Intraoperative Dosimetry for Prostate Brachytherapy Using Fluoroscopy and Ultrasound
| Status: | Active, not recruiting |
|---|---|
| Conditions: | Prostate Cancer, Cancer |
| Therapuetic Areas: | Oncology |
| Healthy: | No |
| Age Range: | 18 - Any |
| Updated: | 11/9/2018 |
| Start Date: | August 2014 |
| End Date: | March 2021 |
Phase II Study of Dynamic Intraoperative Dosimetry for Prostate Brachytherapy Using Registered Fluoroscopy and Ultrasound
The purpose of this study is to assess the performance of a system of intraoperative dynamic
dosimetry during prostate seed implantation (brachytherapy) including its new elements, to
evaluate and refine technical methods of using the system, as well as confirm its performance
and accuracy.
dosimetry during prostate seed implantation (brachytherapy) including its new elements, to
evaluate and refine technical methods of using the system, as well as confirm its performance
and accuracy.
The use of brachytherapy or implantation of radioactive sources into the prostate for
adenocarcinoma has advantages over external beam radiation in that a very high dose can be
delivered to the tumor while limiting the doses to the surrounding normal tissue (i.e., bowel
and bladder). It is established that outcomes after treatment with brachytherapy are related
to the technical quality of source placement within the gland. Accurate placement of the
radioactive sources with achievement of optimum dose distributions within the prostate is key
to the success of brachytherapy with regard to both killing tumor as well as minimizing
toxicity.
Due to factors such as deformations of the prostate during needle insertion, needle deviation
from intended path during insertion, prostatic edema from needle trauma, and relaxation of
tissues as well as source migration after needle removal, the actual source positions upon
completion of the procedure may fail to accurately match their intended placement, resulting
in variations from the idealized dosimetric plan.
One way to overcome this complex problem is to have the capability of visualizing the sources
once they are in the prostate and then continuously updating the dosimetric plan in real
time. To this end, we have developed a mechanism whereby ultrasound and fluoroscopy are
quantitatively integrated to allow for real-time visualization of source positions
intraoperatively. A prior Phase I study performed by this group evaluated a prototype version
of this mechanism, resulting in the successful treatment of 6 patients with true
intraoperative dynamic dosimetry. Dosimetric outcomes within this cohort of patients was
excellent, and the intraoperative doses predicted by the system more accurate than that
predicted by the current standard method (ultrasound-based dosimetry).
adenocarcinoma has advantages over external beam radiation in that a very high dose can be
delivered to the tumor while limiting the doses to the surrounding normal tissue (i.e., bowel
and bladder). It is established that outcomes after treatment with brachytherapy are related
to the technical quality of source placement within the gland. Accurate placement of the
radioactive sources with achievement of optimum dose distributions within the prostate is key
to the success of brachytherapy with regard to both killing tumor as well as minimizing
toxicity.
Due to factors such as deformations of the prostate during needle insertion, needle deviation
from intended path during insertion, prostatic edema from needle trauma, and relaxation of
tissues as well as source migration after needle removal, the actual source positions upon
completion of the procedure may fail to accurately match their intended placement, resulting
in variations from the idealized dosimetric plan.
One way to overcome this complex problem is to have the capability of visualizing the sources
once they are in the prostate and then continuously updating the dosimetric plan in real
time. To this end, we have developed a mechanism whereby ultrasound and fluoroscopy are
quantitatively integrated to allow for real-time visualization of source positions
intraoperatively. A prior Phase I study performed by this group evaluated a prototype version
of this mechanism, resulting in the successful treatment of 6 patients with true
intraoperative dynamic dosimetry. Dosimetric outcomes within this cohort of patients was
excellent, and the intraoperative doses predicted by the system more accurate than that
predicted by the current standard method (ultrasound-based dosimetry).
Inclusion Criteria:
- Histologically confirmed, localized adenocarcinoma of the prostate
- Clinical stages T1b - T3a
- The patient has decided to undergo brachytherapy (or brachytherapy plus external beam
radiation) as a treatment modality for his prostate cancer
- Karnofsky Performance Status > 60
- Prostate volume by transrectal ultrasound (TRUS) < 55 cc
- International Prostate symptom score (IPSS) 20 or less
- Ability to have MRI as part of post-implant assessment
- Signed study-specific consent form prior to registration
Exclusion Criteria:
- Stage T3b or greater disease.
- Prior history of pelvic radiation therapy
- Significant obstructive symptoms (IPSS greater than 20)
- Major medical or psychiatric illness which, in the investigator's opinion, would
prevent completion of treatment and would interfere with follow up.
- Implanted device or apparatus which obstruct visibility of the implanted sources on
fluoroscopy
- Metallic implants, claustrophobia not amenable to medication, or known
contraindications to undergoing MR scanning
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