Original scientific paper
https://doi.org/10.20471/LO.2022.50.01.02
Dosimetric analysis of treatment planning optimization techniques for CO-60 and IR-192 HDR brachytherapy sources in carcinoma cervix patients
Rajni Verma
; Department of Radiological Physics, SMS Medical College & Hospital, Jaipur, India
Gourav Kumar Jain
; Department of Radiological Physics, SMS Medical College & Hospital, Jaipur, India
Arun Chougule
; Department of Radiological Physics, SMS Medical College & Hospital, Jaipur, India
Abstract
Introduction: The study was designed to dosimetrically compare the treatment planning optimization techniques to analyze the equivalence of Co-60 and Ir-192 HDR Brachytherapy sources. Further, the present study planned to analyze the equivalence on the basis of technical, logistical and clinical aspects for both the sources.
Methods: Thirty-two patients with confirmed diagnosis of carcinoma cervix were included in the study. Comparative treatment plans were made for three different treatment planning optimization techniques for both the sources Co-60 and Ir-192 i.e. (a) plans with prescription on Point A (Manchester system) with identical dwell position, (b) plans with inverse planning and (c) plans with prescription on HR-CTV with manual optimization. Treatment plans were evaluated on the basis of clinical parameters HR-CTV V200%, V150%, V100%, D95%, D50%, D2cc Bladder, D2cc rectum and point dose on ICRU Rectum and Bladder reference point.
Results: For the plans with prescription on Point A with identical dwell position, the average percentage difference were found HR-CTV V200% (6.3%), V150% (5.1%), V100% (1.8%), D2cc rectum (2.3%) and ICRU Rectum reference point (2.1%) and all these parameters were statistically significant for both the sources. For the Plans with inverse planning optimization, these parameters were found significant with average percentage difference HR-CTV V200% (6.1%), V150% (4.9%), D50% (2.1%) and ICRU Rectum reference point (2.3%). For the plans with dose prescription on HR-CTV and manual optimization, most of the average percentage differences were found non-significant and clinical parameters were observed clinically comparable to each other for both the sources. Further, it was also observed that on an average Ir-192 source required only 42% of the treatment time required by Co-60 for the same treatment plan delivery.
Conclusion: Among all the three planning techniques, the planning technique with prescription on HR-CTV & manual optimization was found to have comparable clinical quality for both the sources. This analysis revealed that geometry of source placement can overcome the differences in individual source characteristics.
Keywords
cobalt-60; iridium-192; high dose rate brachytherapy; cervical cancer
Hrčak ID:
277741
URI
Publication date:
12.5.2022.
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