High Dose Rate Brachytherapy Research Articles

PPP02 Presentation Time: 10:39 AM: Comparison of the Efficiency of Two Modes of High-Dose Rate Brachytherapy: One or Two Fractions?

PPP02 Presentation Time: 10:39 AM: Comparison of the Efficiency of Two Modes of High-Dose Rate Brachytherapy: One or Two Fractions?

PO0120: Implementation of Titanium Tandem and Ovoid Solid Models in CT- and MR-Based Planning of HDR Brachytherapy for Cervical Cancer

PO0120: Implementation of Titanium Tandem and Ovoid Solid Models in CT- and MR-Based Planning of HDR Brachytherapy for Cervical Cancer

Thursday, July 11, 20245:00 PM - 6:00 PMMSOR1 Presentation Time: 5:00 PM: Biological Characterization of Cervical Cancer Response to Treatment with Clinical HDR Brachytherapy and EBRT Using a Novel 3D Printed Platform

Thursday, July 11, 20245:00 PM - 6:00 PMMSOR1 Presentation Time: 5:00 PM: Biological Characterization of Cervical Cancer Response to Treatment with Clinical HDR Brachytherapy and EBRT Using a Novel 3D Printed Platform

PO0104: Advancing CT Based GYN HDR Brachytherapy with Automatic Deep Learning Based Segmentation Tool

PO0104: Advancing CT Based GYN HDR Brachytherapy with Automatic Deep Learning Based Segmentation Tool

GSOR03 Presentation Time: 5:10 PM: Using Virtual Reality Technology to Improve Patient Experience and Reduce Opioids Use During HDR Brachytherapy for Patients with Gynecological Cancer

GSOR03 Presentation Time: 5:10 PM: Using Virtual Reality Technology to Improve Patient Experience and Reduce Opioids Use During HDR Brachytherapy for Patients with Gynecological Cancer

PHSOR12 Presentation Time: 9:55 AM: A Novel Method for Validation of MR/TRUS Deformable Registration for Real-Time Needle Guidance in Gynecological HDR Brachytherapy

PHSOR12 Presentation Time: 9:55 AM: A Novel Method for Validation of MR/TRUS Deformable Registration for Real-Time Needle Guidance in Gynecological HDR Brachytherapy

PO0426: Novel Approach to Optimizing Dosimetry of Ultrasound Based HDR Brachytherapy Treatment of Prostate Cancer: Proof of Concept Report

PO0426: Novel Approach to Optimizing Dosimetry of Ultrasound Based HDR Brachytherapy Treatment of Prostate Cancer: Proof of Concept Report

PO0311: Clinical Outcome Modelling Indicates Minimum Dose to be a Good Predictor in Evaluating Cervical Cancer HDR Brachytherapy Plans

PO0311: Clinical Outcome Modelling Indicates Minimum Dose to be a Good Predictor in Evaluating Cervical Cancer HDR Brachytherapy Plans

PO0411: Retrospective Analysis of Patients Treated with HDR Brachytherapy for Prostate Cancer

PO0411: Retrospective Analysis of Patients Treated with HDR Brachytherapy for Prostate Cancer

The dosimetric accuracy of a commercial model-based dose calculation algorithm in modeling a six-groove direction modulated brachytherapy tandem applicator

Objective.With advancements in high-dose rate brachytherapy, the clinical translation of intensity modulated brachytherapy (IMBT) innovations necessitates utilization of model-based dose calculation algorithms (MBDCA) for accurate and rapid dose calculations. This study uniquely benchmarks a commercial MBDCA, BrachyVision ACUROSTM(BVA), against Monte Carlo (MC) simulations, evaluating dose distributions for a novel IMBT applicator, termed as thesix-grooveDirection Modulated Brachytherapy (DMBT) tandem, expanding beyond previous focus on partially shielded vaginal cylinder applicators, through a novel methodology.Approach.The DMBT tandem applicator, made of a tungsten alloy with six evenly spaced grooves, was simulated using the GEANT4 MC code. Subsequently, two main scenarios were created using the BVA and reproduced by the MC simulations: 'Source at the Center of the Water Phantom (SACWP)' and 'Source at the Middle of the Applicator (SAMA)' for three cubical virtual water phantoms (20 cm)3, (30 cm)3, and (40 cm)3. A track length estimator was utilized for dose calculation and 2D/3D scoring were performed. The difference in isodose surfaces/lines (i.e. coverage) at each voxel,ΔDIsodose Levels/Lines, was thus calculated for relevant normalization points (rref).Results.The coverage was comparable, based on 2D scoring, between the BVA and MC isodose surfaces/lines for the region of clinical relevance, (i.e. within 5 cm radius from the source) withΔDIsodose Lines(rref: 1 cm from the source) falling within 2% for the two scenarios for all phantom sizes. For the phantom (20 cm)3,ΔDIsodose Levels(3D scoring) recorded the range [-3.0% +6.5%] ([-7.4% +7.3%]) for 95% of the voxels of the same scoring volume for the SACWP (SAMA) scenario.Significance.The results indicated that the BVA could render comparable coverage as compared to the MC simulations in the region of clinical relevance for different phantom sizes.ΔDIsodose Linesmay offer an advantageous metric for evaluation of MBDCAs in clinical setting.

The Australian paediatric brachytherapy experience: A pathway to a national programme.

Paediatric cancers are rare, and most children requiring radiation therapy receive external beam radiation (EBRT). Although EBRT may offer organ preservation compared to surgery, it can be associated with significant late effects. Image-guided brachytherapy is a highly specialised technique offering both organ preservation and dose conformity to minimise late toxicity. This is a retrospective mono-institutional review of paediatric brachytherapy in one of the largest paediatric centres in Australia. Outcomes and toxicities are presented as well as brachytherapy versus proton plan comparison in four patients. A total of 14 patients were treated with adjuvant brachytherapy between 2012 and 2022. The predominant histology was rhabdomyosarcoma, and all patients had pelvic tumours. High-dose rate (HDR) brachytherapy was given for 13 patients with one patient receiving low-dose rate (LDR) brachytherapy. Only one grade three late toxicity was reported and two patients developed metastatic disease within one year of completion of treatment. The brachytherapy plan was superior to protons in two of four patients and equivocal in one patient. This is the first Australian publication of a paediatric brachytherapy series from a single institution. This retrospective series demonstrates the feasibility and safety of brachytherapy in paediatric pelvic tumours. The initial work presented here demonstrates the value of a comprehensive radiation plan review in selecting the optimal modality for an individual paediatric patient.

A new insight on the effects of Schiff Base Iron (III) complexes in breast cancer cells for clinical radiotherapy

PurposeBreast cancer is a significant global health concern, and researchers strive to enhance radiotherapy outcomes while minimizing the side effects. Schiff Base Iron (III) Complexes are one of the prospective elements that can be used as radiosensitizer or radioprotective agents in cancer radiotherapy. This study investigates the potential effects of Schiff base (ligand 2; L2) with Fe(III) in MCF-7 breast cancer cells under clinical radiotherapy treatment. MethodsThe effects of the Schiff Base Iron (III) Complexes were measured using clonogenic assay with MCF-7 breast cancer cells. The cells were irradiated with megavoltage 6 MV photon, 6 MeV electron and high dose rate (HDR) brachytherapy with 192Ir source at different doses. Intercellular localization of Fe(III)-L2 complexes and antioxidant activities were also investigated. ResultsThe Fe(III)-L2 complexes were observed to be internalized by cellular nuclei without any effects on the cells. Interestingly, the Fe(III)-L2 complexes indicate radioprotective effects which provide intriguing insight towards application of metal ions complexes as radioprotector in cancer radiotherapy. The Fe(III)-L2 complexes also exhibit scavenging activities of free radical which further proved the antioxidative properties and radioprotective effects. ConclusionThe Fe(III)-L2 complexes show the radioprotective effects and antioxidant properties in MCF-7 cells, particularly for HDR brachytherapy. The findings suggest potential applications of the Fe(III)-L2 complexes as radioprotector agents in clinical radiotherapy.

Retrospective assessment of HDR brachytherapy dose calculation methods in locally advanced cervical cancer patients: AcurosBV vs. AAPM TG43 formalism.

This retrospective analysis was completed to investigate the use of a model-based dose calculation algorithm (MBDCA) AcurosBV, for use in HDR BT treatments for locally advanced cervical cancer treated with tandem and ovoid applicators with interstitial needles. A cohort of 32 patients receiving post-EBRT HDR brachytherapy boost with a prescription dose of 5.5Gy × 5 fractions to the high-risk clinical target volume (CTVHR) were selected for this study. For standard TG43 dose calculation, applicators were manually digitized on the planning images, while for AcurosBV calculations, solid renderings of Titanium Fletcher Suite Delclos (FSD) applicators included in BrachyVision were matched to those used clinically and Ti needles were manually digitized. The dose was recalculated using Varian's AcurosBV 13.5 and dose-to-medium-in-medium (Dm,m) was reported. EQD2 values for targets and organs at risk were compared between dose calculation formalisms. D90% and D98% values were reported for the high and intermediate-risk CTVs, and values were reported for OARs including bladder, rectum, sigmoid, bowel, and vagina. Due to variability within the patient cohort, the dosimetric impact of AcurosBV was investigated corresponding to planning image modality (CT vs. CBCT), presence of Ti needles, and contrast within vaginal balloons used to stabilize implants. AcurosBV showed lower dosimetric values for all plans compared to TG43. The average±standard deviation of dosimetric reduction in D90% was 4.33±0.09% for CTVHR and 4.12±0.09% for CTVIR. The reduction to OARs was: 4.99±0.15% for bladder, 7.87±0.16% for rectum, 5.79±0.17% for sigmoid, 6.91±0.14% for bowel, and 4.55±0.14% for vagina. AcurosBV should be utilized for HDR BT GYN cases, treated with tandem and ovoid applicators, with high degrees of heterogeneity and calculated in tandem with TG43.

Plaque Radiotherapy for Ocular Melanoma

Plaque radiotherapy is an effective treatment modality for medium-sized ocular tumors such as uveal melanoma. The authors review the available literature and concisely summarize the current state of the art of ophthalmic plaque brachytherapy. The choice of radioisotope, which includes Ruthenium-106 and Iodine-125, depends on the intended treatment duration, tumor characteristics, and side effect profiles. Ophthalmic plaques may be customized to allow for the delivery of a precise radiation dose by adjusting seed placement and plaque shape to minimize collateral tissue radiation. High dose rate (HDR) brachytherapy, using beta (e.g., Yttrium-90) and photon-emitting sources (e.g., Ytterbium-169, Selenium-75), allows for rapid radiation dose delivery, which typically lasts minutes, compared to multiple days with low-dose plaque brachytherapy. The efficacy of Ruthenium-106 brachytherapy for uveal melanoma varies widely, with reported local control rates between 59.0% and 98.0%. Factors influencing outcomes include tumor size, thickness, anatomical location, and radiation dose at the tumor apex, with larger and thicker tumors potentially exhibiting poorer response and a higher rate of complications. Plaque brachytherapy is effective for selected tumors, particularly uveal melanoma, providing comparable survival rates to enucleation for medium-sized tumors. The complications of plaque brachytherapy are well described, and many of these are treatable.

Proof-of-concept of real-time electromagnetic guidance for gynecologic interstitial catheters in high dose rate brachytherapy

Background and PurposeThe addition of interstitial needles to intracavitary gynecologic (GYN) high dose rate (HDR) brachytherapy has been shown to improve target coverage and organs-at-risk (OAR) sparing. However, no commercial solution allows real-time guidance of interstitial catheter placement. This phantom study aimed to evaluate the feasibility of an electromagnetic (EM) tracking system guidance workflow for GYN HDR brachytherapy treatment in a magnetic resonance imaging (MRI) and real-time transrectal ultrasound (TRUS) fusion scenario. Materials and MethodsA clinical investigational system combining a treatment planning system and the EM tracking technology was used. The 3D T2 weighted magnetic resonance (MR) image set of a patient treated with intracavitary and interstitial HDR brachytherapy was retrospectively chosen. The MR image set was used to delineate the target and the OARs. A preplan was generated to determine needles positions in advance. The implant was reproduced in a water phantom. A 3D TRUS scan was acquired, and a rigid registration between the MR and the TRUS images was performed. ResultsThe accuracy of the EM tracking system was < 1 mm for both the sagittal and the transverse modes of the TRUS probe. Contours that were delineated on the MRI were propagated on the TRUS images after the rigid registration. Needle insertion was successfully guided in real time with the EM tracking system on the TRUS live image using the MRI contours for guidance. ConclusionBased on this proof-of-concept, real-time EM-guidance of interstitial needle for GYN HDR brachytherapy appears to be feasible.

High dose rate brachytherapy for lip cancer with interstitial, surface, or a combination of interstitial and surface mold technique

High-dose-rate brachytherapy (HDR-BT) is now becoming more common than low-dose-rate and pulsed-dose-rate BT in the treatment of lip cancer. However, due to the limited history of HDR-BT, relatively few studies have been published. Two institutions (in Ukraine and the USA) reviewed their clinical outcomes of lip cancer patients treated with HDR-BT as monotherapy or in combination with external beam radiotherapy (EBRT). An interstitial (IS), surface custom mold (SC), or a combination of IS and SC (IS+SC) was used for treatments based on the depth of tumor invasion. Prescription doses were 24 Gy in 6 BID fractions when combined with 46-50 Gy of EBRT, 45-55 Gy in 9-10 BID fractions for IS and IS+SC monotherapy or 3 Gy × 16 daily fractions for SC monotherapy. A total of 33 cases of lip cancer were treated from 2015 to 2021. By using TNM staging classification, there were 14 stage I (42.4%), 15 stage II (45.5%), and 4 stage III (12.1%) lip cancers. Thirty-one patients (93.9%) had a complete response to the treatment. Only 2 patients (6.1%) displayed local recurrence. Grade 1, 2, and 3 acute toxicities were observed in 30.3%, 51.5%, and 18.2% of patients, respectively. Grade 1, 2, and 3 late toxicities were observed in 39.4%, 21.2%, and 0.0% of cases. Cosmetic results were excellent in 21.2%, good in 54.5%, fair in 18.2%, and poor in 6.1% of patients. HDR-BT is an effective and safe treatment for lip carcinomas with excellent local control, functional, and cosmetic outcomes and should be considered as a standard treatment.

A pilot study to evaluate the combination of surgery and brachytherapy for local tumor control in young children with perianal rhabdomyosarcoma

BackgroundPerianal rhabdomyosarcoma ((P)RMS) are rare and have a poor prognosis. Data in young children are limited and local therapy is not well defined. Combined brachytherapy and surgery is routinely being used for RMS at other sites in children as it provides good oncologic outcomes and allows for organ-sparing surgery. The objective of this study was to evaluate this combination treatment for local tumor control and organ-sparing surgery in young children with (P)RMS. MethodsA retrospective review of the medical records of all children who underwent surgery and brachytherapy for (P)RMS at our institution since 2009 was conducted. ResultsSurgery for (P)RMS was performed in 6 patients at a median age of 19 months (range 8–50). Embryonal RMS was diagnosed in 4 patients and alveolar RMS in 2 patients, of which 1 patient had FOXO1 fusion-positive RMS. All patients underwent postoperative high-dose rate (HDR) brachytherapy. Organ-preserving surgery was achieved in 5 of 6 patients (83 %). In 1 patient, the entire sphincter was infiltrated, making organ-preserving resection impossible. 5 of 6 patients (83 %) exhibited an event-free and overall survival at a median follow-up of 26 months (range 8–107). One patient died due to locoregional recurrence. Complications were urethral leakage in 1 patient followed by urethral stenosis and delayed wound healing and vaginal stenosis in another patient. No patient reported fecal incontinence. ConclusionsCombined treatment with surgery and HDR brachytherapy is feasible in very young children with (P)RMS and leads to a favorable oncologic outcome. Preliminary data show a good functional preservation.

Systematic review and recommendations for re-irradiation for intraprostatic radiorecurrent prostate cancer after definitive radiation therapy.

Intraprostatic recurrence (IRR) of prostate cancer after radiation therapy is increasingly identified. Our objective was to review the literature to determine the optimal workup for identifying IRR, the management options, and practical considerations for the delivery of re-irradiation as salvage local therapy. We performed a systematic review of available publications and ongoing studies on the topics of IRR, with a focus on salvage re-irradiation. Work up of biochemically recurrent prostate cancer includes PSMA PET/CT and multiparametric MRI, followed by biopsy to confirm IRR. Management options include continued surveillance, palliative hormonal therapy, and salvage local therapy. Salvage local therapy can be delivered using re-irradiation with low dose rate brachytherapy, high dose rate (HDR) brachytherapy, and stereotactic body radiotherapy (SBRT), as well as non-radiation modalities, such as cryotherapy, high-intensity focused ultrasound, irreversible electroporation and radical prostatectomy. Data demonstrate that HDR brachytherapy and SBRT have similar efficacy compared to the other salvage local therapy modalities, while having more favorable side effect profiles. Recommendations for radiation therapy planning and delivery using HDR and SBRT based on the available literature are discussed. Salvage re-irradiation is safe and effective and should be considered in patients with IRR.

Comprehensive commissioning of a cone beam CT imaging ring for treatment of HDR GYN patients

PurposeA new mobile cone beam computed tomography (CBCT) imaging ring (IRm, Elekta, v2.10.6, Veenendaal, Netherlands) has recently been proposed for brachytherapy to improve procedure efficiency. We describe the commissioning process and end-to-end tests for GYN HDR brachytherapy employing IRm CBCT imaging. Materials and MethodsCommissioning included imaging isocenter test, 3D image quality, 2D imaging quality, image dose, and tube characteristics. CIRS HDR GYN phantom and Venezia CT/MR gynecological applicator were used to perform end-to-end (E2E) tests and optimize workflow. Venezia applicator and four interstitial needles were inserted into the phantom and IRm CBCT images were acquired. Phantom and applicator were scanned with CT scanner (Siemens SOMATOM go.Open Pro) using department's pelvis imaging protocol. MR imaging was performed using 0.35T MR Linac TRUFI pulse sequence. CBCT images were registered to CT and MR using rigid registration to assess image quality and applicator geometry fidelity. ResultsAll physics tests passed within acceptance tolerances. Registration of CBCT images to MR and CT scans was acceptable for applicator placement. Applicator registration of CBCT images to CT demonstrated excellent agreement of most distal source dwell position (<1 mm). Slice thickness was also measured to be 1.25 mm, within 0.5 mm of its nominal value. ConclusionBased on E2E and commissioning results, IRm is an appropriate tool for brachytherapy treatment planning. This study demonstrated good image quality in GYN phantom and Venezia applicator using the IRm. Distal source dwell position agreement between CBCT and CT was acceptable for clinical use.

70 Retrospective Analysis of Patients Treated with HDR Brachytherapy for Prostate Cancer

70 Retrospective Analysis of Patients Treated with HDR Brachytherapy for Prostate Cancer