Limits...
A treatment planning study comparing tomotherapy, volumetric modulated arc therapy, Sliding Window and proton therapy for low-risk prostate carcinoma

View Article: PubMed Central - PubMed

ABSTRACT

Background: Comparing radiation treatment plans to ascertain the optimal intensity-modulated radiation technique for low-risk prostate cancer.

Methods: Treatment plans for 20 randomly selected patients were generated using the same dose objectives. A dosimetric comparison was performed between various intensity-modulated techniques, including protons. All treatment plans provided conventional treatment with 79.2Gy. Dosimetric indices for the target volume and organs at risk (OAR), including homogeneity index and four conformity indices were analyzed.

Results: No statistically significant differences between techniques were observed for homogeneity values. Dose distributions showed significant differences at low-to-medium doses. At doses above 50Gy all techniques revealed a steep dose gradient outside the planning target volume (PTV). Protons demonstrated superior rectum sparing at low-to-higher doses (V10-V70, P < .05) and bladder sparing at low-to-medium doses (V10–V30, P < .05). Helical tomotherapy (HT) provided superior rectum sparing compared to Sliding Window (SW) and Rapid Arc (RA) (V10–V70, P < .05). SW displayed superior bladder sparing compared to HT and RA (V10–V50, P < .05). Protons generated significantly higher femoral heads exposure and HT had superior sparing of those.

Conclusion: All techniques are able to provide a homogeneous and highly conformal dose distribution. Protons demonstrated superior sparing of the rectum and bladder at a wide dose spectrum. The radiation technique itself as well as treatment planning algorithms result in different OAR sparing between HT, SW and RA, with superior rectum sparing by HT and superior bladder sparing by SW. Radiation plans can be further optimized by individual modification of dose objectives dependent on treatment plan strategy.

Electronic supplementary material: The online version of this article (doi:10.1186/s13014-016-0707-6) contains supplementary material, which is available to authorized users.

No MeSH data available.


Treatment plans for tomotherapy (HT), Sliding Window (SW), Rapid Arc (RA), and protons (IMPT). Representative dose distribution with V10 (yellow), V30 (green), V50 (blue), and V70 (orange) isodoses. The prostate is delineated in red, rectum in brown, urinary bladder in yellow
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

License 1 - License 2
getmorefigures.php?uid=PMC5037612&req=5

Fig1: Treatment plans for tomotherapy (HT), Sliding Window (SW), Rapid Arc (RA), and protons (IMPT). Representative dose distribution with V10 (yellow), V30 (green), V50 (blue), and V70 (orange) isodoses. The prostate is delineated in red, rectum in brown, urinary bladder in yellow

Mentions: A greater difference in dose distribution between the techniques was found at the low-to-medium dose ranges compared to the higher doses (Figs. 1 and 2). The patient-averaged DVH revealed IMPT had statistically superior rectum sparing at low-to-higher doses compared to all other techniques (V10–V70, P = <.05), with the exception of HT at V70 (Fig. 3, Table 3). Significantly lower rectum exposure was provided by HT compared to SW and RA at low-to-higher doses (V10–V70, P < .05) (Fig. 3, Table 3). A statistical difference in Dmean values was found in all tested pairs, with lower absolute values for protons and a maximum of absolute values for RA. Lowest Dmax value was achieved by SW, and D1ccm values revealed protons produced the lowest radiation exposure and RA produced the greatest coverage (Table 3).Fig. 1


A treatment planning study comparing tomotherapy, volumetric modulated arc therapy, Sliding Window and proton therapy for low-risk prostate carcinoma
Treatment plans for tomotherapy (HT), Sliding Window (SW), Rapid Arc (RA), and protons (IMPT). Representative dose distribution with V10 (yellow), V30 (green), V50 (blue), and V70 (orange) isodoses. The prostate is delineated in red, rectum in brown, urinary bladder in yellow
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC5037612&req=5

Fig1: Treatment plans for tomotherapy (HT), Sliding Window (SW), Rapid Arc (RA), and protons (IMPT). Representative dose distribution with V10 (yellow), V30 (green), V50 (blue), and V70 (orange) isodoses. The prostate is delineated in red, rectum in brown, urinary bladder in yellow
Mentions: A greater difference in dose distribution between the techniques was found at the low-to-medium dose ranges compared to the higher doses (Figs. 1 and 2). The patient-averaged DVH revealed IMPT had statistically superior rectum sparing at low-to-higher doses compared to all other techniques (V10–V70, P = <.05), with the exception of HT at V70 (Fig. 3, Table 3). Significantly lower rectum exposure was provided by HT compared to SW and RA at low-to-higher doses (V10–V70, P < .05) (Fig. 3, Table 3). A statistical difference in Dmean values was found in all tested pairs, with lower absolute values for protons and a maximum of absolute values for RA. Lowest Dmax value was achieved by SW, and D1ccm values revealed protons produced the lowest radiation exposure and RA produced the greatest coverage (Table 3).Fig. 1

View Article: PubMed Central - PubMed

ABSTRACT

Background: Comparing radiation treatment plans to ascertain the optimal intensity-modulated radiation technique for low-risk prostate cancer.

Methods: Treatment plans for 20 randomly selected patients were generated using the same dose objectives. A dosimetric comparison was performed between various intensity-modulated techniques, including protons. All treatment plans provided conventional treatment with 79.2Gy. Dosimetric indices for the target volume and organs at risk (OAR), including homogeneity index and four conformity indices were analyzed.

Results: No statistically significant differences between techniques were observed for homogeneity values. Dose distributions showed significant differences at low-to-medium doses. At doses above 50Gy all techniques revealed a steep dose gradient outside the planning target volume (PTV). Protons demonstrated superior rectum sparing at low-to-higher doses (V10-V70, P&thinsp;&lt;&thinsp;.05) and bladder sparing at low-to-medium doses (V10&ndash;V30, P&thinsp;&lt;&thinsp;.05). Helical tomotherapy (HT) provided superior rectum sparing compared to Sliding Window (SW) and Rapid Arc (RA) (V10&ndash;V70, P&thinsp;&lt;&thinsp;.05). SW displayed superior bladder sparing compared to HT and RA (V10&ndash;V50, P&thinsp;&lt;&thinsp;.05). Protons generated significantly higher femoral heads exposure and HT had superior sparing of those.

Conclusion: All techniques are able to provide a homogeneous and highly conformal dose distribution. Protons demonstrated superior sparing of the rectum and bladder at a wide dose spectrum. The radiation technique itself as well as treatment planning algorithms result in different OAR sparing between HT, SW and RA, with superior rectum sparing by HT and superior bladder sparing by SW. Radiation plans can be further optimized by individual modification of dose objectives dependent on treatment plan strategy.

Electronic supplementary material: The online version of this article (doi:10.1186/s13014-016-0707-6) contains supplementary material, which is available to authorized users.

No MeSH data available.