scholarly journals Influence of the breast prosthesis volume in dose distribution in radiotherapy planning

Mastology ◽  
2021 ◽  
Vol 31 ◽  
Author(s):  
Paulo Victor Fonseca ◽  
Danilo Salviano ◽  
Laura Ercolin ◽  
Fernanda Buongosto ◽  
Allison Borges ◽  
...  
Keyword(s):  
Breast Tissue ◽  
Clinical Target Volume ◽  
Target Volume ◽  
Important Variable ◽  
Radiotherapy Planning ◽  
Breast Prosthesis ◽  
Significant Difference ◽  
Oncological Results ◽  
The Mean ◽  
The Ideal

Introduction: The challenge of modern radiotherapy (RT) in breast cancer is to maintain its satisfactory oncological results, adapting to oncoplastic surgery and avoiding possible cosmetic damage. Considering that the breast prosthesis is not a target volume in RT planning, this study sought to analyze the effect of this volume on the coverage of the clinical target volume (CTV) of the breast. Methods: We performed a retrospective analysis of plans in 48 patients who submitted to RT in the first half of 2014. Two volumes were measured, such as breast CTV (breast tissue with the prosthesis) and real CTV (breast tissue excluding the prosthesis). The D95% values (dose that covers 95% of the volume) for each of them were verified and related to the volume of each one as well as the volume of breast prosthesis. Results: The analysis of the CTVs showed a significant difference between the mean volumes for the real CTV and breast CTV. While performing the CTV coverage, including the prosthesis, there is a perception that the dose covered 95% of the volume. Nevertheless, the analysis of the same plan after prosthesis volume exclusion revealed a difficulty in covering 95% of the breast tissue volume, indicating the interference of the prosthesis in therapy planning. Considering the dosimetric aspects, there were patients with real CTV values below the ideal dose of 47.5 Gy, after exclusion of implant volume. Conclusions: Our data reflected the volume of the prosthesis as an important variable that should be considered when planning adjuvant RT.

Radiotherapy planning: PET/CT scanner performances in the definition of gross tumour volume and clinical target volume

2005 ◽  
Vol 32 (12) ◽  
pp. 1392-1399 ◽  
Author(s):  
Ernesto Brianzoni ◽  
Gloria Rossi ◽  
Sergio Ancidei ◽  
Alfonso Berbellini ◽  
Francesca Capoccetti ◽  
...  
Keyword(s):  
Clinical Target Volume ◽  
Tumour Volume ◽  
Target Volume ◽  
Radiotherapy Planning ◽  
Gross Tumour Volume ◽  
Ct Scanner ◽  
Pet Ct ◽  
Definition Of

scholarly journals Pattern of Recurrence of Glioblastoma Versus Grade 4 IDH-Mutant Astrocytoma Following Chemoradiation

2021 ◽  
Author(s):  
James Stewart ◽  
Arjun Sahgal ◽  
Aimee K.M. Chan ◽  
Hany Soliman ◽  
Chia-Lin Tseng ◽  
...  
Keyword(s):  
Gross Tumor Volume ◽  
Clinical Target Volume ◽  
Tumor Volume ◽  
Extent Of Resection ◽  
Target Volume ◽  
Radiotherapy Planning ◽  
Recurrence Pattern ◽  
Wild Type ◽  
Failure Patterns ◽  
Pattern Of Recurrence

Abstract Purpose To quantitatively compare the recurrence pattern of glioblastoma (IDH-wild type) versus grade 4 IDH-mutant astrocytoma (herein referred to as wtIDH and mutIDH, respectively) following primary chemoradiation. Methods Twenty-two wtIDH and 22 mutIDH patients matched by sex, extent of resection, and corpus callosum involvement were enrolled. The recurrent gross tumor volume (rGTV) was compared with both the gross tumor volume (GTV) and clinical target volume (CTV) from radiotherapy planning. Failure patterns were quantified by the incidence and volume of the rGTV outside the GTV and CTV, and positional differences of the rGTV centroid from the GTV and CTV. Results The GTV was smaller in wtIDH compared to the mutIDH group (mean±SD: 46.5±26.0 cm3 v. 72.2±45.4 cm3, p=0.026). The rGTV was 10.7±26.9 cm3 and 46.9±55.0 cm3 smaller than the GTV for the same groups (p=0.018). The rGTV extended outside the GTV in 22 (100%) and 15 (68%) (p=0.009) of wtIDH and mutIDH patients, respectively; however, the volume of rGTV outside the GTV was not significantly different (12.4±16.1 cm3 vs. 8.4±14.2 cm3, p=0.443). The rGTV metrics extending outside the CTV was not different between the groups. The rGTV centroid was within 5.7 mm of the closest GTV edge for 21 (95%) and 22 (100%) of wtIDH and mutIDH patients, respectively. Conclusion The rGTV extended beyond the GTV less often in mutIDH patients, suggesting limited margin radiotherapy could be beneficial in this group. The results support the study of small margin adaptive radiotherapy per the ongoing UNITED MR-Linac 5 mm CTV trial (NCT04726397).

scholarly journals Effect of Photon Energy on Conventional Intensity-Modulated Radiotherapy and Rapid Arc Radiotherapy Planning for Deep-Seated Targets in Carcinoma Cervix

2019 ◽  
Vol 05 (01) ◽  
pp. 24-33
Author(s):  
Manindra Bhushan ◽  
Girigesh Yadav ◽  
Deepak Tripathi ◽  
Lalit Kumar ◽  
Abhinav Dewan ◽  
...  
Keyword(s):  
Photon Energy ◽  
Intensity Modulated Radiotherapy ◽  
Target Volume ◽  
Radiotherapy Planning ◽  
Treatment Modalities ◽  
Conformity Index ◽  
P Value ◽  
Carcinoma Cervix ◽  
Intensity Modulated ◽  
Significant Difference

Abstract Introduction To evaluate the dosimetric effect of photon energies on fixed field intensity-modulated radiotherapy (IMRT) and dual arc (DA) planning and to compare the dosimetric differences between conventional IMRT and DA radiotherapy planning. Materials and Methods IMRT and DA plans were generated for 15 patients having cervical cancer using different photon energies. IMRT and DA plans were generated using seven fields and double arcs, respectively. Dosimetric comparison was done in terms of planning target volume (PTV) coverage, sparing of organ at risk (OAR), homogeneity index (HI), conformity index (CI), and monitor units (MUs). Photo-neutron (energy ≤10MV) contribution was not considered for this study. Near region (NR) and far region (FR) were contoured to evaluate the dose deposited in nontarget area. Results No significant difference was observed (p > 0.05) in PTV coverage for conventional IMRT and DA; however, 6 MV yielded significantly better coverage over 15 MV (p < 0.05) for both the treatment modalities. Mean bladder dose was significantly more for conventional IMRT compared with DA. For rectal mean dose, p-value was nonsignificant for IMRT in comparison to DA, while significant difference was observed for change in photon energies for both treatment modalities respectively, except for 10 MV versus 15 MV DA plans. Significant improvements in HI (except 6 MV vs. 10 MV DA), CI (except 6 MV vs. 10 MV IMRT and DA), MUs, NR, and FR were noted. Conclusion DA generates more conformal, homogenous plans, requires less numbers of MUs, and deposits fewer doses to NR and FR regions of nontarget tissues in comparison to conventional IMRT. Although increase in photon energy for IMRT and DA plans reduces numbers of MUs and dose deposited to NR and FR regions, yet the choice for treatment of carcinoma cervix remains 6 MV due to production of photo-neutrons at higher energies.

Geometric contour variation in clinical target volume of axillary lymph nodes in breast cancer radiotherapy: an AIRO multi-institutional study

2021 ◽  
pp. 20201177
Author(s):  
Maria Cristina Leonardi ◽  
Matteo Pepa ◽  
Simone Giovanni Gugliandolo ◽  
Rosa Luraschi ◽  
Sabrina Vigorito ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Lymph Nodes ◽  
Clinical Target Volume ◽  
Target Volume ◽  
Radiotherapy Planning ◽  
Axillary Lymph Nodes ◽  
Dice Similarity Coefficient ◽  
Axillary Lymph ◽  
Computed Tomography Images ◽  
Breast Cancer Radiotherapy

Objectives: To determine interobserver variability in axillary nodal contouring in breast cancer (BC) radiotherapy (RT) by comparing the clinical target volume of participating single centres (SC-CTV) with a gold-standard CTV (GS-CTV). Methods: The GS-CTV of 3 patients (P1, P2, P3) with increasing complexity was created in DICOM format from the median contour of axillary CTVs drawn by BC experts, validated using the simultaneous truth and performance level estimation and peer-reviewed. GS-CTVs were compared with the correspondent SC-CTVs drawn by radiation oncologists, using validated metrics and a total score (TS) integrating all of them. Results: Eighteen RT centres participated in the study. Comparative analyses revealed that, on average, the SC-CTVs were smaller than GS-CTV for P1 and P2 (by −29.25% and −27.83%, respectively) and larger for P3 (by +12.53%). The mean Jaccard index was greater for P1 and P2 compared to P3, but the overlap extent value was around 0.50 or less. Regarding nodal levels, L4 showed the highest concordance with the GS. In the intra patient comparison, L2 and L3 achieved lower TS than L4. Nodal levels showed discrepancy with GS which was not statistically significant for P1, and negligible for P2, while P3 had the worst agreement. DICE Similarity Coefficient did not exceed the minimum threshold for agreement of 0.70 in all the measurements. Conclusions: Substantial differences were observed between SC- and GS-CTV, especially for P3 with altered arm set-up. L2 and L3 were the most critical levels. The study highlighted these key points to address. Advances in knowledge The present study compares, by means of validated geometric indexes, manual segmentationsof axillary lymph nodes in breast cancer from different observers and different institutionsmade on radiotherapy planning computed tomography images. Assessing such variability is ofparamount importance, as geometric uncertainties might lead to incorrect dosimetry andcompromise oncological outcome.

scholarly journals Radiotherapy planning: PET/CT scanner performances in the definition of gross tumour volume and clinical target volume

2005 ◽  
Vol 32 (12) ◽  
pp. 1491-1491
Author(s):  
Ernesto Brianzoni ◽  
Gloria Rossi ◽  
Sergio Ancidei ◽  
Alfonso Berbellini ◽  
Francesca Capoccetti ◽  
...  
Keyword(s):  
Clinical Target Volume ◽  
Tumour Volume ◽  
Target Volume ◽  
Radiotherapy Planning ◽  
Gross Tumour Volume ◽  
Ct Scanner ◽  
Pet Ct ◽  
Definition Of

scholarly journals A Comparative Study of the In-Built Torque and Slot Size of MBT Prescription Bracket of Different Manufacturing Companies: A Stereo-Microscopic Study

2020 ◽  
Vol 54 (4) ◽  
pp. 297-303
Author(s):  
Ashish Mathew ◽  
HC Kiran Kumar ◽  
Sadashiva Shetty
Keyword(s):  
Comparative Study ◽  
Manufacturing Companies ◽  
Central Incisor ◽  
Mean Values ◽  
Significant Difference ◽  
Slot Size ◽  
Standard Value ◽  
The Mean ◽  
Torque Values ◽  
The Ideal

Torque is produced by a twist in an “archwire” that creates a couple when interacted with a “bracket slot.” Depending on the magnitude of the twist, the size of the wire, the built-in torque and the size of the slot, the archwire expresses torsional forces to the teeth. When brackets are manufactured, some variations may inadvertently occur in the dimensions of the bracket slot. Hence this study was done to determine the accuracy of different manufacturer’s dimensions of bracket slots and the built-in torque. Method: Seven upper right central incisor brackets of Mclaughlin Bennet and Trevisi (MBT) prescription with 0.022-inch slot from 5 different manufacturers were taken to assess the accuracy of bracket slot dimensions and built-in torque. A stereomicroscope was used to accurately determine slot dimensions and built-in torque. Results: The results showed that all the bracket slots measured in this study were oversized when compared to the standard value. Dentaurum showed significant difference from the ideal slot size and brackets from JJ Orthodontics and Desires showed highly significance difference from ideal slot size. The mean values for built in torque were less in all the brackets. The brackets from JJ Orthodontics and Desires showed highly significant difference from the ideal built in torque values. Interpretation and Conclusion: The above findings of the study suggest that one should be cautious when choosing a commercially available brand in day to day practice as some of the materials may not fulfill the desired standards.

scholarly journals Analysis of Geometric and Dosimetric Effects of Bra Application to Support Large or Pendulous Breasts During Radiotherapy Planning: A Retrospective Single-Center Study

2021 ◽  
Vol 20 ◽  
pp. 153303382110279
Author(s):  
So Hyun Park ◽  
Jinhyun Choi
Keyword(s):  
Clinical Target Volume ◽  
Organs At Risk ◽  
Target Volume ◽  
Radiotherapy Planning ◽  
Homogeneity Index ◽  
Breast Volume ◽  
Breast Cancer Patients ◽  
Single Center Study ◽  
Radiotherapy Field ◽  
Dose Reductions

Purpose: To evaluate geometric and dosimetric effects of bra application during radiotherapy planning for breast cancer patients with large and pendulous breasts. Materials and Methods: Twenty patients with chest sizes >38 inches between April 2019 and July 2019 underwent radiotherapy planning with and without a radiation bra (Chabner XRT®). Geometric and dosimetric parameters included the breast volume, superior-inferior (SI) distance, separation (S) as the distance of the longest diameter of the clinical target volume (CTV), conformity number (CN), and homogeneity index (HI) of CTV. The organs at risk (OARs) were defined as the lungs, heart, and liver. Results: The use of the radiation bra provided mean changes of −0.51 cm for S, −1.45 cm for SI, and −61.18 cc for breast volume (all P < 0.05). Breast volume was correlated with bra-related changes in cross diameter (r = 0.641, P = 0.002) and volume (r = 0.680, P = 0.001). Significant dose reductions were observed for the lungs (mean V10: 19.58 cc, V20: 17.13 cc, Dmean: 86.24 cGy) and heart (Dmean: 170.23 cGy). No significant differences were observed for CN (0.62-0.67) and HI (0.19-0.20) of the CTV. Conclusion: The application of a radiation bra was associated with better geometric and dosimetric planning parameters, with a smaller CTV and lower doses to the OARs (lungs and heart) in the radiotherapy field. In addition, we expect that bra use during radiotherapy would provide emotional benefits.

scholarly journals Definition of Local Recurrence Site in Resected Pancreatic Adenocarcinoma: A Multicenter Study (DOLORES-1)

Cancers ◽  
2021 ◽  
Vol 13 (12) ◽  
pp. 3051
Author(s):  
Alessandra Arcelli ◽  
Federica Bertini ◽  
Silvia Strolin ◽  
Gabriella Macchia ◽  
Francesco Deodato ◽  
...  
Keyword(s):  
Clinical Target Volume ◽  
Postoperative Radiotherapy ◽  
Kernel Density ◽  
Target Volume ◽  
Risk Map ◽  
The Mean ◽  
New Guidelines ◽  
Definition Of ◽  
Dice Index

The study aimed to generate a local failure (LF) risk map in resected pancreatic cancer (PC) and validate the results of previous studies, proposing new guidelines for PC postoperative radiotherapy clinical target volume (CTV) delineation. Follow-up computer tomography (CT) of resected PC was retrospectively reviewed by two radiologists identifying LFs and plotting them on a representative patient CT scan. The percentages of LF points randomly extracted based on CTV following the RTOG guidelines and based on the LF database were 70% and 30%, respectively. According to the Kernel density estimation, an LF 3D distribution map was generated and compared with the results of previous studies using a Dice index. Among the 64 resected patients, 59.4% underwent adjuvant treatment. LFs closer to the root of the celiac axis (CA) or the superior mesenteric artery (SMA) were reported in 32.8% and 67.2% cases, respectively. The mean (± standard deviation) distances of LF points to CA and SMA were 21.5 ± 17.9 mm and 21.6 ± 12.1 mm, respectively. The Dice values comparing our iso-level risk maps corresponding to 80% and 90% of the LF probabilistic density and the CTVs-80 and CTVs-90 of previous publications were 0.45–0.53 and 0.58–0.60, respectively. According to the Kernel density approach, a validated LF map was proposed, modeling a new adjuvant CTV based on a PC pattern of failure.

Sign in / Sign up

Export Citation Format

Share Document