Hysterosalpingography using a flat panel unit: evaluation and optimization of ovarian radiation dose

Conversion factors for effective dose and organ doses with the air Kerma area product in hysterosalpingography

Histerosalpingography (HSG) remains the dominant diagnostic tool for investigation of infertility in women. Conversion factors used to estimate effective (E) and organ doses (H_T) from air Kerma area product (KAP) are needed to estimate patient doses in HSG, performed with state-of-the-art fluoroscopic X-ray systems with digital detectors. In this study, estimates of E and H_T for six critical organs/tissues, were derived on an individual basis in 120 HSG procedures and in 1410 irradiation events, performed on two X-ray systems from information available through the radiation dose structured report using Monte Carlo methods. Mean values of E and H_ovaries were1.0 ± 0.9 mSv and 5.6 ± 5.4 mGy. E/KAP conversion factors of 0.13; 0.18; 0.28 and 0.35 mSv Gy^-1cm^-2 were established for irradiation events with a Cu filtration of 0.0; 0.1; 0.4 and 0.9 mm. A high agreement was obtained between E estimated through Monte Carlo methods and E/KAP conversion factors accounting separately for the different modes of fluoroscopy and the radiography component of HSG, with a systematic error of 0 mSv and lower/upper limits of agreement of -0.6 and 0.5 mSv. On the contrary, the use of a single coefficient of conversion did not provide accurate estimates of E, showing a bias of -0.4 mSv and lower and upper limits of agreement of -1.9 and 1.2 mSv. An algorithm for the estimation of effective and organ doses from KAP has been established in HSG procedures depending on the Cu filtration in the X-ray irradiation events.

Assessment of Patient Absorbed Radiation Dose during Hysterosalpingography: A Pilot Study in Southwest Nigeria

BACKGROUND

Hysterosalpingography (HSG) is an indispensable tool for diagnosing infertility in females. The procedure exposes female reproductive organs to ionizing radiation as the genitals are irradiated during the process. Investigating patient absorbed dose during the procedures is essential for effective radiological protection of the patient.

OBJECTIVE

This study aims to investigate the radiation dose received by patient during HSG examination in the study environment in order to enhance optimization of procedures and the associated dose, thereby minimizing radiation risks.

MATERIAL AND METHODS

The prospective pilot study, was conducted in four tertiary healthcare institutions in Southwest Nigeria. Thermoluminescence dosimeter (TLD 100) was used to determine the Entrance Surface Dose (ESD) of 80 patients presented for HSG investigation. The corresponding effective dose, ovary, uterus and urinary bladder doses were evaluated using PCXMC software.

RESULTS

The mean entrance surface doses (ESD) obtained from the four centers were 18.58±6.31 mGy, 15.18±2.27 mGy, 17.44±3.43 mGy and 34.24±11.98 mGy for SW1, SW2, SW3 and SW4 centers, respectively. The corresponding mean of effective doses were 1.54±0.63 mSv, 1.24±0.28 mSv, 1.41±0.30 mSv and 2.53±0.94 mSv for SW1, SW2, SW3 and SW4 centers, respectively. The resulting mean doses to the ovary, urinary bladder and uterus were also presented.

CONCLUSION

The results obtained in general are comparable with international standards. It was, however, recommended that study centers with high doses should conduct dose audit in order to enhance patient safety.

OPTIMISATION OF PATIENT DOSE AND IMAGE QUALITY IN FLUOROSCOPICALLY GUIDED CERVICAL SPINE SURGERY: A PHANTOM-BASED STUDY

The purpose of the current study was to provide useful data, which may help neurosurgeons to manage the patient dose and image quality in spinal surgery procedures, utilising a phantom and a test object. The kerma area product, cumulative dose (CD) and entrance surface dose (ESD) rate on the phantom and image intensifier were measured, for selectable fields of view (FOVs), fluoroscopy modes, two geometric magnifications and various phantom thicknesses. The images were subjectively evaluated regarding low-contrast detectability and high-contrast resolution. Signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), high-contrast spatial resolution (HCSR) and figure of merit (FOM) values were also estimated. The ESD rates increased with increasing phantom thickness, when using electronic or geometric magnification, continuous or high-definition fluoroscopy (HDF). The observers' evaluation showed relatively slight changes in image quality when pulsed fluoroscopy was used. SNR, CNR and HCSR values decreased with increasing phantom thicknesses, while remained almost constant when using pulsed fluoroscopy. SNR and HCSR improved in HDF, while the CNR remained almost constant only for the FOVs 23 and 17 cm. By applying electronic magnification, this resulted in improved HCSR. FOM values decreased in HDF, with increasing phantom thickness and using electronic magnification. For the 'thinnest' patients, CD may overestimate skin dose by 25% than the actual values. Geometric magnification resulted in improved FOM, especially for low-dose fluoroscopy and FOV 23 cm. The knowledge of the increments in dose values, image quality and FOM indices concerning phantom thickness may help neurosurgeons to optimise spinal surgery procedures by selecting the appropriate operational parameters, which could contribute toward the establishment of a radiation protection culture.

OPTIMISATION OF PATIENT DOSE AND IMAGE QUALITY IN ENDOSCOPIC RETROGRADE CHOLANGIOPANCREATOGRAPHY: A PHANTOM-BASED EVALUATION

A phantom-based study is presented aiming to optimise patient dose and image quality (IQ) in endoscopic retrograde cholangiopancreatography procedures, utilising a fluoroscopy system equipped with a flat panel detector. The patient thickness was simulated with various polymethyl methacrylate slabs, whilst IQ was evaluated using the Leeds test object. The main factors evaluated were phantom thickness, distance between phantom and detector, field of view and pulse rate. For all these factors, the dosemetric indices, entrance surface air kerma (ESAK) rate and ESAK per pulse, as well as the IQ parameters, signal-to-noise ratio and high contrast spatial resolution, were measured. Based on these measurements, the figure of merit (FOM) was estimated. The FOM and ESAK rate values indicated the optimum combination of the factors evaluated which could provide adequate clinical information, assuring minimum patient dose.

Estimation of effective dose during hystrosalpingography procedures in certain hospitals in Sudan

The aims of this study were to measure the patients' entrance surface air kerma doses (ESAK), effective doses and to compare practices between different hospitals in Sudan. ESAK were measured for patient using calibrated thermo luminance dosimeters (TLDs, GR200A). Effective doses were estimated using National radiological Protection Board (NRPB) software. This study was conducted in five radiological departments: Two Teaching Hospitals (A and D), two private hospitals (B and C) and one University Hospital (E). The mean ESAK was 20.1mGy, 28.9mGy, 13.6mGy, 17.5mGy, 35.7mGy for hospitals A, B, C, D, and E, respectively. The mean effective dose was 2.4mSv, 3.5mSv, 1.6mSv, 2.1mSv and 4.3mSv in the same order. The study showed wide variations in the ESDs with three of the hospitals having values above the internationally reported values.