Hostname: page-component-68945f75b7-wph62 Total loading time: 0 Render date: 2024-08-05T18:49:39.217Z Has data issue: false hasContentIssue false
  • English
  • Français

A new index: Triple Point Conformity Scale (CS3) and its implication in qualitative evaluation of radiotherapy plan

Published online by Cambridge University Press:  26 July 2018

Shahnawaz Ansari ,
Subrat K. Satpathy ,
Imteyaz Ahmad ,
Priyanka K. Singh ,
Santosh Lad ,
Nimish Thappa  and
B. K. Singh
Shahnawaz Ansari*
Affiliation:
Department of Medical Physics, Apollo Hospitals Bilaspur, Bilaspur, Chhattisgarh, India
Subrat K. Satpathy
Affiliation:
Department of Medical Physics, Apollo Hospitals Bilaspur, Bilaspur, Chhattisgarh, India
Imteyaz Ahmad
Affiliation:
Department of Medical Physics, Apollo Hospitals Bilaspur, Bilaspur, Chhattisgarh, India
Priyanka K. Singh
Affiliation:
Department of Medical Physics, Apollo Hospitals Bilaspur, Bilaspur, Chhattisgarh, India
Santosh Lad
Affiliation:
Department of Medical Physics, Apollo Hospitals Bilaspur, Bilaspur, Chhattisgarh, India
Nimish Thappa
Affiliation:
Department of Medical Physics, Apollo Hospitals Bilaspur, Bilaspur, Chhattisgarh, India
B. K. Singh
Affiliation:
Department of Medical Physics, Apollo Hospitals Bilaspur, Bilaspur, Chhattisgarh, India
*
Author for correspondence: Shahnawaz Ansari, Department of Medical Physics, Apollo Hospitals Bilaspur, Bilaspur, Chhattisgarh 495006, India. Tel: +91 775224833451. E-mail: ansarisnz05@gmail.com
Get access Rights & Permissions [Opens in a new window]

Abstract

Background

Across the history of radiotherapy, with gradual technological progress and various methods of irradiation, the purpose has always been to deliver homogeneously 100% of the prescribed dose to 100% of the target volume containing the identifiable tumour and/or tumour cells potentially present while limiting the dose to adjacent normal tissues.

Material and methods

The formula for triple point conformity scale is: CS3=(V95+V100+V105)/3VT. (a) Lower limit determination: CS3=(VT+0·93 VT+0·0)/3VT=0·643; (b) Upper limit determination: in order to find out an empirical relation in between V105 and VT, we studied over 593 cancer patients of various sites by taking planning target volume as target, and an empirical relation is derived out as: V105/VT=0·0007. Hence, CS3=(VT+VT+0·0007 VT)/3VT=0·6667~0·667.

Result

Upper and lower limits of CS3 have been calculated at 0·643 and 0·667, respectively. Maximum value of CS3 index is recorded 0·656 while minimum value is 0·478.

Discussion

The CS3 scale constitutes an attractive tool because it could facilitate decisions during analysis of various treatment plans proposed for conformal radiotherapy. Its major advantages are its simplicity and integration of multiple parameters.

Conclusion

The triple point conformity scale (CS3) provides better qualitative information about radiotherapy plans as compared to other conformity indices. This study advises the users to use the CS3 scale to evaluate a conformal radiotherapy plan which encompasses a wide range of relevant clinical volumes, and is able to extract qualitative dosimetric information.

Keywords

conformity indexevaluation toolisodose linepanning target volume
Type
Original Article
Information
Journal of Radiotherapy in Practice , Volume 17 , Issue 3 , September 2018 , pp. 309 - 312
Copyright
© Cambridge University Press 2018 

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

1. Huchet, A, Caudry, M, Belkacémi, Y et al. Volume-effect and radiotherapy part two: volume-effect and normal tissue. Cancer Radiother 2003; 7: 353–362.Google Scholar
2. Menzel, H. Prescribing, recording and reporting photon beam therapy (supplement to ICRU Report 50). Report 62, International Commission on Radiation Units and Measurements, Washington, DC, 1993.Google Scholar
3. Armstrong, J, Raben, A, Zelefsky, M et al. Promising survival with three-dimensional onformal radiation therapy for non small cell lung cancer. Radiother Oncol 1997; 44: 17–22.Google Scholar
4. Armstrong, J, McGibney, C. The impact of three-dimensional radiation on the treatment of non-small cell lung cancer. Radiother Oncol 2000; 56: 157–167.Google Scholar
5. Dearnaley, D P, Khoo, V S, Norman, A R et al. Comparison of radiation side-effects of conformal and conventional radiotherapy in prostate cancer: a randomised trial. Lancet 1999; 353: 267–272.Google Scholar
6. Lee, W R, Hanks, G E, Hanlon, A L et al. Lateral rectal shielding reduces late rectal morbidity following high dose three-dimensional conformal radiation therapy for clinically localized prostate cancer: further evidence for a significant dose effect. Int J Radiat Oncol Biol Phys 1996; 35: 251–257.Google Scholar
7. Rosenwald, J C, Gaboriaud, G, Pontvert, D. Conformal radiotherapy: principles and classification. Cancer Radiother 1999; 3: 367–377.Google Scholar
8. Carrie, C, Ginestet, C, Bey, P et al. Conformal radiation therapy. Federation nationale des centres de lutte contre le cancer (FNCLCC). Bull Cancer 1995; 82: 325–330.Google Scholar
9. Kolitsia, Z, Dahlb, O, Van Loonc, R et al. Quality assurance in conformal radiotherapy: DYNARAD consensus report on practice guidelines. Radiother Oncol 1997; 45: 217–223.Google Scholar
10. Bey, P, Gerard, J P. Practical determination of volume and doses in conformal radiotherapy. Cancer Radiother 1998; 2: 615–618.Google Scholar
11. Chavaudra, J. Last ICRU recommendations for the prescription, recording and reporting of external beam therapy. Cancer Radiother 1998; 2: 607–614.Google Scholar
12. Garcia, R, Oozeer, R, Le Thanh, H et al. Are there physical, technical and morphological limits to conformational radiotherapy? Cancer Radiother 2001; 5: 53s–56s.Google Scholar
13. Pommier, P, Ginestet, C, Carrie, C. Is conformational radiotherapy progressing? What are its difficulties and limits? Cancer Radiother 2001; 5: 57s–67s.Google Scholar
14. Piotrowski, T, Martenka, P, Patoul, N et al. The two-component conformity index formula (TCCI) and dose volume comparisons of the pituitary gland and tonsil cancer IMRT plans using a linear accelerator and helical tomotherapy. Rep Pract Oncol Radiother 2009; 14 (4): 133–145.Google Scholar
15. Feuvret, L, Noël, G, Mazeron, J J, Bey, P. Conformity index: a review. Int J Radiat Oncol Biol Phys 2006; 64 (2): 333–342.Google Scholar
16. Nakamura, J L, Verhey, L J, Smith, V et al. Dose conformity of gamma knife radiosurgery and risk factors for complications. Int J Radiat Oncol Biol Phys 2001; 51: 1313–1319.Google Scholar
17. Knoos, T, Kristensen, I, Nilsson, P. Volumetric and dosimetric evaluation of radiation treatment plans: radiation conformity index. Int J Radiat Oncol Biol Phys 1998; 42: 1169–1176.Google Scholar