Rectum Dose Analysis Employing a Multi-purpose Brachytherapy Phantom

Huh, Hyun Do; Kim, Woo Chul; Loh, John J.K.; Lee, Suk; Kim, Chul Yong; Lee, Sang Hoon; Shin, Dong Oh; Shin, Dongho; Cho, Sam Ju; Jang, Jisun; Lim, Sangwook; Cho, Kwang Hwan; Kwon, Soo Il; Kim, Seong Hoon

doi:10.1093/jjco/hym032

Cited by 7 publications

(3 citation statements)

References 17 publications

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“…The shift could be caused by detector movement between the time of CT scan and irradiation. Rectal peristaltic motion or patient movement has also been reported to affect in-vivo dose measurement (Allahverdi et al, 2012;Allahverdi et al, 2013;Waldhäusl et al, 2005;Huh et al, 2007;Alecu et al, 1999). Many studies have reported significant diode displacement, which has been attributed primarily to being a source of error in performing in-vivo dosimetry in brachytherapy.…”

Section: Discussionmentioning

confidence: 99%

In-vivo Comparison of Planned and Measured Rectal Doses during Cobalt-60 HDR CT-based Intracavitary Brachytherapy Applications of Cervical Cancer Using the PTW 9112 Semiconductor Probe

Johan

Lobo

Athiyamaan

et al. 2023

Asian Pac J Cancer Prev

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Section: Discussionmentioning

confidence: 99%

In-vivo Comparison of Planned and Measured Rectal Doses during Cobalt-60 HDR CT-based Intracavitary Brachytherapy Applications of Cervical Cancer Using the PTW 9112 Semiconductor Probe

Johan

Lobo

Athiyamaan

et al. 2023

Asian Pac J Cancer Prev

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“…Calculation of absorbed dose distribution in a patient before treatment is one of the main steps in treatment planning of radiation therapy. In high-dose-rate (HDR) brachytherapy, the accuracy of calculation becomes an important issue because of the higher dose rate and prescribed dose per session [ 5 , 6 ]. Thus, inaccuracies in dose distribution measurement may lead to higher dose to healthy tissues or lower dose to the tumor.…”

Section: Purposementioning

confidence: 99%

The effect of tandem-ovoid titanium applicator on points A, B, bladder, and rectum doses in gynecological brachytherapy using 192 Ir

Sadeghi¹,

Sina²,

Mehdizadeh³

et al. 2018

jcb

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PurposeThe dosimetry procedure by simple superposition accounts only for the self-shielding of the source and does not take into account the attenuation of photons by the applicators. The purpose of this investigation is an estimation of the effects of the tandem and ovoid applicator on dose distribution inside the phantom by MCNP5 Monte Carlo simulations.Material and methodsIn this study, the superposition method is used for obtaining the dose distribution in the phantom without using the applicator for a typical gynecological brachytherapy (superposition-1). Then, the sources are simulated inside the tandem and ovoid applicator to identify the effect of applicator attenuation (superposition-2), and the dose at points A, B, bladder, and rectum were compared with the results of superposition. The exact dwell positions, times of the source, and positions of the dosimetry points were determined in images of a patient and treatment data of an adult woman patient from a cancer center. The MCNP5 Monte Carlo (MC) code was used for simulation of the phantoms, applicators, and the sources.ResultsThe results of this study showed no significant differences between the results of superposition method and the MC simulations for different dosimetry points. The difference in all important dosimetry points was found to be less than 5%.ConclusionsAccording to the results, applicator attenuation has no significant effect on the calculated points dose, the superposition method, adding the dose of each source obtained by the MC simulation, can estimate the dose to points A, B, bladder, and rectum with good accuracy.

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“…Of patients who receive radiotherapy, 3–10% experience rectum and bladder sequelae such as proctitis, cystitis, and fistule 6 . The incidence rate increases with an increasing dose per fraction 7 8 .…”

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confidence: 99%

HDR Brachytherapy Dose Distribution is Influenced by the Metal Material of the Applicator

Liao

Shiau

et al. 2015

Sci Rep

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Applicators containing metal have been widely used in recent years when applying brachytherapy to patients with cervical cancer. However, the high dose rate (HDR) treatment-planning system (TPS) that is currently used in brachytherapy still assumes that the treatment environment constitutes a homogeneous water medium and does not include a dose correction for the metal material of the applicator. The primary purpose of this study was to evaluate the HDR 192Ir dose distribution in cervical cancer patients when performing brachytherapy using a metal-containing applicator. Thermoluminescent dosimeter (TLD) measurements and Monte Carlo N-Particle eXtended (MCNPX) code were used to explore the doses to the rectum and bladder when using a Henschke applicator containing metal during brachytherapy. When the applicator was assumed to be present, the absolute dose difference between the TLD measurement and MCNPX simulation values was within approximately 5%. A comparison of the MCNPX simulation and TPS calculation values revealed that the TPS overestimated the International Commission of Radiation Units and Measurement (ICRU) rectum and bladder reference doses by 57.78% and 49.59%, respectively. We therefore suggest that the TPS should be modified to account for the shielding effects of the applicator to ensure the accuracy of the delivered doses.

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Rectum Dose Analysis Employing a Multi-purpose Brachytherapy Phantom

Cited by 7 publications

References 17 publications

In-vivo Comparison of Planned and Measured Rectal Doses during Cobalt-60 HDR CT-based Intracavitary Brachytherapy Applications of Cervical Cancer Using the PTW 9112 Semiconductor Probe

In-vivo Comparison of Planned and Measured Rectal Doses during Cobalt-60 HDR CT-based Intracavitary Brachytherapy Applications of Cervical Cancer Using the PTW 9112 Semiconductor Probe

The effect of tandem-ovoid titanium applicator on points A, B, bladder, and rectum doses in gynecological brachytherapy using 192 Ir

HDR Brachytherapy Dose Distribution is Influenced by the Metal Material of the Applicator

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