Critical Factors of Dose Distribution in Breast Cancer Tomotherapy With Metallic Port Breast Tissue Expander: Image Correction, Delivery Mode, and Volume Impact

Objectives: Breast reconstruction helps patients enhance their body image after mastectomy. Metallic ports in tissue expanders lead to dose attenuation during radiotherapy. Tissue expander volume shifts the metallic port position, possibly causing various dose alterations. This study aimed to evalua...

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Main Authors: Hsing-Yi Lee MS, Yu-Hsiu Yen MD, PhD, Yu-Lun Tsai MD, Pei-Chih Tu MS, Chi-Ming Pu PhD, Chia-Hong Lin MS, Louis Tak Lui MD, Suzun Shaw MD, Ching-Jung Wu MD, Hsin-Hua Nien MD
Format: Article
Language:English
Published: SAGE Publishing 2022-04-01
Series:Technology in Cancer Research & Treatment
Online Access:https://doi.org/10.1177/15330338221093148
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author Hsing-Yi Lee MS
Yu-Hsiu Yen MD, PhD
Yu-Lun Tsai MD
Pei-Chih Tu MS
Chi-Ming Pu PhD
Chia-Hong Lin MS
Louis Tak Lui MD
Suzun Shaw MD
Ching-Jung Wu MD
Hsin-Hua Nien MD
author_facet Hsing-Yi Lee MS
Yu-Hsiu Yen MD, PhD
Yu-Lun Tsai MD
Pei-Chih Tu MS
Chi-Ming Pu PhD
Chia-Hong Lin MS
Louis Tak Lui MD
Suzun Shaw MD
Ching-Jung Wu MD
Hsin-Hua Nien MD
author_sort Hsing-Yi Lee MS
collection DOAJ
description Objectives: Breast reconstruction helps patients enhance their body image after mastectomy. Metallic ports in tissue expanders lead to dose attenuation during radiotherapy. Tissue expander volume shifts the metallic port position, possibly causing various dose alterations. This study aimed to evaluate the impact of the MAGNA-SITE TM tissue expander volume on tomotherapy. Methods: Boluses and MAGNA-SITE TM were placed on a Rando phantom to simulate the tissue expander under the pectoralis major. Computed tomography simulation images were transformed through replacing the electron density of (a) metallic artifact region only (Image metallic port) and (b) metallic port and artifact regions (Image Homo). Planning was calculated using fixed-beam and helical-mode techniques. Radiation was delivered with different volumes of the tissue expander. Results: Integrated 997 dose points were calculated. Planning with Image metallic port provided a calculated dose significantly closer to a realistic dose. The percentage of doses achieving the prescribed dose was significantly higher in the helical mode. In layer 2, the 100-mL tissue expander had a significantly lower measurement dose than all other volumes. Volume 150 mL had the highest increase in the measured dose difference from the plan dose at layer 2. Volume 250 mL had the highest percentage of measurement doses passing the 5% dose difference from plan dose. The coldest dose areas were noted in layers 1 and 2, especially in the metallic port–direct image mode. The average dose reduction of the measured cold areas was 6.03 ± 1.94%. Conclusion: Dose distribution was affected by the volume of the metallic port tissue expander. Tomotherapy with proper image heterogeneity correction and helical mode can reduce the attenuation from the metallic port. A tissue expander volume of 150 to 250 mL is suitable. Patients with high risk at the chest wall should be evaluated carefully to avoid underdosing. Radiation oncologists should closely cooperate with plastic surgeons to optimize treatment for each patient.
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spelling doaj.art-777a13b01e9549ba88cb3b38808df92d2022-12-22T01:51:32ZengSAGE PublishingTechnology in Cancer Research & Treatment1533-03382022-04-012110.1177/15330338221093148Critical Factors of Dose Distribution in Breast Cancer Tomotherapy With Metallic Port Breast Tissue Expander: Image Correction, Delivery Mode, and Volume ImpactHsing-Yi Lee MS0Yu-Hsiu Yen MD, PhD1Yu-Lun Tsai MD2Pei-Chih Tu MS3Chi-Ming Pu PhD4Chia-Hong Lin MS5Louis Tak Lui MD6Suzun Shaw MD7Ching-Jung Wu MD8Hsin-Hua Nien MD9 Department of Radiation Oncology, Oncology Treatment Center, , New Taipei City, Taiwan School of Medicine, , New Taipei City, Taiwan Institute of Epidemiology and Preventive Medicine, College of Public Health, , Taipei, Taiwan Department of Radiation Oncology, Oncology Treatment Center, , New Taipei City, Taiwan School of Medicine, , New Taipei City, Taiwan Department of Radiation Oncology, Oncology Treatment Center, , New Taipei City, Taiwan Department of Radiation Oncology, , Taipei, Taiwan Department of Radiation Oncology, , Taipei, Taiwan Department of Biomedical Engineering, I-Shou University, Kaohsiung, Taiwan Institute of Biomedical Engineering, College of Electrical and Computer Engineering, , Hsinchu, TaiwanObjectives: Breast reconstruction helps patients enhance their body image after mastectomy. Metallic ports in tissue expanders lead to dose attenuation during radiotherapy. Tissue expander volume shifts the metallic port position, possibly causing various dose alterations. This study aimed to evaluate the impact of the MAGNA-SITE TM tissue expander volume on tomotherapy. Methods: Boluses and MAGNA-SITE TM were placed on a Rando phantom to simulate the tissue expander under the pectoralis major. Computed tomography simulation images were transformed through replacing the electron density of (a) metallic artifact region only (Image metallic port) and (b) metallic port and artifact regions (Image Homo). Planning was calculated using fixed-beam and helical-mode techniques. Radiation was delivered with different volumes of the tissue expander. Results: Integrated 997 dose points were calculated. Planning with Image metallic port provided a calculated dose significantly closer to a realistic dose. The percentage of doses achieving the prescribed dose was significantly higher in the helical mode. In layer 2, the 100-mL tissue expander had a significantly lower measurement dose than all other volumes. Volume 150 mL had the highest increase in the measured dose difference from the plan dose at layer 2. Volume 250 mL had the highest percentage of measurement doses passing the 5% dose difference from plan dose. The coldest dose areas were noted in layers 1 and 2, especially in the metallic port–direct image mode. The average dose reduction of the measured cold areas was 6.03 ± 1.94%. Conclusion: Dose distribution was affected by the volume of the metallic port tissue expander. Tomotherapy with proper image heterogeneity correction and helical mode can reduce the attenuation from the metallic port. A tissue expander volume of 150 to 250 mL is suitable. Patients with high risk at the chest wall should be evaluated carefully to avoid underdosing. Radiation oncologists should closely cooperate with plastic surgeons to optimize treatment for each patient.https://doi.org/10.1177/15330338221093148
spellingShingle Hsing-Yi Lee MS
Yu-Hsiu Yen MD, PhD
Yu-Lun Tsai MD
Pei-Chih Tu MS
Chi-Ming Pu PhD
Chia-Hong Lin MS
Louis Tak Lui MD
Suzun Shaw MD
Ching-Jung Wu MD
Hsin-Hua Nien MD
Critical Factors of Dose Distribution in Breast Cancer Tomotherapy With Metallic Port Breast Tissue Expander: Image Correction, Delivery Mode, and Volume Impact
Technology in Cancer Research & Treatment
title Critical Factors of Dose Distribution in Breast Cancer Tomotherapy With Metallic Port Breast Tissue Expander: Image Correction, Delivery Mode, and Volume Impact
title_full Critical Factors of Dose Distribution in Breast Cancer Tomotherapy With Metallic Port Breast Tissue Expander: Image Correction, Delivery Mode, and Volume Impact
title_fullStr Critical Factors of Dose Distribution in Breast Cancer Tomotherapy With Metallic Port Breast Tissue Expander: Image Correction, Delivery Mode, and Volume Impact
title_full_unstemmed Critical Factors of Dose Distribution in Breast Cancer Tomotherapy With Metallic Port Breast Tissue Expander: Image Correction, Delivery Mode, and Volume Impact
title_short Critical Factors of Dose Distribution in Breast Cancer Tomotherapy With Metallic Port Breast Tissue Expander: Image Correction, Delivery Mode, and Volume Impact
title_sort critical factors of dose distribution in breast cancer tomotherapy with metallic port breast tissue expander image correction delivery mode and volume impact
url https://doi.org/10.1177/15330338221093148
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