Evaluation of permanent I-125 prostate implants using radiography and magnetic resonance imaging

Moerland, Marinus A.; Wijrdeman, Harm K.; Beersma, R.; Bakker, Chris J.G.; Battermann, Jan J.

doi:10.1016/s0360-3016(96)00575-5

Cited by 142 publications

(73 citation statements)

References 16 publications

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“…63 Another problem is postoperative edema, which typically increases the prostate volume by 40 to 50% compared to the preoperative volume. 59,60,66 If the postimplant CT scan is obtained immediately after the implant is performed, the dose may be underestimated. The edema increases the distance between the seeds, as well as the volume, thereby lowering the dose rate.…”

Section: Technical Issuesmentioning

confidence: 99%

“…Fusion of CT and MR images may also be a viable solution, as MR provides adequate visualization of the prostate while CT provides localization of the implanted seeds. 66,67 These numerous difficulties and technical challenges notwithstanding, the standards for seed implant quality are being defined in terms of quantitative CT-based dosimetric evaluation. Willins and Wallner 68 reported that, for CT scans obtained on the day of implantation, coverage of 80% or more of the target volume by the prescription dose is probably adequate.…”

Section: Technical Issuesmentioning

confidence: 99%

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Permanent prostate seed implant brachytherapy: Report of the American Association of Physicists in Medicine Task Group No. 64

et al. 1999

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There is now considerable evidence to suggest that technical innovations, 3D image-based planning, template guidance, computerized dosimetry analysis and improved quality assurance practice have converged in synergy in modern prostate brachytherapy, which promise to lead to increased tumor control and decreased toxicity. A substantial part of the medical physicist's contribution to this multi-disciplinary modality has a direct impact on the factors that may singly or jointly determine the treatment outcome. It is therefore of paramount importance for the medical physics community to establish a uniform standard of practice for prostate brachytherapy physics, so that the therapeutic potential of the modality can be maximally and consistently realized in the wider healthcare community. A recent survey in the U.S. for prostate brachytherapy revealed alarming variance in the pattern of practice in physics and dosimetry, particularly in regard to dose calculation, seed assay and time/method of postimplant imaging. Because of the large number of start-up programs at this time, it is essential that the roles and responsibilities of the medical physicist be clearly defined, consistent with the pivotal nature of the clinical physics component in assuring the ultimate success of prostate brachytherapy. It was against this background that the Radiation Therapy Committee of the American Association of Physicists in Medicine formed Task Group No. 64, which was charged ͑1͒ to review the current techniques in prostate seed implant brachytherapy, ͑2͒ to summarize the present knowledge in treatment planning, dose specification and reporting, ͑3͒ to recommend practical guidelines for the clinical medical physicist, and ͑4͒ to identify issues for future investigation.

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Section: Technical Issuesmentioning

confidence: 99%

Section: Technical Issuesmentioning

confidence: 99%

Permanent prostate seed implant brachytherapy: Report of the American Association of Physicists in Medicine Task Group No. 64

et al. 1999

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“…To make the time integration in Eq. (1) expressible in a closed analytic form for easy analysis, we have parameterized the overall dose fall-off around the radioactive source, g(r)/r 2 , by a single inverse power function of distance, ∞r −τ , such that the instantaneous dose rate at P in presence of edema became, (5) where Ḋ P (0), identical to the same quantity in Eq. (2), is thus related to the conventional dose prescription in absence of edema.…”

Section: B Edema-induced Dose Reductionmentioning

confidence: 99%

On the Need to Compensate for Edema-Induced Dose Reductions in Preplanned 131Cs Prostate Brachytherapy

Chen

Deng

Roberts

et al. 2008

International Journal of Radiation Oncology*Biology*Physics

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Purpose-Surgical-trauma-induced edema and its protracted resolution can lead to significant dose reduction in pre-planned 131 Cs prostate brachytherapy. The purpose of this work was to examine whether these dose reductions should be actively compensated and to estimate the magnitude of additional irradiations needed for dose compensation.Methods and Materials-Quantitative edema resolution characteristics observed by Waterman et. el. were used to examine the physical and radiobiological effects of prostate edema in preplanned 131 Cs implants. The need for dose compensation was assessed based on the dose-responses observed in 125 I and 103 Pd prostate implants. Biologically effective dose calculated with full consideration of edema evolution was used to estimate the additional irradiations needed for dose compensation.Results-Edema-induced dose reduction in pre-planned 131 Cs implants could easily exceed 10% prescription dose for implants with moderate or large edemas. These dose reductions could lead to more than 10% reduction in biochemical recurrence-free survival for individual patients if the effect of edema was ignored. For a prescribed dose of 120 Gy, the number of 2-Gy external-beam fractions needed to compensate a 5%, 10%, 15%, 20%, or 25% edema-induced dose reduction could be 1, 4, 6, 7, or 9, respectively, for prostate cancers with a median potential doubling time of 42 days. The required additional irradiation increases for tumors that are fast growing and/or are less efficient in sub-lethal damage repair.Conclusions-Compensation of edema-induced dose reductions in pre-planned 131 Cs prostate brachytherapy should be actively considered for those implants with moderate or large edemas.

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“…3). The implant quality can be evaluated after implantation with the use of CT [42]or MRI [43]. Roy et al [42]analyzed 10 patients treated with 125 I by CT scanning and demonstrated a 150–Gy coverage in 78–96% of cases.…”

Section: Brachytherapymentioning

confidence: 99%

Current Status of Minimally Invasive Treatment Options for Localized Prostate Carcinoma

Beerlage¹,

Thüroff²,

Madersbacher

et al. 2000

European Urology

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Evaluation of permanent I-125 prostate implants using radiography and magnetic resonance imaging

Cited by 142 publications

References 16 publications

Permanent prostate seed implant brachytherapy: Report of the American Association of Physicists in Medicine Task Group No. 64

Permanent prostate seed implant brachytherapy: Report of the American Association of Physicists in Medicine Task Group No. 64

On the Need to Compensate for Edema-Induced Dose Reductions in Preplanned 131Cs Prostate Brachytherapy

Current Status of Minimally Invasive Treatment Options for Localized Prostate Carcinoma

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