A dosimetric study to evaluate the inverse planning simulated annealing (IPSA) and hybrid inverse planning optimization (HIPO) algorithms in HDR brachytherapy of cervical cancer

Abstract

Purpose: To compare the effectiveness of the inverse planning simulated annealing (IPSA) and hybrid inverse planning optimization (HIPO) algorithms in interstitial HDR brachytherapy for treatment of cervical cancer. Methods and Materials: A dosimetric study was conducted on 46 cervical cancer patients who underwent multi catheter interstitial cervical HDR brachytherapy using the Martinez Universal Perineal Interstitial Template (MUPIT). Dosimetric parameters, plan evaluation indices, and mean treatment time were assessed for each algorithm. All the parameters were compared using statistical analysis. Results: With HIPO, significant improvements were observed in D<inf>90</inf>, D<inf>100</inf>, V<inf>100</inf>, and V<inf>200</inf> (P < 0.05). Additionally, HIPO plans demonstrated lower doses to the bladder (B<inf>2cc</inf>) as compared to IPSA plans, whereas IPSA plans exhibited lower rectum (R<inf>2cc</inf>) and sigmoid (S<inf>2cc</inf>) doses, with statistical significance observed only for sigmoid doses. HIPO plans had better results in the plan evaluation indices such as CI, COIN, DHI, DNR, ODI, EI, NV<inf>100</inf>, GF<inf>B</inf>, GF<inf>R</inf>, GF, PQI<inf>1</inf>, PQI<inf>2,</inf> and PQS with statistical significance (P < 0.05) except for GF<inf>S</inf>. Moreover, HIPO plans had shorter mean treatment time compared to IPSA plans by 5.52 seconds, although this difference did not reach statistical significance. It was found that HIPO plans demonstrated superior dose-volumetric parameters for the high-risk clinical target volume (HR-CTV). Conclusions: In conclusion, HIPO emerged as the preferred algorithm for interstitial cervical HDR brachytherapy due to improved dose distribution in HR-CTV and plan quality as well. © 2025 Journal of Cancer Research and Therapeutics | Published by Wolters Kluwer - Medknow.