Measurement of the12C(p,n)12N reaction cross section below 150 MeV

Objective. Proton therapy currently faces challenges from clinical complications on organs-at-risk due to range uncertainties. To address this issue, positron emission tomography (PET) of the proton-induced11C and15O activity has been used to provide feedback on the proton range. However, this approach is not instantaneous due to the relatively long half-lives of these nuclides. An alternative nuclide,12N (half-life 11 ms), shows promise for real-timein vivoproton range verification. Development of12N imaging requires better knowledge of its production reaction cross section.Approach. The12C(p,n)12N reaction cross section was measured by detecting positron activity of graphite targets irradiated with 66.5, 120, and 150 MeV protons. A pulsed beam delivery with 0.7-2 × 108protons per pulse was used. The positron activity was measured during the beam-off periods using a dual-head Siemens Biograph mCT PET scanner. The12N production was determined from activity time histograms.Main results. The cross section was calculated for 11 energies, ranging from 23.5 to 147 MeV, using information on the experimental setup and beam delivery. Through a comprehensive uncertainty propagation analysis, a statistical uncertainty of 2.6%-5.8% and a systematic uncertainty of 3.3%-4.6% were achieved. Additionally, a comparison between measured and simulated scanner sensitivity showed a scaling factor of 1.25 (±3%). Despite this, there was an improvement in the precision of the cross section measurement compared to values reported by the only previous study.Significance. Short-lived12N imaging is promising for real-timein vivoverification of the proton range to reduce clinical complications in proton therapy. The verification procedure requires experimental knowledge of the12N production cross section for proton energies of clinical importance, to be incorporated in a Monte Carlo framework for12N imaging prediction. This study is the first to achieve a precise measurement of the12C(p,n)12N nuclear cross section for such proton energies.

Development of a scenario-based blood bank model to maximize reducing the blood wastage

INTRODUCTION

Blood is a valuable as well as a perishable commodity that has a limited lifespan. So, keeping it in a blood bank requires careful attention and management. In this study, a management model has been designed for the blood bank that can cover all the requests sent through the hospital subunits in such a way that it has the least waste.

MATERIALS AND METHODS

First, by examining the blood inventory system of a hospital, the number of inventories per month and the distribution of blood products in subunits of the hospital, and the amount of blood wastage every six months were estimated. Then, using ARENA simulation, all parts of the blood bank, including the request section, emergency blood section, donated blood section, and other sections were simulated. Finally, 10 scenarios were extracted by placing various parameters and the best scenarios were discussed and concluded.

RESULTS AND DISCUSSION

The scenarios for the four blood groups included A, B, AB, and O were applied for six months in one year. The results showed that if the amount of blood injected into the blood bank is appropriate and at the right time, the amount of wastage can be reduced by up to 80% for most of the blood groups.

CONCLUSION

The results of this study showed that if the system of receiving blood products built upon a precise management model is predetermined and placed with appropriate parameters, the amount of wastage will be reduced to the minimum possible number.