Combining Transarterial Radioembolization (TARE) and CT-Guided High-Dose-Rate Interstitial Brachytherapy (CT-HDRBT): A Retrospective Analysis of Advanced Primary and Secondary Liver Tumor Treatment

Purpose: Treatment of patients with primary and secondary liver tumors remains challenging. This study analyzes the efficacy and safety of transarterial radioembolization (TARE) combined with CT-guided high-dose-rate interstitial brachytherapy (CT-HDRBT) for the treatment of primary and secondary liver tumors. Patients and Methods: A total of 77 patients (30 female) with various liver malignancies were treated. Primary endpoints were median overall survival (OS) and time to untreatable progression (TTUP). Additionally, subgroup analyses were performed in consideration of diagnosis and procedure sequence. Median OS and TTUP prediction were estimated using Kaplan-Meier analysis and hazard ratios (HR) were calculated using a multivariate Cox proportional hazard model. Results: A total of 115 CT-HDRBT and 96 TARE procedures were performed with Purpose: Treatment of patients with primary and secondary liver tumors remains challenging. This study analyzes the efficacy and safety of transarterial radioembolization (TARE) combined with CT-guided high-dose-rate interstitial brachytherapy (CT-HDRBT) for the treatment of primary and secondary liver tumors. Patients and methods: A total of 77 patients (30 female) with various liver malignancies were treated. Primary endpoints were median overall survival (OS) and time to untreatable progression (TTUP). Additionally, subgroup analyses were performed in consideration of diagnosis and procedure sequence. Median OS and TTUP prediction were estimated using Kaplan-Meier analysis and hazard ratios (HR) were calculated using a multivariate Cox proportional hazard model. Results: A total of 115 CT-HDRBT and 96 TARE procedures were performed with no significant complications recorded. Median OS and TTUP were 29.8 (95% CI 18.1-41.4) and 23.8 (95% CI 9.6-37.9) months. Median OS for hepatocellular carcinoma (HCC)-, cholangiocarcinoma carcinoma (CCA) and colorectal cancer (CRC) patients was 29.8, 29.6 and 34.4 months. Patients starting with TARE had a median OS of 26.0 (95% CI 14.5-37.5) compared to 33.7 (95% CI 21.6-45.8) months for patients starting with CT-HDRBT. Hazard ratio of 1.094 per month was shown for patients starting with CT-HDRBT. Conclusion: Combining TARE and CT-HDRBT is effective and safe for the treatment of advanced stage primary and secondary liver tumors. Our data indicate that early TARE during the disease progression may have a positive effect on survival.no significant complications recorded. Median OS and TTUP were 29.8 (95% CI 18.1-41.4) and 23.8 (95% CI 9.6-37.9) months. Median OS for hepatocellular carcinoma (HCC)-, cholangiocarcinoma carcinoma (CCA) and colorectal cancer (CRC) patients was 29.8, 29.6 and 34.4 months. Patients starting with TARE had a median OS of 26.0 (95% CI 14.5-37.5) compared to 33.7 (95% CI 21.6-45.8) months for patients starting with CT-HDRBT. Hazard ratio of 1.094 per month was shown for patients starting with CT-HDRBT. Conclusion: Combining TARE and CT-HDRBT is effective and safe for the treatment of advanced stage primary and secondary liver tumors. Our data indicate that early TARE during the disease progression may have a positive effect on survival

Contrast-Enhanced Magnetic Resonance Angiography Using a Novel Elastin-Specific Molecular Probe in an Experimental Animal Model

Objectives. The aim of this study was to test the potential of a new elastin-specific molecular agent for the performance of contrast-enhanced first-pass and 3D magnetic resonance angiography (MRA), compared to a clinically used extravascular contrast agent (gadobutrol) and based on clinical MR sequences. Materials and Methods. Eight C57BL/6J mice (BL6, male, aged 10 weeks) underwent a contrast-enhanced first-pass and 3D MR angiography (MRA) of the aorta and its main branches. All examinations were on a clinical 3 Tesla MR system (Siemens Healthcare, Erlangen, Germany). The clinical dose of 0.1 mmol/kg was administered in both probes. First, a time-resolved MRA (TWIST) was acquired during the first-pass to assess the arrival and washout of the contrast agent bolus. Subsequently, a high-resolution 3D MRA sequence (3D T1 FLASH) was acquired. Signal-to-noise ratios (SNRs) and contrast-to-noise ratios (CNRs) were calculated for all sequences. Results. The elastin-specific MR probe and the extravascular imaging agent (gadobutrol) enable high-quality MR angiograms in all animals. During the first-pass, the probes demonstrated a comparable peak enhancement (300.6 +/- 32.9 vs. 288.5 +/- 33.1, p > 0.05). Following the bolus phase, both agents showed a comparable intravascular enhancement (SNR: 106.7 +/- 11 vs. 102.3 +/- 5.3; CNR 64.5 +/- 7.4 vs. 61.1 +/- 7.2, p > 0.05). Both agents resulted in a high image quality with no statistical difference (p > 0.05). Conclusion. The novel elastin-specific molecular probe enables the performance of first-pass and late 3D MR angiography with an intravascular contrast enhancement and image quality comparable to a clinically used extravascular contrast agent

From BEXUS to HEMERA: The application of lessons learned on the development and manufacturing of stratospheric payloads at S5Lab

In the last years the S5Lab (Sapienza Space Systems and Space Surveillance Laboratory) from Sapienza University of Rome has given to the students the opportunity to gather knowledge on stratospheric payloads by supporting the design and development of two experiments selected for the participation in the REXUS/BEXUS educational Programme, managed by three european space institutions. The insights and lessons learned gathered during the participations in the REXUS/BEXUS educational programme gave the possibility to the student to take part in the development of a third experiment in the frame of the professional research programme HEMERA and complete it successfully. STRATONAV (STRATOspheric NAVigation experiment) was a stratospheric experiment based on Software Defined Radios (SDRs) technology whose aim was the testing of the VOR (VHF Omnidirectional Range) navigation system, evaluating its performance above the standard service volume, which was launched on BEXUS 22 in October 2016. TARDIS (Tracking and Attitude Radio-based Determination In Stratosphere) was developed as a follow up of STRATONAV between 2018 and 2019. Similarly to its predecessor TARDIS was a stratospheric experiment aimed at exploiting the VOR signal, with the aid of SDRs, to perform in-flight attitude and position determination, and was launched on BEXUS 28 in October 2019. After the launch of TARDIS, a team composed both by former STRATONAV and TARDIS students was formed for the development of a third stratospheric experiment going by the name of STRAINS (Stratospheric Tracking Innovative Systems), conceived by Sapienza University of Rome and ALTEC and supported by ASI. STRAINS main objective was the proof of concept of the possibility of achieving the Time Difference of Arrival (TDOA) and the Frequency Difference of Arrival (FDOA) for navigation purposes with the aid of SDRs. The experiment was developed between 2020 and 2021 exploiting the lessons learned from the former team members of the two BEXUS campaigns and was launched on board of the Hemera H2020 stratospheric balloon in September 2021 from Esrange Space Center, Kiruna, Sweden. After a brief description of the stratospheric payloads design and manufacturing, the paper will present the major lessons learned from the previous stratospheric experiments, STRATONAV and TARDIS, and their application to the development and manufacturing of the latest launched stratospheric experiment STRAINS, as well as their educational return to the students involved in the projects

Fluid preinjection for microwave ablation in an ex vivo bovine liver model assessed with volumetry in an open MRI system

PURPOSEWe aimed to detect possible differences in microwave ablation (MWA) volumes after different fluid preinjections using magnetic resonance imaging (MRI).MATERIALS AND METHODSMWA volumes were created in 50 cuboid ex vivo bovine liver specimens (five series: control [no injection], 10 mL water, 10 mL 0.9% NaCl, 10 mL 6% NaCl, and 10 mL 12% NaCl preinjections; n=10 for each series). The operating frequency (915 megahertz), ablation time (7 min), and energy supply (45 watts) were constant. Following MWA, two MR sequences were acquired, and MR volumetry was performed for each sequence.RESULTSFor both sequences, fluid preinjection did not lead to significant differences in MWA ablation volumes compared to the respective control group (sequence 1: mean MWA volumes ranged from 7.0±1.2 mm [water] to 7.8±1.3 mm [12% NaCl] vs. 7.3±2.1 mm in the control group; sequence 2: mean MWA volumes ranged from 4.9±1.4 mm [12% NaCl] to 5.5±1.9 mm [0.9% NaCl] vs. 4.7±1.6 mm in the control group). The ablation volumes visualized with the two sequences differed significantly in general (P < 0.001) and between the respective groups (control, P ≤ 0.001; water, P < 0.001; 0.9% NaCl, P < 0.001; 6% NaCl, P ≤ 0.001; 12% NaCl, P < 0.001). The volumes determined with sequence 1 were closer to the expected ablation volume of 8 mL compared to those determined with sequence 2.CONCLUSIONFor the fluid qualities and concentrations assessed, there is no evidence that fluid preinjection results in larger coagulation volumes after MWA. Because ablation volumes determined by MRI vary with the sequence used, interventionalists should gain experience in how to interpret postinterventional imaging findings (with the MR scanner, sequences, and parameters used) to accurately estimate the outcome of the interventions they perform

CT-guided high-dose brachytherapy (CT-HDRBT): results of the therapy of liver tumors within and beyond the indications of radiofrequency ablation (RFA)

Die CT-gesteuerte Hochdosis-Brachytherapie (CT-HDRBT) ist ein radiogenes Ablationsverfahren bei dem, CT-gesteuert, ein spezieller Katheter in den Tumor eingebracht wird und über den eine Iridium-192 (192Ir) Strahlenquelle temporär eingebracht wird. Zu den wesentlichen Vorteilen der CT-HDRBT gegenüber der perkutanen Bestrahlung zählen die genaue Dosisapplikation innerhalb des Zielvolumens und die hohe Dosis innerhalb des Zielvolumens bei raschem Dosisabfall gegenüber der Umgebung. Dank dieser Vorteile ermöglicht die CT- HDRBT die Bestrahlung der Zielläsion mit sehr hohen Dosen bei weitestgehender Schonung umliegender Strukturen. Ziel der vorliegenden Arbeiten war die Untersuchung der onkologischen Effektivität dieser Technik in der Behandlung von primären und sekundären Lebertumoren innerhalb und jenseits der Indikationen der Radiofrequenzablation. Darüber hinaus wurden die Ergebnisse mit den publizierten Daten anderer minimal-invasiver Techniken wie der Radiofrequenzablation (RFA) und der transarterielle Chemoembolisation (TACE) in Relation gesetzt. Für das hepatozelluläre Karzinom (Originalarbeit 1) konnte bei 98 Patienten und 212 HCC-Tumoren mittels CT-HDRBT eine lokale Tumorkontrollrate von 91,5% erreicht werden. Der Durchmesser der HCC-Knoten betrug im mittel 5 cm, die Tumore reichten jedoch von 1,8 cm bis 12 cm im Durchmesser. Von der Tumorcharakteristik entsprachen die meisten Patienten einem BCLC-Stadium B, so dass nach Leitlinien eine Chemoembolisation (TACE) zu empfehlen wäre. Innerhalb der Nachbeobachtungszeit von 23,1 Monaten verstarben 46 Patienten. Das mediane OS nach CT-HDRBT betrug 29,2 Monate. Gemäß Kaplan- Meier-Analyse betrugen die 1-Jahres-, 2-Jahres- und 3-Jahres-OS-Raten 80, 62 und 46 %. Insgesamt beweisen die Ergebnisse der vorliegenden Arbeit, dass die CT-HDRBT eine sichere und wirksame Therapie für Patienten mit inoperablem HCC darstellt. Die hohe lokale Tumorkontrolle und die vielversprechenden Überlebensraten nach CT-HDRBT machen aus dieser Therapie eine erfolgversprechende Alternative zu den bestehenden therapeutischen Optionen bei Patienten mit inoperablem HCC. Beim cholangiozellulären Karzinom (CCC) kommt es trotz kurativ intendierter Leberreesektion häufig zu einem intrahepatischen Tumorrezidiv. In der anschließenden Arbeit (Originalerbeit 2) wurde untersucht, ob diese Patienten erfolgreich mittels CT-HDRBT behandelt werden können. Bei allen Patienten hatte eine Leberresektion stattgefunden und ein intrahepatisches Tumorrezidiv war bildgebend nachgewiesen. Mittels der CT- HDRBT konnte die mediane Überlebenszeit der Patienten nach primärer Leberresektion auf 85 Monate verlängert werden. Keiner, der zum Zeitpunkt der Analyse noch lebenden Patienten (60%) entwickelte ein lokales Rezidiv nach CT- HDRBT. Vier Patienten erlitten ein multifokales Rezidiv und waren zum Zeitpunkt der Auswertung verstorben. Die 1- und 5-Jahres Überlebensrate der gesamten Kohorte betrug 100% und 78,7%. Nach dem Auftreten des intrahepatischen Rezidivs betrug die 1- und 5-Jahres-Überlebensrate jeweils 77,1% und 51,4%. Insgesamt suggerieren die Ergebnisse dieser Machbarkeitsstudie, dass die CT-HDRBT als alternative Behandlungsoption für Patienten mit intrahepatischem Rezidiv eines CCC nach Leberresektion eingesetzt werden kann. Lebermetastasen stellen im klinischen Alltag eine große Herausforderung dar und oftmals sind diese Determinanten der weiteren Prognose der Patienten. In einer Kohorte von 80 Patienten mit 179 nicht resektablen kolorektalen Lebermetastasen (Originalarbeit 3) konnte mittels der CT-HDRBT eine lokale Tumorkontrolle (LTC) von 87,1% innerhalb der medianen Nachbeobachtungszeit von 16,9 Monaten erreicht werden. Bei den Lebermetastasen des kolorektalen Karzinoms war die lokale Tumorkontrolle abhängig vom Durchmesser der Metastasen: Die LTC bei Metastasen mit einem Durchmesser < 4 cm betrug 94% und 86,8% nach 12 und 24 Monaten, bei den Metastasen ≥ 4 cm 65,8% und 58,5% (p = 0,00421). Das mediane progressionsfreie Überleben betrug 5 Monate. Das Gesamtüberleben nach 12, 24 und 36 Monaten war 87,6% und 57,3% und 41,6%. Die mediane Überlebenszeit nach CT-HDRBT betrug 18 Monate. Lebermetastasen eines Mammakarzinoms (BCLM) sind eine therapeutische Herausforderung. Im Gegensatz zu kolorektalen Lebermetasen sind Lebermetastasen des Mammakarzinoms Ausdruck einer systemischen Metastasierung und die meisten Patientinnen haben simultane extrahepatische Metastasen. In einer weiteren Studie (Originalarbeit 4) wurde das onkologische Ergebnis nach CT-HDRBT im Sinne einer minimal- invasiven Cytoreduction bei 37 Patientinnen mit 80 nicht resektablen BCLM untersucht. Das durchschnittliche Follow-up nach CT-HDRBT betrug 11,6 Monate. Eine lokale Tumorprogression konnte lediglich in zwei (2,6%) der behandelten Metastasen festgestellt werden. Beide progrediente Metastasen konnten erfolgreich mittels erneuter CT-HDRBT behandelt werden und blieben progressionsfrei im weiteren Verlauf. Etwa ein Drittel der Patientinnen (31,4%) entwickelten neue Lebermetastasen im Verlauf. Das mediane progressionsfreie Überleben betrug 8 Monate. Sieben Patienten (20%) starben während des Follow-up. Die mediane Gesamtüberlebenszeit betrug 18 Monate (Spannweite: 3-39 Monate). Die Tumorgröße hat einen wesentlichen Einfluss auf die Anwendbarkeit thermischer Ablationstechniken wie der RFA und die internationalen Leitlinien empfehlen den Einsatz thermischer Verfahren nur für Tumore bis 3,5 cm im Durchmesser. Bei Tumoren zwischen 3,5 und 5 cm Durchmesser wird über die Kombination von TACE und thermischer Ablation nachgedacht. Ziel einer weiteren Arbeit (Originalarbeit 5) war es, den Einfluss der Tumorgröße auf die lokale Kontrolle nach CT-HDRBT bei großen Tumoren zu untersuchen. Zu diesem Zweck wurden die Daten einer Untergruppe von 35 Patienten mit hepatozellulären Karzinomen größer als 5 cm im Durchmesser gesondert analysiert. Der mittlere Tumordurchmesser betrug 7,1 cm (Spannweite: 5-12 cm). Nach einem mittleren Follow-up von 12,8 Monaten zeigten zwei der behandelten Patienten eine lokale Progression (6,7%). Neun Patienten (30%) zeigten eine systemische Progression. Die mittlere progressionsfreie Zeit betrug 8,75 Monate (Spannweite: 2–21 Monate). Alle Patienten waren zum Zeitpunkt der Auswertung noch am Leben. Die mediane Gesamtüberlebenszeit betrug 15,4 Monate. Somit konnte gezeigt werden, dass die lokale Tumorkontrolle der CT-HDRBT beim HCC primär nicht von der Größe der HCC-Herde abhängig ist. Eine hilusnahe, intrahepatische Tumorlokalisation stellt eine große therapeutische Herausforderung dar. In der Chirurgie muss bei einer Resektion, aufgrund der zentralen Lage der Blut- und Gallengangsgefäße, oftmals ein größerer Leberanteil mitentfernt werden. Bei der thermischen Ablation führen die zentralen Blutgefäße zu einer Kühlung der Tumorzellen und somit zu einer onkologischen Ineffektivität der Therapie mit hoher Lokalrezidivrate („heat sink effect“). Darüberhinaus kann die thermische Verletzung der Gallengangsstrukturen zu schwerwiegenden postinterventionellen Komplikationen führen. Aus diesem Grund wurde der Einsatz der CT-HDRBT bei der Behandlung von hilusnahen Lebermetastasen untersucht (Originalarbeit 6). Die Daten von 32 Patienten mit 34 hilusnahen Lebermetastasen wurden retrospektiv ausgewertet. Es konnte nur eine schwerwiegende Komplikation (biliogener Leberabszess 7 Monate nach Ablation) verzeichnet werden. Während der Nachbeobachtungszeit trat bei vier der 32 Patienten (Lokale Tumorkontrollrate 88,2%) ein lokaler Progress auf. Die mittlere lokale Tumorkontrolle betrug 17,3 Monate. Die mediane Gesamtüberlebenszeit betrug 20,2 Monate. Die vorgestellten Studien konnten nicht nur die Sicherheit und Effektivität der CT-HDRBT als mögliche therapeutische Alternative zu den etablierten Therapien zeigen, sondern auch ihren sicheren und erfolgreichen Einsatz jenseits der Indikationen der thermischen Ablationsverfahren bei Patienten mit großen oder ungünstig gelegenen Lebertumoren.CT-guided high-dose-rate brachytherapy is a radioablative technique in which an iridium-192 (192Ir) source is temporarily inserted into the tumor using special afterloading catheters placed under CT guidance. The key benefit of CT-HDRBT compared to percutaneous irradiation is the accurate dose application within the target volume allowing irradiation of the target volume with very high radiation doses while sparing surrounding risk structures. The aim of the present work was to investigate the clinical effectiveness of CT-HDRBT in the treatment of primary and secondary liver tumors within and beyond the indications of radiofrequency ablation. For hepatocellular carcinoma (HCC) (original work 1), a local tumor control rate of 91.5% could be achieved in 98 patients with 212 unresectable HCC using CT-HDRBT. The average diameter of the tumors was 5 cm (range: 1.8 cm to 12 cm). Within the follow-up period of 23.1 months, 46 patients died. The median OS after CT-HDRBT was 29.2 months. According to Kaplan-Meier analysis, the 1-year, 2-year, and 3-year OS rates were 80, 62, and 46%. Overall, the results of the present work demonstrate that the CT-HDRBT is a safe and effective therapy for patients with inoperable HCC. The high local tumor control and the promising survival rates after CT- HDRBT make this therapy a promising alternative to the existing therapeutic options in patients with inoperable HCC. In patients with cholangiocellular carcinoma (CCC), intrahepatic tumor recurrences after curative liver resection are common. The subsequent feasibility study (original work 2) evaluated the use of CT-HDRBT in patients with intrahepatic recurrent CCC following liver resection. CT-HDRBT was used to extend the median survival of patients after primary liver resection to 85 months. None of the patients still alive at the time of analysis (60%) experienced a local progression after CT-HDRBT. Four patients displayed a multifocal recurrence and were deceased at time of evaluation. The 1 and 5-year survival rate of the whole cohort was 100% and 78.7%. After the onset of intrahepatic recurrence, the 1- and 5-year survival rates were 77.1% and 51.4%, respectively. Overall, the results of this feasibility study suggest that CT-HDRBT may be used as an alternative treatment option for patients with intrahepatic CCC recurrence following liver resection. Liver metastases represent a major challenge in everyday clinical practice and are often crucial determinants of patient’s prognosis. In a cohort of 80 patients with 179 unresectable colorectal liver metastases (original work 3), a local tumor control (LTC) of 87.1% within the median follow-up period of 16.9 months was achieved using CT-HDRBT. In patients with colorectal liver metastases the local tumor control was dependent on the diameter of the metastases: the LTC rate for metastases with a diameter <4 cm was 94% and 86.8% after 12 and 24 months, while patients with metastases ≥ 4 cm displayed a LTC rate of 65.8% and 58.5%, respectively (p = 0.00421). The overall median progression-free survival was 5 months. The overall survival after 12, 24 and 36 months was 87.6% and 57.3% and 41.6%. The median overall survival time after CT-HDRBT was 18 months. In contrast to colorectal liver metastases, breast cancer liver metastases (BCLM) are regarded as the expression of a systemic disease and most patients show simultaneous extrahepatic metastases. In a further study (original work 4) we evaluated the use of CT-HDRBT for minimally invasive cytoreduction of 80 unresectable BCLM in 37 patients. The average follow-up after CT-HDRBT was 11.6 months. A local tumor progression could be detected in two (2.6%) of the treated metastases. Both progressive metastases were successfully re-treated by CT-HDRBT and remained locally controlled during follow-up. About one-third of the patients (31.4%) developed new liver metastases during follow-up period. The median progression-free survival was 8 months. Seven patients (20%) died during the follow-up. The median overall survival time was 18 months (range: 3-39 months). Tumor size has a significant influence on the applicability of thermal ablation techniques such as radiofrequency ablation (RFA). The international guidelines recommend the use of thermal techniques for tumors up to 3.5 cm in diameter. For tumors between 3.5 and 5 cm in diameter, the combination of TACE and thermal ablation is considered. The aim of this study (original work 5) was to investigate the influence of the tumor size on local tumor control following CT-HDRBT. For this purpose the data of a subgroup of 35 patients with large hepatocellular carcinomas (≥ 5 cm in diameter) were analyzed separately. The mean tumor diameter was 7.1 cm (range: 5-12 cm). After a mean follow-up of 12.8 months, two of the treated patients showed a local progression (6.7%). Nine patients (30%) showed systemic progression. The mean progression-free survival was 8.75 months (range: 2-21 months). All patients were still alive at the time of evaluation. Median overall survival was 15.4 months. Accordingly, in patients with unresectable HCC, the local tumor control following CT-HDRBT was not primarily dependent on the size of the tumor. Treatment of liver metastasis located close to the hilum is anatomically challenging due to nearby structures at risk such as central bile ducts and great vessels. Both surgical and ablative therapies have limitations in these patients and are associated with an increased risk of morbidity. Thermal ablative techniques are limited by the cooling effect of central blood vessels ("heat sink effect"), leading to a elevated rate of local progression. In addition, thermal injury to the central bile duct structures can lead to frightening complications. For this reason, the use of CT-HDRBT, a non-thermal technique, was investigated in the treatment of perihilar liver metastases (original work 6). Data from 32 patients with 34 perihilar liver metastases were retrospectively evaluated. Only one severe complication (intrahepatic abscess 7 months after ablation) was recorded. During the follow-up period, local progression occurred in four out of the 32 patients (local tumor control rate 88.2%). The mean local tumor control was 17.3 months. Median overall survival was 20.2 months. The presented studies not only demonstrate the safety and efficacy of CT-HDRBT as a possible therapeutic alternative to the established therapies within as well as beyond the indications of thermal ablative techniques

Percutaneous CT-guided High-Dose Brachytherapy (CT-HDRBT) ablation of primary and metastatic lung and liver tumors

Die CT-gesteuerte-Hochdosis-Brachytherapie (CT-HDRBT) ist eine neue radioablative Therapieoption, die vor ca. 10 Jahren, als Ergebnis einer engen wissenschaftlichen Zusammenarbeit zwischen Radiologie und Strahlentherapie an der Charité entstand. Unsere Studien sollten die Sicherheit und Effizienz der CT-HDRBT zur lokalen Tumorkontrolle bei Lungen- und Lebermalignomen untersuchen. In der Studie zu Lungenmalignomen (LM-Studie) wurden 22 Patienten eingeschlossen, bei denen 33 Lungentumoren mittels CT-HDRBT behandelt wurden. In diesem Patientenkollektiv zeigte die CT-HDRBT vielversprechende Ergebnisse mit einer sehr guten lokalen Tumorkontrolle. Nach einer mittleren Nachbeobachtungsdauer von 13,7 Monaten betrug die lokale Tumorkontrollrate 93,75%. Die progressionsfreie Zeit betrug im Mittel 7,8 Monate (2-29 Monate). Die Ergebnisse der LM-Studie verdeutlichen die Vorteile dieser Technik gegenüber den thermischen Ablationsverfahren: die CT-HDRBT eignet sich nämlich auch für die Behandlung von hilusnahen und größeren Tumoren sowie von Läsionen in der Nähe größerer Blutgefässe. In der Studie zur Behandlung von intrahepatischen Cholangiokarzinomen (IHC-Studie) schlossen wir insgesamt 15 Patienten mit 22 IHC ein. Die mittlere lokale Tumorkontrolle nach Ablation lag bei 10 Monaten (range: 1-25). Das mediane progressionsfreie Überleben betrug 13 Monate (range: 1-27). Das mittlere Gesamtüberleben nach der primärer Ablation betrug 16 ± 8,4 Monate (range: 4-30). Unsere Ergebnisse deuten darauf hin, dass die CT-HDRBT dazu führen kann das Überleben von inoperablen IHC- Patienten zu verlängern. Der Hauptvorteil der CT-HDRBT ist die Möglichkeit selbst große Tumormassen, wie sie sich oft bei symptomatischen IHC-Patienten bei Diagnosestellung präsentierten, zu therapieren. Sieben Patientinnen mit 12 isolierten Lebermetastasen eines Ovarialkarzinoms wurden in die OC-Studie eingeschlossen. Die mittlere Nachbeobachtungsdauer betrug 15,4 Monate (range: 11-19). Keine der Patientinnen entwickelte eine lokale Progression während der Nachbeobachtungsdauer. Bei 2 Patientinnen zeigte sich im Verlauf ein systemisches Fortschreiten der Tumorerkrankung. Die Ergebnisse dieser retrospektiven Analyse zeigen, dass die CT-HDRBT als sichere und effektive Alternative für die minimal invasive Zytoreduktion von isolierten Lebermetastasen bei Ovarialkarzinom eingesetzt werden kann. Unsere Studienergebnisse zeigen, dass es sich bei der CT-HDRBT um eine sichere und aussichtsreiche Behandlungsoption für Patienten mit primären und sekundären Lungen- und Lebertumoren handelt. Der große Vorteil der CT-HDRBT gegenüber den thermischen Ablationstechniken ist die Unabhängigkeit dieser radioablativen Technik von der Größe und der Lokalisation der zu behandelnden Tumoren. Dank der computertomographischen 3D-Bestrahlungsplanung besitzt diese Technik eine sehr hohe Genauigkeit in der Dosisapplikation. Diese ermöglicht eine sehr hohe Strahlenexposition innerhalb des klinischen Zielvolumens und eine gleichzeitige Schonung benachbarter Risikoorgane.CT-guided high-dose-rate Brachytherapy (CT-HDRBT) is a novel radioablative technique established at the beginning of this decade at our institution. The aim of the present work was to evaluate safety and efficacy of CT-HDRBT ablation of primary and metastatic lung and liver tumors. In the LM-Study 22 patients with 33 primary or metastatic lung tumors, unsuitable for surgery, were treated with CT-HDRBT. In these patients CT-HDRBT demonstrated promising local tumor control rates. The mean follow-up time was 13.7 (3 – 29) months. Two of 32 lesions (6.25 %) developed a local tumor progression. 8 patients (36.3 %) developed a distant tumor progression. After 17.7 months, 13 patients were alive and 9 patients had died. The results of the LM-Study illustrate the advantages of this technique compared to thermal ablation: CT-HDRBT allows targeted destruction of tumor tissue with simultaneous preservation of important lung structures. Furthermore, CTHDRBT is independent of the size of the lesion and its location within the lung parenchyma. In the study about the treatment of intrahepatic cholangiocarcinoma (IHC-Study) we included 15 consecutive patients with histologically proven cholangiocarcinoma. After a median follow-up of 18 (range, 1–27) months after local ablation, 6 of the 15 patients are still alive; 4 of them did not get further chemotherapy and are regarded as disease-free. The reached median local tumor control was 10 months; median local tumor control, including repetitive local ablation, was 11 months. Median survival after local ablation was 14 months and after primary diagnosis 21 months. Our results suggest that CT-HDRBT represents a promising and safe technique for patients with IHC who are not eligible for tumor resection. The main advantage of CT-HDRBT in this patients cohort, is the possibility to successfully treat large tumors. Seven patients with 12 isolated ovarian cancer metastases to the liver were included in the OC-Study. The mean follow-up period was 15.4 months. Tumors ranged from 13 to 120 mm in diameter. No local progression was observed in any of the included patients. Two patients experienced systemic tumor progression. Two patients died after 14 and 25 months, respectively. The results of the retrospective study demonstrates that CT-HDRBT is a safe and valid technique for performing minimally invasive cytoreduction of metachronous isolated liver metastases from ovarian cancer. Our study results indicate that CT HDRBT is a safe and promising treatment option for patients with primary and secondary lung and liver tumors. The big advantage of CT HDRBT compared to thermal ablation techniques is the independence of this radioablative technique on the size and location of the tumor. Trough the 3D treatment planning, this technique has a very high accuracy in dose delivery. This allows a high radiation exposure within the clinical target volume and a simultaneous preservation of adjacent organs at risk