TY - JOUR
T1 - Improving plan quality and consistency by standardization of dose constraints in prostate cancer patients treated with cyberknife
AU - Descovich, Martina
AU - Carrara, Mauro
AU - Morlino, Sara
AU - Pinnaduwage, Dilini S.
AU - Saltiel, Daniel
AU - Pouliot, Jean
AU - Nash, Marc B.
AU - Pignoli, Emanuele
AU - Valdagni, Riccardo
AU - Roach, Mack
AU - Gottschalk, Alexander R.
PY - 2013
Y1 - 2013
N2 - Treatment plans for prostate cancer patients undergoing stereotactic body radiation therapy (SBRT) are often challenging due to the proximity of organs at risk. Today, there are no objective criteria to determine whether an optimal treatment plan has been achieved, and physicians rely on their personal experience to evaluate the plan's quality. In this study, we propose a method for determining rectal and bladder dose constraints achievable for a given patient's anatomy. We expect that this method will improve the overall plan quality and consistency, and facilitate comparison of clinical outcomes across different institutions. The 3D proximity of the organs at risk to the target is quantified by means of the expansion-intersection volume (EIV), which is defined as the intersection volume between the target and the organ at risk expanded by 5 mm. We determine a relationship between EIV and relevant dosimetric parameters, such as the volume of bladder and rectum receiving 75% of the prescription dose (V75%). This relationship can be used to establish institution-specific criteria to guide the treatment planning and evaluation process. A database of 25 prostate patients treated with CyberKnife SBRT is used to validate this approach. There is a linear correlation between EIV and V75% of bladder and rectum, confirming that the dose delivered to rectum and bladder increases with increasing extension and proximity of these organs to the target. This information can be used during the planning stage to facilitate the plan optimization process, and to standardize plan quality and consistency. We have developed a method for determining customized dose constraints for prostate patients treated with robotic SBRT. Although the results are technology-specific and based on the experience of a single institution, we expect that the application of this method by other institutions will result in improved standardization of clinical practice.
AB - Treatment plans for prostate cancer patients undergoing stereotactic body radiation therapy (SBRT) are often challenging due to the proximity of organs at risk. Today, there are no objective criteria to determine whether an optimal treatment plan has been achieved, and physicians rely on their personal experience to evaluate the plan's quality. In this study, we propose a method for determining rectal and bladder dose constraints achievable for a given patient's anatomy. We expect that this method will improve the overall plan quality and consistency, and facilitate comparison of clinical outcomes across different institutions. The 3D proximity of the organs at risk to the target is quantified by means of the expansion-intersection volume (EIV), which is defined as the intersection volume between the target and the organ at risk expanded by 5 mm. We determine a relationship between EIV and relevant dosimetric parameters, such as the volume of bladder and rectum receiving 75% of the prescription dose (V75%). This relationship can be used to establish institution-specific criteria to guide the treatment planning and evaluation process. A database of 25 prostate patients treated with CyberKnife SBRT is used to validate this approach. There is a linear correlation between EIV and V75% of bladder and rectum, confirming that the dose delivered to rectum and bladder increases with increasing extension and proximity of these organs to the target. This information can be used during the planning stage to facilitate the plan optimization process, and to standardize plan quality and consistency. We have developed a method for determining customized dose constraints for prostate patients treated with robotic SBRT. Although the results are technology-specific and based on the experience of a single institution, we expect that the application of this method by other institutions will result in improved standardization of clinical practice.
KW - Dose constraints
KW - Plan optimization
KW - prostate
KW - Stereotactic body radiation therapy
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M3 - Article
C2 - 24036869
AN - SCOPUS:84884140098
VL - 14
SP - 162
EP - 172
JO - Journal of Applied Clinical Medical Physics
JF - Journal of Applied Clinical Medical Physics
SN - 1526-9914
IS - 5
ER -