Cystodefecoperitoneography in patients with genital prolapse.

The aim of the study was to prospectively evaluate pre- and postoperative findings of cystodefecoperitoneography (CDP) and to correlate the findings to the clinical examination in patients with genital prolapse. Twenty-five female patients were investigated both pre- and postoperatively with a standardized questionnaire, clinical examination and CDP, including contrast medium in the rectum, vagina, bladder, small bowel and peritoneal cavity. At preoperative clinical examination a rectocele was diagnosed in 24 patients, a cystocele in 7 and an enterocele in 2. At the preoperative CDP a rectocele was diagnosed in 21 patients, a cystocele in 22 patients and a peritoneocele in 9, of which six contained small bowel (i.e. an enterocele). Surgery was performed according to the clinical findings. At the postoperative clinical examination no rectocele was diagnosed, a cystocele was diagnosed in 3 patients and an enterocele in 1. Postoperative CDP showed a rectocele in 4 patients, a cystocele in 24 and a peritoneocele in 7 patients, of which three contained small bowel (i.e. an enterocele). CDP may complement the clinical assessment of patients with genital prolapse, in particular to confirm or detect defects involving the posterior compartment. The radiologic definition of cystocele needs further evaluation.

Calculation of absorbed dose and biological effectiveness from photonuclear reactions in a bremsstrahlung beam of end point 50 MeV.

The absorbed dose due to photonuclear reactions in soft tissue, lung, breast, adipose tissue and cortical bone has been evaluated for a scanned bremsstrahlung beam of end point 50 MeV from a racetrack accelerator. The Monte Carlo code MCNP4B was used to determine the photon source spectrum from the bremsstrahlung target and to simulate the transport of photons through the treatment head and the patient. Photonuclear particle production in tissue was calculated numerically using the energy distributions of photons derived from the Monte Carlo simulations. The transport of photoneutrons in the patient and the photoneutron absorbed dose to tissue were determined using MCNP4B; the absorbed dose due to charged photonuclear particles was calculated numerically assuming total energy absorption in tissue voxels of 1 cm3. The photonuclear absorbed dose to soft tissue, lung, breast and adipose tissue is about (0.11-0.12)+/-0.05% of the maximum photon dose at a depth of 5.5 cm. The absorbed dose to cortical bone is about 45% larger than that to soft tissue. If the contributions from all photoparticles (n, p, 3He and 4He particles and recoils of the residual nuclei) produced in the soft tissue and the accelerator, and from positron radiation and gammas due to induced radioactivity and excited states of the nuclei, are taken into account the total photonuclear absorbed dose delivered to soft tissue is about 0.15+/-0.08% of the maximum photon dose. It has been estimated that the RBE of the photon beam of 50 MV acceleration potential is approximately 2% higher than that of conventional 60Co radiation.