Qualitative Dosimetric and Radiobiological Evaluation of High – Dose – Rate Interstitial brachytherapy Implants

Kehwar, Than S.; Akber, Syed F.; Passi, Kamlesh

doi:10.7150/ijms.5.41

Cited by 15 publications

(12 citation statements)

References 24 publications

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“…Park et al in their work on effect of source step size have concluded that the optimal step sizes which provide the most homogenous dose distributions are 4-6 mm. 27,28 Moreover they find that finer step sizes (1-3 mm) do not improve dose homogeneity whereas coarser step sizes (7-10 mm) provide lower dose homogeneity the findings of our study are more or less in good agreement with the published studies.…”

Section: Discussionsupporting

confidence: 83%

Impact of discrete source step size on the 3D dosimetry of interstitial implants with high dose rate brachytherapy

Maurya

et al. 2018

Int J Res Med Sci

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Background: High dose rate remote after loading brachytherapy machines have seen tremendous advancement both technologically and their clinical applications during the last 25 years. With the introduction of computerized remote after loading machines and computerized planning system, stepping source dosimetry system (SSDS) has become the system of choice making almost all traditional dosimetry systems obsolete. In this study we evaluated the impact of source step size on dosimetry of interstitial implant using parameters of ICRU-58 and various quality indices (QI).Material & Methods: For this study, 10 implant cases which have 3-D CT image based planning were selected. Contouring of clinical target volume and various organs were done following standard guidelines for the same. Plans were optimized to achieve the desired clinical outcome using different source step sizes of 2.5, 5 and 10 mm respectively. Cumulative DVH’s were calculated for the estimation of various ICRU-58 parameters and quality indices.Results and Conclusion: The mean values of the target volumes, minimum target doses, treated volumes, low dose volumes; high dose volumes, overdose volumes, reference volumes, coverage, external volume, relative dose homogeneity, overdose volume and COIN indices have been presented for the source step sizes of 2.5 mm, 5 mm and 10 mm respectively. Among source step sizes used in this study, most favorable clinically acceptable dose distributions & dose homogeneity occurs around step size of 5 mm as predicted by the various parameters of ICRU-58 and dose quality indices. Keywords: Brachytherapy, interstitial implant, source step-size, remote after loading, optimization, quality indices.

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Section: Discussionsupporting

confidence: 83%

Impact of discrete source step size on the 3D dosimetry of interstitial implants with high dose rate brachytherapy

Maurya

et al. 2018

Int J Res Med Sci

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“…According to American brachytherapy society recommendations Coverage Index of 100%, Dose Homogeneity Index of more than 0.75 and External Volume Index of zero (EVI = 0) should be achieved with more than 90% of dose delivered to >90% target volume. Baltas et al, stated that conformal index should be one (1) in order to achieve better quality of tumor irradiation and normal tissue sparing by interstitial brachytherapy [26]- [28].…”

Section: Discussionmentioning

confidence: 99%

Will High Dose Rate Interstitial Brachytherapy Be a Surrogate to Surgery in Early Mobile Squamous Cell Carcinoma of Tongue—An Indian Experience

Vedasoundaram¹,

Reddy²,

Selvarajan³

et al. 2014

IJMPCERO

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The study was intended to highlight functional outcome and survival advantage when High Dose Rate (HDR) interstitial implant was used for anterior 2/3 rd tongue, either as a primary or as boost depending upon stage of disease. Materials and Methods: Fifty-one patients with squamous cell carcinoma of anterior 2/3 rd tongue received interstitial brachytherapy either as primary or as boost with Iridium 192 remote after loading high dose rate (Microselectron or Gamma MediX) machines from November 2008 to September 2013. Age group ranged from 32 to 73 years, mean 52.1. Of these 51, 37 were males and 14 were females. 8 patients belonged to Stage I, 18 from Stage II and 28 patients were Stage III. Stage I patients received primary brachytherapy alone of dose 38.50 Gy to 40 Gy and fraction dose ranged from 250 cGy to 350 cGy. Stage II and Stage III patients received external beam radiation of dose 44 Gy/200cGy per fraction for 22 fractions followed by spinal cord sparing for 6 Gy/200cGy per fraction for 3 fractions. Brachytherapy boost of dose 21 Gy was delivered after external beam radiation. Stage III patients received concurrent chemotherapy with Injection Cisplatin along with external beam radiotherapy 44 Gy/200cGy per fraction for 22 fractions followed by spinal cord sparing for 6 Gy/200cGy per fraction for 3 fractions. Brachytherapy boost of dose 21 Gy was delivered after external beam radiation. 55% of patients were habituated to tobacco and alcohol in one form or the other or both. Surprisingly 45% of patients were nonsmokers and non-alcoholic. Results: Follow-up period ranged from eight months to sixty months. 42 patients had complete response. 9 patients had residual disease. 2 patients died due to non-cancerous cause though they had excellent local control, one with pulmonary tuberculosis and the other with massive Myocardial Infarction. 2 patients died due to disease progression. P. Vedasoundaram et al. 144 Overall complete response rate was 82.35%. Those patients who had good coverage index and conformal index had good response compared to those patients with lesser these values. Conclusion: It is surprising to observe from the study that oral cavity cancers are not uncommon in nonsmokers and non-alcoholics. Overall complete response of 82% is comparable to any other study quoted in literature. Surgery offers same cure rate but at the rate of organ loss and functional impairment. Organ preservation with good functional outcome is possible in radiotherapy unlike surgery. This study proves brachytherapy can be considered as a surrogate to surgery in early stage tongue cancers with good functional outcome and with lesser morbidity.

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“…To assess the quality of interstitial implants, many investigators have introduced a number of QIs (16)(17)(18)(19)(20), including the coverage index (CI), the relative dose-homogeneity index (DHI), the dose nonuniformity ratio (DNR), and the overdose index (ODI), which are defined as the fraction of the target volume that receives a dose equal to or greater than the prescribed dose in the range of 1.0 to 1.5 times the prescribed dose; equal to or greater than 1.5 times the prescribed dose; and equal to or greater than 2.0 times the prescribed dose, respectively. QI values were calculated from the DVH of each implant, generated from preneedle US, postneedle US, and postimplant CT volumes on day 0, day 14, and day 28.…”

Section: Qis Of An Implantmentioning

confidence: 99%

“…In this study, we present the results of our investigation of the potential effects of edema on various quality indices (QIs), which were defined previously (16)(17)(18)(19)(20) for low-dose-rate interstitial seed implants and biologically effective doses (BED) at D 80 , D 90 and D 100 .…”

Section: Introductionmentioning

confidence: 99%

Influence of Prostatic Edema on 131Cs Permanent Prostate Seed Implants: A Dosimetric and Radiobiological Study

Kehwar

Jones

Huq

et al. 2011

International Journal of Radiation Oncology*Biology*Physics

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Qualitative Dosimetric and Radiobiological Evaluation of High – Dose – Rate Interstitial brachytherapy Implants

Cited by 15 publications

References 24 publications

Impact of discrete source step size on the 3D dosimetry of interstitial implants with high dose rate brachytherapy

Impact of discrete source step size on the 3D dosimetry of interstitial implants with high dose rate brachytherapy

Will High Dose Rate Interstitial Brachytherapy Be a Surrogate to Surgery in Early Mobile Squamous Cell Carcinoma of Tongue—An Indian Experience

Influence of Prostatic Edema on 131Cs Permanent Prostate Seed Implants: A Dosimetric and Radiobiological Study

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