PurposeBrachytherapy in the oral cavity is an important alternative to conventional treatment, and provides a high localized dose and short overall treatment time. A rapid fall of dose beyond radioactive source makes it possible for increased tumour control and sparing surrounding tissue, while short overall treatment duration reduces risk of tumour repopulation. Moulds are fabricated to hold the catheters in position as closely as possible to tumour surface to provide adequate dose coverage of tumour volume and increase distance to other normal surrounding structures. Image based planning and dose optimisation help in better defining target volume and dose coverage.Material and methodsA retrospective analysis of patients of early squamous cell carcinomas of lip and buccal mucosa from September 2011 to June 2014 to study response to mould brachytherapy. Double plane moulds were prepared for all lip cancer cases and single plane for buccal mucosa cases. Patients are being followed up till disease recurrence. In this study evaluation was done of the technique used, planning details, response to therapy, and reactions encountered.ResultsNine patients treated by mould therapy were reviewed; seven cases were of lip and two of buccal mucosal cancers. Dose delivered ranged from 12.5-48 Gy in fraction sizes of 2.5-3.5 Gy. Equivalent dose in 2 Gy fractions (EQD2) ranged from 18-64 Gy. Maximum dose to organs at risk (OAR) was 91% of prescribed dose. Local mucositis was only reaction in all cases, which resolved in 3-6 weeks. Median follow-up was 19 months. Eight out of nine patients are in remission at a minimum of 7 months (1 case, rest over 14 months) post therapy and only patient had nodal recurrence at 18 months.ConclusionsMould therapy is an effective treatment method for selected early and superficial squamous cell carcinomas of the oral cavity, although indications are limited.
PurposeRadiotherapy for breast cancer includes different techniques and methods. The purpose of this study is to compare dosimetric calculations using TG-43 dose formalism and Varian Acuros™ BV (GBBS) dose calculation algorithm for interstitial implant of breast using metal catheters in high-dose-rate (HDR) brachytherapy, using 192Ir.Material and methodsTwenty patients who were considered for breast conservative surgery (BCS), underwent lumpectomy and axillary dissection. These patients received perioperative interstitial HDR brachytherapy as upfront boost using rigid metal implants. Whole breast irradiation was delivered TG-43 after a gap of two weeks. Standard brachytherapy dose calculation was done by dosimetry. This does not take into account tissue heterogeneity, attenuation and scatter in the metal applicator, and effects of patient boundary. Acuros™ BV is a Grid Based Boltzmann Solver code (GBBS), which takes into consideration all the above, was used to compute dosimetry and the two systems were compared.ResultsComparison of GBBS and TG-43 formalism on interstitial metal catheters shows difference in dose prescribed to CTV and other OARs. While the estimated dose to CTV was only marginally different with the two systems, there is a significant difference in estimated doses of starting from 4 to 53% in the mean value of all parameters analyzed.ConclusionsTG-43 algorithm seems to significantly overestimate the dose to various volumes of interest; GBBS based dose calculation algorithm has impact on CTV, heart, ipsilateral lung, heart, contralateral breast, skin, and ribs of the ipsilateral breast side; the prescription changes occurred due to effect of metal catheters, inhomogeneities, and scatter conditions.
BackgroundThe study aimed to assess the effect of High Dose Rate (HDR) Interstitial Brachytherapy when used alone or in combination with External Beam Radiotherapy (EBRT), in early and locally advanced squamous cell carcinoma of buccal mucosa.Materials and methodsThirty three patients with histologically proven squamous cell carcinoma of the buccal mucosa received high dose rate interstitial brachytherapy either as primary treatment or as a boost from November 2008 to April 2013. Stage I patients received interstitial brachytherapy alone to a dose of 38.50 Gy, 3.5 Gy per fraction, twice daily at six hours apart for 11 fractions. Stage II patients received EBRT to a dose of 50 Gy in 25 fractions of two Gy each followed by brachytherapy boost to 21 Gy, 3.5 Gy per fraction, twice daily at six hours apart for six fractions. Stage III patients received the same radiotherapy schedule (i.e., same EBRT & Brachytherapy schedule) and with addition of Injection Cisplatin 70 mg/m2 in three divided doses every three weeks along with EBRT.ResultsFollow up ranged from 12 to 60 months, median follow up was 26 months. Complete response was observed in 28 patients. Five patients had residual disease and were referred for surgical salvage. One patient died of disease progression. Stage I patients had 100% local control, whereas Stage II and Stage III patients had 84.6% and 80% local control respectively.ConclusionHDR Interstitial Brachytherapy used either as a primary treatment modality or as a boost in buccal mucosal cancers provides results comparable to that of surgery, with the advantages of organ preservation, better cosmetic and functional outcomes.
AimTo compare the image-based three-dimensional treatment planning using AcurosTM BV and AAPM TG-43 algorithm for intracavitary brachytherapy of carcinoma cervix.Materials and methodsTwenty-seven patients with cancer cervix, stage IIB or IIIB with vaginal involvement limited to the upper third of the vagina was included into the study. Intracavitary treatments with the patient in this study done with computed tomography and magnetic resonance imaging compatible ring applicator. Groupe European de Curietherapie and European Society for Therapeutic Radiology and Oncology recommended doses to target volumes and organs at risk compared using dose volume histogram.ResultsThe mean value of Point ‘A’ dose was compared between AcurosTM BV and TG-43, which indicates 0·13% difference. The differences in the mean dose to gross tumour volume for various volumes are V100% 0·28%, V150% 1·22% and V200% 1·03%; all volumes showed small difference but statistical significant (p<0·05). The mean dose of high-risk clinical target volume (HRCTV) D90 using AcurosTM BV was 8·47 Gy, which was 1·63% less compared with TG-43. The mean point A dose using AcurosTM BV is 1·04 times the dose to D90 of mean HRCTV. The same difference was observed in comparison with TG43. D2cc and D0·1cc of the bladder, rectum and sigmoid showed a statistically significant difference (p<0·05) in comparison with TG-43.ConclusionThe differences in dosimetric parameters between the AcurosTM BV and TG-43 proved to be statistically significant. The difference is very small, and they are clinically insignificant.
PurposeSoft tissue sarcomas of the extremities account for half of all soft tissue sarcomas. Radiotherapy and surgery have been the standard modalities in the treatment of this type of cancer. Brachytherapy can be used as the sole therapy, if the target volume is localized and easily accessible. This work reports three cases of shoulder soft tissue sarcomas with positive deep resected margins, treated with a combination of external beam radiotherapy and surface mould brachytherapy boost technique.Material and methodsBetween January and June 2014, three patients received brachytherapy with sites close to the shoulder, and post-surgery involved deep resected margins. Each mould was made on a base of thermoplastic, over which dental wax was coated and catheters implanted. The target volume was defined as the tissue covering the tumor bed with lateral margins of 2-2.5 cm and depth of 1-1.5 cm. Treatment planning was computed tomography-based and dose prescribed was 85-100% isodose. Treatments has been delivered twice daily, six hours interval, and a review of reactions evaluated.ResultsVolume receiving more than 150% of the prescribed dose has been limited to less than 2%, and that above 200% to be inside the mould. Brachytherapy equivalent dose at 2 Gy per fraction (EQD2) of these patients was 24 and 28.6 Gy. Maximum dose to organ at risk (OAR) (2 cc of OAR) ranged between 55-87% of prescribed dose, with a median dose being 80%. All cases had only grade 1 post-radiotherapy skin immediate reactions, which resolved within four weeks. In all patients, no treatment failures were noted at nearly 2-years post-irradiation.ConclusionsSurface mould brachytherapy in soft tissue sarcomas could be a useful alternative to interstitial brachytherapy, especially where the target volume is superficially extensive with underlying critical structures, and where catheter placement may be difficult, such as the shoulder.
Purpose: Post-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 192 Ir source for HDR brachytherapy in chest wall scar boost using catheter flap.Material and methods: A 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.Results: The mean D 98% CTV-HDR_evl coverage decreased by 1.16% compared to TG-43, and near-maximum dose decreased by 8.18% (p = 0.000), mean D max dose to CTV-HDR_evl, and mean D mean dose was lesser by 6.25% (p = 0.000) and 10.82% (p = 0.000), respectively, compared to TG-43. Heart D 2% showed significant results, whereas D median (cGy) revealed very significant difference. A 5 mm thick skin contour showed statistically significant results (p = 0.000) for V 150% and V 200% .Conclusions: The 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.
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