1
|
Falade I, Switalla K, Quirarte A, Baxter M, Soroudi D, Rothschild H, Abe SE, Goodwin K, Piper M, Wong J, Foster R, Mukhtar RA. Oncologic Safety of Immediate Oncoplastic Surgery Compared with Standard Breast-Conserving Surgery for Patients with Invasive Lobular Carcinoma. Ann Surg Oncol 2024:10.1245/s10434-024-15326-5. [PMID: 38713388 DOI: 10.1245/s10434-024-15326-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2024] [Accepted: 04/01/2024] [Indexed: 05/08/2024]
Abstract
BACKGROUND Invasive lobular carcinoma (ILC) of the breast grows in a diffuse pattern, resulting in a high risk of positive margins at surgical resection. Oncoplastic approaches have been shown to reduce this risk, but concerns persist around the safety of immediate oncoplastic surgery for those with ILC. This study evaluated the short- and long-term oncologic outcomes of immediate oncoplastic surgery for patients with ILC. METHODS This study retrospectively analyzed an institutional database of stages I to III ILC patients who underwent breast-conserving surgery (BCS) with or without immediate oncoplastic surgery (oncoplastic closure or oncoplastic reduction mammoplasty [ORM]). The study compared positive margin rates, rates of successful BCS, and recurrence-free survival (RFS) by type of surgery. RESULTS For 494 patients the findings showed that the use of immediate ORM was associated with significantly lower odds of positive margins (odds ratio [OR], 0.34; 95 % confidence interval [CI], 0.17-0.66; p = 0.002). Both lumpectomy with oncoplastic closure and ORM were significantly associated with higher rates of successful BCS than standard lumpectomy (94.2 %, 87.8 %, and 73.9 %, respectively; p < 0.001). No difference in RFS was observed between those undergoing immediate oncoplastic surgery and those undergoing standard lumpectomy alone. CONCLUSIONS The patients with stages I to III ILC who underwent immediate oncoplastic surgery had significant benefits including lower odds of positive margins and higher rates of successful BCS, with both types of immediate oncoplastic surgery showing similar RFS compared with lumpectomy alone. This supports the oncologic safety of immediate oncoplastic surgery for diffusely growing tumors such as ILC, providing it an ideal option for patients desiring BCS.
Collapse
Affiliation(s)
- Israel Falade
- School of Medicine, University of California-San Francisco, San Francisco, CA, USA.
| | - Kayla Switalla
- University of Minnesota Medical School, Minneapolis, MN, USA
- Division of Surgical Oncology, Department of Surgery, University of California-San Francisco, San Francisco, CA, USA
| | - Astrid Quirarte
- Division of Surgical Oncology, Department of Surgery, University of California-San Francisco, San Francisco, CA, USA
| | - Molly Baxter
- Division of Surgical Oncology, Department of Surgery, University of California-San Francisco, San Francisco, CA, USA
| | - Daniel Soroudi
- School of Medicine, University of California-San Francisco, San Francisco, CA, USA
| | - Harriet Rothschild
- School of Medicine, University of California-San Francisco, San Francisco, CA, USA
| | - Shoko Emily Abe
- Division of Surgical Oncology, Department of Surgery, University of California-San Francisco, San Francisco, CA, USA
| | - Karen Goodwin
- Division of Surgical Oncology, Department of Surgery, University of California-San Francisco, San Francisco, CA, USA
| | - Merisa Piper
- Division of Plastic and Reconstructive Surgery, Department of Surgery, University of California-San Francisco, San Francisco, CA, USA
| | - Jasmine Wong
- Division of Surgical Oncology, Department of Surgery, University of California-San Francisco, San Francisco, CA, USA
| | - Robert Foster
- Division of Plastic and Reconstructive Surgery, Department of Surgery, University of California-San Francisco, San Francisco, CA, USA
| | - Rita A Mukhtar
- Division of Surgical Oncology, Department of Surgery, University of California-San Francisco, San Francisco, CA, USA
| |
Collapse
|
2
|
Mast M, Leong A, Korreman S, Lee G, Probst H, Scherer P, Tsang Y. ESTRO-ACROP guideline for positioning, immobilisation and setup verification for local and loco-regional photon breast cancer irradiation. Tech Innov Patient Support Radiat Oncol 2023; 28:100219. [PMID: 37745181 PMCID: PMC10511493 DOI: 10.1016/j.tipsro.2023.100219] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2023] [Accepted: 09/10/2023] [Indexed: 09/26/2023] Open
Affiliation(s)
- M.E. Mast
- Department of Radiation Oncology, Haaglanden Medical Center, Leidschendam, The Netherlands
| | - A. Leong
- Department of Radiation Therapy, University of Otago, Wellington, New Zealand
- Bowen Icon Cancer Centre, Wellington, New Zealand
| | - S.S. Korreman
- Department of Clinical Medicine, Aarhus University, Denmark
- Department of Oncology, Aarhus University Hospital, Denmark
- Danish Center for Particle Therapy, Aarhus University Hospital, Denmark
| | - G. Lee
- Radiation Medicine Program, Princess Margaret Cancer Centre, Toronto, Canada
- Department of Radiation Oncology, University of Toronto, Toronto, Canada
| | - H. Probst
- Sheffield Hallam University, Sheffield, United Kingdom
| | - P. Scherer
- Department of Radiotherapy and Radio-Oncology, LKH Salzburg, Paracelsus Medical University Clinics, Salzburg, Austria
| | - Y. Tsang
- Radiation Medicine Program, Princess Margaret Cancer Centre, Toronto, Canada
- Department of Radiation Oncology, University of Toronto, Toronto, Canada
| |
Collapse
|
3
|
Benkhaled S, Gomes da Silveira Cauduro C, Jullian N, Desmet A, Rodriguez D, Jourani Y, Van Gestel D, De Caluwé A. Inter-fraction heart displacement during voluntary deep inspiration breath hold radiation therapy without visual feedback measured by daily CBCT. Front Oncol 2022; 12:936088. [PMID: 36059622 PMCID: PMC9433564 DOI: 10.3389/fonc.2022.936088] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2022] [Accepted: 07/18/2022] [Indexed: 11/13/2022] Open
Abstract
Purpose/Objective Deep Inspiration Breath Hold (DIBH) is now considered as the standard of care for many breast cancer patients. However, there are still uncertainties about the dose given to the heart, and it is unknown if patients may improve voluntary DIBH depth by gaining experience during treatment. In this study, we will examine the interfractional three-dimensional (3D) heart displacement throughout voluntary DIBH (vDIBH) radiotherapy by means of daily cone-beam computed tomography (CBCT). Material and methods Two hundred twenty-five unique CBCTs from 15 patients treated in 15 fractions were analyzed. During CBCT, a vDIBH was conducted without any visual feedback. Patients performed their DIBH freely after receiving explanations and training. After daily CBCT matching to the chest wall (CW), surface-guided radiation therapy (SGRT) tracked DIBH depth to ensure that the CW position was the same as the daily acquired CBCT. The CBCTs were retrospectively registered to the DIBH planning-CT to calculate daily changes in heart displacement relative to the CW. Results The mean displacement of the heart during DIBH treatment relative to the DIBH planning-CT was as follows: 1.1 mm to the right, interquartile range (IQR) 8.0; 0.5 mm superiorly, IQR 4.8; and 0 mm posteriorly, IQR 6.4. The Spearman correlation coefficients (rs) were -0.15 (p=0.025), 0.04 (p=0.549), and 0.03 (p=0.612) for the X, Y, and Z directions, respectively. The differences in median heart displacement were significant: Friedmann rank sum test p=0.031 and pairwise comparison using the Wilcoxon rank-sum test were p=0.008 for X and Y; p=0.33 for X and Z; and p=0.07 for Y and Z. The total median heart motion was δtot median= 7.26 mm, IQR= 6.86 mm. Conclusion During DIBH, clinicians must be aware of the wide range of intra- and inter-individual heart position variations. The inter-individual heterogeneity shown in our study should be investigated further in order to avoid unexpected cardiac overexposure and to develop a more accurate heart dose-volume model.
Collapse
Affiliation(s)
- Sofian Benkhaled
- Department of Radiation-Oncology, Institut Jules Bordet-Université Libre de Bruxelles, Brussels, Belgium
- *Correspondence: Sofian Benkhaled,
| | | | - Nicolas Jullian
- Department of Radiation-Oncology, Institut Jules Bordet-Université Libre de Bruxelles, Brussels, Belgium
| | - Antoine Desmet
- Department of Radiation-Oncology, Institut Jules Bordet-Université Libre de Bruxelles, Brussels, Belgium
| | - Diana Rodriguez
- Department of Medical-Physics, Institut Jules Bordet-Université Libre de Bruxelles, Brussels, Belgium
| | - Younes Jourani
- Department of Medical-Physics, Institut Jules Bordet-Université Libre de Bruxelles, Brussels, Belgium
| | - Dirk Van Gestel
- Department of Radiation-Oncology, Institut Jules Bordet-Université Libre de Bruxelles, Brussels, Belgium
| | - Alex De Caluwé
- Department of Radiation-Oncology, Institut Jules Bordet-Université Libre de Bruxelles, Brussels, Belgium
| |
Collapse
|
4
|
Naidoo W, Leech M. Feasibility of surface guided radiotherapy for patient positioning in breast radiotherapy versus conventional tattoo-based setups- a systematic review. Tech Innov Patient Support Radiat Oncol 2022; 22:39-49. [PMID: 35481261 PMCID: PMC9035716 DOI: 10.1016/j.tipsro.2022.03.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2021] [Revised: 02/07/2022] [Accepted: 03/09/2022] [Indexed: 11/17/2022] Open
Abstract
Background Traditionally tattoos are used for patient setup in radiotherapy. However they may pose challenges for the radiotherapists to achieve precise patient alignment, and serve as a permanent visual reminder of the patient’s diagnosis and often challenging cancer journey. The psychological impact of tattoos has been recognized in recent years. The increasing complexity of treatment techniques and the utilization of hypofractionated regimes, requires an enhanced level of accuracy and safety. Surface guided radiotherapy (SGRT) enables improvements in the accuracy and reproducibility of patient isocentric and postural alignment, enhanced efficiency, and safety in breast radiotherapy. Purpose The aim of this review was to compare the accuracy and reproducibility of SGRT to conventional tattoo-based setups in free-breathing breast radiotherapy and to determine if SGRT can reduce the frequency of routine image guided radiotherapy (IGRT). Materials and Methods A systematic literature review was performed as per PRISMA guidelines. Papers identified through PubMed, Embase, Web of Science and Google Scholar database searches between 2010 and 2021, were critically appraised. Systematic, random, mean residual errors and 3D vector shifts as determined by IGRT verification were analysed. Results A review of 13 full papers suggests SGRT improves the accuracy and reproducibility of patient setup in breast radiotherapy with consistent reductions in the residual errors. There appears to be a good correlation between SGRT setups and radiographic imaging. The frequency of IGRT and the corresponding dose could potentially be reduced. Additionally, SGRT improves treatment efficiency. Conclusion SGRT appears to have improved the accuracy and reproducibility of patient setup and treatment efficiency of breast radiotherapy compared to conventional tattoo/laser-based method, with the potential to reduce the frequency of routine IGRT. The reliance on tattoos in breast radiotherapy are likely to become obsolete with positive implications for both patients and clinical practice.
Collapse
|
5
|
Baeza JA, Zegers CM, de Groot NA, Nijsten SM, Murrer LH, Verhoeven K, Boersma L, Verhaegen F, van Elmpt W. Automatic dose verification system for breast radiotherapy: Method validation, contour propagation and DVH parameters evaluation. Phys Med 2022; 97:44-49. [DOI: 10.1016/j.ejmp.2022.03.017] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Revised: 02/26/2022] [Accepted: 03/27/2022] [Indexed: 12/30/2022] Open
|
6
|
Kadman B, Takemura A, Ito T, Okada N, Kojima H, Ueda S. Accuracy of patient setup positioning using surface‐guided radiotherapy with deformable registration in cases of surface deformation. J Appl Clin Med Phys 2022; 23:e13493. [PMID: 35077004 PMCID: PMC9398221 DOI: 10.1002/acm2.13493] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2021] [Revised: 11/16/2021] [Accepted: 11/17/2021] [Indexed: 11/29/2022] Open
Abstract
The Catalyst™ HD (C‐RAD Positioning AB, Uppsala, Sweden) is surface‐guided radiotherapy (SGRT) equipment that adopts a deformable model. The challenge in applying the SGRT system is accurately correcting the setup error using a deformable model when the body of the patient is deformed. This study evaluated the effect of breast deformation on the accuracy of the setup correction of the SGRT system. Physical breast phantoms were used to investigate the relationship between the mean deviation setup error obtained from the SGRT system and the breast deformation. Physical breast phantoms were used to simulate extension and shrinkage deformation (−30 to 30 mm) by changing breast pieces. Three‐dimensional (3D) Slicer software was used to evaluate the deformation. The maximum deformations in X, Y, and Z directions were obtained as the differences between the original and deformed breasts. We collected the mean deviation setup error from the SGRT system by replacing the original breast part with the deformed breast part. The mean absolute difference of lateral, longitudinal, vertical, pitch, roll, and yaw, between the rigid and deformable registrations was 2.4 ± 1.7 mm, 1.3 ± 1.2 mm, 6.4 ± 5.2 mm, 2.5° ± 2.5°, 2.2° ± 2.4°, and 1.0° ± 1.0°, respectively. Deformation in the Y direction had the best correlation with the mean deviation translation error (R = 0.949) and rotation error (R = 0.832). As the magnitude of breast deformation increased, both mean deviation setup errors increased, and there was greater error in translation than in rotation. Large deformation of the breast surface affects the setup correction. Deformation in the Y direction most affects translation and rotation errors.
Collapse
Affiliation(s)
- Boriphat Kadman
- Division of Health Sciences Graduate School of Medical Sciences, Pharmaceutical and Health Sciences Kanazawa University 5‐11‐80 Kodatsuno Kanazawa Ishikawa 9200942 Japan
| | - Akihiro Takemura
- Faculty of Health Sciences Institute of Medical, Pharmaceutical and Health Sciences Kanazawa University 5‐11‐80 Kodatsuno Kanazawa Ishikawa 9200942 Japan
| | - Tatsuya Ito
- Department of Radiological Technology Japanese Red Cross Aichi Medical Center Nagoya Daini Hospital 2‐9 Myouke‐cho, Showa‐ku Nagoya Aichi 4668650 Japan
| | - Naoki Okada
- Division of Health Sciences Graduate School of Medical Sciences, Pharmaceutical and Health Sciences Kanazawa University 5‐11‐80 Kodatsuno Kanazawa Ishikawa 9200942 Japan
| | - Hironori Kojima
- Department of Radiology Kanazawa University Hospital 13‐1 Takara‐machi Kanazawa Ishikawa 9208641 Japan
| | - Shinichi Ueda
- Department of Radiology Kanazawa University Hospital 13‐1 Takara‐machi Kanazawa Ishikawa 9208641 Japan
| |
Collapse
|
7
|
Li C, Lu Z, He M, Sui J, Lin T, Xie K, Sun J, Ni X. Augmented reality-guided positioning system for radiotherapy patients. J Appl Clin Med Phys 2022; 23:e13516. [PMID: 34985188 PMCID: PMC8906221 DOI: 10.1002/acm2.13516] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2021] [Revised: 11/18/2021] [Accepted: 12/15/2021] [Indexed: 01/22/2023] Open
Abstract
In modern radiotherapy, error reduction in the patients’ daily setup error is important for achieving accuracy. In our study, we proposed a new approach for the development of an assist system for the radiotherapy position setup by using augmented reality (AR). We aimed to improve the accuracy of the position setup of patients undergoing radiotherapy and to evaluate the error of the position setup of patients who were diagnosed with head and neck cancer, and that of patients diagnosed with chest and abdomen cancer. We acquired the patient's simulation CT data for the three‐dimensional (3D) reconstruction of the external surface and organs. The AR tracking software detected the calibration module and loaded the 3D virtual model. The calibration module was aligned with the Linac isocenter by using room lasers. And then aligned the virtual cube with the calibration module to complete the calibration of the 3D virtual model and Linac isocenter. Then, the patient position setup was carried out, and point cloud registration was performed between the patient and the 3D virtual model, such the patient's posture was consistent with the 3D virtual model. Twenty patients diagnosed with head and neck cancer and 20 patients diagnosed with chest and abdomen cancer in the supine position setup were analyzed for the residual errors of the conventional laser and AR‐guided position setup. Results show that for patients diagnosed with head and neck cancer, the difference between the two positioning methods was not statistically significant (P > 0.05). For patients diagnosed with chest and abdomen cancer, the residual errors of the two positioning methods in the superior and inferior direction and anterior and posterior direction were statistically significant (t = −5.80, −4.98, P < 0.05). The residual errors in the three rotation directions were statistically significant (t = −2.29 to −3.22, P < 0.05). The experimental results showed that the AR technology can effectively assist in the position setup of patients undergoing radiotherapy, significantly reduce the position setup errors in patients diagnosed with chest and abdomen cancer, and improve the accuracy of radiotherapy.
Collapse
Affiliation(s)
- Chunying Li
- Department of Radiotherapy, Changzhou Second People's Hospital, Nanjing Medical University, Changzhou, China.,Laboratory of Medical Physics Center, Nanjing Medical University, Jiangning District, Nanjing, China.,Changzhou Key Laboratory of Medical Physics, Changzhou, China
| | - Zhengda Lu
- Department of Radiotherapy, Changzhou Second People's Hospital, Nanjing Medical University, Changzhou, China.,Laboratory of Medical Physics Center, Nanjing Medical University, Jiangning District, Nanjing, China.,Changzhou Key Laboratory of Medical Physics, Changzhou, China
| | - Mu He
- Department of Radiotherapy, Changzhou Second People's Hospital, Nanjing Medical University, Changzhou, China.,Laboratory of Medical Physics Center, Nanjing Medical University, Jiangning District, Nanjing, China.,Changzhou Key Laboratory of Medical Physics, Changzhou, China
| | - Jianfeng Sui
- Department of Radiotherapy, Changzhou Second People's Hospital, Nanjing Medical University, Changzhou, China.,Laboratory of Medical Physics Center, Nanjing Medical University, Jiangning District, Nanjing, China.,Changzhou Key Laboratory of Medical Physics, Changzhou, China
| | - Tao Lin
- Department of Radiotherapy, Changzhou Second People's Hospital, Nanjing Medical University, Changzhou, China.,Laboratory of Medical Physics Center, Nanjing Medical University, Jiangning District, Nanjing, China.,Changzhou Key Laboratory of Medical Physics, Changzhou, China
| | - Kai Xie
- Department of Radiotherapy, Changzhou Second People's Hospital, Nanjing Medical University, Changzhou, China.,Laboratory of Medical Physics Center, Nanjing Medical University, Jiangning District, Nanjing, China.,Changzhou Key Laboratory of Medical Physics, Changzhou, China
| | - Jiawei Sun
- Department of Radiotherapy, Changzhou Second People's Hospital, Nanjing Medical University, Changzhou, China.,Laboratory of Medical Physics Center, Nanjing Medical University, Jiangning District, Nanjing, China.,Changzhou Key Laboratory of Medical Physics, Changzhou, China
| | - Xinye Ni
- Department of Radiotherapy, Changzhou Second People's Hospital, Nanjing Medical University, Changzhou, China.,Laboratory of Medical Physics Center, Nanjing Medical University, Jiangning District, Nanjing, China.,Changzhou Key Laboratory of Medical Physics, Changzhou, China
| |
Collapse
|
8
|
Marc L, Fabiano S, Wahl N, Linsenmeier C, Lomax AJ, Unkelbach J. Combined proton-photon treatment for breast cancer. Phys Med Biol 2021; 66. [PMID: 34736246 DOI: 10.1088/1361-6560/ac36a3] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2021] [Accepted: 11/04/2021] [Indexed: 11/12/2022]
Abstract
Objective.Proton therapy remains a limited resource due to gantry size and its cost. Recently, a new design without a gantry has been suggested. It may enable combined proton-photon therapy (CPPT) in conventional bunkers and allow the widespread use of protons. In this work, we explore this concept for breast cancer.Methods.The treatment room consists of a LINAC for intensity modulated radiation therapy (IMRT), a fixed proton beamline (FBL) with beam scanning and a motorized couch for treatments in lying positions with accurate patient setup. Thereby, proton and photon beams are delivered in the same fraction. Treatment planning is performed by simultaneously optimizing IMRT and IMPT plans based on the cumulative dose. The concept is investigated for three breast cancers where the goal is to minimize mean dose to the heart and lung while delivering 40.05 Gy in 15 fractions to the PTV with a SIB of 48 Gy to the tumor bed. The probabilistic approach is applied to mitigate the sensitivity to range uncertainties.Results. CPPT is particularly advantageous for irradiating concave target volumes that wrap around a curved chest wall. There, protons may deliver dose to the peripheral and medial parts of the target volume including lymph nodes. Thereby, the mean dose in normal tissues is reduced compared to single-modality IMRT. However, tangential photon beams may treat parts of the target volume near the interface to the lung. To ensure target coverage for range undershoot in an IMPT plan, proton beams have to deliberately overshoot into the lung tissue-a problem that can be mitigated via the photon component which ensures plan conformity and robustness.Conclusion.CPPT using an FBL may represent a realistic approach to make protons available to more patients. In addition, CPPT may generally improve treatment quality compared to both single-modality proton and photon treatments.
Collapse
Affiliation(s)
- Louise Marc
- Department of Radiation Oncology, University Hospital Zurich, Switzerland
| | - Silvia Fabiano
- Department of Radiation Oncology, University Hospital Zurich, Switzerland
| | - Niklas Wahl
- Department of Medical Physics in Radiation Oncology, German Cancer Research Center DKFZ, Heidelberg, Germany
| | | | - Antony J Lomax
- Center for Proton Therapy, Paul Scherrer Institute, Switzerland.,Department of Physics, ETH Zurich, Switzerland
| | - Jan Unkelbach
- Department of Radiation Oncology, University Hospital Zurich, Switzerland
| |
Collapse
|
9
|
Esposito PG, Castriconi R, Mangili P, Fodor A, Pasetti M, Di Muzio NG, Del Vecchio A, Fiorino C. Virtual Tangential-fields Arc Therapy (ViTAT) for whole breast irradiation: Technique optimization and validation. Phys Med 2020; 77:160-168. [PMID: 32866777 DOI: 10.1016/j.ejmp.2020.08.011] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Revised: 08/07/2020] [Accepted: 08/09/2020] [Indexed: 12/20/2022] Open
Abstract
PURPOSE To test the performances of a volumetric arc technique named ViTAT (Virtual Tangential-fields Arc Therapy) mimicking tangential field irradiation for whole breast radiotherapy. METHODS ViTAT plans consisted in 4 arcs whose starting/ending position were established based on gantry angle distribution of clinical plans for right and left-breast. The arcs were completely blocked excluding the first and last 20°. Different virtual bolus densities and thicknesses were preliminarily evaluated to obtain the best plan performances. For 40 patients with tumor laterality equally divided between right and left sides, ViTAT plans were optimized considering the clinical DVHs for OARs (resulting from tangential field manual planning) to constrain them: ViTAT plans were compared with the clinical tangential-fields in terms of DVH parameters for both PTV and OARs. RESULTS Distal angle values were suggested in the ranges [220°,240°] for the right-breast and [115°,135°] for the left-breast cases; medial angles were [60°,40°] for the right side and [295°,315°] for the left side, limiting the risk of collision. The optimal virtual bolus had -500 HU density and 1.5 cm thickness. ViTAT plans generated dose distributions very similar to the tangential-field plans, with significantly improved PTV homogeneity. The mean doses of ipsilateral OARs were comparable between the two techniques with minor increase of the low-dose spread in the range 2-15 Gy (few % volume); contralateral OARs were slightly better spared with ViTAT. CONCLUSION ViTAT dose distributions were similar to tangential-fields. ViTAT should allow automatic plan optimization by developing knowledge-based DVH prediction models of patients treated with tangential-fields.
Collapse
Affiliation(s)
| | - Roberta Castriconi
- Medical Physics, San Raffaele Hospital Scientific Institute, Milan, Italy
| | - Paola Mangili
- Medical Physics, San Raffaele Hospital Scientific Institute, Milan, Italy
| | - Andrei Fodor
- Radiotherapy, San Raffaele Hospital Scientific Institute, Milan, Italy
| | - Marcella Pasetti
- Radiotherapy, San Raffaele Hospital Scientific Institute, Milan, Italy
| | - Nadia G Di Muzio
- Radiotherapy, San Raffaele Hospital Scientific Institute, Milan, Italy
| | | | - Claudio Fiorino
- Medical Physics, San Raffaele Hospital Scientific Institute, Milan, Italy.
| |
Collapse
|