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Evaluation of the dosimetric impact of loss and displacement of seeds in prostate low-dose-rate brachytherapy.

Wang Y, Nasser NJ, Borg J, Saibishkumar EP - J Contemp Brachytherapy (2015)

Bottom Line: Two hundred and seventeen prostate cancer patients have been treated with LDR brachytherapy.Their impact on prostate dosimetry had been examined.Prostate length difference between pre-plan and post-implant images was within 6 mm in more than 98% of cases.

View Article: PubMed Central - PubMed

Affiliation: Department of Radiation Physics, Princess Margaret Cancer Centre, University Health Network, Toronto, Ontario, Canada.

ABSTRACT

Purpose: To analyze the seed loss and displacement and their dosimetric impact in prostate low-dose-rate (LDR) brachytherapy while utilizing the combination of loose and stranded seeds.

Material and methods: Two hundred and seventeen prostate cancer patients have been treated with LDR brachytherapy. Loose seeds were implanted in the prostate center and stranded seeds in the periphery of the gland. Patients were imaged with transrectal ultrasound before implant and with computerized tomography/magnetic resonance imaging (CT/MR) one month after implant. The seed loss and displacement had been analyzed. Their impact on prostate dosimetry had been examined. The seed distribution beyond the prostate inferior boundary had been studied.

Results: The mean number of seeds per patient that were lost to lung, pelvis/abdomen, urine, or unknown destinations was 0.21, 0.13, 0.03, and 0.29, respectively. Overall, 40.1% of patients had seed loss. Seed migration to lung and pelvis/abdomen occurred in 15.5% and 10.5% of the patients, respectively. Documented seed loss to urine was found in 3% of the patients while 20% of patients had seed loss to unknown destinations. Prostate length difference between pre-plan and post-implant images was within 6 mm in more than 98% of cases. The difference in number of seeds inferior to prostate between pre-plan and post-implant dosimetry was within 7 seeds for 93% of patients. At time of implant, 98% of seeds, inferior to prostate, were within 5 mm and 100% within 15 mm, and in one month post-implant 83% within 9 mm and 96.3% within 15 mm. Prostate post-implant V100, D90, and rectal wall RV100 for patients without seed loss were 94.6%, 113.9%, and 0.98 cm(3), respectively, as compared to 95.0%, 114.8%, and 0.95 cm(3) for the group with seed loss.

Conclusions: Seed loss and displacement have been observed to be frequent. No correlation between seed loss and displacement and post-plan dosimetry has been reported.

No MeSH data available.


Related in: MedlinePlus

The distribution of the distance of seeds inferior to the prostate as identified in the CT/MR images one month post-implant
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Figure 0004: The distribution of the distance of seeds inferior to the prostate as identified in the CT/MR images one month post-implant

Mentions: All seeds inferior to prostate apex were planned within 5 mm of prostate. At the implant procedure, 98.4% of these seeds were observed within 5 mm of the prostate apex, 99.8% of them were within 10 mm, and 100% were within 15 mm. The percentage of the seeds inferior to the prostate as identified in the CT/MR images one month post-implant is shown as a function of distance from the prostate apex in Fig. 4. 96.3% of all inferior seeds were within 15 mm from the prostate apex. The remaining 3.7% of the inferior seeds were located more than 15 mm beyond the prostate, two seeds of which (each from a different patient) were 30 mm below the prostate. The one (0.056% of all inferior seeds) far most seed (found in another patient) was 33 mm inferior to the prostate apex.


Evaluation of the dosimetric impact of loss and displacement of seeds in prostate low-dose-rate brachytherapy.

Wang Y, Nasser NJ, Borg J, Saibishkumar EP - J Contemp Brachytherapy (2015)

The distribution of the distance of seeds inferior to the prostate as identified in the CT/MR images one month post-implant
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4499516&req=5

Figure 0004: The distribution of the distance of seeds inferior to the prostate as identified in the CT/MR images one month post-implant
Mentions: All seeds inferior to prostate apex were planned within 5 mm of prostate. At the implant procedure, 98.4% of these seeds were observed within 5 mm of the prostate apex, 99.8% of them were within 10 mm, and 100% were within 15 mm. The percentage of the seeds inferior to the prostate as identified in the CT/MR images one month post-implant is shown as a function of distance from the prostate apex in Fig. 4. 96.3% of all inferior seeds were within 15 mm from the prostate apex. The remaining 3.7% of the inferior seeds were located more than 15 mm beyond the prostate, two seeds of which (each from a different patient) were 30 mm below the prostate. The one (0.056% of all inferior seeds) far most seed (found in another patient) was 33 mm inferior to the prostate apex.

Bottom Line: Two hundred and seventeen prostate cancer patients have been treated with LDR brachytherapy.Their impact on prostate dosimetry had been examined.Prostate length difference between pre-plan and post-implant images was within 6 mm in more than 98% of cases.

View Article: PubMed Central - PubMed

Affiliation: Department of Radiation Physics, Princess Margaret Cancer Centre, University Health Network, Toronto, Ontario, Canada.

ABSTRACT

Purpose: To analyze the seed loss and displacement and their dosimetric impact in prostate low-dose-rate (LDR) brachytherapy while utilizing the combination of loose and stranded seeds.

Material and methods: Two hundred and seventeen prostate cancer patients have been treated with LDR brachytherapy. Loose seeds were implanted in the prostate center and stranded seeds in the periphery of the gland. Patients were imaged with transrectal ultrasound before implant and with computerized tomography/magnetic resonance imaging (CT/MR) one month after implant. The seed loss and displacement had been analyzed. Their impact on prostate dosimetry had been examined. The seed distribution beyond the prostate inferior boundary had been studied.

Results: The mean number of seeds per patient that were lost to lung, pelvis/abdomen, urine, or unknown destinations was 0.21, 0.13, 0.03, and 0.29, respectively. Overall, 40.1% of patients had seed loss. Seed migration to lung and pelvis/abdomen occurred in 15.5% and 10.5% of the patients, respectively. Documented seed loss to urine was found in 3% of the patients while 20% of patients had seed loss to unknown destinations. Prostate length difference between pre-plan and post-implant images was within 6 mm in more than 98% of cases. The difference in number of seeds inferior to prostate between pre-plan and post-implant dosimetry was within 7 seeds for 93% of patients. At time of implant, 98% of seeds, inferior to prostate, were within 5 mm and 100% within 15 mm, and in one month post-implant 83% within 9 mm and 96.3% within 15 mm. Prostate post-implant V100, D90, and rectal wall RV100 for patients without seed loss were 94.6%, 113.9%, and 0.98 cm(3), respectively, as compared to 95.0%, 114.8%, and 0.95 cm(3) for the group with seed loss.

Conclusions: Seed loss and displacement have been observed to be frequent. No correlation between seed loss and displacement and post-plan dosimetry has been reported.

No MeSH data available.


Related in: MedlinePlus