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Dong YC, Nieves LM, Hsu JC, Kumar A, Bouché M, Krishnan U, Mossburg KJ, Saxena D, Uman S, Kambayashi T, Burdick JA, Kim MM, Dorsey JF, Cormode DP. Novel Combination Treatment for Melanoma: FLASH Radiotherapy and Immunotherapy Delivered by a Radiopaque and Radiation Responsive Hydrogel. CHEMISTRY OF MATERIALS : A PUBLICATION OF THE AMERICAN CHEMICAL SOCIETY 2023; 35:9542-9551. [PMID: 38933522 PMCID: PMC11198981 DOI: 10.1021/acs.chemmater.3c01390] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/28/2024]
Abstract
Immunotherapies have become the standard treatment for melanoma. To further improve patient responses, combinations of immunotherapies and radiotherapy (RT) are being studied, since radiotherapies can potentially provide additional immune stimulation, in addition to direct antitumor effects. FLASH-RT is a novel, ultrahigh dose rate, radiation delivery approach, with the potential of at least equivalent tumor control efficacy and reduced damage to healthy tissue. However, the effects of combining FLASH-RT and immunotherapy have not been extensively studied in melanoma. Toll-like receptor (TLR) agonists, such as imiquimod (IMQ), are potent immunostimulatory agents, although their utility is limited due to poor solubility and systemic side effects. We therefore developed a novel combination therapy for melanoma consisting of IMQ delivered to the tumor via a radiopaque and radiation responsive hydrogel combined with FLASH-RT. We found that FLASH was able to effectively stimulate IMQ release from the hydrogel. In addition, we found that the combination of FLASH and released IMQ resulted in synergistic melanoma cell killing in vitro. The combination therapy reduced tumor growth compared to controls, enhanced survival, and resulted in remarkable enhancements in certain tumor cytokine levels. CT imaging allowed the hydrogel to be monitored in vivo. In addition, no adverse effects of the treatment were observed. Overall, this IMQ-gel and FLASH-RT combination may have potential as an improved treatment for melanoma and indicates that the interactions of FLASH-RT and TLR agonists merit further study.
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Affiliation(s)
- Yuxi C Dong
- Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States; Department of Bioengineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - Lenitza M Nieves
- Department of Biochemistry and Molecular Biophysics, Perelman School of Medicine of the University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - Jessica C Hsu
- Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States; Department of Bioengineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - Ananyaa Kumar
- Department of Bioengineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | | | - Uma Krishnan
- Department of Radiation Oncology, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - Katherine J Mossburg
- Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States; Department of Bioengineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - Deeksha Saxena
- Department of Radiation Oncology, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - Selen Uman
- Department of Bioengineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - Taku Kambayashi
- Department of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - Jason A Burdick
- Department of Bioengineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States; Department of Chemical and Biological Engineering, University of Colorado Boulder, Boulder, Colorado 80303, United States
| | - Michele M Kim
- Department of Radiation Oncology, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - Jay F Dorsey
- Department of Radiation Oncology, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - David P Cormode
- Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States; Department of Bioengineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
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Riberdy V, Ruiz E, Hoekstra N, Struik G, Pignol JP. Comparison of visibility of iodinated hydrogel and gadolinium-modified hyaluronic acid spacer gels on computed tomography and onboard imaging. Phys Imaging Radiat Oncol 2022; 21:48-53. [PMID: 35243031 PMCID: PMC8861832 DOI: 10.1016/j.phro.2022.02.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Revised: 02/10/2022] [Accepted: 02/11/2022] [Indexed: 11/18/2022] Open
Abstract
Background and purpose In accelerated partial breast irradiation (APBI), accurate definition of the tumour bed is crucial to reduce the risk of local recurrence and the volume of healthy tissue irradiated. Recently, hydrogels have been proposed to improve visibility of the lumpectomy cavity for APBI. The aim of this study was to alter two commercially available hyaluronic acid (HA) gels, with gadopentenate dimeglumine (GD), a magnetic resonance imaging (MRI) contrast agent. We hypothesize that after injection in the surgical cavity, the mixtures will be visible with computed tomography (CT) for improved treatment planning, cone-beam CT (CBCT) for improved patient setup and planar kilovoltage (kV) x-ray for real-time tracking during treatment. Materials and methods In this ex vivo study, GD was mixed with the two HA gels, and 1 mL of each mixture was injected into fatty and muscular tissue of a pork phantom. Visibility with CT, CBCT and planar x-ray imaging was assessed. Contrast-to-noise ratios (CNR) were measured and compared to commercially available iodinated polyethylene glycol (PEG). Results The gel mixtures showed increased visibility over HA gels without GD. When comparing CNR of the gel mixtures to that of iodinated PEG on CT, there was a 4-fold increase in muscle for both mixtures and a 1.6-fold to 3.6-fold increase in fat, depending on the HA gel. Gel mixtures showed better visibility with planar kV imaging over iodinated PEG. Conclusion Addition of GD to HA gels increases visibility with CT, CBCT and planar x-ray imaging, indicating potential for improved delineation and positioning in APBI.
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Affiliation(s)
- Vlora Riberdy
- Department of Physics and Atmospheric Science, Dalhousie University, Halifax, NS, Canada
- Corresponding author at: Department of Medical Physics, 5820 University Ave., Halifax, NS B3H 1V7, Canada.
| | - Ethan Ruiz
- Department of Physics and Atmospheric Science, Dalhousie University, Halifax, NS, Canada
| | - Nienke Hoekstra
- Department of Radiation Oncology, Erasmus MC Cancer Institute, Rotterdam, The Netherlands
| | - Gerson Struik
- Department of Surgery, Franciscus Gasthuis and Vlietland, Rotterdam, The Netherlands
- Department of Surgery, Erasmus MC Cancer Institute, Rotterdam, The Netherlands
| | - Jean-Philippe Pignol
- Department of Physics and Atmospheric Science, Dalhousie University, Halifax, NS, Canada
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Gladwish A, Didiodato G, Conway J, Stevens C, Follwell M, Tam T, Mclean J, Hanrahan R. Implications of Oncoplastic Breast Surgery on Radiation Boost Delivery in Localized Breast Cancer. Cureus 2021; 13:e20003. [PMID: 34984151 PMCID: PMC8715955 DOI: 10.7759/cureus.20003] [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] [Accepted: 11/29/2021] [Indexed: 11/23/2022] Open
Abstract
Background Oncoplastic partial mastectomy (OPM) is a technique utilized to improve aesthetic and survivorship outcomes in patients with localized breast cancer. This technique leads to breast tissue rearrangement, which can have an impact on target definition for boost radiotherapy (BRT). The aim of this study was to determine if the choice of surgical technique independently affected the decision to deliver a radiation boost. Materials and methods This was a retrospective study of patients treated between January 2017 and December 2018. We selected consecutive patients based on surgical procedure: 50 undergoing standard breast-conserving surgery and 50 having had an OPM. The primary outcome was average treatment effect (ATE) of surgery type on reception of BRT. Secondary outcomes included ATE of surgery type on the time to reception of radiotherapy and incidence of ipsilateral breast tumor recurrence (IBTR). The ratio of boost clinical target volume (CTV) to pathologic tumor size was also compared between the two groups. Treatment effects regression adjustment and inverse-probability weighted analysis was used to estimate ATEs for both primary and secondary outcomes. Results For the entire cohort, the median age was 64 years (range: 37-88 years). The median tumor size was 1.5 cm (range: 0.1-6.5 cm). The majority of patients were with ≤ stage IIA (78%), invasive ductal subtype (80%), negative lymphovascular space invasion (78%), negative margin (90%), and positive ER/PR (estrogen receptor/progesterone receptor) (69%). Overall, surgical technique was not associated with differences in the proportion of patients receiving BRT (ATE: 6.0% [95% CI: -4.5 to 16.0]). There were no differences in delays to radiation treatment between the two groups (ATE: 32.8 days [95% CI: -22.1 to 87.7]). With a median follow-up time of 419 days (range: 30-793 days), there were only five recurrences, with one case of IBTR in each group. There was no difference in the ratio of CTV volume to tumor size between the two groups (p=0.38). Conclusions OPM did not affect the decision to offer localized BRT following standard whole breast radiotherapy or significantly affect treatment times or radiation volumes. The decision to offer OPM should include a multi-disciplinary approach.
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Dong YC, Bouché M, Uman S, Burdick JA, Cormode DP. Detecting and Monitoring Hydrogels with Medical Imaging. ACS Biomater Sci Eng 2021; 7:4027-4047. [PMID: 33979137 PMCID: PMC8440385 DOI: 10.1021/acsbiomaterials.0c01547] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Hydrogels, water-swollen polymer networks, are being applied to numerous biomedical applications, such as drug delivery and tissue engineering, due to their potential tunable rheologic properties, injectability into tissues, and encapsulation and release of therapeutics. Despite their promise, it is challenging to assess their properties in vivo and crucial information such as hydrogel retention at the site of administration and in situ degradation kinetics are often lacking. To address this, technologies to evaluate and track hydrogels in vivo with various imaging techniques have been developed in recent years, including hydrogels functionalized with contrast generating material that can be imaged with methods such as X-ray computed tomography (CT), magnetic resonance imaging (MRI), optical imaging, and nuclear imaging systems. In this review, we will discuss emerging approaches to label hydrogels for imaging, review the advantages and limitations of these imaging techniques, and highlight examples where such techniques have been implemented in biomedical applications.
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Affiliation(s)
- Yuxi C Dong
- Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
- Department of Bioengineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - Mathilde Bouché
- Université de Lorraine, CNRS, L2CM UMR 7053, F-54000 Nancy, France
| | - Selen Uman
- Department of Bioengineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - Jason A Burdick
- Department of Bioengineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - David P Cormode
- Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
- Department of Bioengineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
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Struik GM, Schermers B, Mares I, Lont HE, Bradshaw JW, Ten Haken B, Ruers TJM, Mourik JEM, Birnie E, Klem TMAL. Randomized controlled trial comparing magnetic marker localization (MaMaLoc) with wire-guided localization in the treatment of early-stage breast cancer. Breast J 2021; 27:638-650. [PMID: 34142409 DOI: 10.1111/tbj.14262] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Revised: 05/23/2021] [Accepted: 05/24/2021] [Indexed: 11/29/2022]
Abstract
Wire-guided localization (WGL) is the standard of care in the surgical treatment of nonpalpable breast tumors. In this study, we compare the use of a new magnetic marker localization (MaMaLoc) technique to WGL in the treatment of early-stage breast cancer patients. Open-label, single-center, randomized controlled trial comparing MaMaLoc (intervention) to WGL (control) in women with early-stage breast cancer. Primary outcome was surgical usability measured using the System Usability Scale (SUS, 0-100 score). Secondary outcomes were patient reported, clinical, and pathological outcomes such as retrieval rate, operative time, resected specimen weight, margin status, and reoperation rate. Thirty-two patients were analyzed in the MaMaLoc group and 35 in the WGL group. Patient and tumor characteristics were comparable between groups. No in situ complications occurred. Retrieval rate was 100% in both groups. Surgical usability was higher for MaMaLoc: 70.2 ± 8.9 vs. 58.1 ± 9.1, p < 0.001. Patients reported higher overall satisfaction with MaMaLoc (median score 5/5) versus WGL (score 4/5), p < 0.001. The use of magnetic marker localization (MaMaLoc) for early-stage breast cancer is effective and has higher surgical usability than standard WGL.
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Affiliation(s)
- Gerson M Struik
- Department of Surgery, Franciscus Gasthuis and Vlietland, Rotterdam, The Netherlands
| | - Bram Schermers
- Department of Surgery, The Netherlands Cancer Institute, Amsterdam, The Netherlands.,Technical Medical Centre, University of Twente, Enschede, The Netherlands
| | - Ingeborg Mares
- Department of Surgery, Franciscus Gasthuis and Vlietland, Rotterdam, The Netherlands
| | - Harold E Lont
- Department of Surgery, Franciscus Gasthuis and Vlietland, Rotterdam, The Netherlands
| | - Jennifer W Bradshaw
- Department of Radiology, Franciscus Gasthuis and Vlietland, Rotterdam, The Netherlands
| | - Bernard Ten Haken
- Technical Medical Centre, University of Twente, Enschede, The Netherlands
| | - Theo J M Ruers
- Department of Surgery, The Netherlands Cancer Institute, Amsterdam, The Netherlands.,Technical Medical Centre, University of Twente, Enschede, The Netherlands
| | - Jurgen E M Mourik
- Department of Medical Physics, Franciscus Gasthuis and Vlietland, Rotterdam, The Netherlands
| | - Erwin Birnie
- Department of Statistics and Education, Franciscus Gasthuis and Vlietland, Rotterdam, The Netherlands.,Department of Genetics, University Medical Centre Groningen, University of Groningen, Amsterdam, The Netherlands
| | - Taco M A L Klem
- Department of Surgery, Franciscus Gasthuis and Vlietland, Rotterdam, The Netherlands
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Steybe D, Russe MF, Ludwig U, Sprave T, Vach K, Semper-Hogg W, Schmelzeisen R, Voss PJ, Poxleitner P. Intraoperative marking of the tumour resection surface for improved radiation therapy planning in head and neck cancer: preclinical evaluation of a novel liquid fiducial marker. Dentomaxillofac Radiol 2021; 50:20200290. [PMID: 32915672 DOI: 10.1259/dmfr.20200290] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
OBJECTIVE To evaluate a novel liquid fiducial marker for intraoperative marking of the tumour resection surface in oral cancer patients to facilitate precise postoperative delineation of the interface between the tumour resection border and reconstructed tissue for intensity-modulated radiation therapy. METHODS A total of 200 markers were created by injecting the volumes of 10 µl, 20 µl, 30 µl, 40 µl and 50 µl of a liquid marker composed of sucrose acetoisobutyrate (SAIB) and iodinated sucrose acetoisobutyrate (x-SAIB) into the soft tissue of porcine mandible segments. Visibility of the resulting markers was quantified by threshold-based segmentation of the marker volume in CT- and CBCT imaging and by a comparison of signal intensities in MRI. RESULTS Even the lowest volume of SAIB-/x-SAIB investigated (10 µl) resulted in a higher visibility (CTSoft tissue: 88.18 ± 13.23 µl; CTBone: 49.55 ± 7.62 µl; CBCT: 54.65 ± 12.58 µl) than observed with the incorporation of titanium ligature clips (CTSoft tissue: 50.15 ± 7.50 mm3; CTBone: 23.90 ± 3.39 mm3; CBCT: 33.80 ± 9.20 mm3). Markers created by the injection of 10 µl and 20 µl could reliably be delineated from markers created by the injection of higher volumes. CONCLUSION SAIB/x-SAIB, which has recently become available as a Conformité Européenne (CE)-marked fiducial marker, provides an option for fast and reliable production of markers with excellent visibility in imaging modalities used in oral cancer radiation therapy (RT) planning routine.
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Affiliation(s)
- David Steybe
- Department of Oral and Maxillofacial Surgery, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Maximilian Frederik Russe
- Department of Diagnostic and Interventional Radiology, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Ute Ludwig
- Medical Physics, Department of Radiology, Faculty of Medicine, Medical Center - University of Freiburg, University of Freiburg, Freiburg, Germany
| | - Tanja Sprave
- Department of Radiation Oncology, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Kirstin Vach
- Institute of Medical Biometry and Statistics, Faculty of Medicine and Medical Center - University of Freiburg, Freiburg, Germany
| | - Wiebke Semper-Hogg
- Department of Oral and Maxillofacial Surgery, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Rainer Schmelzeisen
- Department of Oral and Maxillofacial Surgery, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Pit Jacob Voss
- Department of Oral and Maxillofacial Surgery, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Philipp Poxleitner
- Department of Oral and Maxillofacial Surgery, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany.,Berta-Ottenstein-Programme for Clinician Scientists, Faculty of Medicine, University of Freiburg, Freiburg, Germany
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O'Connor RÍ, Kiely PA, Dunne CP. The relationship between post-surgery infection and breast cancer recurrence. J Hosp Infect 2020; 106:522-535. [PMID: 32800825 DOI: 10.1016/j.jhin.2020.08.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2020] [Accepted: 08/06/2020] [Indexed: 02/06/2023]
Abstract
Breast cancer is the second most prevalent form of cancer in women worldwide, with surgery remaining the standard treatment. The adverse impact of the surgery remains controversial. It has been suggested that systemic factors during the postoperative period may increase the risk of recurrence, specifically surgical site infection (SSI). The aim of this review was to critically appraise current published literature regarding the influence of SSIs, after primary breast cancer surgery, on breast cancer recurrence, and to delve into potential links between these. This systematic review adopted two approaches: to identify the incidence rates and risk factors related to SSI after primary breast cancer surgery; and, secondly, to examine breast cancer recurrence following SSI occurrence. Ninety-nine studies with 484,605 patients were eligible in the SSI-focused searches, and 53 studies with 17,569 patients for recurrence-focused. There was a 13.07% mean incidence of SSI. Six-hundred and thirty-eight Gram-positive and 442 Gram-negative isolates were identified, with methicillin-susceptible Staphylococcus aureus and Escherichia coli most commonly identified. There were 2077 cases of recurrence (11.8%), with 563 cases of local recurrence, 1186 cases of distant and 25 cases which recurred both locally and distantly. Five studies investigated the association between SSI and breast cancer recurrence with three concluding that an association did exist. In conclusion, there is association between SSI and adverse cancer outcomes, but the cellular link between them remains elusive. Confounding factors of retrospective study design, surgery type and SSI definition make results challenging to compare and interpret. A standardized prospective study with appropriate statistical power is justified.
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Affiliation(s)
- R Í O'Connor
- School of Medicine, University of Limerick, Ireland; Health Research Institute, University of Limerick, Ireland; Bernal Institute, University of Limerick, Ireland
| | - P A Kiely
- School of Medicine, University of Limerick, Ireland; Health Research Institute, University of Limerick, Ireland; Bernal Institute, University of Limerick, Ireland; Centre for Interventions in Infection, Inflammation & Immunity (4i), University of Limerick, Limerick, Ireland
| | - C P Dunne
- School of Medicine, University of Limerick, Ireland; Health Research Institute, University of Limerick, Ireland; Centre for Interventions in Infection, Inflammation & Immunity (4i), University of Limerick, Limerick, Ireland.
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The use of hyaluronic acid hydrogel as a tumour bed marker in breast-conserving therapy. Radiother Oncol 2020; 152:8-13. [PMID: 32738260 DOI: 10.1016/j.radonc.2020.07.041] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2019] [Revised: 07/12/2020] [Accepted: 07/23/2020] [Indexed: 11/23/2022]
Abstract
PURPOSE To evaluate usefulness of hyaluronic acid (HA) hydrogel as a tumour bed marker in breast conserving therapy (BCT). To analyze inter- (Inter-OV) and intraobserver (Intra-OV) variability of contouring boost target volume (CTVboost) in external beam radiotherapy (EBRT). MATERIALS AND METHODS Thirty-two patients in the HA group and 30 patients in the control group with an early stage breast cancer were included in the study. During the surgery 1-3 ml of HA hydrogel was injected into breast to mark the tumour bed for every patient in the HA group. Moreover, surgical clips were placed underneath the lumpectomy cavity. Patients in the control group were marked only by metal markers. Three radiation oncologists delineated CTVboost twice for every patient. Three parameters were calculated to quantify contouring variability: coefficient of variation for volumes (COVV), center of mass displacement (CoMd) and conformity index (CI). RESULTS There were no significant differences between mean values of COVV for HA and control group, neither for Intra-OV (0.14 vs 0.13) nor Inter-OV (0.19 vs 0.18) calculations. The mean CoMd were 6.1 mm and 9.1 mm for Inter-OV calculations and 3.9 mm and 6.4 mm for Intra-OV in the HA and the control group respectively. The mean CI for Intra-OV improved from 0.61 to 0.65 and from 0.47 to 0.56 for Inter-OV in the control and HA group respectively. CONCLUSION HA hydrogel used as a tumour bed marker improves tumour bed visibility and reduces inter- and intraobserver variability of EBRT boost target volume delineations.
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Aldosary G, Tse T, Arnaout A, Caudrelier JM, Czyrnyj C, Romain R, McLean L, Foottit C, Belec J, Vandervoort E. Radiological, dosimetric and mechanical properties of a deformable breast phantom for radiation therapy and surgical applications. Biomed Phys Eng Express 2020; 6:035028. [PMID: 33438673 DOI: 10.1088/2057-1976/ab834a] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The displacement of tumor bed walls during oncoplastic breast surgery (OBS) decreases the accuracy of using surgical clips as the sole surrogate for tumor bed location. This highlights the need for better communication of OBS techniques to radiation oncologists. To facilitate OBS practice and investigate clip placement reliability, a realistic silicone-based breast phantom was constructed with components emulating a breast parenchyma, epidermis, areola, nipple, chest wall, and a tumor. OBS was performed on the phantom and surgical clips were placed to mark the tumor bed. The phantom was imaged with CT, MRI, and ultrasound (US). The parenchyma's signal-to-noise ratio (SNR) and clips to parenchyma's contrast-to-noise ratio (CNR) were measured. The phantom's CT Hounsfield Unit (HU), relative electron density (RED), and mass density were determined. 6 and 10 MV photon beam attenuation measurements were performed in phantom material. The Young's Modulus and ultimate tensile strength (UTS) of the phantom parenchyma and epidermis were measured. Results showed that the breast phantom components were visible on all imaging modalities with adequate SNR and CNR. The phantom's HU is 130 ± 10. The RED is 0.983. Its mass density is 1.01 ± 0.01 g cm-3. Photon attenuation measurements in phantom material were within 1% of those in water. The Young's Moduli were 13.4 ± 4.2 kPa (mechanical) and 30.2 ± 4.1 kPa (US elastography) for the phantom parenchyma. The UTS' were 0.05 ± 0.01 MPa (parenchyma) and 0.23 ± 0.12 MPa (epidermis). We conclude that the phantom's imaging characteristics resemble a fibroglandular breast's and allow clear visualization of high-density markers used in radiation therapy. The phantom material is suitable for dose measurements in MV photon beams. Mechanical results confirmed the phantom's similarity to breast tissue. The phantom enables investigation of surgical clip displacements pre- and post-OBS, and is useful for radiation therapy quality assurance applications.
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Affiliation(s)
- Ghada Aldosary
- Department of Physics, Carleton University, Ottawa, Ontario, Canada. Radiation Oncology Section, Department of Oncology, King Abdulaziz Medical City, National Guard Health Affairs, Riyadh, Saudi Arabia
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