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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 number of patients, number of seeds lost, and number of seeds implanted versus the prostate volume post implant. The number of patients and seeds lost are shown in the left scale, while the number of seeds implanted is shown in the right scale. The horizontal axis is the prostate volume post implant with a bin size of 10 cm3
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Figure 0003: The number of patients, number of seeds lost, and number of seeds implanted versus the prostate volume post implant. The number of patients and seeds lost are shown in the left scale, while the number of seeds implanted is shown in the right scale. The horizontal axis is the prostate volume post implant with a bin size of 10 cm3

Mentions: The relationship between seed loss and the prostate volume post implant is shown in Fig. 3. The prostate volume ranged from 19.9 to 87.5 cm3 with a mean (± SD) of 42.5 ± 12.0 cm3, and was grouped with a bin size of 10 cm3. The number of seed loss per patient was 0.00, 0.17, 0.55, 0.82, 1.00, 0.80, 1.00, and 1.50 for the groups with a volume from the first bin (between 10 to 20 cm3), to the last bin (between 80 to 90 cm3), respectively. The seed loss rate (the ratio of the number of seeds lost to the number of seeds implanted) was 0.0%, 0.2%, 0.5%, 0.7%, 0.8%, 0.6%, 0.7%, and 1.0% for the corresponding groups, respectively. The mean seed loss rate of all prostate volume groups was 0.6 ± 0.2%.


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 number of patients, number of seeds lost, and number of seeds implanted versus the prostate volume post implant. The number of patients and seeds lost are shown in the left scale, while the number of seeds implanted is shown in the right scale. The horizontal axis is the prostate volume post implant with a bin size of 10 cm3
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Figure 0003: The number of patients, number of seeds lost, and number of seeds implanted versus the prostate volume post implant. The number of patients and seeds lost are shown in the left scale, while the number of seeds implanted is shown in the right scale. The horizontal axis is the prostate volume post implant with a bin size of 10 cm3
Mentions: The relationship between seed loss and the prostate volume post implant is shown in Fig. 3. The prostate volume ranged from 19.9 to 87.5 cm3 with a mean (± SD) of 42.5 ± 12.0 cm3, and was grouped with a bin size of 10 cm3. The number of seed loss per patient was 0.00, 0.17, 0.55, 0.82, 1.00, 0.80, 1.00, and 1.50 for the groups with a volume from the first bin (between 10 to 20 cm3), to the last bin (between 80 to 90 cm3), respectively. The seed loss rate (the ratio of the number of seeds lost to the number of seeds implanted) was 0.0%, 0.2%, 0.5%, 0.7%, 0.8%, 0.6%, 0.7%, and 1.0% for the corresponding groups, respectively. The mean seed loss rate of all prostate volume groups was 0.6 ± 0.2%.

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