I want to model the edema formation of the prostate during brachytherapy and I can't find any references to the initial phase of the edema right after the seeds insertion. Is there anyone with experience in this domain who could help me?
For the past 20 years, we have obtained a CT of our prostate implants as soon as the patient is released from the recovery room, about 1 to 2 hours after the completion of the implant. We did a study on a small group of patients followed with sequential CTs and found that the maximum prostate volume was on the first postimplant scan. (GS Merrick et al., Influence of timing on the dosimetric analysis of transperineal ultrasound-guided, prostatic conformal brachytherapy. Radiat Oncol Investig. 1998; 6:182-190, http://www.ncbi.nlm.nih.gov/pubmed/9727878). Furthermore, the use of dexamethasone does not prevent edema but merely postpones it. (GS Merrick et al., Influence of prophylactic dexamethasone on edema following prostate brachytherapy. Tech Urol. 2000; 6:117-122, http://www.ncbi.nlm.nih.gov/pubmed/10798812).
Zhe Chen and colleagues presented an excellent theoretical analysis of the extent of edema and its rate of resolution. (Z Chen et al., Dosimetric effects of edema in permanent prostate seed implants: a rigorous solution. Int J Radiat Oncol Biol Phys. 2000; 47:1405-19, http://www.ncbi.nlm.nih.gov/pubmed/10889396).
For a long time, we thought that edema and its detrimental effect on urinary function was primarily due to needle trauma. Then 10 years ago we started doing transperineal mapping biopsies with over 50 cores taken from most patients. Their urinary function returned to normal much faster than our implant patients, so we feel that most implant edema is due to radiation effects rather than trauma. (GS Merrick et al., The morbidity of transperineal template-guided prostate mapping biopsy. BJU Int. 2008; 101:1524-1529, http://www.ncbi.nlm.nih.gov/pubmed/18325064).
Thank you very much Dr Butler. I have come up with some of the referenced articles but you also shared some new necessary information. However I search for works that have concentrate on the mechanisms of prostates edematic reaction (considering the edema formating period) but unhopefully as i have found out in my literature research most of the work have been done regarding the resolution of the edema and the return of the prostate in the initial condition.
Konstantinos i think this is due to edema is completely personnal, their is no standard response of prostate to puncture trauma or radiation effect, this is why most of the work have been done in the resolution and return to normal values because they also exist prostates that never swallow or suffer edema during or after ldr implant
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