Imaginary case of nasopharyngeal cancer

                                                        9 ports irradiation (whole neck 7 ports + 2 ports for boost or SIB )

This plan was made using 'Level II-V whole neck plan' with 2 ports boost or SIB. In Japan, whole neck irradiation is usually prescribed 50 Gy. So several dose weight are changed in this plan, but essentially this plan was made by same methodology.

Caution: Dose rate of this plan is high like as other 'conventional method', but IMRT is essentially 'low dose rate therapy'. So I recommend that you should not believe the clinical results based on IMRT. The side effects you do not expect may happen.

Caution 2: If you use this template, please several parameters. You should make fine adjustments for each cases in MLC of middle portion. Some cases need more wider margin for spinal cord or parotid glands. I think that prescribed dose should more lower dose compare with now standard IMRT prescriptions.

Prescribed dose : Nasopharyngeal region 75Gy, Level II-V Lymphnodes are 60Gy

CTV1 (nasopharynx)                 Spinal cord            

Dmin   5408                         Dmin   1983

Dmax   8539                        Dmax   5251

Dmean 7714                        Dmean 3717

D60  99%                                            

D70   93%                                            

D75   68%                                            

D77   54%                                            

D83   17%                                            

CTV2 (LNs level II-V)             Right parotis        

Dmin   2727                        Dmin   1664

Dmax   8153                       Dmax   4972

Dmean 6565                       Dmean 3447

D60 96%                                             

PTV                                   Left parotis         

Dmin   1037                        Dmin   2050

Dmax   8563                        Dmax   5398

Dmean 6545                        Dmean 3792

D60 89%                                              

This detail will be shown after future publication

Another sample with same template

- For the reference -

IMRT Plan - 135 segments

This plan does not do optimization enough. But I think this case is difficult to plan.

<For exsample - Without MLC ->

CAUTION!: This plan is contain unacceptable high dose area. This plan nees several adjustment ( such as Pb BLOCK ) for parotis etc.

- Without MLC plan -

CTV1 (nasopharynx)                 Spinal cord            

Dmin   5492                         Dmin   2468

Dmax   8948                        Dmax   5425

Dmean 7929                        Dmean 3839

D60 100%                                            

D70   96%                                            

D75   80%                                            

D77   68%                                            

D80   48%                                            

CTV2 (LNs level II-V)             Right parotis        

Dmin   2696                        Dmin   3116

Dmax   8763                       Dmax   8471

Dmean 6417                       Dmean 6721

D60 84%                                             

PTV                                   Left parotis         

Dmin   1073                        Dmin   4114

Dmax   9088                        Dmax   8862

Dmean 6489                        Dmean 7298

D60 81%                                              

  last modification date: 2006/04/05