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Strahlentherapie und Onkologie

, Volume 195, Issue 2, pp 145–152 | Cite as

MRI-guided localization of the dominant intraprostatic lesion and dose analysis of volumetric modulated arc therapy planning for prostate cancer

  • Jörg TamihardjaEmail author
  • Maria Zenk
  • Michael Flentje
Original Article
  • 124 Downloads

Abstract

Purpose

Primary radiation therapy is a curative treatment option for prostate cancer. The aim of this study was to evaluate the detection of the dominant intraprostatic lesion (DIL) with magnetic resonance imaging (MRI) for radiotherapy treatment planning, the comparison with transrectal ultrasound (TRUS)-guided biopsies and the examination of the dose distribution in relation to the DIL location.

Materials and methods

In all, 54 patients with treatment planning MRI for primary radiotherapy of prostate cancer from 03/2015 to 03/2017 at the Universitätsklinikum Würzburg were identified. The localization of the DIL was based on MRI with T2- and diffusion-weighted imaging. After registration of the MR image sets within Pinnacle3 (Philips Radiation Oncology Systems, Fitchburg, WI, USA), the dose distribution was analyzed. The location of the DIL was compared to the pathology reports in a side-based manner.

Results

The DIL mean dose (Dmean) was 77.51 ± 0.77 Gy and in 50/51 cases within the tolerance range or exceeded the prescribed dose. There was a significant difference in Dmean between ventral (n = 21) and dorsal (n = 30) DIL (77.87 ± 0.67 vs. 77.26 ± 0.77 Gy; p = 0.005). MRI-guided localization showed an accuracy and sensitivity of up to 78.8% and 82.1% for inclusion of secondary lesions, respectively.

Conclusion

Up to 82.1% of histologically verified intraprostatic lesions were identified in the context of MRI-guided radiotherapy treatment planning. As expected, dorsal DIL tend to be minimally underdosed in comparison to ventral DIL. Adequate dose coverage was achieved in over 98% of patients.

Keywords

Prostate cancer Image-guided radiotherapy Magnetic resonance imaging Dose distribution Index lesion 

MRT-gestützte Lokalisation der dominanten intraprostatischen Läsion und Dosisanalyse im Rahmen der volumenmodulierten Radiotherapieplanung des Prostatakarzinoms

Zusammenfassung

Einleitung

Die primäre perkutane Radiotherapie ist eine kurative Therapieoption für das Prostatakarzinom. Das Ziel dieser Studie war die Evaluation der Detektion der dominanten intraprostatischen Läsion (DIL) mithilfe einer Magnetresonanztomographie (MRT) zur Radiotherapieplanung, der Vergleich mit der TRUS(transrektaler Ultraschall)-gestützten Stanzbiopsie und die Untersuchung der Dosisdistribution in Abhängigkeit von der anatomischen Lage der DIL.

Material und Methoden

Ausgewertet wurden 54 Patienten mit von März 2015 bis März 2017 im Rahmen der primären Radiotherapie des Prostatakarzinoms am Universitätsklinikum Würzburg durchgeführten Bestrahlungsplanungs-MRT. Die Lokalisation der DIL erfolgte anhand der MRT mit T2- und diffusionsgewichteten Sequenzen. Nach Registrierung der MR-Bilderserien innerhalb des Pinnacle3 (Philips Radiation Oncology Systems, Fitchburg, WI, USA) Planungssystems wurde die Dosisdistribution analysiert. Die Lage der DIL wurde mit den pathologischen Stanzbiopsiebefunden seitengetrennt verglichen.

Ergebnisse

Die mittlere Dosis (Dmean) der DIL betrug 77,51 ± 0.77 Gy, wobei in 50/51 Fällen der vorgegebene Toleranzbereich eingehalten oder überschritten wurde. Im Vergleich zwischen ventraler (n = 21) und dorsaler (n = 30) Lage der DIL zeigte sich ein signifikanter Unterschied der Dmean (77,87 ± 0,67 vs. 77,26 ± 0,77 Gy; p = 0,005). Die MRT-gestützte Lokalisierung erreichte eine Genauigkeit und eine Sensitivität von bis zu 78,8 bzw. 82,1% für die Inklusion von sekundären Läsionen.

Schlussfolgerung

Bis zu 82,1% histologisch verifizierter intraprostatischer Läsionen konnten im Kontext der MRT-gestützten Radiotherapieplanung identifiziert werden. Erwartungsgemäß tendieren dorsal gelegene DIL im Vergleich mit ventral gelegenen Läsionen zu einer minimalen Unterdosierung. Eine adäquate Dosisabdeckung konnte bei mehr als 98% der Patienten erreicht werden.

Schlüsselwörter

Prostatakarzinom Bildgesteuerte Radiotherapie Magnetresonanztomographie Dosisverteilung Indexläsion  

Notes

Compliance with ethical guidelines

Conflict of interest

J. Tamihardja, M. Zenk and M. Flentje declare that they have no competing interests.

Ethical standards

This article does not contain any studies with animals performed by any of the authors. All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards. Written informed consent was obtained from all patients before treatment. An additional individual consent for this analysis was not needed.

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Copyright information

© Springer-Verlag GmbH Germany, part of Springer Nature 2018

Authors and Affiliations

  1. 1.Klinik und Poliklinik für StrahlentherapieUniversitätsklinikum WürzburgWürzburgGermany

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