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Advances in radiation therapy dosimetry.

Paliwal B, Tewatia D - J Med Phys (2009)

Bottom Line: Advanced techniques are less tolerant to poor implementation than are standard techniques.Mis-administrations are more difficult to detect and can possibly lead to poor outcomes for some patients.Some of the major challenges in the above areas are discussed.

View Article: PubMed Central - PubMed

Affiliation: University of Wisconsin Radiation Oncology Physics 600 Highland Ave., K4/B100 - 0600 Madison, USA.

ABSTRACT
During the last decade, there has been an explosion of new radiation therapy planning and delivery tools. We went through a rapid transition from conventional three-dimensional (3D) conformal radiation therapy to intensity-modulated radiation therapy (IMRT) treatments, and additional new techniques for motion-adaptive radiation therapy are being introduced. These advances push the frontiers in our effort to provide better patient care; and with the addition of IMRT, temporal dimensions are major challenges for the radiotherapy patient dosimetry and delivery verification. Advanced techniques are less tolerant to poor implementation than are standard techniques. Mis-administrations are more difficult to detect and can possibly lead to poor outcomes for some patients. Instead of presenting a manual on quality assurance for radiation therapy, this manuscript provides an overview of dosimetry verification tools and a focused discussion on breath holding, respiratory gating and the applications of four-dimensional computed tomography in motion management. Some of the major challenges in the above areas are discussed.

No MeSH data available.


Related in: MedlinePlus

CT density calibration curve for full phan (Head d-phan) mode of CBCT (all possible modes of scanning), along with conventional CT
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Figure 0008: CT density calibration curve for full phan (Head d-phan) mode of CBCT (all possible modes of scanning), along with conventional CT

Mentions: Online volumetric CBCT matching with planning CT can be expedited using auto-matching algorithms available in some of the commercial systems, as shown in Figure 5. The image sets obtained from these modalities if carefully quantified can lead to dramatic improvement in the quality assurance processes employed in radiation therapy. Both MVCT- and CBCT-based images can be used for dose re-computation for implementing the dose-adaptive radiotherapy. Proper CT density calibration curves are needed prior to the implementation of dose-adaptive radiotherapy. CBCT has 2 modes of scanning, namely, full fan mode (head d-phan) and half fan mode (body d-phan). A separate CT density calibration curve is required for both the scanning modes for all the settings available, as shown in Figures 6 and 7. Moreover, average CT number can vary with cone angle due to scatter, as shown in Figure 8. Although these new technologies demonstrate the very good promise for achieving a precise goal of radiotherapy, there are some inherent problems to be solved. Ring artifacts due to detector inadequacy, streaking artifacts due to beam hardening and scatter and cupping artifacts due to the scattering and beam hardening, as shown in Figure 9. Similarly, MVCT number-to-density calibration is required in order to implement dose-adaptive radiotherapy.


Advances in radiation therapy dosimetry.

Paliwal B, Tewatia D - J Med Phys (2009)

CT density calibration curve for full phan (Head d-phan) mode of CBCT (all possible modes of scanning), along with conventional CT
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2807673&req=5

Figure 0008: CT density calibration curve for full phan (Head d-phan) mode of CBCT (all possible modes of scanning), along with conventional CT
Mentions: Online volumetric CBCT matching with planning CT can be expedited using auto-matching algorithms available in some of the commercial systems, as shown in Figure 5. The image sets obtained from these modalities if carefully quantified can lead to dramatic improvement in the quality assurance processes employed in radiation therapy. Both MVCT- and CBCT-based images can be used for dose re-computation for implementing the dose-adaptive radiotherapy. Proper CT density calibration curves are needed prior to the implementation of dose-adaptive radiotherapy. CBCT has 2 modes of scanning, namely, full fan mode (head d-phan) and half fan mode (body d-phan). A separate CT density calibration curve is required for both the scanning modes for all the settings available, as shown in Figures 6 and 7. Moreover, average CT number can vary with cone angle due to scatter, as shown in Figure 8. Although these new technologies demonstrate the very good promise for achieving a precise goal of radiotherapy, there are some inherent problems to be solved. Ring artifacts due to detector inadequacy, streaking artifacts due to beam hardening and scatter and cupping artifacts due to the scattering and beam hardening, as shown in Figure 9. Similarly, MVCT number-to-density calibration is required in order to implement dose-adaptive radiotherapy.

Bottom Line: Advanced techniques are less tolerant to poor implementation than are standard techniques.Mis-administrations are more difficult to detect and can possibly lead to poor outcomes for some patients.Some of the major challenges in the above areas are discussed.

View Article: PubMed Central - PubMed

Affiliation: University of Wisconsin Radiation Oncology Physics 600 Highland Ave., K4/B100 - 0600 Madison, USA.

ABSTRACT
During the last decade, there has been an explosion of new radiation therapy planning and delivery tools. We went through a rapid transition from conventional three-dimensional (3D) conformal radiation therapy to intensity-modulated radiation therapy (IMRT) treatments, and additional new techniques for motion-adaptive radiation therapy are being introduced. These advances push the frontiers in our effort to provide better patient care; and with the addition of IMRT, temporal dimensions are major challenges for the radiotherapy patient dosimetry and delivery verification. Advanced techniques are less tolerant to poor implementation than are standard techniques. Mis-administrations are more difficult to detect and can possibly lead to poor outcomes for some patients. Instead of presenting a manual on quality assurance for radiation therapy, this manuscript provides an overview of dosimetry verification tools and a focused discussion on breath holding, respiratory gating and the applications of four-dimensional computed tomography in motion management. Some of the major challenges in the above areas are discussed.

No MeSH data available.


Related in: MedlinePlus