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A scintillation detector for the calibration of individual seeds within an Ir-192 ribbon
Proceedings
of the 34th Annual
ASTRO
Meeting
287
1080 IRIDlUM 192 TEMPLATE THERAPY IN LOCALIZED PROSTATE CANCER Eashwer K. Reddy, M.D., FACR,
Leela Krishnan, M.D., Winston Mebust, M.D., John Weigel, M.D.
University of Kansas Medical Center, Kansas City, KS
66103
PURPOSE: To review the technique and results of Iridium 192 implant followed by external radiation in localized prostate cancer. MATERIALS AND METHODS: In 1986, we have adopted Iridium 192 perineal template technique. This procedure is carried on at the time of pelvic lymphadenectomy. Between November, 1986 and February, 1989, we have treated 23 patients with localized prostate cancer (22 primary and 1 recurrent disease). The median age is 68 years with a range of 62 to 78 years. Stage distribution is as follows: A2-1; Bl-6; B2-6; C-9. Implant dose ranged from 20-35 Gy in 40-60 hours, where as external radiation dose (started 2-4 weeks after the implant) ranged from 30-45 Gy in 3-5 weeks. RESULTS: Twenty-two patients are followed to a minumum of 36 months to 60 months or until death. The patient with recurrent disease died within one year. Majority of the patients showed a rapid, clinically complete tumor regression at completion of treatment. Follow up examination included: PSA levels, DRE and TRUS with a biopsy if indicated. Only 2 of 22 patients showed biopsy proven recurrence. Both of these patients had initial Stage C disease. Another patient had biopsy and reported to be positive but tissue culture was negative. He is living four years later with normal PSA levels. Hence the local control is 90 percent. One patient died from disseminated disease. Overall survival is 95% (21/22) and disease free survival is 86% (19/22). There are no major complications. One patient developed hematuria and bloody ejaculation which subsided within a year. CONCLUSION: The follow up period is short and numbers are small to draw any conclusions. The procedure is well tolerated with no major complications. Unlike permanent implant, with removable implant, we have total control on dosimetry. With Ir-192, it is possible to deliver much higher biological dose in a short period of time. This could result in a better local control of the disease.
1081 INFLUENCE M.
Busch,
Dept.
OF G.
of
BLADDER
Kaiser,
Radiotherapy,
U.
VOLUME Burrnester,
University
ON D.
of
INTEGRAL
Metthaei,
Gottinpen,
ORGAN
DOSES
IN
HDR-INTRACERVICAL
AFTERLOADING
E. Diihmke Medical
Center,
Garmany
The role of hiph dose rate efterloadrnc therapy usinp Iridium-192 is now widely accepted. From the standards of intracavitary radium therapy (Ra-226) metal applicators ouidin9 the iridium source were developed. But now we use which are inserted into the uterine cervix without dilatation, without anesthesia and flexible plastic applicators, without the danper of perforation. Insertion can be controlled by ultrasound, computertomopraphy (CT) and mapnetic resonance imacinp (MN) without metal artefacts. We show CT’s and MN’s of intrauterine flexible afterloadinp of the uterus is not applicators scanned after intracavitary irradiation. As can be seen on the scans, the position determined by external fixation because of the flexibility of the applicator. The position depends from the volume of the bladder In most cases. As a 9eneral rule, the position of the uterus has a certain influence on the intepral bladder and rectum doses. Therafore, we studied the influence of the volume of the bladder on afterloadinp doses to bladder and rectal wall “sin9 an anatomical model based on computerized CT- and MRI-scans from our patients. The table shows that at small bladder volumes (< 30 ml) more than half on the bladder mucosa is irradiated with hi9h sinple doses. In this situation only 9 % of the rectal wall pets the entire sinole dose. At hipher bladder volumes the intepral dose to the bladder is quite lower, but more of the rectal wall gets < 50 % of the single dose. The bladder volume influences afterloadinp doses to the orpans at risk (bladder and rectum) usinp flexible intraThere is no need for insurinp an exact predetermined volume of the bladder, but cervical afterloading applicators. both complete emptyinp and fillinp of the bladder up to a maximum durinp irradiation should be avoided in intracervical afterloadinp with flexible applicators. 30
BI vol
140
50
475
I
30
50
140
475
RECTUM
BLADDER
% of
dose ref. pt. < 100 < 90 < 80 < 70 < 60 < 50 Percent
of
66.5 12.12 12.12 9.0
rectal
or
39.32 4.5 3.0 4.5 4.5 16.6 bladder
tissue
33.3 3.3 3.3 3.3 16.6 40.0 as a function
21.4 8.9 12.5 3.5 1.8 51.8
28.37 4.05 4.05 4.05 8.1 51.3 of
bladder
volume
(ml).
20.4 9.3 5.5 9.3 3.1 51 .a
26.6 1.9 9.5 7.6 6.6 47.6
20.18 3.7 11.0 11 .o 11 .o 43.11
of the 34th Annual
ASTRO
Meeting
287
1080 IRIDlUM 192 TEMPLATE THERAPY IN LOCALIZED PROSTATE CANCER Eashwer K. Reddy, M.D., FACR,
Leela Krishnan, M.D., Winston Mebust, M.D., John Weigel, M.D.
University of Kansas Medical Center, Kansas City, KS
66103
PURPOSE: To review the technique and results of Iridium 192 implant followed by external radiation in localized prostate cancer. MATERIALS AND METHODS: In 1986, we have adopted Iridium 192 perineal template technique. This procedure is carried on at the time of pelvic lymphadenectomy. Between November, 1986 and February, 1989, we have treated 23 patients with localized prostate cancer (22 primary and 1 recurrent disease). The median age is 68 years with a range of 62 to 78 years. Stage distribution is as follows: A2-1; Bl-6; B2-6; C-9. Implant dose ranged from 20-35 Gy in 40-60 hours, where as external radiation dose (started 2-4 weeks after the implant) ranged from 30-45 Gy in 3-5 weeks. RESULTS: Twenty-two patients are followed to a minumum of 36 months to 60 months or until death. The patient with recurrent disease died within one year. Majority of the patients showed a rapid, clinically complete tumor regression at completion of treatment. Follow up examination included: PSA levels, DRE and TRUS with a biopsy if indicated. Only 2 of 22 patients showed biopsy proven recurrence. Both of these patients had initial Stage C disease. Another patient had biopsy and reported to be positive but tissue culture was negative. He is living four years later with normal PSA levels. Hence the local control is 90 percent. One patient died from disseminated disease. Overall survival is 95% (21/22) and disease free survival is 86% (19/22). There are no major complications. One patient developed hematuria and bloody ejaculation which subsided within a year. CONCLUSION: The follow up period is short and numbers are small to draw any conclusions. The procedure is well tolerated with no major complications. Unlike permanent implant, with removable implant, we have total control on dosimetry. With Ir-192, it is possible to deliver much higher biological dose in a short period of time. This could result in a better local control of the disease.
1081 INFLUENCE M.
Busch,
Dept.
OF G.
of
BLADDER
Kaiser,
Radiotherapy,
U.
VOLUME Burrnester,
University
ON D.
of
INTEGRAL
Metthaei,
Gottinpen,
ORGAN
DOSES
IN
HDR-INTRACERVICAL
AFTERLOADING
E. Diihmke Medical
Center,
Garmany
The role of hiph dose rate efterloadrnc therapy usinp Iridium-192 is now widely accepted. From the standards of intracavitary radium therapy (Ra-226) metal applicators ouidin9 the iridium source were developed. But now we use which are inserted into the uterine cervix without dilatation, without anesthesia and flexible plastic applicators, without the danper of perforation. Insertion can be controlled by ultrasound, computertomopraphy (CT) and mapnetic resonance imacinp (MN) without metal artefacts. We show CT’s and MN’s of intrauterine flexible afterloadinp of the uterus is not applicators scanned after intracavitary irradiation. As can be seen on the scans, the position determined by external fixation because of the flexibility of the applicator. The position depends from the volume of the bladder In most cases. As a 9eneral rule, the position of the uterus has a certain influence on the intepral bladder and rectum doses. Therafore, we studied the influence of the volume of the bladder on afterloadinp doses to bladder and rectal wall “sin9 an anatomical model based on computerized CT- and MRI-scans from our patients. The table shows that at small bladder volumes (< 30 ml) more than half on the bladder mucosa is irradiated with hi9h sinple doses. In this situation only 9 % of the rectal wall pets the entire sinole dose. At hipher bladder volumes the intepral dose to the bladder is quite lower, but more of the rectal wall gets < 50 % of the single dose. The bladder volume influences afterloadinp doses to the orpans at risk (bladder and rectum) usinp flexible intraThere is no need for insurinp an exact predetermined volume of the bladder, but cervical afterloading applicators. both complete emptyinp and fillinp of the bladder up to a maximum durinp irradiation should be avoided in intracervical afterloadinp with flexible applicators. 30
BI vol
140
50
475
I
30
50
140
475
RECTUM
BLADDER
% of
dose ref. pt. < 100 < 90 < 80 < 70 < 60 < 50 Percent
of
66.5 12.12 12.12 9.0
rectal
or
39.32 4.5 3.0 4.5 4.5 16.6 bladder
tissue
33.3 3.3 3.3 3.3 16.6 40.0 as a function
21.4 8.9 12.5 3.5 1.8 51.8
28.37 4.05 4.05 4.05 8.1 51.3 of
bladder
volume
(ml).
20.4 9.3 5.5 9.3 3.1 51 .a
26.6 1.9 9.5 7.6 6.6 47.6
20.18 3.7 11.0 11 .o 11 .o 43.11