Implementing online position monitoring for prostate radiotherapy using an in-house position monitoring system: User experience and impact on workforce

INTRODUCTION

To evaluate the feasibility of prostate intrafraction motion monitoring using the SeedTracker real-time image guidance system in order to improve targeting accuracy in prostate radiotherapy.

METHODS

SeedTracker was used to monitor prostate gold fiducial seeds with kV x-ray imaging during radiotherapy in 30 patients. Feedback from radiation therapists was collected via the use of a user evaluation form. The impact on treatment time was established by using a record and verify system. The effective dose and a risk of exposure-induced cancer death (REID) were estimated for a 60-year-old patient when using the SeedTracker system.

RESULTS

A total of 22 radiation therapists completed user evaluation forms. The time taken to prepare a reference data set for one patient varied with three (13.6%) radiation therapists taking less than 2 min, 10 (45.5%) between 2 and 4 min, eight (36.4%) between 4 and 6 min and one (4.5%) between 6 and 8 min. The useability of the SeedTracker system was reported as 'easy' by 21 (95.5%) radiation therapists and 'hard' by 1 (4.5%) radiation therapist. Mean treatment time changed from 6 to 7 min with prostate-only radiotherapy treatment and from 6.9 to 10.2 min with prostate and whole pelvis radiotherapy treatments. The maximum effective dose with the SeedTracker was 1.6276 mSv, and increase in REID was 0.007%.

CONCLUSION

The SeedTracker real-time image guidance system is a feasible tool to use in radiotherapy departments to monitor and correct for prostate intrafraction motion.

Assessing Lung Parenchymal Enhancement on Dual-Energy CT Pulmonary Angiograms: Potential utility of dual-energy technique as an angiographic and parenchymal 'one-stop shop' in the initial workup of patients with pulmonary symptoms

OBJECTIVE

The aim of this study was to assess the enhancement of lung parenchyma on dual-energy (DE) computed tomogram (CT) by comparing attenuation between routine post-contrast and dual-energy generated virtual unenhanced (VU) images.

METHODS

Patients presenting to the Emergency Department who subsequently underwent DE-CT pulmonary angiogram from the 1st to the 30th of November were enrolled. The DE data set obtained was used to generate VU images. Attenuation in Hounsfield units (HU) was measured at two sites for each patient and compared between VU and routine post-contrast (PC) reconstructions. Statistical analysis was performed using paired-samples t-test.

RESULTS

There is a statistical difference between lung parenchymal attenuation value between the CV and PC images, denser in the PC dataset and also towards the bases, with a mean HU of -841 and -817 (difference of 24) respectively.

CONCLUSIONS

This study confirms increased lung parenchymal density when comparing PC and VU reconstructions. Based on results, the paper recommends utilising dual-energy capabilities for VU reconstructions in CTPAs to optimise assessment of lung parenchyma.