open access

Vol 25, No 6 (2020)
Original research articles
Published online: 2020-11-01
Submitted: 2020-03-26
Get Citation

Dosimetric comparison of manual forward planning with uniform dwell times versus volume-based inverse planning in interstitial brachytherapy of cervical malignancies

Siddanna R. Palled, Nikhila K. Radhakrishna, Senthil Manikantan, Hashmath Khanum, Bindu K. Venugopal, Lokesh Vishwanath
DOI: 10.1016/j.rpor.2020.08.005
·
Rep Pract Oncol Radiother 2020;25(6):851-855.

open access

Vol 25, No 6 (2020)
Original research articles
Published online: 2020-11-01
Submitted: 2020-03-26

Abstract

Aim

Dosimetic comparison of manual forward planning(MFP) with inverse planning(IP) for interstitial brachytherapy(ISBT) in cervical carcinoma.

Background

Brachytherapy planning by MFP is more reliable but time-consuming method, whereas IP has been explored more often for its ease and rapidness. The superiority of either is yet to be established.

Methodology

Two plans were created on data sets of 24 patients of cervical carcinoma who had undergone ISBT, one by MFP with uniform dwell times and another IP on BrachyVision 13.7 planning system with a dose prescription of 600 cGy. Isodose shaper was used for improving conformity & homogeneity. Dosimetric parameters for target and organs at risk (OARs) were recorded. Conformity index (COIN), dose homogeneity index (DHI), overdose index (OI), Coverage index (CI) and dose nonuniformity ratio (DNR) were calculated.

Results

Mean high risk clinical target volume: 73.05(±20.7)cc, D90: 5.51 Gy vs. 5.6 Gy (p = 0.017), V100: 81.77 % vs. 83.74 % (p = 0.002), V150: 21.7 % vs. 24.93 % (p = 0.002), V200: 6.3 % vs. 6.4 % (p=0.75) for IP and MFP, respectively. CI: 0.81(IP) and 0.83(MFP) (p = 0.003); however, COIN was 0.79 for both plans. D2cc of OARs was statistically better with IP (bladder 54.7 % vs. 56.1 %, p = 0.03; rectum 63 % vs. 64.7 %, (p = 0.0008).

Conclusion

Both MFP and IP are equally acceptable dosimetrically. With higher dose achieved to the target, for a similar OAR dose, MFP provides greater user flexibility of dwell positions within the target as well as better optimization. Isodose shaper may be carefully used for fine tuning. Larger sample sizes and clinical correlation will better answer the superiority of one over the other.

Abstract

Aim

Dosimetic comparison of manual forward planning(MFP) with inverse planning(IP) for interstitial brachytherapy(ISBT) in cervical carcinoma.

Background

Brachytherapy planning by MFP is more reliable but time-consuming method, whereas IP has been explored more often for its ease and rapidness. The superiority of either is yet to be established.

Methodology

Two plans were created on data sets of 24 patients of cervical carcinoma who had undergone ISBT, one by MFP with uniform dwell times and another IP on BrachyVision 13.7 planning system with a dose prescription of 600 cGy. Isodose shaper was used for improving conformity & homogeneity. Dosimetric parameters for target and organs at risk (OARs) were recorded. Conformity index (COIN), dose homogeneity index (DHI), overdose index (OI), Coverage index (CI) and dose nonuniformity ratio (DNR) were calculated.

Results

Mean high risk clinical target volume: 73.05(±20.7)cc, D90: 5.51 Gy vs. 5.6 Gy (p = 0.017), V100: 81.77 % vs. 83.74 % (p = 0.002), V150: 21.7 % vs. 24.93 % (p = 0.002), V200: 6.3 % vs. 6.4 % (p=0.75) for IP and MFP, respectively. CI: 0.81(IP) and 0.83(MFP) (p = 0.003); however, COIN was 0.79 for both plans. D2cc of OARs was statistically better with IP (bladder 54.7 % vs. 56.1 %, p = 0.03; rectum 63 % vs. 64.7 %, (p = 0.0008).

Conclusion

Both MFP and IP are equally acceptable dosimetrically. With higher dose achieved to the target, for a similar OAR dose, MFP provides greater user flexibility of dwell positions within the target as well as better optimization. Isodose shaper may be carefully used for fine tuning. Larger sample sizes and clinical correlation will better answer the superiority of one over the other.

Get Citation

Keywords

Manual forward planning; Inverse optimization; Interstitial brachytherapy; Brachytherapy indices

About this article
Title

Dosimetric comparison of manual forward planning with uniform dwell times versus volume-based inverse planning in interstitial brachytherapy of cervical malignancies

Journal

Reports of Practical Oncology and Radiotherapy

Issue

Vol 25, No 6 (2020)

Pages

851-855

Published online

2020-11-01

DOI

10.1016/j.rpor.2020.08.005

Bibliographic record

Rep Pract Oncol Radiother 2020;25(6):851-855.

Keywords

Manual forward planning
Inverse optimization
Interstitial brachytherapy
Brachytherapy indices

Authors

Siddanna R. Palled
Nikhila K. Radhakrishna
Senthil Manikantan
Hashmath Khanum
Bindu K. Venugopal
Lokesh Vishwanath

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