Impact of pretreatment second look 18FDG-PET/CT on stage and treatment changes in head and neck cancer

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The potential value of a second look PET/CT prior to radiotherapy was investigated.

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New lymph node metastases were discovered in half of the patients.

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Progression of the primary tumor and distant metastases were also observed.

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This strategy led to changes in treatment planning in more than half of the cases.

Background

Patients diagnosed with locoregionally advanced head and neck squamous cell carcinoma (LAHNSCC) regularly undergo staging with ¹⁸F-FDG PET/CT in our center. In cases of delays in radiotherapy (RT) planning CT more than 4 weeks after initial PET/CT or clinically suspected progress, PET/CT is repeated for restaging and as an RT planning reference. Our aim was to determine the impact of second-look PET/CT on stage migration, treatment change and RT planning.

Methods

Consequent treatment changes were categorized as minor and major. Minor changes were defined as PET/CT-based modifications of RT plans, e.g., the addition of anatomical compartments, changes in high- and low-risk dose levels or both. Major changes included changes from curative to palliative treatment intent and alterations of interdisciplinary treatment plans, such as the addition of induction chemotherapy, switch to primary surgery, no treatment and/or the necessity of additional diagnostic work-up resulting in the postponement or cancellation of treatment.

Results

Thirty-two newly diagnosed LAHNSCC patients who were treated between 2014 and 2018 underwent second-look PET/CT (median interval 42.5 days). Second-look PET/CT led to locoregional and distant upstaging in 3/32 and 1/32 patients, respectively. In 1/32 patients (3%), second-look PET/CT led to a palliative approach with systemic treatment. New lymph node metastases were discovered in 16 patients, 6 of whom also showed significant progression of the primary tumor, resulting in minor changes in 16 of the remaining 31 patients (52%) who were treated curatively.

Conclusion

If RT treatment planning of LAHNSCC was delayed by more than 4 weeks after initial PET/CT staging or when progression was clinically suspected, a second look at ¹⁸FDG-PET/CT was performed. This led to changes in treatment planning in more than half of the cases, which is expected to directly influence oncologic outcomes.

The Effect of a Distal Centralizer on Cemented Femoral Stems in Arthroplasty Shown on Radiographs and SPECT/CT: A Case Report

CASE

A 70-year-old female patient underwent total hip arthroplasty (HA) using a stem cemented line-to-line without centralizer. Postoperatively, she complained of load-dependent thigh pain. Conventional radiographs identified cortical overload because of a distal cement mantle discontinuity at the level of the stem's tip, confirmed by single-photon emission computed tomography/computed tomography scan (SPECT/CT). After cement-in-cement revision using a stem with centralizer, pain ceased rapidly. The cortical overload disappeared, as confirmed on a following SPECT/CT performed for low back pain.

CONCLUSION

In HA, the stem's tip may cause overload on the bone's cortex if the cement mantle is incomplete. Implanting a stem with centralizer avoids or cures this.

Appropriate use criteria for dementia amyloid imaging in Switzerland - mini-review and statement on behalf of the Swiss Society of Nuclear Medicine and the Swiss Memory Clinics

While FDG-PET imaging of the brain for the differential diagnosis of dementia has been covered by the compulsory health insurance in Switzerland for more than a decade, beta-amyloid-PET just recently has been added to the catalogue of procedures that have been cleared for routine use, provided that a set of appropriate use criteria (AUC) be followed. To provide guidance to dementia care practitioners, the Swiss Society of Nuclear Medicine and the Swiss Memory Clinics jointly report a mini-review on beta-amyloid-PET and discuss the AUC set into effect by the Swiss Federal Office of Public Health, as well as their application and limitations.

Successful Treatment of a Resistant Subclone in ALK-Rearranged NSCLC

Anaplastic lymphoma kinase (ALK) tyrosine kinase inhibitors (TKIs) are established effective therapies in patients with ALK-rearranged advanced non-small-cell lung cancer (NSCLC). Upon progressive disease, patients normally receive a subsequent ALK TKI. However, when disease progression occurs in a limited number of sites, an oligoprogressive approach is a treatment option. In our case, FDG-PET/CT scan detected a progressive site in a patient with ceritinib therapy. Biopsy of the lesion was not possible because of its location. Progression was therefore confirmed by liquid biopsy with identification of the resistant subclone ALK G1202R. Definitive radiotherapy of the progressive site led to the disappearance of the ALK-resistant mutation. Meanwhile, ceritinib therapy was continued. The absence of disease both on repeated imaging and liquid biopsy indicates that eradication of a resistant subclone with an oligoprogressive treatment approach might be possible.

3D printing of radioactive phantoms for nuclear medicine imaging

Background

For multicenter clinical studies, PET/CT and SPECT/CT scanners need to be validated to ensure comparability between various scanner types and brands. This validation is usually performed using hollow phantoms filled with radioactive liquids. In recent years, 3D printing technology has gained increasing popularity for manufacturing of phantoms, as it is cost-efficient and allows preparation of phantoms of almost any shape. So far, however, direct 3D printing with radioactive building materials has not yet been reported. The aim of this work was to develop a procedure for preparation of ^99mTc-containing building materials and demonstrate successful application of this material for 3D printing of several test objects.

Method

The desired activity of a [^99mTc]pertechnetate solution eluted from a ⁹⁹Mo/^99mTc-generator was added to the liquid 3D building material, followed by a minute amount of trioctylphosphine. The resulting two-phase mixture was thoroughly mixed. Following separation of the phases and chemical removal of traces of water, the radioactive building material was diluted with the required volume of non-radioactive building material and directly used for 3D printing.

Results

Using our optimized extraction protocol with trioctylphosphine as complex-forming phase transfer agent, technetium-99m was efficiently transferred from the aqueous ⁹⁹Mo/^99mTc-generator eluate into the organic liquid resin monomer. The observed radioactivity concentration ratio between the organic phase and the water phase was > 2000:1. The radioactivity was homogeneously distributed in the liquid resin monomer. We did not note differences in the 3D printing behavior of the radiolabeled and the unlabeled organic liquid resin monomers. Radio-TLC and SPECT studies showed homogenous 2D and 3D distribution of radioactivity throughout the printed phantoms. The radioactivity was stably bound in the resin, apart from a small amount of surface-extractable radioactivity under harsh conditions (ethanol at 50 °C).

Conclusions

3D printing of radioactive phantoms using ^99mTc-containing building materials is feasible. Compared to the classical fillable phantoms, 3D printing with radioactive building materials allows manufacturing of phantoms without cold walls and in almost any shape. Related procedures with longer-lived radionuclides will enable production of phantoms for scanner validation and quality control.

Towards guidelines to harmonize textural features in PET: Haralick textural features vary with image noise, but exposure-invariant domains enable comparable PET radiomics

Purpose

Image texture is increasingly used to discriminate tissues and lesions in PET/CT. For quantification or in computer-aided diagnosis, textural feature analysis must produce robust and comparable values. Because statistical feature values depend on image count statistics, we investigated in depth the stability of Haralick features values as functions of acquisition duration, and for common image resolutions and reconstructions.

Methods

A homogeneous cylindrical phantom containing 9.6 kBq/ml Ge-68 was repeatedly imaged on a Siemens Biograph mCT, with acquisition durations ranging from three seconds to three hours. Images with 1.5, 2, and 4 mm isometrically spaced voxels were reconstructed with filtered back-projection (FBP), ordered subset expectation maximization (OSEM), and the Siemens TrueX algorithm. We analysed Haralick features derived from differently quantized (3 to 8-bit) grey level co-occurrence matrices (GLCMs) as functions of exposure E, which we defined as the product of activity concentration in a volume of interest (VOI) and acquisition duration. The VOI was a 50 mm wide cube at the centre of the phantom. Feature stability was defined for df/dE → 0.

Results

The most stable feature values occurred in low resolution FBPs, whereas some feature values from 1.5 mm TrueX reconstructions ranged over two orders of magnitude. Within the same reconstructions, most feature value-exposure curves reached stable plateaus at similar exposures, regardless of GLCM quantization. With 8-bit GLCM, median time to stability was 16 s and 22 s for FBPs, 18 s and 125 s for OSEM, and 23 s, 45 s, and 76 s for PSF reconstructions, with longer durations for higher resolutions. Stable exposures coincided in OSEM and TrueX reconstructions with image noise distributions converging to a Gaussian. In FBP, the occurrence of stable values coincided the disappearance of negatives image values in the VOI.

Conclusions

Haralick feature values depend strongly on exposure, but invariance exists within defined domains of exposure. Here, we present an easily replicable procedure to identify said stable exposure domains, where image noise does not substantially add to textural feature values. Only by imaging at predetermined feature-invariant exposure levels and by adjusting exposure to expected activity concentrations, can textural features have a quantitative use in PET/CT. The necessary exposure levels are attainable by modern PET/CT systems in clinical routine.

Value of bone marrow biopsy in Hodgkin lymphoma patients staged by FDG PET: results from the German Hodgkin Study Group trials HD16, HD17, and HD18

Background

Bone marrow (BM) involvement defines advanced-stage Hodgkin lymphoma and thus has impact on the assignment to treatment. Our aim was to evaluate whether the established BM biopsy may be omitted in patients if 18F-fluorodeoxyglucose positron emission tomography (PET) scanning is carried out during staging.

Patients and methods

Our analysis set consisted of 832 Hodgkin lymphoma patients from the German Hodgkin Study Group trials HD16, HD17, and HD18 who underwent both PET scanning and BM biopsy before treatment. All PET studies were centrally reviewed and BM was categorized as showing focal involvement or not.

Results

Taking BM biopsy as reference standard, baseline PET showed a negative predictive value of 99.9% [95% confidence interval (CI) 99.2% to 100%] with true-negative results in 702 of 703 cases. The sensitivity of PET for detecting BM involvement was 95.0% (95% CI 75.1% to 99.9%) as it could identify 19 out of 20 patients with positive BM biopsy. Moreover, PET found 110 additional subjects with focal BM lesions who would have been considered negative by biopsy.

Conclusions

When compared with BM biopsy, PET was able to detect focal BM lesions in a large number of additional patients. This indicates that conventional BM biopsy may substantially underestimate the actual incidence of BM involvement. Given the high negative predictive value, baseline PET scanning can safely be used to exclude BM involvement in Hodgkin lymphoma. BM biopsy should be considered only in such patients in whom PET-detected lesions lead to a change of treatment protocol.

Registered trials

The trials included in this analysis were registered at ClinicalTrials.gov: HD16-NCT00736320, HD17-NCT01356680, and HD18-NCT00515554.

Cardiac Implantable Electronic Device-Related Infection Due to Granulicatella adiacens

Cardiac implantable electronic device–related infection is clinically challenging. Curative treatment commonly includes system removal. A case caused by Granulicatella adiacens occurred in a 32-year-old woman. Clinical course, literature review, and biofilm investigations enabled successful antibiotic management without system removal.

Metabolic Tumour Volume for Response Prediction in Advanced-Stage Hodgkin Lymphoma

Rationale: (18F)fluoro-2-deoxy-D-glucose (18F-FDG) positron emission tomography (PET)/computed tomography (CT) for staging Hodgkin lymphoma may allow for accurate and reliable assessment of the metabolic tumour volume (MTV) as baseline risk factor. Our aim was to analyse the prognostic impact of MTV measurements, obtained by different means in advanced-stage Hodgkin lymphoma patients treated within the German Hodgkin Study Group HD18 trial. Methods: Within the German Hodgkin Study Group trial HD18, 310 patients underwent 18F-FDG PET/CT scanning for staging which was available to the central review panel for quantitative analysis. We calculated the MTV by four different thresholding methods and performed receiver operating characteristic (ROC) analysis to evaluate the potential for prediction of early response determined by PET after two cycles (PET-2) dose-escalated bleomycin, etoposide, doxorubicin, cyclophosphamide, vincristine, procarbazine, and prednisone (eBEACOPP). Logistic regression was used to evaluate its prognostic value concerning progression-free survival (PFS) and overall survival (OS). Results: All different MTV calculations used predicted PET-2 response to a moderate and comparable degree (area under the curve = 0.62-0.63, P = 0.01-0.06). With none of the measuring methods did the ROC curves point to any unique cut-off values, but indicated a wide range of possible cut-offs. However, none of the MTV measurements was prognostic for PFS (Hazard ratio 1.2-1.5, P = 0.15-0.52) or OS (Hazard ratio 1.0-1.5, P = 0.95 - 0.27). Conclusion: Baseline MTV as determined by different means, is a predictive factor for early response to eBEACOPP after two cycles. However, value as a prognostic factor after highly effective PET-2 adapted treatment strategy could not be observed.

Technical Note: Transconvolution based equalization of positron energy effects for the use of 68 Ge/68 Ga phantoms in determining 18 F PET recovery

PURPOSE

Avoiding measurement variability from ¹⁸ F phantom preparation by using ⁶⁸ Ge/⁶⁸ Ga phantoms for the determination of ¹⁸ F recovery curves (RC) in clinical quality assurance measurements and for PET/CT site qualification in multicentre clinical trials.

METHODS

RCs were obtained from PET/CT measurements of seven differently sized phantom spheres filled either with ¹⁸ F or with ⁶⁸ Ga. RCs for the respective other isotope were then determined by two different methods: In the first method, images were convolved with positron range transconvolution functions derived from positron annihilation distributions found in literature. This method generated recasted images matching images using the respective other isotope. In the second method, the PET/CT system's isotope independent (intrinsic) point spread function was determined from said phantom measurements and convolved with numerical representations simulating hot spheres filled with the respective other isotope. These simulations included the isotope specific positron annihilation distributions. Recovered activity concentrations were compared between recasted images, simulated images, and the originally acquired images.

RESULTS

¹⁸ F and ⁶⁸ Ga recovery was successfully determined from image acquisitions of the respective opposite isotope as well as from the simulations. ⁶⁸ Ga RCs derived from ¹⁸ F data had a normalized root-mean-square deviation (NRMSD) from real ⁶⁸ Ga measurements of 0.019% when using the first method and of 0.008% when using the second method. ¹⁸ F RCs derived from ⁶⁸ Ga data had a NRMSD from real ¹⁸ F measurements of 0.036% when using the first method and of 0.038% when using the second method.

CONCLUSIONS

Applying the principles of transconvolution, ¹⁸ F RCs can be recalculated from ⁶⁸ Ga phantom measurements with excellent accuracy. The maximal additionally introduced error was below 0.4% of the error currently accepted for RCs in the site qualification of multicentre clinical trials by the EARL program of the European Association of Nuclear Medicine (EANM). Therefore, our methods legitimately allow for the use of long-lived solid state ⁶⁸ Ge/⁶⁸ Ga phantoms instead of manually prepared ¹⁸ F phantoms to characterize comparability of ¹⁸ F measurements across different imaging sites or of longitudinal ¹⁸ F measurements at a single PET/CT system.

Technical Note: Determination of individual thyroid clearance effective half-life with a common handheld electronic dosimeter

PURPOSE

To determine the thyroid clearance effective half-life T with a common handheld electronic dosimeter (ED) in patients undergoing radioiodine treatment for hyperthyroidism.

METHODS

Dose rates from 12 inpatients were measured daily with an ED and with a clinical uptake counter. The ED was attached to the patient with two different setups, one using a cervical collar and another employing a neck strap. Estimation of T was performed by linear regression analysis of the log of both the ED and the uptake counter measurements versus time. The latter provided the reference data.

RESULTS

Based on repeated neck strap dose rate measurements, individual Ts were determined with clinically required accuracy. The mean difference from the reference method equaled to -0.09 ± 0.35 days.

CONCLUSIONS

Determination of individual T is feasible with a common handheld ED using the simple and easy to instruct neck strap measurement setup. This simple method complements stationary uptake counter measurements and thus may improve the accuracy of radioiodine treatment planning by adding an individual T for dose calculation.

Zevalin and BEAM (Z-BEAM) versus rituximab and BEAM (R-BEAM) conditioning chemotherapy prior to autologous stem cell transplantation in patients with mantle cell lymphoma

Early relapse is common in patients with mantle cell lymphoma (MCL) highlighting the unmet need for further improvement of therapeutic options for these patients. CD20 inhibition combined with induction chemotherapy as well as consolidation with high-dose chemotherapy (HDCT) is increasingly considered cornerstones within current therapy algorithms of MCL whereas the role of radioimmunotherapy is unclear. This retrospective single center study compared 46 consecutive MCL patients receiving HDCT in first or second remission. Thirty-five patients had rituximab and BEAM (R-BEAM), and 11 patients received ibritumomab tiuxetan (Zevalin®), an Yttrium-90 labeled CD20 targeting antibody, prior to BEAM (Z-BEAM) followed by autologous stem cell transplantation (ASCT). We observed that the 5-year overall survival (OS) in the R-BEAM and Z-BEAM groups was 55% and 71% (p = 0.288), and the 4-year progression free survival (PFS) was 32% and 41%, respectively (p = 0.300). There were no treatment related deaths in both groups, and we observed no differences in toxicities, infection rates or engraftment. Our data suggest that the Z-BEAM conditioning regimen followed by ASCT is well tolerated, but was not associated with significantly improved survival compared to R-BEAM. Copyright © 2015 John Wiley & Sons, Ltd.

Regional Radiation Pneumonitis After SIRT of a Subcapsular Liver Metastasis: What is the Effect of Direct Beta Irradiation?

We herein present a patient undergoing selective internal radiation therapy with an almost normal lung shunt fraction of 11.5%, developing histologically proven radiation pneumonitis. Due to a predominance of pulmonary consolidations in the right lower lung and its proximity to a large liver metastases located in the dome of the right liver lobe a Monte Carlo simulation was performed to estimate the effect of direct irradiation of the lung parenchyma. According to our calculations direct irradiation seems negligible and RP is almost exclusively due to ectopic draining of radioactive spheres.

Transconvolution and the virtual positron emission tomograph--a new method for cross calibration in quantitative PET∕CT imaging

PURPOSE

Positron emission tomography (PET)∕computed tomography (CT) measurements on small lesions are impaired by the partial volume effect, which is intrinsically tied to the point spread function of the actual imaging system, including the reconstruction algorithms. The variability resulting from different point spread functions hinders the assessment of quantitative measurements in clinical routine and especially degrades comparability within multicenter trials. To improve quantitative comparability there is a need for methods to match different PET∕CT systems through elimination of this systemic variability. Consequently, a new method was developed and tested that transforms the image of an object as produced by one tomograph to another image of the same object as it would have been seen by a different tomograph. The proposed new method, termed Transconvolution, compensates for differing imaging properties of different tomographs and particularly aims at quantitative comparability of PET∕CT in the context of multicenter trials.

METHODS

To solve the problem of image normalization, the theory of Transconvolution was mathematically established together with new methods to handle point spread functions of different PET∕CT systems. Knowing the point spread functions of two different imaging systems allows determining a Transconvolution function to convert one image into the other. This function is calculated by convolving one point spread function with the inverse of the other point spread function which, when adhering to certain boundary conditions such as the use of linear acquisition and image reconstruction methods, is a numerically accessible operation. For reliable measurement of such point spread functions characterizing different PET∕CT systems, a dedicated solid-state phantom incorporating (68)Ge∕(68)Ga filled spheres was developed. To iteratively determine and represent such point spread functions, exponential density functions in combination with a Gaussian distribution were introduced. Furthermore, simulation of a virtual PET system provided a standard imaging system with clearly defined properties to which the real PET systems were to be matched. A Hann window served as the modulation transfer function for the virtual PET. The Hann's apodization properties suppressed high spatial frequencies above a certain critical frequency, thereby fulfilling the above-mentioned boundary conditions. The determined point spread functions were subsequently used by the novel Transconvolution algorithm to match different PET∕CT systems onto the virtual PET system. Finally, the theoretically elaborated Transconvolution method was validated transforming phantom images acquired on two different PET systems to nearly identical data sets, as they would be imaged by the virtual PET system.

RESULTS

The proposed Transconvolution method matched different PET∕CT-systems for an improved and reproducible determination of a normalized activity concentration. The highest difference in measured activity concentration between the two different PET systems of 18.2% was found in spheres of 2 ml volume. Transconvolution reduced this difference down to 1.6%. In addition to reestablishing comparability the new method with its parameterization of point spread functions allowed a full characterization of imaging properties of the examined tomographs.

CONCLUSIONS

By matching different tomographs to a virtual standardized imaging system, Transconvolution opens a new comprehensive method for cross calibration in quantitative PET imaging. The use of a virtual PET system restores comparability between data sets from different PET systems by exerting a common, reproducible, and defined partial volume effect.

Age-related normal structural and functional ventricular values in cardiac function assessed by magnetic resonance

Background

The heart is subject to structural and functional changes with advancing age. However, the magnitude of cardiac age-dependent transformation has not been conclusively elucidated.

Methods

This retrospective cardiac magnetic resonance (CMR) study included 183 subjects with normal structural and functional ventricular values. End systolic volume (ESV), end diastolic volume (EDV), and ejection fraction (EF) were obtained from the left and the right ventricle in breath-hold cine CMR. Patients were classified into four age groups (20–29, 30–49, 50–69, and ≥70 years) and cardiac measurements were compared using Pearson’s rank correlation over the four different groups.

Results

With advanced age a slight but significant decrease in ESV (r=−0.41 for both ventricles, P<0.001) and EDV (r=−0.39 for left ventricle, r=−0.35 for right ventricle, P<0.001) were observed associated with a significant increase in left (r=0.28, P<0.001) and right (r=0.27, P<0.01) ventricular EF reaching a maximal increase in EF of +8.4% (P<0.001) for the left and +6.1% (P<0.01) for the right ventricle in the oldest compared to the youngest patient group. Left ventricular myocardial mass significantly decreased over the four different age groups (P<0.05).

Conclusions

The aging process is associated with significant changes in left and right ventricular EF, ESV and EDV in subjects with no cardiac functional and structural abnormalities. These findings underline the importance of using age adapted values as standard of reference when evaluating CMR studies.

[SPECT/CT diagnostics for skeletal infections]

CLINICAL/METHODICAL ISSUE

Skeletal infections are often a diagnostic and clinical challenge.

STANDARD RADIOLOGICAL METHODS

Nuclear imaging modalities used in the diagnostic workup of acute and chronic skeletal infections include three-phase bone scintigraphy and scintigraphy with labelled leucocytes.

METHODICAL INNOVATIONS

The introduction of hybrid technologies, such as single photon emission computed tomography/computed tomography (SPECT/CT) has dramatically changed nuclear medical imaging of infections.

PERFORMANCE

In general SPECT/CT leads to a considerably more accurate diagnosis than planar or SPECT imaging.

ACHIEVEMENTS

Given the integrated acquisition of metabolic, functional and morphological information, SPECT/CT has increased in particular the specificity of three-phase skeletal scanning and scintigraphy with labeled leucocytes.

Hypodense regions in unenhanced CT identify nonviable myocardium: validation versus 18F-FDG PET

PURPOSE

The aim of the present study was to evaluate the accuracy of hypodense regions in non-contrast-enhanced cardiac computed tomography (unenhanced CT) to identify nonviable myocardial scar tissue.

METHODS

Hypodense areas were visually identified in unenhanced CT of 80 patients in the left ventricular anterior, apical, septal, lateral and inferior myocardium and CT density was measured in Hounsfield units (HU). Findings were compared to (18)F-fluorodeoxyglucose uptake by positron emission tomography (FDG PET), which served as the standard of reference to distinguish scar (<50 % FDG uptake) from viable tissue (≥50 % uptake).

RESULTS

Visually detected hypodense regions demonstrated a sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of 74, 97, 84 and 94 %, respectively. A receiver-operating characteristic (ROC) curve analysis revealed a cutoff value of mean HU at <28.8 for predicting scar tissue with an area under the curve of 0.93 yielding a sensitivity, specificity, PPV and NPV of 94, 90, 67 and 99 %, respectively.

CONCLUSION

Hypodense regions in unenhanced cardiac CT scans allow accurate identification of nonviable myocardial scar tissue.

Multimodal target correction by local bone registration: a PET/CT evaluation

PET/CT guidance for percutaneous interventions allows biopsy of suspicious metabolically active bone lesions even when no morphological correlation is delineable in the CT images. Clinical use of PET/CT guidance with conventional step-by-step technique is time consuming and complicated especially in cases in which the target lesion is not shown in the CT image. Our recently developed multimodal instrument guidance system (IGS) for PET/CT improved this situation. Nevertheless, bone biopsies even with IGS have a trade-off between precision and intervention duration which is proportional to patient and personnel exposure to radiation. As image acquisition and reconstruction of PET may take up to 10 minutes, preferably only one time consuming combined PET/CT acquisition should be needed during an intervention. In case of required additional control images in order to check for possible patient movements/deformations, or to verify the final needle position in the target, only fast CT acquisitions should be performed. However, for precise instrument guidance accounting for patient movement and/or deformation without having a control PET image, it is essential to be able to transfer the position of the target as identified in the original PET/CT to a changed situation as shown in the control CT.

Die Rolle der PET bei der bildgebenden Untersuchung von Patienten mit malignen Lymphomen

Die Positronen-Emissions-Tomographie (PET) hat sich während der letzten 20 Jahre zum diagnostischen Goldstandard in der Bildgebung einer Mehrzahl von malignen Tumorerkrankungen entwickelt, darunter insbesondere für die bildgebende Untersuchung von Patienten mit malignen Lymphomen. Mit der Entwicklung und Verbreitung von sogenannten Hybridgeräten, die gleichzeitig eine PET-Untersuchung und eine Computertomographie (CT) ermöglichen, und die mit Hilfe fusionierter PET/CT Bilder auch kleinste krankhafte Prozesse zuverlässig zuordnen lassen, wurde die Wertigkeit der Methode nochmals erheblich verbessert. Die hohe Empfindlichkeit der Stoffwechselbildgebung mit PET bzw. PET/CT ermöglicht eine zuverlässige Gesamtbeurteilung von Patienten mit malignen Lymphom für die Stadieneinteilung vor Therapiebeginn, die frühe Diagnose von Therapieversagern unter Therapie sowie das sichere Erkennen von Rezidiven nach Therapie.

PET/CT-guided biopsies of metabolically active bone lesions: applications and clinical impact

PURPOSE

In a minority of cases a definite diagnosis and stage grouping in cancer patients is not possible based on the imaging information of PET/CT. We report our experience with percutaneous PET/CT-guided bone biopsies to histologically verify the aetiology of hypermetabolic bone lesions.

METHODS

We retrospectively reviewed the data of 20 consecutive patients who underwent multimodal image-guided bone biopsies using a dedicated PET/CT system in a step-by-step technique. Technical and clinical success rates of PET/CT-guided biopsies were evaluated. Questionnaires were sent to the referring physicians to assess the impact of biopsies on patient management and to check the clinical need for PET/CT-guided biopsies.

RESULTS

Clinical indications for biopsy were to histologically verify the aetiology of metabolically active bone lesions without a morphological correlate confirming the suspicion of metastases in 15 patients, to determine the origin of suspected metastases in 3 patients and to evaluate the appropriateness of targeted therapy options in 2 patients. Biopsies were technically successful in all patients. In 19 of 20 patients a definite histological diagnosis was possible. No complications or adverse effects occurred. The result of PET/CT-guided bone biopsies determined a change of the planned treatment in overall 56% of patients, with intramodality changes, e.g. chemotherapy with palliative instead of curative intent, and intermodality changes, e.g. systemic therapy instead of surgery, in 22 and 50%, respectively.

CONCLUSION

PET/CT-guided bone biopsies are a promising alternative to conventional techniques to make metabolically active bone lesions-especially without a distinctive morphological correlate-accessible for histological verification. PET/CT-guided biopsies had a major clinical impact in patients who otherwise cannot be reliably stage grouped at the time of treatment decisions.

Therapeutic impact of 2-[fluorine-18]fluoro-2-deoxy-D-glucose positron emission tomography in the pre- and postoperative staging of patients with clinically intermediate or high-risk breast cancer

BACKGROUND

Positron emission tomography with 2-[fluorine-18]fluoro-2-deoxy-D-glucose (FDG-PET) is an accurate imaging modality for the staging of breast cancer. The aim of this study was to determine the potential therapeutic impact of pre- and postoperative FDG-PET in patients with clinically intermediate or high-risk breast cancer.

PATIENTS AND METHODS

One hundred and fourteen patients with newly diagnosed breast cancer were examined before (73) or after (41) surgery. Patient data were translated into three scoring sheets corresponding to information available before positron emission tomography (PET), after PET and after further diagnostic tests. Three medical oncologists independently reviewed the retrospectively acquired patient data and prospectively made decisions on the theoretically planed treatment for each time point, according to the recommendations of St Gallen Consensus Guidelines 2005.

RESULTS

FDG-PET changed the planed treatment in 32% of 114 patients. In 20% of cases, therapeutic intention (curative versus palliative) was modified. Radiation treatment planning was changed in 27%, surgical planning in 9%, chemotherapy in 11% and intended therapy with bisphosphonates in 13% of all patients.

CONCLUSION

Based on current treatment guidelines, FDG-PET, as a staging procedure in patients with newly diagnosed clinically intermediate or high-risk breast cancer examined pre- and postoperatively, may have a substantial therapeutic impact on treatment planning.

PET scanning and patient reported dysphagia before and after chemotherapy (CT) for prediction of pathological response after CT and chemoradiotherapy (CRT) in patients with locally advanced esophageal cancer (EC): A multicenter phase ll trial of the Swiss

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Background: Only responding patients (pts) ultimately benefit from preoperative therapy for locally advanced EC. To predict response quality after CRT and detect non-responders earlier, we evaluated changes from baseline in FDG uptake by PET scans and patient reported dysphagia after two cycles of CT. Methods: Pts with resectable, locally advanced squamous cell carcinoma or adenocarcinoma of the esophagus were treated with 2 cycles of CT with docetaxel/cisplatin (DC) q3w followed by CRT (DC weekly x5 with concomitant 45 Gy RT) and surgery. PET imaging using [F]-deoxyglucose (FDG) uptake and subjective dysphagia assessment using a quality of life module specific to EC (EORTC QLQ-OES24) were performed at baseline and after the 2nd cycle of CT. 40% decrease of FDG uptake was prospectively hypothesized to be an early predictor for a pathological complete remission (tumor regression grade 1, TRG) and subtotal regression (TRG 2) after the CRT. The predictive value of improvement in dysphagia was tested by analysis of covariance with baseline dysphagia as covariate. Results: Out of included 66 pts, 56 completed preoperative therapy and surgery. Dysphagia scores (range 0–100) were available in 51 pts, mean changes were 14 (n=13), 12 (n=16) and 12 (n=22) for pts with TRG 1, 2 or >2, respectively, lacking any significance. 44 pts had two PET scans (5: centers not participating, 3: no FDG-uptake at baseline, 4: second scan too late or not done). Mean FDG-decrease was 49% (n=7), 44% (n=17), 15% (n=20) for pts with TRG 1, 2 or >2, respectively. Less than 40% reduction in FDG uptake predicted non-response (TRG>2) with sensitivity 70%, specificity 50%, negative predictive value 70% and positive predictive value 50%. FDG- uptake reduction indicated reduced risk of TRG>2 in a logistic regression model (p<0.01, 95%-CI 2–273). Conclusions: Decreased FDG uptake in sequential PET scans strongly correlates with tumor response, but is not accurate enough to early identify non- responders. Early improvement of dysphagia after 2 cycles CT did not predict TRG after CRT.

No significant financial relationships to disclose.

Increased pulmonary FDG uptake in bleomycin-associated pneumonitis

BACKGROUND

Bleomycin is an antineoplastic agent that is mainly used in combination regimens. Dose-limiting toxicity is the bleomycin-induced pneumonitis (BIP) that can be diagnosed by clinical and radiological findings. The early diagnosis of BIP is often challenging.

CASE REPORT

We report the occurrence of a diffuse pulmonary increase of FDG uptake in the FDG-PET scan in association with suspected BIP in a patient treated for relapsed seminoma. A retroperitoneal relapse was treated with a combination chemotherapy containing cisplatin, etoposide, and bleomycin. After 3 cycles of this regimen the patient developed mild clinical signs of early BIP. A following FDG-PET in order to evaluate treatment response showed a diffuse increased FDG uptake of the right lung. The subsequent HRCT revealed pathological findings consistent with BIP. After cessation of bleomycin and a systemic steroid trial a prompt normalization of the abnormal radiological and clinical findings occurred together with a disappearance of the increased pulmonary FDG uptake.

CONCLUSION

FDG-PET can be used for evaluation of residual disease in patients treated for advanced seminoma. In cases of otherwise unexplained increased pulmonary FDG uptake in patients under treatment with bleomycin an evaluation for early BIP as a possible cause of this finding is warranted.

Major tumor regression after paclitaxel and carboplatin polychemotherapy in a patient with advanced penile cancer

Penile cancer is rare in Western countries. High-risk patients are considered for prophylactic inguinal lymphadenectomy. For advanced disease, a triplet drug regimen consisting of bleomycin, methotrexate, and cisplatin is the most active combination tested so far. A 62-year-old man with penile cancer underwent partial penile amputation but presented 10 months later with inguinal nodal metastasis. He received three cycles of paclitaxel/carboplatin with marked clinical and radiologic (computed tomography and positron emission tomography) tumor regression. Later, complete resection of the inguinal nodal metastasis was performed. The paclitaxel/carboplatin combination has potential activity in penile cancer. Positron emission tomography may be used for screening of nodal metastases.