open access

Vol 13, No 1 (2008)
Untitled
Published online: 2008-01-01
Submitted: 2007-04-17
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Real-time brachytherapy for prostate cancer – implant analysis

Marta Szlag, Krzysztof Ślosarek, Agata Rembielak, Brygida Białas, Marek Fijałkowski, Joanna Bystrzycka
DOI: 10.1016/S1507-1367(10)60076-4
·
Rep Pract Oncol Radiother 2008;13(1):9-14.

open access

Vol 13, No 1 (2008)
Untitled
Published online: 2008-01-01
Submitted: 2007-04-17

Abstract

Background

In HDR brachytherapy precision of catheter implantation is crucial for conformal treatment planning as a starting point for better optimization process.

Aim

The aim was to investigate differences between virtual and real needle position and the effect of needle displacement on dosimetric parameters as a function of prostate volume for better evaluation of “real” implant with respect to final dose distribution.

Materials/Methods

Thirty treatment plans calculated by Nucletron SWIFT™ were randomly selected. Dosimetric data including V100 for prostate gland and D10 for urethra were analyzed as a function of prostate volume and needle displacement.

Needle displacement was determined by measuring the distance between virtual and real positions of respective needles in three sectional images: at the base, apex of the prostate gland and reference image. Dosimetric parameters were determined for consecutive computer plans: virtual (before implantation), live (after implantation and renewed optimization). For the purpose of this study a new parameter, VD (Volume-Dose), was created.

Results

VD indicates the quality of “real” dose distribution with respect to “virtual” treatment plan. In order to realize the assumption of virtual plan (VD<1) for a given prostate volume, mean values of needle displacement r should not exceed racceptable according to the formula: racceptable (Vp) ∝ Vp2. For larger glands (above 30cc) final dose distribution is less dependent on needle displacement than smaller ones.

Conclusions

The experiment determined maximum values of needle displacement for a given Vp parameter, allowing one to take advantage of optimization algorithms and to improve the final dose distribution.

Abstract

Background

In HDR brachytherapy precision of catheter implantation is crucial for conformal treatment planning as a starting point for better optimization process.

Aim

The aim was to investigate differences between virtual and real needle position and the effect of needle displacement on dosimetric parameters as a function of prostate volume for better evaluation of “real” implant with respect to final dose distribution.

Materials/Methods

Thirty treatment plans calculated by Nucletron SWIFT™ were randomly selected. Dosimetric data including V100 for prostate gland and D10 for urethra were analyzed as a function of prostate volume and needle displacement.

Needle displacement was determined by measuring the distance between virtual and real positions of respective needles in three sectional images: at the base, apex of the prostate gland and reference image. Dosimetric parameters were determined for consecutive computer plans: virtual (before implantation), live (after implantation and renewed optimization). For the purpose of this study a new parameter, VD (Volume-Dose), was created.

Results

VD indicates the quality of “real” dose distribution with respect to “virtual” treatment plan. In order to realize the assumption of virtual plan (VD<1) for a given prostate volume, mean values of needle displacement r should not exceed racceptable according to the formula: racceptable (Vp) ∝ Vp2. For larger glands (above 30cc) final dose distribution is less dependent on needle displacement than smaller ones.

Conclusions

The experiment determined maximum values of needle displacement for a given Vp parameter, allowing one to take advantage of optimization algorithms and to improve the final dose distribution.

Get Citation

Keywords

real-time brachytherapy; interstitial implant; prostate volume

About this article
Title

Real-time brachytherapy for prostate cancer – implant analysis

Journal

Reports of Practical Oncology and Radiotherapy

Issue

Vol 13, No 1 (2008)

Pages

9-14

Published online

2008-01-01

DOI

10.1016/S1507-1367(10)60076-4

Bibliographic record

Rep Pract Oncol Radiother 2008;13(1):9-14.

Keywords

real-time brachytherapy
interstitial implant
prostate volume

Authors

Marta Szlag
Krzysztof Ślosarek
Agata Rembielak
Brygida Białas
Marek Fijałkowski
Joanna Bystrzycka

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