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The use of biologically related model (Eclipse) for the intensity-modulated radiation therapy planning of nasopharyngeal carcinomas.

Kan MW, Leung LH, Yu PK - PLoS ONE (2014)

Bottom Line: BBTP plans reduced the volume of parotid glands receiving doses of above 40 Gy compared to DVTP plans.There were no significant differences in the NTCP values between the two approaches for the serial organs.Our results showed that the BBTP approach could be a potential alternative approach to the DVTP approach for NPC.

View Article: PubMed Central - PubMed

Affiliation: Department of Oncology, Princess Margaret Hospital, Hong Kong SAR, China; Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong, Hong Kong SAR, China.

ABSTRACT

Purpose: Intensity-modulated radiation therapy (IMRT) is the most common treatment technique for nasopharyngeal carcinoma (NPC). Physical quantities such as dose/dose-volume parameters are used conventionally for IMRT optimization. The use of biological related models has been proposed and can be a new trend. This work was to assess the performance of the biologically based IMRT optimization model installed in a popular commercial treatment planning system (Eclipse) as compared to its dose/dose volume optimization model when employed in the clinical environment for NPC cases.

Methods: Ten patients of early stage NPC and ten of advanced stage NPC were selected for this study. IMRT plans optimized using biological related approach (BBTP) were compared to their corresponding plans optimized using the dose/dose volume based approach (DVTP). Plan evaluation was performed using both biological indices and physical dose indices such as tumor control probability (TCP), normal tissue complication probability (NTCP), target coverage, conformity, dose homogeneity and doses to organs at risk. The comparison results of the more complex advanced stage cases were reported separately from those of the simpler early stage cases.

Results: The target coverage and conformity were comparable between the two approaches, with BBTP plans producing more hot spots. For the primary targets, BBTP plans produced comparable TCP for the early stage cases and higher TCP for the advanced stage cases. BBTP plans reduced the volume of parotid glands receiving doses of above 40 Gy compared to DVTP plans. The NTCP of parotid glands produced by BBTP were 8.0 ± 5.8 and 7.9 ± 8.7 for early and advanced stage cases, respectively, while those of DVTP were 21.3 ± 8.3 and 24.4 ± 12.8, respectively. There were no significant differences in the NTCP values between the two approaches for the serial organs.

Conclusions: Our results showed that the BBTP approach could be a potential alternative approach to the DVTP approach for NPC.

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Related in: MedlinePlus

One of the axial computed tomography (CT) slices comparing the isodose curves between the BBTP plan and the DVTP plan of a typical NPC patient.
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pone-0112229-g002: One of the axial computed tomography (CT) slices comparing the isodose curves between the BBTP plan and the DVTP plan of a typical NPC patient.

Mentions: Table 6 summarized the average results for OARs of early stage NPC patients. For all the serial organs including brain stem, spinal cord, optic nerve and optic chiasma, there were no significant differences in the values of D1% and NTCP between BBTP plans and DVTP plans. All D1% values were lower than the tolerance dose level and the NTCP values approach to zero for both types of plans. The D5% for spinal cord of BBTP plans was 2.8 Gy lower than that of DVBP plans and was statistically significant. This could also be reflected by the DVH curve shown in figure 1 (e). For parotid glands, the average NTCP value was 21.3% for DVTP plans, while it was only 8.0% for BBTP plans, indicating a significant reduction in the NTCP value with the use of biological optimization. The mean dose and V30Gy of BBTP plans were slightly lower when compared to DVTP plans. However, V40Gy and V50Gy (volumes receiving higher doses), were significantly reduced from 25.0% to 10.8% and 13.3% to 4.0%, respectively, when using BBTP plans rather than DVTP plans. The DVH curve of figure 1 (f) also showed that a significantly lower volume of the parotid glands under the BBTP plans received the higher dose values. The isodose lines shown in figure 2 shows that the dose fall off near the parotid glands was steeper for the BBTP plan than that for the DVTP plan of a typical patient. For eye retina and lens, the average mean doses for DVTP plans were 1.8 and 1.9 Gy lower than those of the BBTP plans, respectively, inducing no significant difference in NTCP values.


The use of biologically related model (Eclipse) for the intensity-modulated radiation therapy planning of nasopharyngeal carcinomas.

Kan MW, Leung LH, Yu PK - PLoS ONE (2014)

One of the axial computed tomography (CT) slices comparing the isodose curves between the BBTP plan and the DVTP plan of a typical NPC patient.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4221619&req=5

pone-0112229-g002: One of the axial computed tomography (CT) slices comparing the isodose curves between the BBTP plan and the DVTP plan of a typical NPC patient.
Mentions: Table 6 summarized the average results for OARs of early stage NPC patients. For all the serial organs including brain stem, spinal cord, optic nerve and optic chiasma, there were no significant differences in the values of D1% and NTCP between BBTP plans and DVTP plans. All D1% values were lower than the tolerance dose level and the NTCP values approach to zero for both types of plans. The D5% for spinal cord of BBTP plans was 2.8 Gy lower than that of DVBP plans and was statistically significant. This could also be reflected by the DVH curve shown in figure 1 (e). For parotid glands, the average NTCP value was 21.3% for DVTP plans, while it was only 8.0% for BBTP plans, indicating a significant reduction in the NTCP value with the use of biological optimization. The mean dose and V30Gy of BBTP plans were slightly lower when compared to DVTP plans. However, V40Gy and V50Gy (volumes receiving higher doses), were significantly reduced from 25.0% to 10.8% and 13.3% to 4.0%, respectively, when using BBTP plans rather than DVTP plans. The DVH curve of figure 1 (f) also showed that a significantly lower volume of the parotid glands under the BBTP plans received the higher dose values. The isodose lines shown in figure 2 shows that the dose fall off near the parotid glands was steeper for the BBTP plan than that for the DVTP plan of a typical patient. For eye retina and lens, the average mean doses for DVTP plans were 1.8 and 1.9 Gy lower than those of the BBTP plans, respectively, inducing no significant difference in NTCP values.

Bottom Line: BBTP plans reduced the volume of parotid glands receiving doses of above 40 Gy compared to DVTP plans.There were no significant differences in the NTCP values between the two approaches for the serial organs.Our results showed that the BBTP approach could be a potential alternative approach to the DVTP approach for NPC.

View Article: PubMed Central - PubMed

Affiliation: Department of Oncology, Princess Margaret Hospital, Hong Kong SAR, China; Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong, Hong Kong SAR, China.

ABSTRACT

Purpose: Intensity-modulated radiation therapy (IMRT) is the most common treatment technique for nasopharyngeal carcinoma (NPC). Physical quantities such as dose/dose-volume parameters are used conventionally for IMRT optimization. The use of biological related models has been proposed and can be a new trend. This work was to assess the performance of the biologically based IMRT optimization model installed in a popular commercial treatment planning system (Eclipse) as compared to its dose/dose volume optimization model when employed in the clinical environment for NPC cases.

Methods: Ten patients of early stage NPC and ten of advanced stage NPC were selected for this study. IMRT plans optimized using biological related approach (BBTP) were compared to their corresponding plans optimized using the dose/dose volume based approach (DVTP). Plan evaluation was performed using both biological indices and physical dose indices such as tumor control probability (TCP), normal tissue complication probability (NTCP), target coverage, conformity, dose homogeneity and doses to organs at risk. The comparison results of the more complex advanced stage cases were reported separately from those of the simpler early stage cases.

Results: The target coverage and conformity were comparable between the two approaches, with BBTP plans producing more hot spots. For the primary targets, BBTP plans produced comparable TCP for the early stage cases and higher TCP for the advanced stage cases. BBTP plans reduced the volume of parotid glands receiving doses of above 40 Gy compared to DVTP plans. The NTCP of parotid glands produced by BBTP were 8.0 ± 5.8 and 7.9 ± 8.7 for early and advanced stage cases, respectively, while those of DVTP were 21.3 ± 8.3 and 24.4 ± 12.8, respectively. There were no significant differences in the NTCP values between the two approaches for the serial organs.

Conclusions: Our results showed that the BBTP approach could be a potential alternative approach to the DVTP approach for NPC.

Show MeSH
Related in: MedlinePlus