Christian Rosner

Liver Malignancies: CT-Guided Interstitial Brachytherapy in Patients with Unfavorable Lesions for Thermal Ablation

PURPOSE To evaluate computed tomography (CT)-guided brachytherapy in patients with very large liver malignancies or with liver tumors located adjacent to the liver hilum. MATERIALS AND METHODS In this prospective nonrandomized phase II trial, we treated 20 patients (19 liver metastases and one cholangiocarcinoma) with CT-guided high-dose-rate (HDR) brachytherapy using a (192) Iridium source. All patients demonstrated no functional liver degradation prior to irradiation. Entry criteria were liver tumors > 5 cm (group A, n = 11, no upper limit) or liver tumors < or = 5 cm adjacent to the liver hilum (group B, n = 9). Dose planning for brachytherapy was performed with three dimensional (3D) CT data acquired after percutaneous applicator positioning. Magnetic resonance (MR) imaging follow-up was performed 6 weeks and every 3 months post intervention. Primary endpoints were complications, local tumor control (absence of tumor growth after treatment followed by shrinkage of the lesion starting at 6 months) and progression-free survival. RESULTS The mean tumor diameter was 7.7 cm (range, 5.5-10.8 cm) in group A, 3.6 cm (range, 2.2-4.9 cm) in group B. On average, a minimal dose of 17 Gy in the target volume was applied (range, 12-25 Gy). Severe side effects were recorded in two patients (10%). One patient demonstrated an obstructive jaundice caused by tumor edema after irradiation of a metastasis adjacent to the bile duct bifurcation. One patient developed intra-abdominal hemorrhage that was treated by a single blood transfusion and has ceased. We frequently encountered moderate increases of liver enzymes (70% of patients) and bilirubin (50% of patients) without clinical symptoms and thus considered to be insignificant. The median follow-up was 13 months. In group A (tumors > 5 cm), primary local tumor control after 6 and 12 months was 74% and 40%, respectively; in group B, it was 100% and 71%, respectively. All but one local recurrence (in a patient with diffuse tumor progression) were successfully treated during another CT-guided brachytherapy leading to a primary assisted local control of 93% after 12 months. CONCLUSION CT-guided brachytherapy based on individual dose plans and 3D CT data sets generated encouraging results in large liver malignancies as well as in tumors located adjacent to the liver hilum.

Influence of attenuation correction by integrated low-dose CT on somatostatin receptor SPECT.

AimSomatostatin receptor scintigraphy (SRS) is well-established in neuroendocrine tumour (NET) imaging. This study evaluated the impact of attenuation correction (AC) on SRS SPECT data in patients examined by SPECT–CT. MethodsPlanar scintigraphy and SPECT–CT of 17 patients (10 men, seven women; age, 40–74 years; mean, 62 years) suffering from NET were included. For the visual assessment of AC, the intensity and contrast of foci classified as pathological were rated in both the non-attenuation corrected (NAC) and the attenuation corrected (AC) SPECT images using a 5-point score. The change in signal intensity after AC was semiquantified two-fold for each focus in both SPECTAC and SPECTNAC: firstly by using tumour-to-background (TB) ratios (defined as Tmax/Bmean) for the determination of a TBAC/TBNAC ratio. Secondly, by a Tmax,AC/Tmax,NAC ratio. Both ratios were correlated to the focus depth. ResultsA total of 46 pathological foci were found. Focus contrast and intensity significantly increased in 14/46 foci (30%) after AC (mean, 3.7–4.0) in the visual analysis (P<0.001). While TB ratios increased only in 24/46 foci after AC and no correlation between the TBAC/TBNAC ratio and focus depth (r=0.027; P=0.856) was found, Tmax was higher after AC in all foci and the Tmax,AC/Tmax,NAC ratio showed the expected correlation to focus depth (r=0.650; P<0.01), indicating the superiority of the Tmax approach for the demonstration of the effects of attenuation correction on focal uptake. ConclusionAttenuation correction of SRS SPECT data by SPECT–CT results in visually more clearly contrasted foci. Moreover, as focus intensity increases, especially in the more centrally localised foci, CT-based AC has a potential to further improve the sensitivity of SRS SPECT.

Endovascular Brachytherapy Using Liquid Beta-Emitting Rhenium-188 for the Treatment of Long-Segment Femoropopliteal In-Stent Stenosis

Purpose To evaluate the efficacy and safety of endovascular brachytherapy with liquid beta-emitting rhenium-188 (Re-188) in patients with long-segment in-stent stenosis in the femoropopliteal segment. Methods From July 2009 to April 2011, 90 consecutive patients (59 men; mean age 68.3±10.3 years, range 43–86) with symptomatic in-stent stenosis/occlusion (24.6-cm mean lesion length) of the femoropopliteal segment underwent angioplasty and subsequent endovascular brachytherapy. The liquid beta-emitting Re-188 was applied to the target lesion within an angioplasty balloon using a dose of 13 Gy at a depth of 2 mm into the vessel wall. Clinical and angiographic follow-up data were collected up to 2 years. The main study endpoints were the 6- and 12-month primary patency rates defined as <50% in-stent stenosis as detected by duplex ultrasound. Clinical endpoints were the cumulative rates of death, amputation, and bypass surgery, as well as improvement in the Rutherford category and the ankle-brachial index. Results were correlated with patient and lesion characteristics. Results Primary technical success was achieved in all patients, with 1 early stent thrombosis, but no other complications related to the irradiation. Eighty-eight patients reached the 6-month and 82 the 12-month examinations; the primary patency was 95.2% and 79.8%, respectively. In-stent stenosis occurred in 9 patients, while 10 patients had reocclusion of the treated segment. During follow-up, there were 2 late acute thrombotic occlusions, both after discontinuation of clopidogrel. The clinical status improved in 67.0% and 62.2% of the patients after 6 and 12 months, respectively. No patient, lesion, or procedure variables were predictive of restenosis after EVBT. Conclusion EVBT with liquid beta-emitting Re-188 was safe and effective in preventing restenosis in long-segment femoropopliteal ISS.

CT-gesteuerte Brachytherapie@@@CT-Guided Brachytherapy. A Novel Percutaneous Technique for Interstitial Ablation of Liver Malignancies: Eine neue perkutane Technik zur interstitiellen Ablation von Lebermetastasen

Ziel:Analyse der Sicherheit und Effektivität CT-gesteuerter Brachytherapie zur Ablation von Lebermalignomen.Patienten und Methodik:21 Patienten mit 21 Lebermalignomen (19 Metastasen, zwei primäre Lebermalignome) wurden mit perkutaner, CT-gesteuerter interstitieller Brachytherapie mit 192Ir behandelt. Alle Patienten wiesen Umstände auf, die eine bildgeführte thermische Ablation mit Radiofrequenz oder laserinduzierter Thermotherapie (LITT) einschränkten: Tumordurchmesser ≥ 5 cm bei sieben, enge Lagebeziehung zu Pfortader oder großen Lebervenen bei zehn, enge Lagebeziehung zur Hepatikusgabel bei vier Patienten. Die Dosimetrie erfolgte über unmittelbar nach CT-geführter Applikatorpositionierung akquirierte dreidimensionale CT-Datensätze.Ergebnisse:Die mittlere Tumorgröße betrug 4,6 cm (2,5–11 cm). Die minimale Dosis innerhalb des Tumorvolumens lag im Mittel bei 17 Gy (12–20 Gy). Der Volumenanteil gesunden Leberparenchyms mit einer Exposition > 5 Gy betrug 18% (5–39%) vom Lebergesamtvolumen abzüglich Tumorlast. Übelkeit und Erbrechen traten bei sechs Patienten auf (28%). Ein Patient entwickelte eine Obstruktion des Ductus choledochus durch ein strahleninduziertes Tumorödem in unmittelbarer Nachbarschaft. Leberenzymparameter und Bilirubinwerte zeigten regelhaft diskrete Anstiege ohne klinisches Korrelat. Die lokale Tumorkontrolle betrug 87% nach 6 Monaten und 70% nach 12 Monaten.Schlussfolgerung:CT-gesteuerte Brachytherapie ist sicher und effektiv. Die Technik ermöglicht gegenüber thermischen Ablationsverfahren eine breitere Indikationsstellung hinsichtlich Tumorgröße und Tumorlokalisation.Purpose:To assess safety and efficacy of CT-guided brachytherapy of liver malignancies.Patients and Methods:21 patients with 21 liver malignancies (19 metastases, two primary liver tumors) were treated with interstitial CT-guided brachytherapy applying a 192Ir source. In all patients, the use of image-guided thermal tumor ablation such as by radiofrequency or laser-induced thermotherapy (LITT) was impeded either by tumor size ≥ 5 cm in seven, adjacent portal or hepatic vein in ten, or adjacent bile duct bifurcation in four patients. Dosimetry was performed using three-dimensional CT data sets acquired after CT-guided positioning of the brachytherapy catheters.Results:The mean tumor diameter was 4.6 cm (2.5–11 cm). The mean minimal tumor dose inside the tumor margin amounted to 17 Gy (12–20 Gy). The proportion of the liver parenchyma exposed to > 5 Gy was 18% (5–39%) of total liver parenchyma minus tumor volume. Nausea and vomiting were observed in six patients after brachytherapy (28%). One patient demonstrated obstructive jaundice due to tumor edema after irradiation of a metastasis adjacent to the bile duct bifurcation. We commonly encountered asymptomatic increases of liver enzymes. Local control rates after 6 and 12 months were 87% and 70%, respectively.Conclusion:CT-guided brachytherapy is safe and effective. This technique displays broader indications compared to image-guided thermal ablation by radiofrequency or LITT with respect to tumor size or localization.