Study of the dosimetric differences between 192Ir and 60Co sources of high dose rate brachytherapy for breast interstitial implant

Sinnatamby, Mourougan; Nagarajan, Vivekanandan; Sathyanarayana, Reddy Kanipakam; Karunanidhi, Gunaseelan; Singhavajala, Vivekanandam

doi:10.1016/j.rpor.2016.03.005

Cited by 11 publications

(8 citation statements)

References 17 publications

(15 reference statements)

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“…reported a mean value for D max to the skin of 30.9 Gy, which was comparable with our results [19]. According to Sinnatamby et al ., D max to the skin for all patients was 92.93%, while the ribs accounted for only 20.05% of the prescribed dose [20]. The value of the skin dose is identical to ours, while the ribs’ doses have a significant difference.…”

Section: Discussionsupporting

confidence: 63%

Experience in multicatheter interstitial high-dose-rate breast brachytherapy: dose-volume histogram analysis of the first results

Demianovich

Sanin

Martynova

et al. 2019

jcb

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PurposeTo report characteristics of our treatment scheme of high-dose-rate (HDR) brachytherapy of breast cancer and to show the first outcomes of dosimetric planning analysis based on dose-volume histogram (DVH).Material and methodsSince August 2017, 25 patients diagnosed with T1N0M0 breast cancer have received a treatment in our center. There was lumpectomy and following breast HDR brachytherapy (10 fractions of 3.4 Gy) administered to each patient. A planning target volume (PTV) and organs at risk (OARs) were recorded with DVH analysis.ResultsThe study describes the full procedure of breast HDR brachytherapy with the lumpectomy. Twenty-five patients were treated, including 9 with cancer of the left breast and 16 of the right breast. The median age was 65 years. The first analysis of DVH data shows that the main OARs were ribs and skin. Mean value of Dmax (ribs) for all patients was 19.90 Gy (55.88% of prescribed dose) and for the skin 30.88 Gy (90.74% of prescribed dose). During the treatment, there was only one case of toxic effects, which was pigmentation on the skin due to excess of dose limit of 1.4 Gy. Therefore, the limit exceeding of 1 Gy does not give any significant toxic effects.ConclusionsThis study is the first stage of the dosimetric evaluation of a new method. The analysis allows treating complex localizations of the breast cancer, for example, in a close position to the skin or ribs. In order to minimize the toxic effects, it is necessary to consider patient selection, catheter administration, and dose optimization.

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Section: Discussionsupporting

confidence: 63%

Experience in multicatheter interstitial high-dose-rate breast brachytherapy: dose-volume histogram analysis of the first results

Demianovich

Sanin

Martynova

et al. 2019

jcb

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“…Besides the introduction of image-based dose calculation algorithms for 192 Ir, TG-43 remains the prevalent method for the clinical treatment planning dosimetry in HDR brachytherapy applications. While the equivalence of 60 Co and 192 Ir brachytherapy has been established in a number of studies in the literature [ 1 , 2 , 3 , 4 , 5 , 6 , 8 , 10 , 11 , 12 ], the relative effects of inhomogeneities and patient specific scatter conditions have not been considered. These effects were studied retrospectively in this work, through the comparison of TG-43 based dosimetry with corresponding MC results in groups of clinically equivalent plans with 60 Co and 192 Ir HDR sources for breast, esophageal, and cervical treatments.…”

Section: Discussionmentioning

confidence: 99%

“…This development led to several comparative studies published in the literature. These include comparative evaluations of acute toxicity in gynecological cancer [ 1 , 2 ], and dosimetry studies ranging from single source dosimetry comparison [ 3 , 4 , 5 ] to comparisons of dose distributions in gynecological [ 4 , 5 , 6 , 7 ], prostate [ 8 ], skin [ 9 ], and breast [ 10 , 11 , 12 ] HDR brachytherapy treatments using different techniques. In a comprehensive dosimetry study, Palmer et al .…”

Section: Purposementioning

confidence: 99%

A comparative assessment of inhomogeneity and finite patient dimension effects in 60 Co and 192 Ir high-dose-rate brachytherapy

Fotina¹,

Zourari

Lahanas

et al. 2018

jcb

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PurposeTo perform a comparative study of heterogeneities and finite patient dimension effects in 60Co and 192Ir high-dose-rate (HDR) brachytherapy.Material and methodsClinically equivalent plans were prepared for 19 cases (8 breast, 5 esophagus, 6 gynecologic) using the Ir2.A85-2 and the Co0.A86 HDR sources, with a TG-43 based treatment planning system (TPS). Phase space files were obtained for the two source designs using MCNP6, and validated through comparison to a single source dosimetry results in the literature. Dose to water, taking into account the patient specific anatomy and materials (Dw,m), was calculated for all plans using MCNP6, with input files prepared using the BrachyGuide software tool to analyze information from DICOM RT plan exports.ResultsA general TG-43 dose overestimation was observed, except for the lungs, with a greater magnitude for 192Ir. The distribution of percentage differences between TG-43 and Monte Carlo (MC) in dose volume histogram (DVH) indices for the planning target volume (PTV) presented small median values (about 2%) for both 60Co and 192Ir, with a greater dispersion for 192Ir. Regarding the organs at risk (OARs), median percentage differences for breast V50% were 3% (5%) for 60Co (192Ir). Differences in median skin D2cc were found comparable, with a larger dispersion for 192Ir, and the same applied to the lung D10cc and the aorta D2cc. TG-43 overestimates D2cc for the rectum and the sigmoid, with median differences from MC within 2% and a greater dispersion for 192Ir. For the bladder, the median of the difference is greater for 60Co (~2%) than for 192Ir (~0.75%), demonstrating however a greater dispersion again for 192Ir.ConclusionsThe magnitude of differences observed between TG-43 based and MC dosimetry and their smaller dispersion relative to 192Ir, suggest that 60Co HDR sources are more amenable to the TG-43 assumptions in clinical treatment planning dosimetry.

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“…Although these two HDR photon sources are both classified as high‐energy sources, the relatively higher average gamma energy of 60 Co has raised concerns about potentially increased rates of toxicity. However, comparative studies have shown similarity (albeit not identity) of physical dose distributions in many disease sites including the cervix for both these sources 17–22 . But the clinical outcomes including tumor control or normal tissue toxicity are more directly linked to the biological dose distributions rather than the physical dose distributions.…”

Section: Introductionmentioning

confidence: 99%

Radiobiological comparison between Cobalt‐60 and Iridium‐192 high‐dose‐rate brachytherapy sources: Part I—cervical cancer

et al. 2021

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This study aimed to compare the biological effective doses (BEDs) to clinical target volume (CTV) and organs at risk (OARs) for cervical cancer patients treated with high-dose-rate (HDR) or Cobalt-60 ( 60 Co) brachytherapy (BT) boost and to determine if the radiobiological differences between the two isotopes are clinically relevant. Methods: Considering all radiosensitivity parameters and their reported variations, the BEDs to CTV and OARs during HDR 60 Co/ 192 Ir BT boost were evaluated at the voxel level. The anatomical differences between individuals were also taken into account by retrospectively considering 25 cervical cancer patients. The intrafraction repair, proliferation, hypoxia-induced radiosensitivity heterogeneity, relative biological effectiveness (RBE), and source aging doserate variation were also taken into account. The comparisons in CTV were performed based on equivalent uniform BED (EUBED). Results: Considering nominal parameters with no RBE correction, the CTV EUBEDs were almost similar with a median ratio of ∼1.00 (p < 0.00001), whereas RBE correction resulted in 3.9%-5.5% (p = 0.005, median = 4.8%) decrease for 60 Co with respect to 192 Ir. For OARs, the median values of D 2cc (in EQD2 3 ) for 60 Co were lower than that of 192 Ir up to 9.2% and 11.3% (p < 0.00001) for nominal parameters and fast repair conditions, respectively. In addition, for a nominal value (reported range) of radiosensitive parameters, the CTV EUBED differences of up to 6% (5%-10%) were assessed for HDR-BT component. Conclusion:The RBE values are the most important cause of discrepancies between the two sources. By comparing BED/EUBEDs to CTV and OARs between 60 Co and 192 Ir sources,this numerical study suggests that a dose escalation to ∼4% is feasible and safe while sparing well the surrounding normal tissues. This 4% dose escalation should be benchmarked with clinical evidences (such as the results of clinical trials) before it can be used in clinical practice.

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Study of the dosimetric differences between 192Ir and 60Co sources of high dose rate brachytherapy for breast interstitial implant

Cited by 11 publications

References 17 publications

Experience in multicatheter interstitial high-dose-rate breast brachytherapy: dose-volume histogram analysis of the first results

Experience in multicatheter interstitial high-dose-rate breast brachytherapy: dose-volume histogram analysis of the first results

A comparative assessment of inhomogeneity and finite patient dimension effects in 60 Co and 192 Ir high-dose-rate brachytherapy

Radiobiological comparison between Cobalt‐60 and Iridium‐192 high‐dose‐rate brachytherapy sources: Part I—cervical cancer

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