Holzscheiter Michael H, Bassler Niels, Agazaryan Nzhde, Beyer Gerd, Blackmore Ewart, DeMarco John J, Doser Michael, Durand Ralph E, Hartley Oliver, Iwamoto Keisuke S, Knudsen Helge V, Landua Rolf, Maggiore Carl, McBride William H, Møller Søren Pape, Petersen Jørgen, Skarsgard Lloyd D, Smathers James B, Solberg Timothy D, Uggerhøj Ulrik I, Vranjes Sanja, Withers H Rodney, Wong Michelle, Wouters Bradly G
Pbar Labs, LLC, Santa Fe, NM, USA.
Radiother Oncol. 2006 Dec;81(3):233-42. doi: 10.1016/j.radonc.2006.09.012. Epub 2006 Oct 27.
Antiprotons travel through tissue in a manner similar to that for protons until they reach the end of their range where they annihilate and deposit additional energy. This makes them potentially interesting for radiotherapy. The aim of this study was to conduct the first ever measurements of the biological effectiveness of antiprotons.
V79 cells were suspended in a semi-solid matrix and irradiated with 46.7MeV antiprotons, 48MeV protons, or (60)Co gamma-rays. Clonogenic survival was determined as a function of depth along the particle beams. Dose and particle fluence response relationships were constructed from data in the plateau and Bragg peak regions of the beams and used to assess the biological effectiveness.
Due to uncertainties in antiproton dosimetry we defined a new term, called the biologically effective dose ratio (BEDR), which compares the response in a minimally spread out Bragg peak (SOBP) to that in the plateau as a function of particle fluence. This value was approximately 3.75 times larger for antiprotons than for protons. This increase arises due to the increased dose deposited in the Bragg peak by annihilation and because this dose has a higher relative biological effectiveness (RBE).
We have produced the first measurements of the biological consequences of antiproton irradiation. These data substantiate theoretical predictions of the biological effects of antiproton annihilation within the Bragg peak, and suggest antiprotons warrant further investigation.
反质子在组织中的穿行方式与质子相似，直至到达射程末端时发生湮灭并释放额外能量。这使得反质子在放射治疗方面具有潜在的吸引力。本研究的目的是首次测量反质子的生物效应。
将V79细胞悬浮于半固体基质中，并用46.7MeV反质子、48MeV质子或钴-60γ射线进行照射。根据沿粒子束方向的深度确定克隆形成存活率。剂量和粒子注量响应关系由粒子束坪区和布拉格峰区的数据构建，并用于评估生物效应。
由于反质子剂量测定存在不确定性，我们定义了一个新术语，称为生物等效剂量比（BEDR），它将最小扩展布拉格峰（SOBP）中的响应与坪区中的响应作为粒子注量的函数进行比较。反质子的该值约为质子的3.75倍。这种增加是由于湮灭在布拉格峰中沉积的剂量增加以及该剂量具有更高的相对生物效应（RBE）所致。
我们首次测量了反质子照射的生物学后果。这些数据证实了布拉格峰内反质子湮灭生物效应的理论预测，并表明反质子值得进一步研究。
