.

[Guideline for therapy of malignant thyroid tumours: pleading for an actualization]. / Leitlinie zur Therapie maligner Schilddrüsentumoren: Plädoyer für eine Aktualisierung.

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).

Brain cholesterol, statins and Alzheimer's Disease.

Growing evidence suggests that cellular cholesterol homeostasis is causally involved in different steps leading to pathological events in the brain of Alzheimer's Disease (AD) patients. It was previously demonstrated that the processing of the amyloid beta-peptide precursor protein (APP) is modulated by pronounced alterations in cellular cholesterol levels using statins or cholesterol extracting agents. However, a cholesterol-rich diet was found to enhance amyloid beta-peptide (Abeta) burden in the brain of transgenic mice without clearly affecting total brain cholesterol levels. Recent retrospective epidemiological studies have reported that the use of statins potentially suppresses the development of AD. Although some HMG-CoA reductase inhibitors seem to influence the central cholesterol pool in vivo, the above epidemiological findings are probably not linked to statin-induced changes in brain membrane cholesterol levels per se since not all statins active in preventing AD enter the central nervous system (CNS). Recently, we reported that different statins, regardless of their brain availability, induce alterations in cellular cholesterol distribution in the brain. Such pleiotropic, cholesterol-synthesis independent statin effects might be indirect and are possibly mediated at the blood-brain barrier (BBB) via nitric oxide (NO) or apolipoprotein E (ApoE).

Esomeprazole-based one-week triple therapy with clarithromycin and metronidazole is effective in eradicating Helicobacter pylori in the absence of antimicrobial resistance.

AIM: This study aimed to investigate the effectiveness of a one-week triple therapy with esomeprazole, clarithromycin and metronidazole for eradication of Helicobacter pylori infection in the absence of antimicrobial resistance. METHODS: Patients testing positive for H. pylori susceptible to metronidazole and clarithromycin (E-test) were randomized to receive a one-week regimen with either esomeprazole 2 x 20 mg or omeprazole 2 x 20 mg in combination with clarithromycin 2 x 250 mg and metronidazole 2 x 400 mg. Follow-up endoscopy with histology and culture and/or rapid urease test was performed 4-8 weeks after the end of treatment. RESULTS: Eighty patients were randomized. Helicobacter pylori infection was cured in 38/39 patients of the esomeprazole group and 31/33 patients of the omeprazole group (per protocol 97.4% (95% confidence interval [CI], 86.2-99.9), 93.7% (95% CI, 79.2-99.2), P=0.59); intention-to-treat 90.4% (95% CI: 77.4-97.3), 81.6% (95% CI: 65.7-92.3), respectively. No major side effects occurred. Minor side effects occurred in eight (20%) and six (23%) patients during esomeprazole and omeprazole therapy, respectively. Post-treatment susceptibility testing revealed resistance to both metronidazole and clarithromycin in two of the three patients who failed. CONCLUSION: We conclude that esomeprazole, clarithromycin and metronidazole as one-week triple therapy is effective for eradication of H. pylori in the absence of antimicrobial resistance.

[PET with (18)F-fluorodeoxyglucose for staging of non-small cell lung cancer]. / PET mit (18)F-Fluordeoxyglukose in der Diagnostik des nicht kleinzelligen Bronchialkarzinoms: evidenzbasierte Empfehlungen und Kosten/Nutzenabwägungen.

AIMS: To evaluate studies on the use of positron emission tomography with the glucose analog (18)F-fluoro-deoxyglucose (FDG-PET) for the preoperative staging of patients with non-small cell lung cancer (NSCLC) according to the criteria of evidence based medicine and to discuss the cost-effectiveness of the technique. METHODS: Clinical studies published between 1995 and 2002 on the preoperative staging of non-small cell lung cancer were used for this analysis. Studies that did not meet the criteria published by the European Agency for the Evaluation of Medicinal Products (EMEA) were excluded. The validity of the studies was evaluated by a standardized rating system developed by the Agency for Health Care Policy and Research (AHCPR). RESULTS: For the detection of mediastinal lymph node metastases the mean sensitivity and specificity of FDG-PET on a patient basis is 85% and 87% (16 studies, 1355 patients). In studies that compared FDG-PET and computed tomography (CT) the mean sensitivity of CT was 66% at a specificity of 71%. In the detection of distant metastases FDG-PET correctly changed the tumor stage in 18% of the patients when compared to CT based staging (10 studies, 1073 patients). Five cost effectiveness analyses from the USA, Japan, and Germany concluded that FDG-PET improves the outcome of treatment at reduced or only slightly increased overall costs. Improvement of patient outcome was also demonstrated in a randomized trial, which found that the risk of a futile thoracotomy was reduced by 51% (p=0.003) when FDG-PET was added to the preoperative staging. CONCLUSION: According to the criteria of the AHCPR the use of FDG-PET for detection of mediastinal lymph node and distant metastases is documented at a level of evidence Ia and Ib, respectively. Since systematic analyses also indicate a favorable cost-effectiveness ratio FDG-PET has to be considered as "strictly indicated" for the preoperative staging of non-small cell lung cancer.

Brain-membrane cholesterol in Alzheimer's disease.

Cholesterol represents an important determinant of the physical state of biological membranes. Growing evidence indicate that changes in brain cholesterol and variations in neuronal membrane structure are involved in the development of Alzheimer's disease (AD). Cholesterol modulates the cleavage of the amyloid precursor protein and thus affect cellular production of beta-amyloid peptides (Ab). On the other hand, cholesterol seems to be protective against the neurotoxic and membrane disordering properties of Ab. Present review summarizes reports focusing on brain membrane changes in AD and the effects of Ab on these structures. Since it has been shown that these Ab effects are cholesterol dependent, recent findings are presented indicating that the modulation of membrane cholesterol refers to different cholesterol pools within the membranes. Further, consequences thereof for possible pharmacological strategies are discussed.

[Optimization of radiotherapy planning for non-small cell lung cancer (NSCLC) using 18FDG-PET]. / Optimierung der Bestrahlungsplanung beim nicht-kleinzelligen Bronchialkarzinom (NSCLC) mit Hilfe von 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.