TY - JOUR
T1 - Effects of urethrography on prostate position
T2 - considerations for radiotherapy treatment planning of prostate carcinoma
AU - Malone, Shawn
AU - Donker, Remco
AU - Broader, Mark
AU - Dahrouge, Simone
AU - Szanto, Janos
AU - Gerig, Lee
AU - Bociek, Greg
AU - Crook, Juanita
PY - 2000/1/1
Y1 - 2000/1/1
N2 - Purpose: Retrograde urethrography is commonly used to define the prostate apex at simulation. This study evaluated the hypothesis that urethrography causes prostate displacement, resulting in an error in treatment planning.Methods and Materials: Forty-five patients with carcinoma of the prostate were evaluated. Gold seeds were placed in the apex, posterior wall, and base of the gland. In the first 20 patients, the position of the seed-defined apex was compared at simulation (with urethrogram) and on day 1 of treatment (without urethrogram). In the second cohort of 25 patients, the effects of urethrography on prostate position were evaluated directly at simulation by comparing the position of apex pre- and post-urethrography. An analysis was performed to estimate the possible impact of urethrogram-induced prostate motion on target coverage.Results: The mean superior displacement in the first and second cohort was 5.2 mm and 6.8 mm, respectively (combined mean shift 6.1 mm). With a 10-mm field margin below the tip of the urethrogram cone, 56% of patients in this study would have inadequate planning target volume (PTV) coverage.Conclusion: Retrograde urethrography causes a significant superior shift of the prostate. Strict reliance on urethrography in determining the inferior field margin could result in inadequate treatment.
AB - Purpose: Retrograde urethrography is commonly used to define the prostate apex at simulation. This study evaluated the hypothesis that urethrography causes prostate displacement, resulting in an error in treatment planning.Methods and Materials: Forty-five patients with carcinoma of the prostate were evaluated. Gold seeds were placed in the apex, posterior wall, and base of the gland. In the first 20 patients, the position of the seed-defined apex was compared at simulation (with urethrogram) and on day 1 of treatment (without urethrogram). In the second cohort of 25 patients, the effects of urethrography on prostate position were evaluated directly at simulation by comparing the position of apex pre- and post-urethrography. An analysis was performed to estimate the possible impact of urethrogram-induced prostate motion on target coverage.Results: The mean superior displacement in the first and second cohort was 5.2 mm and 6.8 mm, respectively (combined mean shift 6.1 mm). With a 10-mm field margin below the tip of the urethrogram cone, 56% of patients in this study would have inadequate planning target volume (PTV) coverage.Conclusion: Retrograde urethrography causes a significant superior shift of the prostate. Strict reliance on urethrography in determining the inferior field margin could result in inadequate treatment.
KW - Conformal radiotherapy
KW - Fiducial markers
KW - Prostate apex
KW - Prostate fiducials
KW - Urethrogram
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U2 - 10.1016/S0360-3016(99)00425-3
DO - 10.1016/S0360-3016(99)00425-3
M3 - Article
C2 - 10656378
AN - SCOPUS:0033970944
VL - 46
SP - 89
EP - 93
JO - International Journal of Radiation Oncology Biology Physics
JF - International Journal of Radiation Oncology Biology Physics
SN - 0360-3016
IS - 1
ER -