Dosimetric analysis of 0.5 cm versus 1cm multileaf collimator (mlc) for intensity modulated radiation therapy (IMRT) of carcinoma of cervix.

ehab a hegazy


Purpose: To evaluate the effect of multileaf collimator (MLC) different widths 0.5 cm and 1 cm mounted on the gantry of linear accelerator on planning treatment radiotherapy for cervical cancer patients.

Materials and methods: Two commercially linear accelerator type Siemens Artiste with 1 cm and 0.5 cm leaf widths were used. Twelve planes were selected with cervical cancer at Ayadi Al-Mostakbal Oncology Center, Alexandria, Egypt. The comparative analysis between two multileaf thickness 1 cm and 0.5 cm techniques were performed by comparing the basic planning optimization radiotherapy physical parameters. Number of monitor units MUs, number of segments, homogeneity index (HI), conformity index (CI), minimum dose (Dmin), Maximum dose (Dmax) and Mean dose (Dmean) were evaluated and compared.

Results and Discussion.

The average MUs required by using 1 cm mlc was (860.66±48.17) and the average MUs required by using 0.5 cm mlc was (743.75±39.12) the average difference (116.91±27.40). Measurements of number of segments showed no significant difference in number of segments. Homogeneity index absolute average difference was (0.02±0.009). Conformity index showed no significant difference between two multileaf collimators. The optimal algorithmic parameters of 0.5 cm mlc were smaller than 1 cm mlc which increase the accuracy of planning by using 0.5 cm than 1 cm mlc. The difference of Dmean,Dmin and Dmax  were   (27.96±3.04), (23.75±2.86) and (54.84± 7.59) respectively.

Conclusion: The results confirmed that 0.5 multileaf collimator gives better dose distribution, more homogenous field, and reduce Dmax, Dmin, and Dmean which optimizes radiotherapy planning and quality of treatments but failed to enhance conformity index or number of segments.


Multileaf, Radiotherapy, Cervical cancer, Planning, homogeneity, conformity

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Lucvan L, Gillian T. Palliative radiotherapy for cervical carcinoma, a system-atic review.Radiotherapy. Oncol 2011; 98:287–91.

Pedicini P, Caivano R, Fiorentino A et al. Comparative dosimetric and radiobiological assessment among a nonstandard Rapid Arc, standard Rapid Arc, classical intensity modulated radiotherapy, and 3D brachytherapy for the treatment of the vaginal vault in patients affected by gynecologic cancer. Med. Dosim. 2012; 37:347–52.

Pedicini P, Strigari L, Caivano R et al. Local tumor control probability to evaluate an applicator-guided volumetric modulated arc therapy solution as alternative of 3D brachytherapy for the treatment of the vaginal vault in patients affected by gynecological cancer. J. Appl. Clin. MED. Phys. 2013; 14:40-75

Michael DH, Brent R, Joel DK et al. Clinical outcomes of intensity-modulated pelvic radiation therapy for carcinoma of the cervix. Int. J. Radiat. Oncol.Biol.Phys.2011;14:36–80

Fischer M, Todorovic M, Drud E, and Cremers F. Commissioning of a double-focused micro multileaf collimator (μMLC). J Appl. Clin. MED. Phys. (2010).11(2):81 – 91

AAPM Report No. 72: Basic Applications of Multileaf Collimators, Report of Task Group 50(2001).

Cho PS, Marks RJ. Hardware-sensitive optimization for intensity modulated radiotherapy. Phys MED Biol (2000); 429:440-45

Hong CS, Ju SG, Kim M. Dosimetric effects of multileaf collimator leaf width on intensity-modulated radiotherapy for head and neck cancer. MED Phys (2014).21:71- 41

Wang S, Gong Y, Xu Q Impacts of multileaf collimators leaf width on intensity-modulated radiotherapy planning for nasopharyngeal carcinoma: analysis of two commercial Elekta devices. MED Dosim (2011) ; 153:159- 36

Cozzi L, Dinshaw KA , Shrivastava SK ,Mahantshetty U , Engineer R , Deshpande D D ,Jamema SV ,Vanetti E ,Clivio A ,Nicolini G ,Fogliata A.A treatment planning study comparing volumetric arc modulation with Rapid Arc and fixed field IMRT for cervix uteri radiotherapy. Radiother. Oncol. 2008 ; 180:191-89

Wang S ,Ai P ,Xie L ,Xu Q ,Bai S ,Lu Y ,Li P , Chen Y. Dosimetric comparison of different multileaf collimator leaves in treatment planning of intensity modulated radiotherapy for cervical cancer. MED. Dosim. 2013; 454:459-38

Shang, Q, Qi P, Ferjani S, Xia P. Effect of MLC leaf width on treatment adaptation and accuracy for concurrent irradiation of prostate and pelvic lymph nodes. MED. Phys. 2013; 61:70-40

Kubo HD, Wilder RB, Pappas CT. Impact of collimator leaf width on stereotactic radiosurgery and 3D conformal radiotherapy treatment plans. Inc.Radiate. Oncol.Biol.Phys. 1999; 937:945-44

Wang L, Movsas B, Jacob R, Fourkal E, Chen L, Price R, Feigenberg S, Konski A, Pollack A, Ma C. Stereotactic IMRT for prostate cancer: dosimetric impact of multi leaf collimator leaf width in the treatment of prostate cancer with IMRT.J.Appl. Clin. MED. Phys. 2004:29–41-5

Wu VW. Effects of multileaf collimator parameters on treatment planning of intensity modulated radiotherapy. MED. Dosim. 2007; 38:43-32

Balatas D, Kolotas C, Geramani K. Conformal index (COIN) to evaluate implant quality and dose specification in brachytherapy. Int. J. Radiat. Oncol. Biol. Phys. 1998; 15:24-40

Mihailidis DN, Plants B, Farinash L. Superiority of equivalent uniform dose (EUD) -based optimization for breast and chest wall. MED. Deism.2010 35:67–76.

Burmeister J, McDermott P , Bossenberger T. Effect of MLC leaf width on the planning and delivery of SMLC IMRT using the CORVUS inverse treatment planning system. MED. Phys. 2014; 87:93 -31

Ding MS, Newman F, Chen CH et al. Dosimetric comparison between 3DCRT and IMRT using different multileaf collimators in the treatment of brain tumors.MED.Dosim. 2009; 1:8-34



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