A novel CBCT-based method for derivation of CTV-PTV margins for prostate and pelvic lymph nodes treated with stereotactic ablative radiotherapy

Ciara A Lyons; Raymond B King; Sarah O S Osman; Stephen J McMahon; Joe M O'Sullivan; Alan R Hounsell; Suneil Jain; Conor K McGarry

doi:10.1186/s13014-017-0859-z

A novel CBCT-based method for derivation of CTV-PTV margins for prostate and pelvic lymph nodes treated with stereotactic ablative radiotherapy

Ciara A Lyons, Raymond B King, Sarah O S Osman, Stephen J McMahon, Joe M O'Sullivan, Alan R Hounsell, Suneil Jain, Conor K McGarry

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Abstract

BACKGROUND

Traditional CTV-PTV margin recipes are not generally applicable in the situation of stereotactic ablative radiotherapy (SABR) treatments of multiple target volumes with a single isocentre. In this work, we present a novel geometric method of margin derivation based on CBCT-derived anatomical data.

METHODS

Twenty patients with high-risk localized prostate cancer were selected for retrospective review. Individual volumes of interest (prostate, prostate and seminal vesicles and pelvic lymph nodes) were delineated on five representative CBCTs and registered to the planning CT using two registration protocols: bone match or prostate-based soft tissue match. Margins were incrementally expanded around composite CTV structures until 95% overlap was achieved.

RESULTS

CTV-PTV margins of 5.2, 6.5 and 7.6 mm were required for prostate, prostate and seminal vesicles and pelvic lymph nodes respectively using a prostate matching protocol. For the prostate and seminal vesicle structures, margins calculated using our method displayed good agreement with a conventional margin recipe (within ±1.0 mm).

CONCLUSIONS

We have presented an alternative method of CTV-PTV margin derivation that is applicable to SABR treatments with more than one isocentric target. These results have informed an institutional trial of prostate and pelvic nodal SABR in men with high-risk localized prostate cancer.

Original language	English
Pages (from-to)	124
Journal	Radiation oncology (London, England)
Volume	12
Issue number	1
DOIs	https://doi.org/10.1186/s13014-017-0859-z
Publication status	Published - 04 Aug 2017

Keywords

Journal Article

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This output contributes to the following UN Sustainable Development Goals (SDGs)

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10.1186/s13014-017-0859-zLicence: CC BY

A novel CBCT-based method for derivation of CTV-PTV margins for prostate and pelvic lymph nodes treated with stereotactic ablative radiotherapy
Copyright 2017 the authors. This is an open access Creative Commons Attribution-NonCommercial License (https://creativecommons.org/licenses/by-nc/4.0/), which permits use, distribution and reproduction for non-commercial purposes, provided the author and source are cited.
Final published version, 820 KBLicence: CC BY

Risk stratification in the management of localised prostate cancer treated with radical radiotherapy
Lyons, C. (Author), Jain, S. (Supervisor), O'Sullivan, J. (Supervisor) & Waugh, D. (Supervisor), Jul 2021
Student thesis: Doctoral Thesis › Doctor of Philosophy

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title = "A novel CBCT-based method for derivation of CTV-PTV margins for prostate and pelvic lymph nodes treated with stereotactic ablative radiotherapy",

abstract = "BACKGROUNDTraditional CTV-PTV margin recipes are not generally applicable in the situation of stereotactic ablative radiotherapy (SABR) treatments of multiple target volumes with a single isocentre. In this work, we present a novel geometric method of margin derivation based on CBCT-derived anatomical data.METHODS Twenty patients with high-risk localized prostate cancer were selected for retrospective review. Individual volumes of interest (prostate, prostate and seminal vesicles and pelvic lymph nodes) were delineated on five representative CBCTs and registered to the planning CT using two registration protocols: bone match or prostate-based soft tissue match. Margins were incrementally expanded around composite CTV structures until 95% overlap was achieved.RESULTSCTV-PTV margins of 5.2, 6.5 and 7.6 mm were required for prostate, prostate and seminal vesicles and pelvic lymph nodes respectively using a prostate matching protocol. For the prostate and seminal vesicle structures, margins calculated using our method displayed good agreement with a conventional margin recipe (within ±1.0 mm).CONCLUSIONS We have presented an alternative method of CTV-PTV margin derivation that is applicable to SABR treatments with more than one isocentric target. These results have informed an institutional trial of prostate and pelvic nodal SABR in men with high-risk localized prostate cancer.",

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author = "Lyons, {Ciara A} and King, {Raymond B} and Osman, {Sarah O S} and McMahon, {Stephen J} and O'Sullivan, {Joe M} and Hounsell, {Alan R} and Suneil Jain and McGarry, {Conor K}",

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T1 - A novel CBCT-based method for derivation of CTV-PTV margins for prostate and pelvic lymph nodes treated with stereotactic ablative radiotherapy

AU - Lyons, Ciara A

AU - King, Raymond B

AU - Osman, Sarah O S

AU - McMahon, Stephen J

AU - O'Sullivan, Joe M

AU - Hounsell, Alan R

AU - Jain, Suneil

AU - McGarry, Conor K

PY - 2017/8/4

Y1 - 2017/8/4

N2 - BACKGROUNDTraditional CTV-PTV margin recipes are not generally applicable in the situation of stereotactic ablative radiotherapy (SABR) treatments of multiple target volumes with a single isocentre. In this work, we present a novel geometric method of margin derivation based on CBCT-derived anatomical data.METHODS Twenty patients with high-risk localized prostate cancer were selected for retrospective review. Individual volumes of interest (prostate, prostate and seminal vesicles and pelvic lymph nodes) were delineated on five representative CBCTs and registered to the planning CT using two registration protocols: bone match or prostate-based soft tissue match. Margins were incrementally expanded around composite CTV structures until 95% overlap was achieved.RESULTSCTV-PTV margins of 5.2, 6.5 and 7.6 mm were required for prostate, prostate and seminal vesicles and pelvic lymph nodes respectively using a prostate matching protocol. For the prostate and seminal vesicle structures, margins calculated using our method displayed good agreement with a conventional margin recipe (within ±1.0 mm).CONCLUSIONS We have presented an alternative method of CTV-PTV margin derivation that is applicable to SABR treatments with more than one isocentric target. These results have informed an institutional trial of prostate and pelvic nodal SABR in men with high-risk localized prostate cancer.

AB - BACKGROUNDTraditional CTV-PTV margin recipes are not generally applicable in the situation of stereotactic ablative radiotherapy (SABR) treatments of multiple target volumes with a single isocentre. In this work, we present a novel geometric method of margin derivation based on CBCT-derived anatomical data.METHODS Twenty patients with high-risk localized prostate cancer were selected for retrospective review. Individual volumes of interest (prostate, prostate and seminal vesicles and pelvic lymph nodes) were delineated on five representative CBCTs and registered to the planning CT using two registration protocols: bone match or prostate-based soft tissue match. Margins were incrementally expanded around composite CTV structures until 95% overlap was achieved.RESULTSCTV-PTV margins of 5.2, 6.5 and 7.6 mm were required for prostate, prostate and seminal vesicles and pelvic lymph nodes respectively using a prostate matching protocol. For the prostate and seminal vesicle structures, margins calculated using our method displayed good agreement with a conventional margin recipe (within ±1.0 mm).CONCLUSIONS We have presented an alternative method of CTV-PTV margin derivation that is applicable to SABR treatments with more than one isocentric target. These results have informed an institutional trial of prostate and pelvic nodal SABR in men with high-risk localized prostate cancer.

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DO - 10.1186/s13014-017-0859-z

M3 - Article

C2 - 28778178

SN - 1748-717X

VL - 12

SP - 124

JO - Radiation oncology (London, England)

JF - Radiation oncology (London, England)

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A novel CBCT-based method for derivation of CTV-PTV margins for prostate and pelvic lymph nodes treated with stereotactic ablative radiotherapy

Abstract

Keywords

UN SDGs

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Student theses

Risk stratification in the management of localised prostate cancer treated with radical radiotherapy

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