Lung cancer ranks high among the causes of mortality in cancer patients, as per the most recent World Health Organization report. Proton therapy offers a precise approach to treating lung cancer by delivering protons with high accuracy to the targeted site. However, inaccuracies in proton delivery can lead to increased toxicity in healthy tissues. This study aims to investigate the correlation between proton beam dose profiles in lung tumours and the scattered gamma particles.

The study utilised the Gate simulation software to simulate proton beam radiation and an imaging system for prompt gamma imaging during proton therapy. An anthropomorphic Non-uniform rational B-spline (NURBS) cardiac and torso (NCAT) phantom was employed to replicate lung tumours of various sizes. The imaging system comprised a multi-slit collimation system, CsI(Tl) scintillator arrays and a multichannel data acquisition system. Simulations were conducted to explore the relationship between prompt gamma detection and proton range for different tumour sizes.

Following 60 MeV proton irradiation of the NCAT phantom, the study examined the gamma energy spectrum, identifying peak intensities at energies of 2.31, 3.8, 4.44, 5.27 and 6.13 MeV. Adjustments to the proton beam source tailored to tumour sizes achieved a coverage rate of 98%. Optimal energies ranging from 77 to 91.5 MeV were determined for varying tumour volumes, supported by dose distribution profiles and prompt gamma distribution illustrations.

The study evaluated the viability of utilising 2D gamma imaging with a multi-slit collimator scintillation camera for real-time monitoring of dose delivery during proton therapy for lung cancer. The findings indicated that this method is most suitable for small lung tumours (radius ≤ 12 mm) due to reduced gamma emission from larger tumours.

While the study demonstrates promising results in range estimation using prompt gamma particles, challenges were encountered in accurately estimating large tumours using this method.

Intensity-modulated radiation therapy (IMRT) has revolutionised the way head and neck cancers can be treated. It allows for a more conformal treatment plan when compared to 3D conformal radiation therapy. In paediatric patients, however, IMRT continues to deliver higher doses than desirable. Proton beam therapy on the other hand has the potential to further spare organs-at-risk.

A 16-year-old boy with a left-sided paraganglioma of the left base of skull manifested by headaches, neck pain and tongue cramping was simulated, planned and treated with proton therapy with significant contralateral organ-at-risk sparing.

For this patient, dosimetric plan comparison between photon and proton plans clearly showed better sparing of contralateral organs-at-risk with protons. The contralateral parotid gland received a mean dose of 386·3 cGy with photons, whereas it received 1·3 cGy (CGE) in the proton plan.

The dosimetric advantage of proton beam over photon beam therapy has successfully been demonstrated in this case study for a paediatric patient with a head and neck tumour. Sparing of contralateral structures is especially important in paediatric patients who are at a greater risk of secondary malignancies due to possible long life expectancy.

This technical note describes a quantitative assessment of the production of radioactive materials during a year-long clinical operation of a Mevion S250i Hyperscan proton therapy system. The production of accumulated radioactive materials plays an important role in determining radiation safety in and around the proton therapy facilities.

We have conducted a weekly room survey, every week for a year, during normal clinical operation.

We estimated the accumulated activity from secondary neutron activation on aluminium structures at 3 m away from isocentre in the beamline to be less than 300 μCi.

In the recent years, some publications (mainly from one group of authors) have dealt with the effectiveness of proton–boron fusion therapy (PBFT). This theory is based on the Q-value of three produced α particles in the reaction of protons with boron (11B). They claim that this reaction significantly increases the absorbed dose in the target volume. However, the current study would re-evaluate their method to show if PBFT is really effective.

A parallel 80-MeV proton beam was irradiated on a water medium in a cubic boron uptake region (BUR). The two-dimensional dose distribution and percentage depth dose of protons, alphas and all particles were calculated using tally F6 and mesh-tallies by Monte Carlo N Particle Transport code.

The results not only showed that the dose enhancement in BUR is neglectable but also the higher density of BUR in comparison with water led to decrement of dose in this region. Because of low cross section of boron for proton beam (<100 mb), the α particles’ dose is 1,000 times lower than the proton dose.

The physical aspects and the simulation results did not show any effectiveness of the PBFT for proton therapy dose enhancement.

To examine detail depth dose characteristics of ideal proton beams using the GATE Monte Carlo technique.

In this study, in order to improve simulation efficiency, we used pencil beam geometry instead of parallel broad-field geometry. Depth dose distributions for beam energies from 5 to 250 MeV in a water phantom were obtained. This study used parameters named Rpeak, R90, R80, R73, R50, full width at half maximum (FWHM), width of 80–20% distal fall-off (W(80–20)) and peak-to-entrance ratio to represent Bragg peak characteristics. The obtained energy–range relationships were fitted into third-order polynomial formulae. The present study also used the GATE Monte Carlo code to calculate the stopping power of proton pencil beams in a water cubic phantom and compared results with the National Institute of Standards and Technology (NIST) standard reference database.

The study results revealed deeper penetration, broader FWHM and distal fall-off and decreased peak-to-entrance dose ratio with increasing beam energy. Study results for monoenergetic proton beams showed that R73 can be a good indicator to characterise a range of incident beams. These also suggest FWHM is more sensitive than W(80–20) distal fall-off in finding initial energy spread. Furthermore, the difference between the obtained stopping power from simulation and NIST data almost in all energies was lower than 1%.

Detail depth dose characteristics for monoenergetic proton beams within therapeutic energy ranges were reported. These results can serve as a good reference for clinical practitioners in their daily practice.

Here, we report the feasibility and long-term efficacy of a granulomatous slack skin disease (GSSD) treatment with combined high-energy photon and proton beams.

A GSSD patient with abdominal disease volume 25×15×2–4 cm deep was recommended for treatment at this institution. In addition to photons and electrons, high-energy protons delivered with advanced planning techniques and patient positioning were used. The patient was irradiated to a total dose of 40 Gy by using 20 Gy matched photon and electrons followed by 20 Gy equivalent protons delivered by using innovative range compensation and patient positioning.

The test patient tolerated the treatment well and is now a 10-year survivor of the disease.

Treatment of GSSD with protons is feasible. The range and narrow penumbra properties of the proton beam provided an ideal capability to match fields accurately to cover large volumes while also sparing underlying normal tissues.