Mould Brachytherapy Research Articles

2118: Extra-Mammary Paget's Disease: Initial Experience with Custom 3D printed Surface Mould Brachytherapy

2118: Extra-Mammary Paget's Disease: Initial Experience with Custom 3D printed Surface Mould Brachytherapy

Clinical and toxicity outcomes with 3D based-HDR surface mold brachytherapy in skin cancer.

Surface mold brachytherapy (SMBT) is an established treatment modality in skin cancer, especially in accessible areas, and has shown comparable outcomes to surgery. We have presented our results for the skin tumor treatment with SMBT treated with high-dose-rate (HDR) brachytherapy in terms of clinical outcomes and toxicity at our institute. In this retrospective analysis, 15 patients with skin cancer were treated with customized tube-based SMBT at our institute between January 2019 and July 2021. The patients were treated using HDR-brachytherapy using Iridium-192. The median dose was 40 Gy in 10 fractions. The dosimetric parameters were assessed, and patients were followed up as per the institutional protocol. All patients underwent individualized CT-based planning. Skin toxicity was assessed using the Dermatology Life Quality Index (DLQI). With the majority of the patients being male, the median age was 59 years and the most common site affected was the face (8/15; 53.3%). Among the 15 cases, five were squamous cell carcinoma, nine were basal cell carcinoma, and a single case of sebaceous cell carcinoma. The median depth of invasion was 4 mm, and the median catheter-to-surface distance was 1 mm. The complete response rate among the 10 definitive cases was 90% and partial response in one case. The treatment was well-tolerated with no grade 3-5 toxicities. The median V95% and V90% were 94.8% and 97.1%, respectively. The mean coverage index (C.I.), dose non-uniformity ratio (DNR), and overdose volume index (ODI) were 0.97, 0.13, and 0.05, respectively. After a median follow-up of 12 months, none of the patients had recurrence. On assessment of DLQI, the scores were found to be significant in association with the tumor size and tumor site with scores favoring <2 cm and non-exposed area lesions. SMBT is a safe and effective treatment modality for skin tumors providing excellent response and cosmetic outcomes. It is well-tolerated and a non-invasive option for elderly patients with comorbidities and lesions in inoperable areas.

Evolution of Radiotherapy- A Brief Review

Beginning with the discovery of X-rays by Wilhelm Conrad Röntgen in 1895 and the subsequent application of X-rays for cancer treatment in 1896, the narrative unfolds through the advancements in radiation therapy modalities. The discussion covers External Beam Radiotherapy (EBRT), including various techniques like 3D-CRT, IMRT, IGRT, stereotactic radiotherapy, and proton therapy. Emerging technologies such as Tomotherapy, Stereotactic Radiosurgery (SRS), Boron Neutron Capture Therapy (BNCT), Carbon Ion Therapy, and Brachytherapy are explored, offering tailored approaches for different cancer types. The article delves into the history and advancements of brachytherapy, highlighting its techniques like intracavitary, interstitial, and HDR surface mould brachytherapy. The continuous pursuit of precision, efficacy, and reduced side effects in cancer treatment is evident throughout the narrative. The article emphasizes the crucial role of radiation therapy, employing various ionizing radiation types, in targeting and eradicating cancer cells while minimizing harm to normal cells. The ongoing quest for advancements in technology and techniques reflects the commitment to improving cancer treatment outcomes. This article provides a comprehensive overview of radiation therapy's historical evolution and current state in cancer treatment Keywords: Radiotherapy, EBRT, Brachytherapy, IMRT, SRS, IGRT, Proton therapy

Surface mold brachytherapy for head and neck non-melanoma skin cancer – local control rates and survival: A retrospective analysis

Surface mold brachytherapy for head and neck non-melanoma skin cancer – local control rates and survival: A retrospective analysis

High-dose-rate mold brachytherapy for mandibular gingival squamous cell carcinoma in outpatient setting – Initial case report

High-dose-rate mold brachytherapy for mandibular gingival squamous cell carcinoma in outpatient setting – Initial case report

PO118: Surface Mould Brachytherapy for Extramammory Paget's Disease: Workflow and Initial Experience

PO118: Surface Mould Brachytherapy for Extramammory Paget's Disease: Workflow and Initial Experience

Optimizing surface mould brachytherapy for treatment of nasal basal cell carcinoma using customized applicators

PURPOSESurface mould brachytherapy (SMBT) is ideal in treating superficial skin cancer over the curved surface of the nasal ala. We describe the process of initiating and optimizing SMBT treatment at our institution including clinical workflow, generation of three dimensional (3D) printed custom applicators, and clinical outcomes. METHODS AND MATERIALSPlanning CT scans were used to acquire images for delineating target volumes. The applicator was designed with customized catheter positioning (3–5mm from target) to cover target volume while sparing dose to organs at risk (OAR) such as adjacent skin and nasal mucosa. Applicators were 3D printed, with transparent resin to aid visualization of underlying skin. Dosimetric parameters evaluated included CTV D90, CTV D0.1cc, and D2cc to OARs. Clinical outcomes assessed were local control, acute and late toxicity (Common Terminology Criteria for Adverse Events v5.0 [CTCAEv5.0]), and cosmesis (Radiation Therapy Oncology Group [RTOG]). RESULTSTen patients were treated with SMBT with a median followup of 17.8 months. Dose prescription was 40 Gy in 10 daily fractions. Mean CTV D90 was 38.5 Gy (range 34.7–40.6), mean CTV D0.1cc 49.2 Gy (range 45.6–53.5), which was <140% of the prescription dose in all patients. Treatment was well tolerated, with acceptable Grade 2 acute, Grade 0–1 late skin toxicity, and good-excellent cosmesis for all patients. Two patients experienced local failure, and both underwent surgical salvage. CONCLUSIONSSMBT was successfully planned and delivered for superficial nasal BCC using 3D printed custom applicators. Excellent target coverage was achieved while minimizing dose to OAR. Toxicity and cosmesis rates were good-excellent.

Synthetic cranial MRI from 3D optical surface scans using deep learning for radiation therapy treatment planning

BackgroundOptical scanning technologies are increasingly being utilised to supplement treatment workflows in radiation oncology, such as surface-guided radiotherapy or 3D printing custom bolus. One limitation of optical scanning devices is the absence of internal anatomical information of the patient being scanned. As a result, conventional radiation therapy treatment planning using this imaging modality is not feasible. Deep learning is useful for automating various manual tasks in radiation oncology, most notably, organ segmentation and treatment planning. Deep learning models have also been used to transform MRI datasets into synthetic CT datasets, facilitating the development of MRI-only radiation therapy planning.AimsTo train a pix2pix generative adversarial network to transform 3D optical scan data into estimated MRI datasets for a given patient to provide additional anatomical data for a select few radiation therapy treatment sites. The proposed network may provide useful anatomical information for treatment planning of surface mould brachytherapy, total body irradiation, and total skin electron therapy, for example, without delivering any imaging dose.MethodsA 2D pix2pix GAN was trained on 15,000 axial MRI slices of healthy adult brains paired with corresponding external mask slices. The model was validated on a further 5000 previously unseen external mask slices. The predictions were compared with the “ground-truth” MRI slices using the multi-scale structural similarity index (MSSI) metric. A certified neuro-radiologist was subsequently consulted to provide an independent review of the model’s performance in terms of anatomical accuracy and consistency. The network was then applied to a 3D photogrammetry scan of a test subject to demonstrate the feasibility of this novel technique.ResultsThe trained pix2pix network predicted MRI slices with a mean MSSI of 0.831 ± 0.057 for the 5000 validation images indicating that it is possible to estimate a significant proportion of a patient’s gross cranial anatomy from a patient’s exterior contour. When independently reviewed by a certified neuro-radiologist, the model’s performance was described as “quite amazing, but there are limitations in the regions where there is wide variation within the normal population.” When the trained network was applied to a 3D model of a human subject acquired using optical photogrammetry, the network could estimate the corresponding MRI volume for that subject with good qualitative accuracy. However, a ground-truth MRI baseline was not available for quantitative comparison.ConclusionsA deep learning model was developed, to transform 3D optical scan data of a patient into an estimated MRI volume, potentially increasing the usefulness of optical scanning in radiation therapy planning. This work has demonstrated that much of the human cranial anatomy can be predicted from the external shape of the head and may provide an additional source of valuable imaging data. Further research is required to investigate the feasibility of this approach for use in a clinical setting and further improve the model’s accuracy.

MSS10 Presentation Time: 4:30 PM: Clinical and Toxicity Outcomes with HDR Surface Mould Brachytherapy in Skin Cancer: Indian Experience

<h3>Purpose</h3> Surface Mold Brachytherapy (SMBT) is an established treatment modality in skin cancer especially in accessible areas and provides outcomes comparable to surgery. We present our results for the skin tumor treatment with SMBT treated with High-dose rate (HDR) brachytherapy in terms of clinical outcomes and toxicity at our institute. <h3>Materials and Methods</h3> this retrospective analysis among skin cancer patients with skin tumors treated at our institute between January 2020 to July 2021 were assessed and a total of 15 patients were evaluated. The patient and disease characteristics were assessed and patients were treated using HDR- Surface Mold Brachytherapy using Iridium-192. The median dose was 40Gy in 10 fractions. The dosimetric parameters were assessed and patients were followed-up as per the institutional protocol. All patients underwent individualized CT-based planning. Skin toxicity was assessed using Dermatology Life Quality Index (DLQI). <h3>Results</h3> With majority of the patients being male, the median age was 59 years and most common site being the face (8/15; 53.3%). The histopathology included 7 Squamous cell carcinoma, 6 Basal cell carcinoma and a single case of sebaceous cell carcinoma. The median depth of invasion was 4 mm and median catheter to surface distance was 1 mm. The Complete response rate among the 10 definitive cases was 90% and partial response in one case. The treatment was well-tolerated with no Grade 3-5 toxicities. The median V95% and V90% were 95.42% and 97.37% respectively. The mean Coverage Index (C.I), Dose non-uniformity ratio (DNR) and overdose volume index (ODI) were 0.97, 0.36 and 0.04 respectively. After a median follow-up of 6 months, none of the patients had recurrence. On assessment of DLQI, the scores were found to be significant in association with the tumor size and tumor site with scores favoring <2cm and non-exposed area lesions. <h3>Conclusion</h3> Surface mould brachytherapy is a safe and effective treatment modality for skin tumours providing excellent response and cosmetic outcomes. It is well-tolerated and a non-invasive option for elderly patients with comorbidities and lesions in inoperable areas.

Step-by-Step Guide to Surface Mold Applicator-Based Brachytherapy in a Case of Early Carcinoma Penis: An Organ-Preserving Approach

Purpose In this report we discuss an individually customized surface mold applicator technique to treat a case of early carcinoma penis. This case report is one of its kind which describes the brachytherapy treatment planning based on orthogonal X-ray technique. Material and methods T1N0 disease with squamous cell carcinoma histology involving the foreskin of penis and abutting the glans penis was treated by surface mold applicator technique. Impression of the organ was taken using alginate. Cast was prepared from the impression using Type 4 gypsum. The acrylic mold-based applicator was fabricated on the cast. The catheters were positioned and fixed on the acrylic mold. The organ is placed in the mold-based applicator and the catheters are reconstructed on two-dimensional imaging. The brachytherapy is delivered by the 18-channel high-dose rate Oncentra brachytherapy using Ir192 source. The dose given was 45 Gy in 15 fractions, twice daily more than 6 hours apart. Results Patient was reviewed after 6 weeks for follow-up and there was complete regression of the ulcer. At present, patient is on follow-up for the last 10 months and is now disease-free. Conclusion With judicious patient selection, surface mold brachytherapy is an attractive alternative to the interstitial brachytherapy. It is comfortable for the patient, is easily repeatable, and is time saving in high work load and limited resource settings. Early results with this technique are promising.

A Facile Strategy for Preparation of Yttrium-90 Therapeutic Sources for Radionuclide Therapy.

Background: Mold brachytherapy using high-energy β--emitting radioisotopes is a promising treatment modality for skin cancers and keloids. Simple methodologies for consistent and stable incorporation of radionuclides into the matrix are desired for preparation of therapeutic sources. Methods: The authors report a facile strategy for the stable incorporation of Yttrium-90 (90Y) into amidoxime-functionalized polyacrylonitrile-polyvinylidene fluoride (PAN-PVDF) membranes. The strategy consisted of surface modification of PAN-PVDF membranes by reaction with hydroxylamine, characterization of the functionalized membranes, and optimization of experimental variables for maximum loading of 90Y onto the membranes. Quality control tests essential for confirming the suitability of the 90Y therapeutic sources for human application, such as uniformity of activity distribution, absence of leaching of activity, and estimation of surface contamination, were performed. Theoretical calculations to estimate the dose imparted by the 90Y therapeutic sources at varying depths of tissue were also carried out to predict the possible therapeutic outcome of treatment. Results: A facile method for large-scale preparation of 90Y-based mold brachytherapy sources could be established. Conclusions: The source fabrication methodology standardized in this work could be tailored for fabrication of custom-made 90Y sources for individualized treatment of superficial tumors, Bowen's disease, and keloids.

Effectiveness of surface mould brachytherapy in electron era.

e21562 Background: In India, skin cancers constitute about 1-2% of all diagnosed cancers.Surgery stays main modality of treatment with adequate surgical margin shown excellent local control rates - generally 95%.However, conditions where surgery is not feasible, brachytherapy is alternative approach.Advanced technology improved the ability to deliver safe and effective radiotherapy, resulting in renewed interest in this modality.Brachytherapy has many advantages: they can deposit a significantly higher dose within a tumor, with better sparing of adjacent normal structures over external beam radiotherapy or electron therapy, which sometimes require irradiating a large volume of tissue in order to provide adequately coverage, which in term increase toxicity. The purpose of our paper is to find out the clinical outcomes of skin tumors and superficial tumours of head and neck region treated with Surface mould brachytherapy (SMB), in terms of survival and toxicity.We report on our institution’s experience with using Co-60 based HDR SMB for the treatment of skin and head and neck superficial malignancies. Methods: A retrospective review of all patients treated with surface mould Co-60-based HDR brachytherapy at our center.A total of 23 patients, with 23 lesions, were treated during this period, and included in the analysis. A total of three of these lesions were treated with a palliative intent, and were included. The most common fractionation scheme was 35 Gy in 10 fractions given daily (52%, n = 12), though a range of doses were used, from 8/2 fractions to 36 Gy/12 fractions. Results: Median age at diagnosis was 52 (range = 28-91). The majority were Squamous cell (43%, n = 10) or Basal cell carcinomas (34%, n = 8). Most lesions were located in the head and neck region. The most commonly used RT dose was 3GyX10 fractions; all patients had individualized CT-based planning.The 5-year overall survival (OS) was 86 %( twenty patients). Three patients were died. Most deaths were from unrelated causes. Response was assessed in OPD 2-4 months post-treatment. Our complete response (CR) rate was 73.9% (seventeen patients), with partial response in three patients; two patients could not be assessed for response and one patient died due to other medical condition. We report a 2-year local control (LC) rate of 91.3%, and local recurrence was found in two patients. The procedure was well tolerated, with no grade 3 or more acute or late toxicities. There was one case of grade 3 ulcer (CTCAE). The 100% isodose line median depth was 0.5 cm, and median surface dose = 126.5%. The median V90 = 92.3%. Conclusions: Surface mould brachytherapy is a safe, effective modality for treatment of skin malignancies or tumors. Brachytherapy was overall well tolerated, with no grade 3-5 acute or late toxicities. This treatment is a good alternative option for those patients unwilling or unable to undergo surgery for their skin malignancies

PO04: A Quantitative Approach to Pre-Treatment Verification of Fractionated Penile HDR Mold Brachytherapy

PO04: A Quantitative Approach to Pre-Treatment Verification of Fractionated Penile HDR Mold Brachytherapy

PO04: A Quantitative Approach to Pre-Treatment Verification of Fractionated Penile HDR Mold Brachytherapy

Purpose: Penile cancer treatment using custom molds with a fractionated HDR schedule has been the subject of several reports. Typically, treatment setup relies on ensuring a good fit of the penis in the mold, and clinical judgment of the staff performing the setup. Here we present a simple mold technique coupled with quantitative X-ray based method for pre-treatment setup verification.

Impact of GBBS algorithm on post-mastectomy scar boost irradiation of breast using catheter flap.

PurposePost-mastectomy radiation therapy significantly reduces locoregional recurrence rates, which can be achieved with external beam radiotherapy delivered to chest wall, followed by scar irradiation either by electron or high-dose-rate (HDR) mould brachytherapy. The present study evaluates dosimetric advantage of Acuros® BV, a TG-186 MBDCA, over TG-43 formalism using 192Ir source for HDR brachytherapy in chest wall scar boost using catheter flap.Material and methodsA total of 25 patients, free of cardiac and pulmonary co-morbidities, who met the inclusion criteria were involved in the study. Catheter flap made of silicon with 20 channels was used to deliver a total dose of 7.5 Gy/3 fx by HDR surface mould brachytherapy to delineated scar volume. Plan was optimized with iterative method to obtain desired results with TG-43 formalism, followed by Acuros® BV (GBBS algorithm) without altering dwell positions or time. The two algorithm plans were analyzed qualitatively and quantitatively with dose-volume histograms.ResultsThe mean D98% CTV-HDR_evl coverage decreased by 1.16% compared to TG-43, and near-maximum dose decreased by 8.18% (p = 0.000), mean Dmax dose to CTV-HDR_evl, and mean Dmean dose was lesser by 6.25% (p = 0.000) and 10.82% (p = 0.000), respectively, compared to TG-43. Heart D2% showed significant results, whereas Dmedian (cGy) revealed very significant difference. A 5 mm thick skin contour showed statistically significant results (p = 0.000) for V150% and V200%.ConclusionsThe presented data showed how Acuros® BV, algorithm-based calculation in scar boost irradiation of breast, accounting for a mass density of the medium and scatter condition, considered actual dose prediction in a medium.

Surface mould brachytherapy in oral and oropharyngeal cancers.

IntroductionThere are insufficient data on surface mold brachytherapy (SMB) in treating oral cancers. We reviewed our institutional experience to investigate the efficacy and toxicity of this treatment modality.Material and methodsWe retrospectively reviewed all the patients treated between 1989 and 2018 with high-dose-rate iridium-192 SMB for oral and oropharyngeal squamous cell carcinomas at our institution. Surface mold brachytherapy was delivered via an acrylic surface mold with 1–5 inserted catheters spaced 1 cm apart fabricated by our dental oncologist. The Kaplan-Meier product estimator was used to assess local control (LC), locoregional control (LRC), distant metastasis-free survival (DMFS), and overall survival (OS). Cox proportional hazards regression analysis was used to assess the relationship of various variables and patient outcomes.ResultsEighteen patients met the inclusion criteria and were evaluated. Indications for treatment were primary tumor (n = 13), local recurrence (2), locoregional recurrence (1), and oligometastatic disease (1). Ten patients received SMB alone and 8 received external beam radiotherapy with an SMB boost. The acute toxicity outcomes were as follows: no toxicity (n = 1), grade 1 (7), grade 2 (9), and grade 3 (1). Late effects were rare, only occurring in 3 patients. The one- and two-year LC were 81% and 68%, LRC 77% and 64%, DMFS 81% and 81%, and OS 77% and 46%.ConclusionsSurface mold brachytherapy is a viable modality as either primary or boost treatment for superficial oral cancers. In our patients, this treatment method has a low toxicity profile and resulted in reasonable LC.

Surface mould brachytherapy planning in giant cell tumour of the tendon sheath of finger and dosimetric comparison with external beam radiotherapy: a case report

AbstractIntroduction:Giant cell tumour of the tendon sheath (GCTTS) is the second most common tumour of the hand. Despite surgery, local recurrence after excision has been reported in up to 45% of cases. Post-operative radiotherapy (PORT) has been found to be promising in preventing these recurrences in high-risk group. One of the reservations of PORT is secondary effects of radiation which may cause a decreased range of motion of the affected joint, sensory changes and nail changes. Surface mould brachytherapy can provide a high dose to target volume with a rapid fall of dose to surrounding structures. Despite this, it is less used, the possible reason can be less technical proficiency.Methods:We have technically illustrated surface mould brachytherapy in a case of GCTTS of the left index finger, and compared dosimetrically with more widely used conventional photon and electron external beam radiotherapy.Conclusion:The 6-MV photon treatment plan with a bolus plan provided the least dose to skin (106%) and phalanges (103%). It has a Homogeneity index (1·06) closest to 1, whereas the Conformity index of all plans was similar. The dose coverage was adequate in all plans. The second-best plan dosimetrically was the surface mould brachytherapy.

Evaluation of a collapsed-cone convolution algorithm for esophagus and surface mold 192Ir brachytherapy treatment planning

PurposeTG43 does not account for a lack of scatter and tissue and applicator heterogeneities. The advanced collapsed-cone engine (ACE) algorithm available for use in the Oncentra Brachy treatment planning system (Elekta AB, Stockholm, Sweden) can model these conditions more accurately and is evaluated for esophageal and surface mold brachytherapy treatments. Methods and MaterialsACE was commissioned for use then compared against TG43 for five esophageal and five surface mold treatment plans. Dosimetric differences between each algorithm were assessed using superimposed comparisons and dose-volume histogram statistics. ResultsEsophagus (6 Gy per fraction): Compared with TG43, ACE demonstrated up to a 0.63% and 0.05 Gy reduction in planning target volume (PTV) V100% and PTV D98, respectively. Lung D2cc and bone D2cc deviated by up to 0.09 Gy and 0.03 Gy, respectively. Lung D0.1 cc and bone D0.1 cc both deviated by up to 0.12 Gy.Surface mold (4.5 Gy per fraction): Compared with TG43, ACE demonstrated up to a 12.5% and 0.18 Gy reduction in PTV V80% and PTV D98, respectively. Bone D2cc and D0.1 cc both reduced by up to 0.2 Gy when modeled with ACE. Increasing mold size laterally increased the dosimetric differences between TG43 and ACE. ConclusionsTG43 generally overestimated dose delivered to the target volume and organs at risk for the sites investigated. Dosimetric differences observed for esophageal treatments were minimal; however, surface mold treatments would benefit from the increased dosimetric accuracy offered by ACE.Implementation should be considered for surface mold 192Ir treatment planning, but increased calculation time, additional contouring, and mass density assignment requirements should be scrutinized with regard to their potentially negative impact on current clinical practice.

Organ preserving radiation strategies for penile cancer.

The majorities of penile cancers are of squamous cell origin and thus are amenable to treatment and cure by radiation. Despite the move toward penile sparing strategies, radiation remains an under-utilized and often neglected option. This paper will review the various radio-therapeutic approaches for penile cancer and the literature supporting their use. English, French and Spanish literature on penile cancer was reviewed for the past 5 decades and classified according to modality: external beam radiotherapy, interstitial brachytherapy and surface mold brachytherapy. Many series span several decades and include a wide range of stages, especially for external beam radiotherapy. Penile preservation obviously will depend on dose prescription and stage at treatment. Nonetheless, in general, penile sparing with external beam ranges from 36% to 66% at 5 years. For the selected patients appropriate for interstitial brachytherapy penile sparing is 77% to 87% at 5 years, decreasing to 70% at 10 years. Mold therapy is selected for those with very superficial disease and penile sparing is consequently higher. The development of centers of excellence for the management of this uncommon disease is encouraged. The required surgical and radiotherapy skill sets cannot be expected to be available in all centers. A multidisciplinary evaluation of each patient will facilitate selection of optimal management from the outset.

Surface Mould Brachytherapy Boost in Carcinoma Palate: Challenges on the Road to a Better Therapeutic Ratio

Surface Mould Brachytherapy Boost in Carcinoma Palate: Challenges on the Road to a Better Therapeutic Ratio