A treatment planning inter-comparison of proton and intensity modulated photon radiotherapy

Abstract

Purpose: A comparative treatment planning study has been undertaken between standard photon delivery techniques,b intensity modulated photon methods and spot scanned protons in order to investigate the merits and limitations of each of these treatment approaches.Methods: Plans for each modality were performed using CT scans and planning information for nine patients with varying indications and lesion sites and the results have been analysed using a variety of dose and volume based parameters.Results: Over all cases, it is predicted that the use of protons could lead to a reduction of the total integral dose by a factor three compared to standard photon techniques and a factor two compared to IM photon plans. In addition, in all but one Organ at Risk (OAR) for one case, protons are predicted to reduce both mean OAR dose and the irradiated volume at the 50% mean target dose level compared to both photon methods. However, when considering the volume of an OAR irradiated to 70% or more of the target dose, little difference could be shown between proton and intensity modulated photon plans. On comparing the magnitude of dose hot spots in OARs resulting from the proton and IM photon plans, more variation was observed, and the ranking of the plans was then found to be case and OAR dependent.Conclusions: The use of protons has been found to reduce the medium to low dose load (below about 70% of the target dose) to OARs and all non-target tissues compared to both standard and inversely planned photons, but that the use of intensity modulated photons can result in similar levels of high dose conformation to that afforded by protons. However, the introduction of inverse planning methods for protons is necessary before general conclusions on the relative ef®cacy of photons and protons can be drawn. q

Dosimetry of very high energy electrons (VHEE) for radiotherapy applications: using radiochromic film measurements and Monte Carlo simulations

“…IMRT has been found to be effective in tumour treatment. However, the total integrated dose in normal tissue for IMRT treatment is a factor of two higher compared with protons (Lomax et al 1999). This aspect is particularly critical if the target volume is in the vicinity of sensitive organs.…”

Sık görülen primer malign kemik tümörlerinde radyoterapinin yeri ve tedaviye genel yaklaşım

“…Ayrıca, hastada radyoterapiden dolayı biriken total enerji (integral doz) proton tedavisi ile anlamlı olarak düşürülür. [47,44] Tipik olarak, proton tedavisi, birim olarak "cobalt gray equivalent" (CGE) ile reçete edilir. [44] Tamamiyle rezeke edilemeyen kafa tabanı ve aksiyel iskeletin kondrojenik tümörlerinde proton tedavisi yararlı bulunmuştur.…”

A review of the impact of photon and proton external beam radiotherapy treatment modalities on the dose distribution in field and out-of-field; implications for the long-term morbidity of cancer survivors

“…The maximum dose in the different OARs for conventional technique is much higher than for the other techniques. For proton beams the data varies to a large extent and no general conclusion can [9] Hypopharynx Parotid 3DCRT, protons (scanned) 5 Pirzkall et al [56] mainly H&N Spinal cord 3DCRT 9 Lomax et al [52] H&N Several organs Standard photons, protons (scanned) 4 Lomax et al [53] Breast Lung, heart Protons (scanned) 1 Johansson et al [51] Breast Lung, heart Standard, protons (scanned) 11 Cella et al [8] Prostate Rectum 3DCRT, protons (scanned) 1 Mock et al [54] Prostate Rectal wall 3DCRT, protons (passive) 5 Aoyama et al [49] Prostate Rectal wall 3DCRT, tomotherapy 5 Johansson et al [50] Rectal ca Small bowel 3DCRT, protons (scanned) 16 Lomax et al [52] Pelvic Several organs Standard photons, protons 4 Weber et al [12] Paraspinal Several organs Protons (scanned) 5 Mu et al [11] Spinal Several organs 3DCRT, protons (scanned) 5…”